Any Shortwave Radio Tips for a Noob Considering the Hobby? - Page 1
Forum section: electronics / general

author: edy
author_rank: Super Contributor
timestamp: December 06, 2019, 06:34:16 am
content: For some time I have been interested in getting a beginner receiver for tuning in to broadcasts around the world. This shortwave listening "hobby" seems to require some technical understanding but also is a fun way to discover interesting stuff that one can find over the air. Apparently there is an art as well as a science, to knowing how to rig the antenna, what time of day is best for listening to things, what bands and how to tune, etc. I would like to learn more about it.My interest was renewed recently after stumbling across some budget AM/FM/Shortware radios on eBay and Amazon. Two of which I have seen some reviews for are Tecsun PL-310ET (digital) for $45, and Tecsun R-909 (analog tuner) for under $20. There are a pile of models from Tecsun and I have no idea which are good or bad. I'm sure there are other budget brands out there.... too many names to mention (Eton, Retekess, Skywave, etc)... all in the $20-50 range. Grundig and Sony are the big names but too expensive for my budget. I don't want to spend much and I don't know where to start. Last time I checked a few years ago I remember radios costing $150+ and so seeing these cheaper devices renewed my interest in getting into the hobby.Can anyone recommend a reliable brand with reasonably good reception (or at least with options to improve the antenna if needed) and something not too simple so it will keep things interesting? I am leaning towards digital tuner vs. analog only because I think it will be easier to lock on to a frequency. What is your practical experience? Is it worth the extra money? Reviews of the R-909 seem to say it is great value, but it is analog dial only and seems very simple. On the other hand, something like the PL-310ET seems to allow very fine control for tuning and memory functions and has lots of features. I haven't looked into other brands, but I am sure there are other comparable models.I'm in Toronto, so does anyone have experience as to what signals you would be expected to pick up with one of these cheaper models? Does it get airline, emergency vehicle or trucker communications? Would you be able to pick up signals from Europe or Asia? ISS? Is the idea to just scan around and find stuff and make a log? Sorry for all the noob questions.**NOTE:I don't know if this topic belongs here in General or the RF, HAM Radio section. I apologise if I posted to wrong section of the forum. The RF, HAM Radio section seems to be more technical based not for a very basic general question like this posting.

author: bob91343
author_rank: Super Contributor
timestamp: December 06, 2019, 07:21:47 am
content: I hate to be a doom sayer but the era of short wave listening is largely over. All the wonderful (and not so wonderful) foreign broadcast stations seem to have shut down.I remember hearing lessons on speaking Chinese, and a station in Holland with a regular jazz program. Of course the majority were religion oriented, begging for contributions. Lots of languages. Very strong signals, so not much antenna needed.It's not like that any more. There aren't many stations left and the signals aren't what they used to be. This latter may be due to the terrible radio propagation of recent years. The hams are unhappy with this situation as well. Many pretend this is the low point in the cycle but they have been saying that for years.Having said all that, you can find gear to buy that isn't expensive. A nice old receiver for under a hundred, and even a transceiver for that. (You don't have to transmit.) The equipment comes in two basic varieties. The 'ham band only' that isn't general coverage and isn't what you want, and the general coverage. However, most relatively recent gear is general coverage. An old tube receiver may or may not be. You will want frequency coverage from the usual AM broadcast band 530-1700 kHz continuous up through 30 MHz (there isn't broadcasting above about 25 MHz). Synthesized is best as you mention. You don't need a crystal filter or even variable selectivity if all you care about it broadcast.In many cases, SWL morphs into amateur radio. It's much more interactive, as you can reach out once you get a license. If you attend an amateur radio club meeting or picnic you may find people to lend or even give you the stuff you want. Many hams have garages packed with gear they will never use again.

author: bd139
author_rank: Super Contributor
timestamp: December 06, 2019, 09:46:33 am
content: Agree. Particularly China Radio International dramas are so terrible they are funny. There's loads out there to listen to still!

author: German_EE
author_rank: Super Contributor
timestamp: December 06, 2019, 11:00:59 am
content: I still find lots of interesting activity on the HF bands to listen to, all it takes is a decent amount of wire up i the air and some patience. To make your listening effective the following may help:1 Get a world map, if possible one centered on Canada. You need to practice something called 'graylining' where there is a sunrise or a sunset between you and the station you want to listen to. Using this technique brings better results than random listening.2 There's something called Maximum Usable Frequency or MUF that you need to pay attention to. Rather than me explain all the details look it up on Wikipedia.3 For HF listening a long length of wire and probably an antenna tuner will be needed. Keep this away from overhead power lines.4 The main manufacturers of ham radio gear (including receivers) are Kenwood, Icom and Yaesu. You can also purchase one of the smaller rigs made by Alinco and just use it as a receiver. If you're into computers then consider the new Software Defined Radio (SDR) systems which are cheap, powerful but can be difficult to set up.Finally5 Be patient. The signals are out there but will need finding.

author: VK3DRB
author_rank: Super Contributor
timestamp: December 06, 2019, 11:53:57 am
content: Try and find a second hand FRG-7 radio and throw up a long wire up a tree to get started. The FRG-7 is a classic short wave receiver. I still have the FRG-7 I bought in 1977, and have hundreds of QSL cards from very interesting stations, the rarest being Radio Gabon in Franceville. Almost all the stations are gone forever. The bands and been abandoned by Voice of America, Radio Australia and pretty much all the rest, which is a crying shame and very short sighted as they all put their eggs into the one Internet basket. There was a time not long ago when Christian stations filled the airwaves in a bid to bring the Word of God to the unsaved in remote places (some still do). Now the SW broadcast bands are mostly polluted with Chinese propaganda stations.But the good news is there are many ham radio operators on the ham bands. As sunspots are low at the moment (but expect to bet a lot better over the next few years), try around 7.1-7.1 MHz. Or around 3.6 MHz. When conditions are good, try around 14.3 MHz. You can learn a lot of good technical info on the ham bands. Hams are into FT-8, Slow scan TV, voice, RTTY, Morse code CW and a whole lot of other fun things. You can download some software to decode the SSTV and CW signals on your computer, without needing a ham license. CB radio on 27 MHz is almost dead, and the only thing you'll learn there perhaps is new swear words.

author: edy
author_rank: Super Contributor
timestamp: December 06, 2019, 01:46:24 pm
content: Thanks for all the great info! I will reach out to a local HAM club (I’m in York region just northern outskirts of Toronto) and see if they have anybody selling basic used listening gear. Sadly a search through Kijiji and Craigslist for “Shortwave” and “HAM radio” returned few listings and those were beyond my budget. I’m worried about buying anything used on eBay as I won’t know if it is performing as it should and shipping may be expensive due to weight. The stuff out of China or Hong Kong is cheap with free shipping. But I noticed the low end units don’t have SSB. How critical is that?I also noticed some very cheap under $20-30 USB plugin software-based radios. I am running Linux so not sure if I’m going to need a Windows machine and how much additionally is the software? Also portability is an issue. I’m not sure I want to take my laptop around just to listen to radio and I’m skeptical about the quality of these cheaper USB radios (compared to a cheaper stand alone digital receiver) and how subject they are to interference from the laptop and other stuff around. Apparently there is a lot of stuff in the house which will mess up reception so I should have something easy to move around and maybe take on a drive into the country away from WiFi lighting and hydro lines. Laptop may be a pain in that case, although I can see how it can be useful to capture data signals.Thanks also for the info regarding the effect of the sun. From the few videos I watched my understanding is that getting long-range reception is all about bouncing signals off the ionosphere. So the sun solar wind creates a “stronger” (for lack of a better word) ionospheric surface for signal bouncing? If I am in Canada and I want to pick up Europe, I want to listen in the morning my time... like 8 or 9am, while Europe is 3pm (meaning the sun is at 12 noon somewhere over the Atlantic) and we are bouncing signals off that? Sun activity generally strengthens the ionosphere so because we are in a low cycle we are not getting help bouncing signals?I’ll see what local HAM club can suggest (or if anyone here is in my area or has connections let me know). I can see how it is a gateway drug so I need to control myself or my wife will kill me.. My way to slide this (yet another) hobby in is to keep it inexpensive and involve the kids, and not take up too much space or install all sorts of wires which will make wife unhappy. That’s why I thought of starting really basic and inexpensive with a new digital receiver... or maybe if I can find something old/used but a bit better in a similar price range from an older HAM (like I did when I got an analog scope for $50) that would be good. I’ll let you know what pans out from the club if anything.ADDED:I just tried to login to a few HAM local club pages and forums and classifieds here to see if I can get a foot in the door. Seems that most cater to members or people already in the HAM world. The clubs are very established with lots of members and social activities. Many will want a call sign for registration. I feel like I am too amateur for these guys... like a fruit fly annoying an elephant. I'll see if I can reach out to someone local that I can find in the club (although I hate emailing people out of the blue) and see if there is a better place for complete noobs to get started, without bothering these very professional "amateurs", especially since at this point I am only looking at cheap receiving equipment, not yet ready to dive in. These are some sites I was perusing:https://www.yrarc.org/http://www.ontars.com/cgi-bin/classifieds/classifieds.cgihttp://www.ontars.com/

author: Bud
author_rank: Super Contributor
timestamp: December 06, 2019, 02:03:52 pm
content: Ontario Swap Shophttp://www.kwarc.org/swapshop/

author: edy
author_rank: Super Contributor
timestamp: December 06, 2019, 02:49:44 pm
content: I'll have a look at the swapshop, thanks! So far the listings all seem to be very sophisticated gear. Could be that the most entry-level basic receiver is just not even part of a typical HAM member's gear anymore (at least not these guys who have moved on to experienced stuff). Like someone on EEVBlog looking to buy a $2 multimeter and spending too much time debating which $2 meter to buy, in a forum where everyone is already using digital scopes.I have a feeling that once you get to the bottom-of-the-barrel entry-level stuff there is no point wasting too much time, you just pick up a Tecsun unit with good reviews and that's it. The only reason I'd like to give a glance at a swapshop or HAM club is to see if they have something a little better and used for the same price as a new Tecsun, maybe from someone local that I can meet face to face to make a contact/introduction. That way later if I decide to get more into the hobby I know a few people who can guide me. I reached out to someone at YRARC and waiting to see if they have any suggestions. I have a feeling they will just tell me to buy a cheap radio and shutup, and when I'm more serious to come back.I will totally understand their point if they tell me to bugger off.By the way I found this local site, it looks to be stale though (latest date is from 2004). I have a feeling it is no longer in operation, but I'll try to reach out and see what happens:http://www3.sympatico.ca/jrlittle/main.htm

author: edy
author_rank: Super Contributor
timestamp: December 06, 2019, 03:53:53 pm
content: Thanks, I found this page and apparently there are some options available for Linux:https://www.rtl-sdr.com/big-list-rtl-sdr-supported-software/And I found a bunch of listing on eBay for $10-20. Not sure which one is reliable and which to buy or is compatible with any of the software. That may be an easy cheap way to start, a lot less than $45-60 for a digital Tecsun. Any suggestions?

author: Sal Ammoniac
author_rank: Super Contributor
timestamp: December 06, 2019, 04:07:22 pm
content: The SW bands are a wasteland compared to fifty years ago when I first got interested in SWL. Almost all of the iconic stations are gone, leaving mostly religious nutjobs like Brother Stair and his ilk and Chinese propaganda.Broadcasters aren't the only inhabitants of the SW bands--there are also utility stations, hams, military, and a few others that are interesting to listen to. Winter nights are also good for listening to distant MW AM stations.

author: German_EE
author_rank: Super Contributor
timestamp: December 06, 2019, 07:33:24 pm
content: Joining a local club is probably a good idea as EVERYONE had to start at the bottom including me, and I've been an active radio ham for over forty years. Some clubs will be more technically minded with lectures and lots of test gear, others will be into contests and portable operation. Be careful of the clubs that tend to specialize in emergency work though as you might end up in a bright yellow jacket doing lots of weekend volunteer work.Get in touch with the RAC to find your local club(s)https://www.rac.ca/You might hear the term 'elmer' once in a while, don't worry about it. Back in the old days an elmer was the old guy who was always willing to help the new guys out. Now I'm one of the old guys and I find that I'm passing my knowledge on so it looks like the tradition is continuing.

author: edy
author_rank: Super Contributor
timestamp: December 08, 2019, 04:15:35 am
content: Thanks again for the suggestions. I've contacted a few clubs and people to see what they suggest. I think I figured out what I'm trying to do and got down the terminology... it's called "Ultralight DXing". Other than seeing if any club members have older equipment they want to get off their hands, I am not sure I want to go full membership at this point. I have too many things on my plate as it is. Perhaps the easiest thing to do at this point is pick up a SW radio or one of those USB dongles which should keep me busy for a while, just logging what I find out there and seeing if it is something I would want to get deeper into. I'd be invested in minimally and if I have to put away the hobby for some time because I get too busy, I wouldn't have sunk much in financially.

author: eti
author_rank: Super Contributor
timestamp: December 08, 2019, 04:27:53 am
content: I'll give you a guess which rock-solid, simple communication system based on physics and not on endless chains of servers and switches, I'd pick to save the life of my family, come a nuclear war? It's pretty simple, and here's a hint; it AIN'T the internet. We think we're SO SO "clever" and we are, but then radio preceded the "ever so pleased with itself" internet by MANY, MANY decades, and they don't use Skype or FaceTime to pilot submarines, so there's a clue as to which is better, merely by virtue of its' simplicity.

author: fourfathom
author_rank: Super Contributor
timestamp: December 08, 2019, 05:41:17 am
content: Quote from: edy on December 06, 2019, 03:53:53 pmBe careful with the cheap SDRs. Most of these are designed for VHF, not HF (shortwave), and you will need something like the "ham it up" converter if you want to use these SDRs on the shortwave bands. The "RTL-SDR V3" unit fromhttps://www.rtl-sdr.com/buy-rtl-sdr-dvb-t-dongles/can be used at these lower frequencies, but still needs quite a bit of work (including external RF filters) to turn it into a halfway decent SWL receiver. If you want to go the SDR route, I would recommend the "SDR-Play RSP1A" (https://www.sdrplay.com/rsp1a/) or perhaps the "funcube dongle pro +". These cost a bit over $100, but are technically far superior to the $10-$20 units.

author: bd139
author_rank: Super Contributor
timestamp: December 08, 2019, 10:50:11 am
content: Quote from: eti on December 08, 2019, 04:27:53 amMy family’s lives are at the mercy of the food supply chain and healthcare which is all built on top of the internet these days as a communication tool. Thus I’d rather concentrate on attempting to keep political matters on the straight and narrow. Because it’s not much point having an off grid HF set up or VHF HT’s if you’re rat food after starving to death.Also like hell amateur radio is reliable. That’s part of the fun. For the military it solves only logistical communications problems. And they have protocols for when it doesn’t because it’s not reliable. Go figure.Also I notice you’re in the U.K. 2m traffic here is whining, brexit, tomato growing advice and complaining about baofeng users. Oh and ironically tech support for people’s printer problems which quickly turns into “send me a text message”

author: VK3DRB
author_rank: Super Contributor
timestamp: December 08, 2019, 12:28:29 pm
content: Quote from: eti on December 08, 2019, 04:27:53 amIt is true that if the Internet were to go down many of us in countries whose infrastructure is addicted to the Internet will suffer a catastrophe. You wont be able to buy food, gasoline, medicines, no nothing. You water supply may well run out and you won't have electricity from the power grid. It just needs any of the lunatic countries that hoard nuclear weapons like Russia and the USA to push the button either on purpose for by accident. The doomsday clock is only TWO MINUTES TO MIDNIGHT. Nuclear attack might not be a matter of if, but when:https://en.wikipedia.org/wiki/List_of_nuclear_close_callsBut if you have a ham radio you will be able to communicate, assuming your infrastructure is destroyed and you were not vaporised. If this sounds far fetched, look what happened in Cyclone Tracey in 1974 which wiped out an entire city of Darwin. Ham radio was the ONLY form of communication to the outside world for several days. The main link was between a ham with a generator in Darwin and a ham in Melbourne.If the doomsday happens, ham radio could also be used to coordinate emergency relief. And be used as an aid to hunt down the leaders of the countries that fired the nukes.A film worth seeing is the 1964 film "Fail Safe". Such a scenario it is very possible. It almost happened in 1983.

author: AllTheGearNoIdea
author_rank: Unknown
timestamp: December 08, 2019, 01:49:39 pm
content: I have SDR but I prefer a real radio. Doesn’t have to be amazing I like old valve based communication receivers something about the tactile nature of heavy switches, weighted tuning knobs and hot valves. A good long wire and long wire tuner is essential. I would also recommend a separate clean Earth if that can be arranged. Lots still out there for listening and enjoyChris.

author: fourfathom
author_rank: Super Contributor
timestamp: December 08, 2019, 03:50:47 pm
content: Quote from: edy on December 06, 2019, 06:34:16 amThat Tecsun 310 looks OK. It has digital tuning and has a BFO (which means it is capable of receiving single sideband and CW). With a long-ish wire external antenna it will work pretty well. A ham radio will have better performance (and virtually any ham rig built in the last 20 years will have a full-range receiver), but the Tecsun will get you started. Even with the built-in whip antenna you will hear plenty of signals, if you listen on the right frequency at the right time.

author: edy
author_rank: Super Contributor
timestamp: December 08, 2019, 03:58:55 pm
content: Thanks again for all the suggestions. I've heard back from a few HAM clubs, I may go to a meeting soon and see what is going on. Meanwhile a few ways I can learn more is read some intro books and I found a page on Ultralight DXing here:http://www.hard-core-dx.com/nordicdx/dxlab/mwdx.htmlIt talks about MW... I'm sure after reading a few books and getting to know the lingo I'll know more about what MW, SW, channels, etc... what it all means. I'm still on the fence but seems like the easiest way to start experiencing the hobby is to pick up an inexpensive MW/SW digital receiver. Even if I am limited by it as time goes on, it is not a huge upfront investment. While I like the RTL-SDR idea, I'm not so sure it is convenient especially if I want to have something bedside at night and plug in a headset before going to sleep, or if I am on a road trip or travel and curious to listen to stuff along the way.I hope it's not a hobby going extinct, although I imagine as the folks involve age there is more incentive to keep the young ones interested (and now you compete with many more hobbies that seem to attract young ones) to pick up the torch.

author: jonovid
author_rank: Super Contributor
timestamp: December 08, 2019, 04:09:49 pm
content: Shortwave long wire antenna best is for 10 to 3MHzurban area RF noise is your biggest problem , this will helpon my antenna setup , the jack gos to a Tecsun PL660 shortwave radioupdateadded the linkhttp://users.telenet.be/d.rijmenants/en/swl.htm

author: wilfred
author_rank: Super Contributor
timestamp: December 08, 2019, 04:11:44 pm
content: Quote from: VK3DRB on December 08, 2019, 12:28:29 pmYou don't have to look back that far. I'm pretty sure I heard Ham radio was involved in saving more than a few lives in the aftermath of hurricane Katrina.

author: edy
author_rank: Super Contributor
timestamp: December 08, 2019, 08:00:22 pm
content: I found a few resources online. I just Googled "Ham Radio for Dummies PDF" and "AARL ham radio license manual pdf" so a few links show up. Both are 300 pages+ so lots of good material in there to get a feeling for what is going on with the entire hobby. I didn't realize what I was getting into!Yeah maybe too much for me to chew on at this point. These books will give me something to do for a while and then I can figure out what's next. Perhaps in the summer once I've read through the basics I will have a better idea if I want to just do "Ultralight DXing" on some cheap sub-$100's hand-held equipment. If anything I can build or buy a slightly better indoor antenna and plug it into the ext antenna plug.Note that I live in a suburb of a major city, with still very dense population density... so much so that I have over a dozen WiFi access points show up in addition to my own every time I load up my computer! I don't have the ability to erect any antennas at the moment or start modifying my house or drilling holes in walls and running wires. I doubt that my reception will be that good, I don't see that antenna wire over 5m happening. I have no trees or poles, I'd have to erect something. I don't see it happening. The books and a cheap radio should keep me busy.[EDIT:]I found a few more books online... Googling "the-beginners-handbook-of-amateur-radio.pdf" produced a link to a 529 page book, and "basic amateur radio course pdf" gives this file:https://csclub.uwaterloo.ca/~ehashman/emcomm-ham-radio.pdf. And there is a whole pile of stuff here:http://www.n5dux.com/ham/files/pdf/. Together with the dummies book and AARL manual, seems like I'll be busy for a long time just reading up on the topic and playing around with a small Tecsun!

author: fourfathom
author_rank: Super Contributor
timestamp: December 08, 2019, 08:14:51 pm
content: Just get that cheap Tecsun 310 and use the whip antenna or throw a skinny wire out the window. This will work well enough to get you some useful hands-on experience while you are reading up on the hobby. If you end up getting a better radio or get your ham ticket the Tecsun will still be a fun radio to have. And they work! For example, I've used a similar (cheap) receiver, with the headphone jack connected to my laptop mic-in jack to pick up and decode NOAA weatherfax signals. I was in northern California and the transmitter was in Hawaii.

author: Bud
author_rank: Super Contributor
timestamp: December 08, 2019, 08:17:03 pm
content: Quote from: edy on December 08, 2019, 03:58:55 pmNo worries, people still go hunting using flintlock muzzleloaders.

author: VK3DRB
author_rank: Super Contributor
timestamp: December 09, 2019, 07:27:00 am
content: Quote from: wilfred on December 08, 2019, 04:11:44 pmIn Texas (where I once resided), ham radio license number plates for you car were $1 per year. That was because the State of Texas recognises the technical contribution and potentially the emergency contribution ham radio operators can provide. The plates cost around $500 in Victoria. When I came back to Victoria, I lobbied to get the law changed to allow hams to get low cost number plates and I was effectively told to get lost. Technical people need a lot more recognition in our society.

author: edy
author_rank: Super Contributor
timestamp: December 09, 2019, 01:51:57 pm
content: Thanks again for all the advice! I ended up biting the bullet and ordered the Tecsun PL-310ET from Amazon. It was roughly ~$43 US or $57 CAN with free shipping. I had about $50 CAN saved up in Amazon gift cards already (for filling out some Developer surveys over the past year) which covered almost all of it. And best of all, it will arrive in 1-2 weeks instead of 2-3 months (like stuff I order from eBay)!Meanwhile I have the following e-books to read through:Ham Radio For Dummies 2nd Ed (2013)The ARRL Ham Radio License Manual (3rd Ed) - TechnicianThe Beginners Handbook of Amateur Radio (4th Ed)Basic Amateur Radio Course (EmComm)So that should get me started and "scratch the itch" with minimal cost invested at this point, to see if I enjoy and want to get into the hobby more. Again, the issue is mostly time. I am already stretched thin with work/family and the wife/kids are not going to enjoy this unless I bring them along with the hobby. So I think this is an easy way to nudge along, do some family listening and exploring and learning.Once I have had my fill of the Tecsun, I will probably explore a RTL-SDR dongle. I run Ubuntu Linux so will need to play around with some of the software and get drivers to make it work, plus figuring out how to set up some antennas. I don't have the ability to go crazy with antennas, so I think I will need to find a solution involving some wires that I can string up in the upstairs bedroom temporarily when I am using the radio, or a clip-on wire that I can make myself (I have plenty of 1/8" jacks, wires and metal clips, coax cable, etc). I was tempted to buy one of the Tecsun "retractable wires" that came suggested by Amazon for another $15 but reviews were mixed as to how much better it was over the standard flip-out telescopic antenna already attached to the unit. So before I shell out more money, I will try the existing antenna and if needed I will try to build something out of scrap from home and see if it helps.Yes I also agree that both the Tecsun and RTL-SDR are cheap enough and fairly portable so I can move them around and play with it on trips, at work, camping, etc.... I looked at some of the cheapest SSB options and they are at least 2-3x the cost of this model. They start around $100-150 CAN and quickly go up in the $200+ range. I also realized that most Ham used equipment is still going to fetch a fairly high price, and anything that is in the lower end is not going to have the convenience of this Tecsun with digital tuning and memory presets. That is the reason I chose the PL-310ET over the R-909, which is less than half the price ($15-20). The tuning on the R-909 will make life harder. At least with a digital display I can save and log signals I find.I also got the Tecsun manual which I downloaded from here:https://www.tecsunradios.com.au/store/wp-content/uploads/2015/12/PL-310ET-MANUAL.pdfIt shows the following frequency range:FM 87~108 MHzRussia 64~108MHzJapan 76~108 MHzEU, USA 87.5~108 MHzMW 522~1620 kHzUSA 520~1710 kHzLW 153~513 kHzSW 2300~21950 kHzI am assuming that "FM" specifically looks for FM signals in that range (Frequency modulated mode). Then should I assume that the signals that are interpreted by my Tecsun in the other ranges (MW, LW, SW) are going to be considered all be "AM" type (amplitude modulation) of the carrier wave? I have seen that all kinds of signals can be transmitted at all kinds of frequencies, from digital signals to TV/picture, to AM/FM encoded and more. I guess the radio will hear a bunch of weird noise when I tune into those frequencies if it is not AM? Will plugging the output into my computer and recording the sound and using some decoder on it be likely to decypher anything? I guess the RTL-SDR software will have various modes that I can use (or it will detect) at each frequency to try and figure out what type of signal is being broadcast?Anyways, I'm jumping ahead of myself. First step is finish reading those e-books while I get my early Christmas present and exhaust the potential of the Tecsun! I think after that I will pick up a RTL-SDR kit and will be kept busy a few more years playing with that on my Linux machine. With my limited time, I will be kept busy enough with this hobby for the foreseeable future with <$100 worth of equipment!

author: fourfathom
author_rank: Super Contributor
timestamp: December 09, 2019, 05:03:41 pm
content: I just downloaded the Tecsun manual, and I *hope* that Tecsun PL-310ET has a BFO! I can't see how to activate it though. The marketing blurb says "Special design of SSB demodulation functions, can receive amateur maritime communications and personal radio", and since HF (3-30 MHz) maritime communications use single sideband the radio will need some sort of BFO function. This radio actually uses a SDR design, which can be very effective (or may be marginal). One deficiency that I hadn't noticed is that on the HF bands the radio only tunes in 1KHz steps. This is fine for AM, and for channelized SSB (such as maritime), but for ham and digital modes you may want 100Hz steps. I see that the radio uses a 32KHz crystal for it's internal clock, and given the typical accuracy of these (perhaps +/- 20 ppm) I think that some kind of "clarifier" or fine-tune control would be useful. Again, for regular shortwave listening this won't matter much.Regarding frequencies and modulation, while you can find all types of modulation all across the radio frequency spectrum, the Tecsun (and other similar radios) are designed to demodulate FM when tuned to the standard FM radio broadcast bands (88-108 MHz in the USA) and perhaps the television broadcast bands (where FM is used for the audio channel, at least on the traditional non-digital frequencies). Elsewhere, the radio will be using its AM detector. One type of AM is SSB (Single Sideband), and the radio has a BFO (Beat Frequency Oscillator) you can enable which will let you receive these signals. With the BFO you can also demodulate CW (Continuous Wave, used for Morse code) and FSK (Frequency Shift Keying, use for many digital modes). Decoding these digital modes can be done by sending the audio from the radio to a computer soundcard input and running one of the many programs designed to decode one or more digital modes. You *need* a BFO to demodulate CW, SSB, and FSK, and the cheaper receivers don't have a BFO.This computer decoding is one reason I like the SDR dongles, since with these you don't need an audio cable and you can have direct computer control of the radio frequency and mode. This ability can really simplify the setup and avoids many potential grounding and power supply noise-related issues. Of course if you just want to listen to shortwave broadcast stations then these additional capabilities aren't a big deal. But in my opinion, most of the interesting stuff in ham radio radio is going on in the digital communications domain (I've been a ham for about 45 years.)Again, bang-for-buck when it comes to a wide-range SDR I really like the "SDR-Play RSP1A".

author: bob91343
author_rank: Super Contributor
timestamp: December 09, 2019, 05:44:34 pm
content: The frequency spectrum is broken into sections by terminology. MW is Medium Wave, or the AM broadcast band. Then comes SW, short wave, from 3 to 30 MHz. This is also called HF, or High Frequency. Then comes VHF, 30 - 300 MHz. UHF is from 300 MHz to 3 GHz. And so on.In your case, your primary interest would be MW and SW/HF. There is very little radio propagation above around 25 MHz these days. In fact, the main range is perhaps from 5 to 15 MHz the way the ionosphere is acting. Yes there is other stuff to hear but it's mostly noise.As an old time ham operator I can say it's one of the most fun hobbies I have. Last night I listened mostly to noise but contacted Hungary. Night before, Japan and Philippines and South Africa. It's exciting when a distant station responds to a call. I have worked well over 300 countries, all states and all continents, including some very rare places like Eritrea and North Korea and Southern Sudan, etc.Of course, this comes with considerable investment in time and effort and space. Not money really, as much of my gear came from swap meets and trades.

author: edy
author_rank: Super Contributor
timestamp: December 09, 2019, 05:47:59 pm
content: You are correct, I do not believe there is a BFO in the Tecsun. However, I have found some people who built their own outboard BFO for SSB reception. Here is one of the websites here:https://wf7ihomebrew.wordpress.com/2019/06/30/outboard-bfo-to-add-ssb-capability-to-am-radios/And here is the schematic:And built in a tin:A fun little project if I want to start exploring this area as well! I will check out the SDR-Play RSP1A. It seemed a bit pricier than the RTL-SDR.COM V3 option (they have a full kit for <$30) but it's probably much better. So many options, so much fun to be had, so little time!Wow. More excited than ever!

author: fourfathom
author_rank: Super Contributor
timestamp: December 09, 2019, 06:37:45 pm
content: Quote from: edy on December 09, 2019, 05:47:59 pmThe RTL-SDR V3 has essentially no input filtering, and when used on the HF bands it is in a "direct sampling" mode which samples the RF input at 28.8 MHz. Without an external filter this leads to pretty terrible "aliasing" artifacts, where input signals above 14.4 MHz get "folded" back down to the 0-14 MHz region.As an experiment I built a receiver / digital gateway for one of the ham digital modes ("JS8" on 10.130 MHz) using one of these SDRs and a Raspberry Pi. With external filtering and a preamp it works reasonably well. Here is a presentation I gave to my local ham club that has some details on the SDR and how I put it all together:http://wb6cxc.com/wp-content/uploads/2019/04/Presentation-1-0.pdfThis is a narrow-band system operating on a single frequency, and it would be more difficult to turn this into a useful general-coverage receiver. The SDR-Play and Funcube SDRs do all this filtering and conversion stuff for you and they do a darn good job of it. The cool thing about the RTL-SDR V3 dongle is that it works in the HF band at all, is very cheap, and has a reasonably stable oscillator.You can certainly build an external BFO, but making one that is tunable and stable can be a challenge. These days I would use digital synthesis for the VFO, and the parts would cost me under $10. One problem with the external VFO concept is that it doesn't give you "opposite sideband rejection". You can still tune in a SSB signal, but you will get more background noise and potential interference.But don't let me discourage you from building stuff! That can be a lot of fun and a great way to learn. One of the simplest receivers you can build is a "direct conversion" design, consisting of a BFO, a mixer, and an audio amplifier. With just a very small handful of parts you can put together a receiver for AM and SSB. I love designing and discussing this stuff, so feel free to ask any questions you like.

author: edy
author_rank: Super Contributor
timestamp: December 12, 2019, 03:19:32 am
content: I'm continuing to read through some basic radio electronics books because I'd like to understand what is going on. I know it is probably more technical than someone needs to know just to get licensed and involved in amateur radio, but for my own education I would like to really be able to start building some basic stuff to understand how it works. Right now I'm working through a series on the websitehttp://www.learnabout-electronics.org/Oscillators/osc10.phpon oscillators. I am looking at the LC tank circuit and the equation for frequency looked very familiar. It looks like that of a simple pendulum:Compare to....I find this fascinating. Probably no surprise to most of you. Is there some analogy one could make with L/g and LC to help learn out things from one to the other? Note that this is the small-angle approximation for pendulum. I wonder if the "angle" limitation also is analogous to some parameter that we need to keep small for an LC tank, otherwise the approximation formula no longer works? I feel that the relationship is like kinetic and potential energy being transferred back and forth. The capacitor stores potential energy, and the inductor is the kinetic.I spoke to someone who said an outboard BFO will not work on a radio like the PL-310ET because of DSP (or probably most modern radios). Since the output of a CW being received by a radio sounds silent (since there is no modulation on top of the CW) and because of DSP handling all the audio before it even gets to the speaker, the BFO would have to be wired into the board internal to the radio where you can somehow patch it in after the receiver most likely converts the signal to the intermediate frequency the radio uses, but before the 2nd detector (demodulator) kicks in to pull out the audio from the CW (https://en.wikipedia.org/wiki/Beat_frequency_oscillator). In this case the beat is analogous to when you are tuning a guitar and you use 2 adjacent strings... you can hear a "beating" if the strings are not same frequencies which gets less and less until they are in tune to each other?I'm also trying to understand SSB.... there is USB/LSB. My understanding is that there is a frequency "X" which is being "tuned" to. However, the LSB is being transmitted about 3 kHz below and USB is at 3 kHz above. So are we really just tuning to a frequency X-3 or X+3? If your radio has sharp enough resolution to tune to minute frequency steps, could you just tune into the LSB or USB frequency on your way through the spectrum? Or are you actually tuning to "X" and using some kind of method to pull out stuff that is slightly below or above that is not exactly tuning? For example if you had a trim somewhere in your radio for calibrating frequencies and it was off by 3 kHz in say the down direction, would you be tuning in the LSB every time you jump to certain frequencies you thought were in the middle (e.g. "X")? My confusion is in that frequencies have a "bandwidth" and not exact, and how it is that some signals can be pushed lower or higher yet we still say we are tuned to a frequency. Oh so much to learn!

author: bob91343
author_rank: Super Contributor
timestamp: December 12, 2019, 04:07:37 am
content: USB and LSB are opposite. If you analyze the spectrum of an amplitude modulated signal you find a carrier wave with two sidebands, one on either frequency side of the carrier.For a low frequency tone modulation, there will be two side frequencies close to the carrier. For a slightly higher modulation frequency, the side frequencies move farther from the carrier, spaced from it by the modulating wave's frequency.It was obvious that the carrier wave carried no information so circuits were devised to avoid transmitting it to allow more power to be put into the sidebands. But since both sidebands are identical, circuits were devised to eliminate one or the other. This is called SSB, single sideband. In order to detect the signal, one must reinsert the carrier signal locally in the receiver. If you are receiving upper sideband, USB, you carefully reinsert a local carrier signal at a frequency just below the signal, where the carrier signal would have been. For LSB you reinsert the carrier on the high frequency side.The frequency of the local signal is very critical. To get intellligible speech, its frequency must be within perhaps 50 or 100 Hz from where it should be. If too far from the sideband, the signal sounds high pitch and unnatural. If too close, it really gets unintelligible due to the 'folding' of the low frequencies.If you don't reinsert carrier, you get garble. It takes a practiced hand to tune the local oscillator satisfactorily. It's kind of fun, too.Most good receivers have 'brick wall' filters in the IF so you can tune just one sideband's worth of signal. Another benefit of this system is that it occupies half the spectrum that an AM signal occupies. As a net result, for the same power you get about 9 dB more received signal. And because, for speech at least, the average power is much lower than the peak power, you can gain even more by taxing the amplifier a bit more, since it won't overheat as soon.That means that today's radio amateur can produce a signal that is perhaps 10 or more times the power than back in the old AM days, and with more compact equipment.

author: fourfathom
author_rank: Super Contributor
timestamp: December 12, 2019, 04:10:08 am
content: Quote from: edy on December 12, 2019, 03:19:32 amProbably correct about not being able to use an external BFO with the PL-310ET. It is remotely possible to inject a strong signal at the radio input, offset the right amount from the desired input, and through overload the two signals will mix and generate the desired beat frequency. But that's not really practical, and that BFO you were looking at is designed to be injected at an internal point in the (fixed-frequency) IF (intermediate frequency) signal chain. DSP radios such as the PL-310 don't have such an IF chain, even in the digital domain. Instead, the input signal is directly mixed down to DC (well the audio range anyway) and the traditional filtering is done via quadrature mixing and signal processing. It's really quite elegant, and now practical because of cheap digital technology.QuoteFirst you need to understand AM modulation. Here we take a carrier signal at "frequency X" and use an audio (or digital) signal to increase or decrease the amplitude of the carrier signal. Wikipedia has a good article on this, and here's one with less math:https://www.electronics-notes.com/articles/radio/modulation/amplitude-modulation-am.php. This modulation process generates sidebands. With a 1 KHz modulation signal, sum and difference products (sidebands) will be generated at "X+1KHz" and "X-1KHz". The carrier is also transmitted in AM. A basic AM receiver can demodulate this AM signal -- this can be as simple as a diode and headphones (you need a strong signal for this to work). With Single Sideband the carrier and one of the sidebands are eliminated, and only one sideband is transmitted. This was traditionally done with filters, and occasionally with analog phasing techniques. These days this can be done with DSP. Wikipedia and the link above also have discussions of SSB. The BFO is used to essentially re-insert the carrier signal at the detector, modulating the SSB signal to produce the original audio. Mixing (modulating) "X" and "X+1KHz" gives you sum and difference products: "2X+1KHz" (which we discard) and "1KHz" (your original audio modulating signal).

author: eti
author_rank: Super Contributor
timestamp: December 12, 2019, 04:19:14 am
content: Quote from: VK3DRB on December 08, 2019, 12:28:29 pmTell this to captain cynical in the post above you ^

author: edy
author_rank: Super Contributor
timestamp: December 12, 2019, 12:36:45 pm
content: Ok thanks, now I got it. I read a few articles onelectronics-notes.comwhich explained it. So in a mix of pure frequence X (carrier) plus Y (modulator) you get X+/-Y. In cases where Y is also a simple wave at a specific frequency you get a peak at each side of the X. But since audio has a range of frequencies that are modulating the peaks flatten out into bands so these 2 bands (LSB and USB) are representing the audio and carry the actual information. Part of my confusion stems from the visualization of frequency spectrum and wrapping my head around the simple AM wave graph showing a simple carrier wave with the amplitude of it being "enveloped" by the modulating wave (audio input). When you look at that diagram you can't really imagine other frequencies... all you see is the CW with a modulation, you don't see the side and frequency visually. Although peaks and valleys combine in such a way that you can end up producing signals that can be Fourier transformed to represent those other frequencies. That also explains channel spacing and other stuff.

author: xrunner
author_rank: Super Contributor
timestamp: December 12, 2019, 03:02:54 pm
content: Your other questions have been answered, but here's some trivia about the sideband practices on the HF bands.The tradition of using LSB below 10 MHz, and USB above 10 MHz, goes back to the very early days of SSB. Early rigs had very simple designs and an IF of 10.7 MHz. These radios passed the lower sideband below the IF frequency, and the upper sideband above the IF frequency. There was no option to choose a particular sideband as there is now. That old limitation has become the standard. But of course it's not illegal to use any sideband you wish on any band.

author: bd139
author_rank: Super Contributor
timestamp: December 12, 2019, 04:00:01 pm
content: Yes we've got some locals on 80m here who like to use USB for some reason. I haven't worked out why.

author: Sal Ammoniac
author_rank: Super Contributor
timestamp: December 12, 2019, 06:22:31 pm
content: Quote from: xrunner on December 12, 2019, 03:02:54 pmCaveat: those sideband practices on the "HF" bands that you describe only apply to the ham bands. Other users of SSB on HF, with very rare exceptions, always use USB regardless of the frequency.

author: fourfathom
author_rank: Super Contributor
timestamp: December 12, 2019, 06:41:33 pm
content: Most (all?) of the FSK-style digital modes use USB on the HF ham bands. However, this is USB in name only, as the actual transmitted signal is a single frequency, or multiple single-frequency signals that are individually modulated in frequency and/or amplitude and/or phase. The only thing "USB" about them is that they are usually generated by sending an audio "baseband" signal into a SSB transceiver (set for upper sideband), and received in the same way. These signals can also (and sometimes are) generated directly at the output frequency by simple frequency-shifting oscillators -- no sidebands.Actually, even these signals have sidebands. In the case of the WSPR mode, the modulation rate (Baud rate) is 1.4648 Hz (yes, that's quite slow), and there will be upper and lower sidebands spreading out from these signals spaced at 2x the baud rate. These fall off quite quickly, so the occupied bandwidth is very small.The same holds true for analog frequency-shift modulation such as marine WFAX (weather facsimile charts) on the HF bands. Your receiver will be in USB mode, and the shifting frequency signal will be converted to an analog baseband audio tone, varying a couple of KHz. The signal isn't *really* USB, but that's how we receive it to get the demodulated audio right-side-up. If we were to receive in LSB mode, then black would decode as white (and the synchronization signals wouldn't work).

author: james_s
author_rank: Super Contributor
timestamp: December 12, 2019, 06:48:11 pm
content: I have a Grundig that I've been fairly happy with but if you want something cheaper I'd say read the reviews on Amazon, you can get something decent for not much money these days.Shortwave is definitely not what it used to be, mostly just dead air these days. I do enjoy picking up and identifying LW NDBs used for air traffic, and as of a few years ago I was still able to find a "numbers" station which I believe was broadcasting out of Cuba, there used to be loads of those used for transmitting covert messages to spies, it was a lot of fun to hunt for them. Occasionally I hear local hams yakking about their medical problems and every now and then there's still some foreign broadcast. Oh and of course WWV/WWVH is still around for now anyway.

author: fourfathom
author_rank: Super Contributor
timestamp: December 12, 2019, 07:02:12 pm
content: Quote from: edy on December 09, 2019, 05:47:59 pmBack to that Tecsun, the marketing blurb says: "Special design of SSB demodulation functions, can receive amateur maritime communications and personal radio". So I think we should expect that you will be able to receive SSB. Please let us know how this works for you! We can give you some pointers to help you find SSB signals to monitor.

author: PA0PBZ
author_rank: Super Contributor
timestamp: December 12, 2019, 07:20:26 pm
content: Quote from: fourfathom on December 12, 2019, 07:02:12 pmI found this only on Amazon and it must be a mistake. In a few reviews (eham.net) they mention it has no SSB capability and since this is a direct sampling radio you can't build an oscillator on the IF frequency (there is no IF). Also, the tuning steps are way too big for SSB.

author: fourfathom
author_rank: Super Contributor
timestamp: December 12, 2019, 08:13:39 pm
content: Quote from: PA0PBZ on December 12, 2019, 07:20:26 pmI agree on the tuning steps, although for channelized marine SSB they might be OK -- assuming that the radio oscillator is accurate. Since the diagram in the manual shows a 32KHz xtal as the SDR reference clock, I would guess that the accuracy isn't all that good and you would need a "clarifier" (fine-tuning) to make it usable on SSB. It is certainly possible to demodulate SSB on an SDR radio, the BFO is implemented in DSP. But you still need 100Hz or finer tuning steps for non-channelized SSB.

author: edy
author_rank: Super Contributor
timestamp: December 12, 2019, 10:00:34 pm
content: I've been thinking more about sidebands. I understand beats fairly well, I can visualize how 2 frequencies that differ slightly will interfere and because they are slightly off they will originally constructively interfere and produce 2x peaks, and then a moment later they will be out of phase (180 degrees) and will cancel out completely. So by combining 2 very-close frequencies you get the beat pattern... and the beat frequency increases as the difference between frequencies gets bigger.... and I have intuitive experience with this as well with tuning guitar strings as you try to tune adjacent strings by playing same note and listening for the beats to try and minimize the beats.To understand the sideband production (when modulating a single CW) I am trying to intuitively understand what is happening, so I flipped it BACKWARDS... and imagine what would happen if you combine a sideband with it's CW. Say if I combine the LSB with CW, then I would pull out the "beats" which in this case ends up giving us the actual audio signal. Similarly, I can combine a USB with the CW and it will create "beats" as well, which is the audio signal. So I understand it in terms of demodulation.... how the beats will come out of combining either LSB+CW or USB+CW. The other way is harder to wrap my head around (how combining CW+modulation generates beats). This video is great to demonstrate it:I am going to try and use Audacity to generate waveforms and combine them. I can generate a tone of a very high frequency (CW) and then a lower frequency tone (modulation) and I believe there are Nyquist filters/functions or coding you can do in Audacity to let you modify one wave using the other. Then I can run it through a spectrum analysis in Audacity and see if it produces the kind of peak patterns that we see in that video.I should also be able to programmatically create a WAVE file. If I can make a RAW file which is essentially just a string of 16 or 32-bit values, I can write out a sine wave and modulate it all in software. I'll have to see the format for writing out RAW wave data and then should be able to write a small C program to do it and test out different things.Regarding the Tecsun, here is the spec sheet:https://www.tecsunradios.com.au/store/product/tecsun-pl310et-multi-band-radio/It says it has selectable IF bandwidth. I don't know what that exactly means. Maybe there are some software-enabled DSP functions for specific frequency ranges that give you some SSB capability. I don't know. Seems to be all done by the chips and there may be a PGA in there with custom firmware doing stuff. I have no idea how these radios are built and haven't yet looked at the block diagram or schematic.

author: Bud
author_rank: Super Contributor
timestamp: December 12, 2019, 10:21:40 pm
content: Quote from: fourfathom on December 12, 2019, 07:02:12 pmWhat is "amateur maritime communication" ?

author: james_s
author_rank: Super Contributor
timestamp: December 12, 2019, 10:58:57 pm
content: Quote from: Bud on December 12, 2019, 10:21:40 pmIt's used for communicating between private ocean going boats mostly. My dad's sailboat came with a SSB transceiver and an old packet modem installed. Previously it was owned by a couple who sailed it all over the world. They used the SSB radio to communicate longer distances than the marine VHF.

author: fourfathom
author_rank: Super Contributor
timestamp: December 12, 2019, 11:27:49 pm
content: Quote from: james_s on December 12, 2019, 10:58:57 pmYes, but I wouldn't call it "amateur". On my sailboat I have an Icom SSB rig, which is designed to operate on the channelized maritime frequencies roughly between 1 and 30 MHz. The mode is upper sideband (but I think the radio can be switched to lower as well -- not sure though). I use a PACTOR modem with it to send and receive email using the private "Sailmail" service. I also use the good old microphone to communicate with other similarly-equipped boats, and occasionally the Coast Guard. You need two licenses to operate the radio, one for the boat, and one for yourself. In the USA there is no test required, just some paperwork and filing fees. I can also legally use this marine radio on the ham bands. Ham radios are not type-approved for use on the marine bands, although many people do so. The technical requirements for stability and signal purity are slightly tougher for marine service radios than for ham, although most modern ham rigs can meet these specs.

author: james_s
author_rank: Super Contributor
timestamp: December 13, 2019, 01:22:08 am
content: It fits the definition of amateur radio that I'm familiar with, ie it's not a commercial broadcast station or government entity. It's not a topic I'm all that familiar with though, and my dad is not a ham so I helped him remove the transceiver to sell it as he had other uses in mind for the space it occupied.

author: fourfathom
author_rank: Super Contributor
timestamp: December 13, 2019, 03:16:04 am
content: Quote from: james_s on December 13, 2019, 01:22:08 amNo big deal, but the FCC classifies this a different thing than the amateur radio service. For example, with marine radio it is perfectly legal to carry out business and other activities that carry a "pecuniary interest". Not so on the ham bands. In fact, this is probably the most common use of the marine service, where it is used by commercial shipping. At least it was common until satellite comms became so easy.

author: edy
author_rank: Super Contributor
timestamp: December 14, 2019, 11:55:44 pm
content: I received my Tecsun and have just played around a little bit with it. Of course the AM/FM reception is phenomenal, but I am trying to now improve my LW/SW reception. I've extended the built-in "whip" antenna and pressed ETM (automatic searching throughout entire range) and it found a few stations but not much. I want to make a simple antenna for it and wondering about the construction, if anyone has some ideas that would be great.First, there is a port that says FM & SW antenna on the outside of the unit, next to headphone jack. It is a 1/8" jack, similar to the headphone. I assume it is a MONO-type connection. I can find a 1/8" jack in my parts bin and connect a wire to it. I have lots of long thin wires. But I am not sure what goes to the 2 (or 3 if I use a stereo jack) terminals. I found this diagram:According to that picture, if I have a 2-contact plug, the tip goes to the long length of wire that I am going to extend along the ceiling of my room or hang out of my window? And the second contact (along the side of the jack) goes where? For example, a jack like this:And then I've seen stuff like this, which seems to suggest a 3-contact connection for the antenna jack?And this one clearly shows on a 2-contact 3.5mm jack:Then there are loop antennas that look like this:... and this ...Any suggestions what I should be doing? Experiment and see what happens?

author: fourfathom
author_rank: Super Contributor
timestamp: December 15, 2019, 12:41:30 am
content: I believe that the antenna jack uses the tip for the antenna hot wire (center conductor of the coax if you use coax between the radio and the antenna) and the sleeve is for the antenna ground (or shield of the coax, if used). The plug "ring" contact can be ignored.I wouldn't bother with tuned / loop antennas just yet. Just a length of wire connected to the jack tip (say 10 feet or more, string it up as best you can, or throw most of it out a window. Even tacked up across the ceiling is worthwhile. Connect the jack sleeve to another wire going in more or less the opposite direction, or if you gave an actual earth ground (say a copper water pipe) clamp the ground wire to that. Or just ignore the sleeve connection. Then see what you get.Later you can try a better outside antenna, perhaps with a balun and coax to the radio. But for now, start simple. Don't let people bully you into thinking it has to be perfect -- it doesn't.

author: james_s
author_rank: Super Contributor
timestamp: December 15, 2019, 01:37:15 am
content: In my somewhat limited experience with shortwave antennas, I've found that a long wire works as well as anything, and the longer the better. You'll get better reception if you ground the radio to a solid earth ground which you can do via the ground contact on the antenna jack, coax is not necessary unless you have the radio indoors in an electrically noisy environment and the antenna outside.Don't expect to find a whole lot on the shortwave band in general, there is still some activity but about 95% of what was there 20-30 years ago is all gone now.

author: edy
author_rank: Super Contributor
timestamp: December 15, 2019, 03:16:45 am
content: I found some telephone wire composed of 4 different wire strands (the type with single-core copper red, yellow, green, black) and pulled out about 20 feet of one of the strands. I connected it to the tip of a 3.5mm phone jack (I only had stereo jacks), and hung it out my upstairs window and tied it down in the backyard to a garden hose-holder (plastic). So it is vertically oriented and fairly "taught" because it is snugly wedged into my window and tied to something in the backyard. I can close the window no problem, the wire is thin enough to pass through. I also connected the "ground" part of the 3.5mm phone jack (the sleeve) to ground earth of a mains plug to see if it will make a difference. I seem to be picking up a few more stations but not a huge number. As before, AM/FM reception is excellent but I'm waiting to see what happens with LW/SW. Perhaps later at night there will be better reception.

author: james_s
author_rank: Super Contributor
timestamp: December 15, 2019, 04:32:08 am
content: You'll probably need a wire 50-100' or longer for best results, and generally they're horizontal, I don't know off hand how much that matters.

author: rdl
author_rank: Super Contributor
timestamp: December 15, 2019, 06:16:59 am
content: If you don't already have one, get a copy of the ARRL Handbook. It's full of info about radio and electronics in general. It doesn't need to be the latest edition, even one 20 years old is still useful. You should be able to find a copy for under $10.

author: bd139
author_rank: Super Contributor
timestamp: December 15, 2019, 11:53:59 am
content: Yeah my newest copy of that is 20 years old

author: edy
author_rank: Super Contributor
timestamp: December 15, 2019, 05:17:31 pm
content: I have no space in my backyard. The depth is about 30 feet max as is the width. I could theoretically put in a diagonal but then have to put up post extensions on the fence and house...that won't happen until the summer (I'm in Toronto). So instead I got about 45-50 foot single piece of solid core copper wire borrowed from a 4-wire telephone line and attached alligator clips to either end. One end I clipped to a curtain on the north end of the house window. Then I pulled it taught almost to the south end of the house and clipped it to my radio antenna. I pressed the ETM button and waited... it pulled in the following this morning 11am:I usedhttps://www.short-wave.infoto try and guess the source...(note I will come back later and edit this list... I am in a kid playground in a strip plaza at the moment... read below... this kids playground has no reception and even my cell phone is one bar... probably enclosed by sheet metal and corrugated roof... terrible)...7400 - China Radio Intl? Kunming-Anning (can't make out anything)9330 - Monticello (eastern tip of Maine)9395/9455 - WRMI Okeechobee (Florida)9505 - WHRI Cypress Creek (South Carolina)9565 - Spanish (Radio y TV Marti - Greenville, North Carolina)9690 - Spanish (R. Exterior De Espana - Spain) ? Huh?9830 - CNR 1 Voice of China (Beijing) *could be interference with 9840*9840 - WHRI Cypress Creek (South Carolina) <-- this one loud and clear10000 - WWV Colorado Denver (can't make out anything)11540 - Either France or Moldova (can't make out anything)11610 -(can't make out anything)11775 - Caribbean Beacon (Anguilla)11995 -12030 - R. Exterior De Espana SPAIN again (like 9690) - fairly good reception15770 - WRMI Okeechobee (Florida) - like 9395/9455Of the above a few were religious, a couple Spanish. I think they are from southern states (Bible Belt) and some Spanish ones from Florida. Now many of these channels were "staticky" but I could move around the radio and get some slight changes. I didn't have anything grounded and I may try using a 3.5mm jack with this wire rather than clipped to the whip antenna. I expect at night I may get some better reception. Interestingly I drove a bit away from my neighbourhood and now inside some indoor kids playground with only my whip antenna and got different stations?!?! None of them are clear but the ETM decided they were signals worth presetting. And FM reception is pretty bad inside here... only 5 or 6 stations come in clearly whereas at home and outside I get almost every station (dozens).Will keep experimenting. I don't want to shell out money for a fancy antenna or some powered gizmo unless I know it will make a difference.

author: james_s
author_rank: Super Contributor
timestamp: December 15, 2019, 05:58:03 pm
content: You shouldn't have to spend money on gizmos, half the fun of shortwave is experimenting with antennas. Due to propagation your reception is likely to vary widely depending on atmospheric conditions and location. Even under the best of circumstances it will usually be a bit staticky, that's just the nature of shortwave AM radio.

author: edy
author_rank: Super Contributor
timestamp: December 17, 2019, 09:18:43 pm
content: Thanks, yes I have seen how some of the fun with the shortwave DXing hobby is playing around with antenna "voodoo" and trying different things!I just have to make sure I don't upset the wife too much with wires and coils all over the house, she will not like that.I strung up a 35 foot wire from my upstairs window to the backyard fence. It clips on to my radio. It is oriented at a bit of an angle because the fence is not as high as my upstairs window and I can't put up a pole (fence shared with a number of houses). The previously used vertical wire is still out my window and about 20 feet straight down. I'm trying to compare both my angled 35 foot to the fence and 20 foot vertical.Still, I'm getting about 20 finds using the auto-scan tune, mostly a few religious stations out of Alabama, Kentucky, South Carolina and Florida. I've got one out of Maine, and I believe I also picked up Cuba, and Spain (as mentioned in my previous post). One interesting find is 9570 which I've attached the audio file for. I can't figure out what this is but according to my search is could be coming out of Korea. How is this possible? (Does anyone understand the language in the attached mp3)?I wish to build a magnetic loop receiver antenna as outlined here:I will use some refrigeration coil copper tubing (10 feet) bent in a circle for the large loop and the smaller coil (1/5th size) out of thick gauge copper wire (like the grounding wire in electrical cabling). I noticed that most people use a capacitor across the larger loop and it is an AIR DIELECTRIC 2 GANG type. Are other options going to work? For example, what about this:https://secure.sayal.com/STORE2/View_SHOP.php?SKU=217693It is CAP TRIM 15-160PF 13MM PCST PL. If I connect 2 of them up in parallel, I can adjust to have 30-320pF range. Why is the air type so popular, or is it because it can handle more voltage for transmitting. If I am only receiving, are there any other cheap variable capacitor options?

author: Sal Ammoniac
author_rank: Super Contributor
timestamp: December 17, 2019, 09:49:25 pm
content: Quote from: edy on December 17, 2019, 09:18:43 pmJust about anything works to some extent. In college I wrapped about five turns of wire around my room up near the ceiling and that picked up lots of SW and MW DX.Loops are great for MW DXing because you can turn them to null out stations on the same frequency. I've found that this also works on SW, but the effect isn't as pronounced and the nulls are not as deep as they are on MW.I hate to say this, but you're getting into SWL in its twilight years. Things today are a mere shadow of what they used to be several decades ago. Most of the big powerhouses are gone and what's left is mainly religious crap and second-rate propaganda. It's still fun, though.Have you tried listening for utility stations on SW? Like SW broadcasting, much of this has gone the way of the dodo, but there's still some interesting stuff around, like commercial air traffic, maritime traffic, military stuff, etc.

author: bd139
author_rank: Super Contributor
timestamp: December 17, 2019, 10:52:17 pm
content: Air traffic is fun to listen to. I live under Heathrow approach. Also at air shows.Please listen to China Radio International dramas though. I am in tears of laughter at how bad they are

author: Sal Ammoniac
author_rank: Super Contributor
timestamp: December 17, 2019, 11:22:58 pm
content: Quote from: bd139 on December 17, 2019, 10:52:17 pmYou're probably listening to air traffic on the VHF bands, which is quite different from the air traffic on the HF bands. HF air traffic happens when aircraft are outside the line-of-sight range of VHF comms (like over the middle of the Atlantic or Pacific oceans) and consist mostly of position and altitude reports at infrequent intervals.

author: edy
author_rank: Super Contributor
timestamp: December 17, 2019, 11:36:00 pm
content: Quote from: Sal Ammoniac on December 17, 2019, 09:49:25 pmYes, it's unfortunate that there isn't more stuff out there. This is my first SW-capable radio and it was relatively inexpensive so it was a light-weight method to join the hobby without breaking the bank. The wire antennas cost me nothing, and if I can build a magnetic loop antenna for $20-30 in parts from the local hardware store that would still be well under $100 for the entire setup that I hope I'll be able to play around with for years, maybe pick up a few more sources. Not a bad investment. I am still fascinated that I was indeed able to pick up Cuba, Spain and even Korea (mp3 file I uploaded earlier)... although I have my doubts still that I could get a signal from Korea. Cuba I believe, maybe Spain, but Korea? Also I figure during different times of the year (summer/winter) and solar cycles may prove to be interesting differences as well in reception.I did not want to pay too much and therefore decided not to get something with SSB, but in the future that may provide me with more listening options. Ultimately if I decide to continue venturing on the path to amateur radio licensing, I would eventually equip myself with better gear that would allow many more decoding options. There is also the cheap RTL-SDR dongle to experiment with over the next few years and I can use that with software that will do morse decoding from CW signal, SSB, and more, plug an upconverter like Spyverter or Ham-It-Up that will let me do lower than 24 Mhz frequencies (the limit of the RTL-SDR). That will hopefully also keep me occupied for some time. The Tecsun SW radio is ultra-portable and fun to take anywhere, so it serves a niche. But if I want to get a little crazier I can start ordering RTL-SDR stuff with the laptop.I trust that would keep me challenged to learn and interested enough that it would overcome the lack of SW sources out there. Now when it comes to LW, I have had *no luck* finding anything from about 153 – 513 kHz which is the LW range the Tecsun scans through. I don't know why, but there is nothing on LW in my area!!! Why? Same goes with aircraft and boating signals... the radio tops out in the FM frequency range (108 Mhz) and doesn't give me options for anything above that (Google says aircraft start at 118 and higher). Unless there is a "down-converter" of some type, I don't believe I can tune in to any aircraft with this Tecsun radio. I think I'd better pick up the RTL-SDR dongle if I want to pick up any of the other bands, the Tecsun isn't going to do it.

author: fourfathom
author_rank: Super Contributor
timestamp: December 18, 2019, 01:13:42 am
content: Cuba? Sure, it all depends on the propagation. Here is a good website for propagation analysis and prediction:https://www.voacap.com/hf/

author: bob91343
author_rank: Super Contributor
timestamp: December 18, 2019, 02:05:14 am
content: You won't hear much but you can find a lot of signals by using a spectrum analyzer. They are very sensitive and cover a wide frequency range.Of course you will just see a display of signals but still it's fun to look around and see what's out there. A small antenna and I can see the entire AM and FM broadcast bands, for instance. The WWV signals and the weather channels around 162 MHz are visible. Repeaters on 2 meters, too.I can analyze the broadcast signals and see the subcarriers, pilot tones, and other interesting stuff.And there is no place on earth where a signal couldn't originate and propagate, so Korea isn't a big deal. With my ham radio, I think the farthest I have contacted is Portugal, long path, perhaps 20,000 miles.

author: Bud
author_rank: Super Contributor
timestamp: December 18, 2019, 02:58:46 am
content: I worked the globe FROM MY CAR, the radio was Icom 706 mk iig into a top loaded whip antenna mounted on the trunk.(@edy: you do not want to get into mobile ham radio)

author: fourfathom
author_rank: Super Contributor
timestamp: December 18, 2019, 05:21:40 am
content: Quote from: bob91343 on December 18, 2019, 02:05:14 amThis is one of the nice things about the SDRs like the ones from SDRplay and Funcube. Most of the programs you use with the SDR will display a spectrum and usually a "waterfall" spectrum plot, over a 2 MHz or wider frequency span. This makes finding signals easy, and to listen in you just have to click on the display.

author: bd139
author_rank: Super Contributor
timestamp: December 18, 2019, 07:57:36 am
content: Quote from: Sal Ammoniac on December 17, 2019, 11:22:58 pmYep that’s exactly it.

author: edy
author_rank: Super Contributor
timestamp: December 18, 2019, 11:21:15 pm
content: I am having fun with the radio, every day I scan at different times and make notes of what I can pick up with my wire. Sometimes the wire makes no difference... I clip it on or take it off, I still hear the station! Sometimes I get better reception by grabbing on to the antenna with my hand! When I remove my hand the signal goes to fuzz! Sometimes it will skip a station when it is doing the autoscan memory (ETM), but I will manually go to that frequency and behold I have a signal there (weak but still audible)!!!! I guess now I know the ETM is *not* perfect in finding everything, but it would be a long process of going through every frequency from 2300 to 21950 in 1 khz steps to find stuff!!!Also I noticed some broadcasts in the high 3000's occasionally at night where people are talking about HAM radio stuff... sometimes I can hear it. And sometimes it sounds like people talking (not a radio show or religious stuff) but I can't make it out. It sounds muffled, like the adults in the Charlie Brown cartoons. Is that because it is on a side-band?I want to make a magnetic loop antenna and found this excellent video (further down below). I was going to go out and spend money on copper tubing and air dielectric capacitor, which is beautiful and all, but I think I will start with something much simpler with stuff I have laying around at home! I only need to buy a couple of variable trim caps but the cheaper type which I can hook up in parallel for fine-tuning, like these:CAP TRIM 15-160PF 13MM PCST PL and CAP TRIM 13-44PF 8MM GRN PCMT. Remember these are for receiving, not transmitting. I know they can't handle high voltages but if I'm using this to receive only then should be ok?I figure if I hook up a couple of the 15-160pF and the 13-44pF in parallel, at the minimum setting for all 3 I could get down to maybe 13+15+15=43pF. If I add a switch on the parallel branch to the 2 larger trim caps (which I would connect below the 1 smaller one), I could take out the larger caps from circuit and then be left with only my 13-44pF trim in circuit. So I could trim 13-44pF, and then to go higher in range I would flip the switch and have all 3 caps and maximum be 44+160+160=364 pF. So I would be able to range from 13 - 44pF with switch one way, and then continue with 43p - 364pF with switch other way. I hope that is a good enough to cover my 2300-21950 kHz range of the radio. Otherwise I'd have to add another large trim cap and then push the max up to 44+160+160+160=524pF. I can buy the trim caps for about $2-2.50 each so all together about $10 in trim caps unless I can salvage something at home. Something like this? What about the coax? Do I use outer mesh only? See photo below and also video:As far as loops go, it sounds like most people are using about 10 feet length of wire/tubing so approximate diameter is 10 foot/pi = 3.2 feet or approximately 1 meter wide. Then they make the smaller loop 20 cm diameter (about 1/5 ratio) which hooks up to the mesh and inner conductor of your coax. The video below actually shows them using a coax. I believe they are shorting the mesh/conductor together at different points so it becomes one. This method allows the antenna to be flexible for portability and then you just rig it up to a mount that supports it in a circle when needed. I may build something like that because it is easy to store away.Any suggestions? The video starts showing these about 16 minute mark... using coax cabling. And then at about 20:30 mark he shows it made of coax for both outer and inner loops, simple, he called it "Cheap as Chips".

author: james_s
author_rank: Super Contributor
timestamp: December 19, 2019, 12:21:56 am
content: Does your radio go down into the 200-400kHz range? One of the things I enjoy doing is receiving NDBs, not too interesting to listen to honestly, all they do is broadcast the callsign over and over but fun none the less. The best explanation I've ever seen is that it's a bit like bird watching.

author: velomane
author_rank: Newbie
timestamp: December 19, 2019, 01:09:08 am
content: The days of ATC on HF are pretty much done, especially when you’re as far south as YYZ. Communication and surveillance technology has undergone big changes over the last decade.To the OP, I have a winradio that I’m willing to part with.

author: edy
author_rank: Super Contributor
timestamp: December 19, 2019, 01:38:39 am
content: The Tecsun PL-310ET will do LW in the 153~513 kHz range. However, I have had absolutely no luck receiving anything in that mode. Nothing but static and I've tuned by 1 kHz steps through that entire range. Maybe my antenna setup is not good enough, and if I build a Loop it will work? Remember the only thing I have is the whip on the radio itself and that ~35 foot tiny single core copper wire I pulled out of a 4-wire telephone cable that I strung outside from my window to the end of the backyard fence and I clip onto the whip.I think I'm going to start working on a coax-based loop like I saw in those videos and a few others I've seen recently (see YouTube videos made by OM0ET). He has done several sizes which should be better for different wavelengths. I though, why not combine them as follows:Then you use a rotary switch to select between the combinations of main loop/small loop so that the proper main loop is hooked up to your tuning capacitor box, and the proper small loop is hooked up to your antenna output to the radio. However, I am worried about the nested loops interfering with each other or inducing each other, as this would reduce the efficiency. Perhaps oriented at 90 degrees from each other? Or 60 degrees if using 3 will reduce the induction? Or moving each pair out of the plane with the next... almost like making an extruded cone.

author: james_s
author_rank: Super Contributor
timestamp: December 19, 2019, 07:07:25 am
content: My portable uses the built in ferrite rod antenna for the low frequency band, it's quite directional. Do you have any airports nearby? Here near Seattle I can usually receive the NDBs at Boeing Field and several up in BC. Once in a while I can pick up 'MNC' from down in Shelton.

author: edy
author_rank: Super Contributor
timestamp: December 19, 2019, 12:39:34 pm
content: This morning (and I've noticed a few others) I find something in the 3885-3915 kHz range that sounds like HAM radio operators. They are talking slowly and describing their signal strength and so on. It is not constant. Apparently this is a place AM enthusiasts with older equipment will convene. Not sure what the rules and regulations are yet, and why they are using AM that anyone can also hear instead of the more sophisticated SSB transmission. I noticed my Tecsun will completely jump over huge swaths of spectrum when it is auto-tuning and not even checking. I will have to manually scan through these areas and listen because I could be missing things! Once I build a mag loop antenna it will be even more tedious as I will need to play with the antenna at each frequency!

author: xrunner
author_rank: Super Contributor
timestamp: December 19, 2019, 01:46:28 pm
content: Quote from: edy on December 19, 2019, 12:39:34 pmWhy? Because it's a hobby and they legally can. Just like the even older CW mode.

author: bd139
author_rank: Super Contributor
timestamp: December 19, 2019, 03:22:16 pm
content: Indeed. The older modes seem quite popular due to the simplicity as well. I ONLY operate CW which is older than AMThe glorious thing about this hobby is the scope and the fact you can escape back to the dark ages if you want to away from computation and complexity.

author: edy
author_rank: Super Contributor
timestamp: December 19, 2019, 08:23:06 pm
content: I noticed something interesting with the Tecsun PL-310ET during the auto-scan ETM function. It normally starts at 2300 and then goes up by 5 kHz (at least on the display) until it gets to 21,950 kHz. However when I've looked at the display I noticed whenever it switches bands it "jumps" over a whole swath of frequencies. I recorded the scan on video and played it back in slow motion and found the following ranges are covered by the ETM auto-scan (the first label, e.g. "120m" is what is shown on the display as the band, and second range e.g. "2300-2550" is the range of frequencies is scans through):120m: 2300-255090m: 3150-345075m: 3850-405060m: 4700-510049m: 7500-630041m: 7080-760031m: 9200-10,00025m: 11,450-12,20022m: 13,500-13,90019m: 15,000-15,90016m: 17,450-17,90015m: 18,850-19,10013m: 21,430-21,950So basically it is skipping the following ranges of frequency when scanning (although I can tune in manually if I choose to):2551 - 31493451 - 38494051 - 46995101 - 56996301 - 70797601 - 919910,001 - 11,44912,201 - 13,49913,901 - 14,99915,901 - 17,44917,901 - 18,84919,101 - 21,429Now I don't know enough about SW bands and frequency ranges agreed upon internationally for certain broadcasts, but that is a lot of spectrum that is being ignored by the ETM function, yet I can manually select those and scan through them. Any idea why this would be implemented this way?I understand the Tecsun displays the "meter" bands strictly in these steps: 13, 15, 16, 19, 22, 25, 31, 41, 49, 60, 75, 90 and 120. However, within each range there is a big variation in wavelength anyways that is scanned. For example, from 2300- 2550 we have 130.3m to 117.5m whereas Tecsun labels it the 120m band. Similarly, for every other band we have a range. Yet the display doesn't say 17 or 18m bands. It will display 16m and then jump to 19m. Here is the display and strict wavelength conversion:22m: 13,500 (22.21m) - 13,900 (21.57m)19m: 15,000 (19.99m) - 15,900 (18.85m)16m: 17,450 (17.18m) - 17,900 (16.75m)So I understand 22m would be appropriate since 21.57-22.21 is centered around 22m. But 19m range has almost 20m, and the 16m range is mostly centered around 17m even!Perhaps there is a convention or some kind of assigned "bands" that relate frequency to meters, and the Tecsun was programmed to those and to skip over sections that are "not allowed" to be used for broadcasts. It seems strange that they would implement it this way and that they wouldn't just calculate the wavelength and be more accurate when tuning... for example, write down 17m (instead of 16m) when I am tuned to 17450 kHz.Here is what I found on "short-wave.info" website, and I quote:Band Frequency Range Notes120 metres 2300-2495 kHz Only used in tropical areas. (Strictly speaking not a short-wave band but a medium wave one!)90 metres 3200-3400 kHz Only used in tropical areas.75 metres 3900-4000 kHz Not used in the Americas. Restricted to 3950-4000 kHz in Europe, Africa and the Middle East.60 metres 4750-4995 kHz Only used in tropical areas.49 metres 5900-6200 kHz41 metres 7200-7450 kHz Restricted to 7300-7450 kHz in the Americas.31 metres 9400-9900 kHz25 metres 11600-12100 kHz22 metres 13570-13870 kHz19 metres 15100-15800 kHz16 metres 17480-17900 kHz Highest frequency band in common daily use.15 metres 18900-19020 kHz Virtually unused!13 metres 21450-21850 kHz11 metres 25670-26100 kHz Little activity other than tests of local digital services.So according to this chart, the Tecsun is basically scanning those ranges (with about 50 kHz additional bracket on either side). I guess there is nothing in between those bands so that is why it skips them.NOTE: It seems like the batteries in this Tecsun never die. I have been using the radio a lot over the past week, with NiMH batteries installed. It is still showing full bars on the battery meter. How long do these things last? I can't believe it!

author: edy
author_rank: Super Contributor
timestamp: December 25, 2019, 02:40:28 am
content: Just an update... It's been a prolific few days since I last posted! I got some help from a few radio/HAM YouTubers and received a few email replies from some folks who built antennas. I will post what I can here and then probably another post to add more photos later. Here is one of the articles in particular that I followed closely to calculate and build a loop antenna for LW range:https://www.randombio.com/loopantenna.htmlI have also attached an EXCEL spreadsheet I put together to help calculate the curves and figure out properties of various size loop antennas. I decided to go for a small antenna at this point due to storage/portability and not to upset the wife too much.The dimensions are as follows... it is 26 cm diameter square, and 22 cm deep, with about 42 turns using 24 AWG stranded wire. This uses up about 43 m of wire, or 143 feet. I built the frame out of spare wood and dowels I had sitting around. I notched the dowels (made grooves) about 0.5cm apart so the windings of wire would sit in the grooves and not slide around as much:Here it is with a few measurements:Next I needed to plug all the numbers in and figure out what kind of tuning range capacitance I will need to get from about 153 to 513 (the LW tuning range of my Tecsun). Here is a graph showing this using the EXCEL spreadsheet I attached:You will notice in the graph that I have a "meas" and "calc" for pF. That's because I had a theoretical inductance based on the equations for a loop antenna from that previous article, and I also measured the inductance using one of those cheap LCR meters I had around. It was actually not too far off, I was surprised:So based on the calculations I needed to be able to vary my capacitance from about 200 pF to about 2500 pF. Not having a convenient source nor the budget to get a proper broadcast gang air dielectric variable capacitor, I decided to use a bunch of trimmers from the local electronics shop and switches to make something that I could tune into that wide range of capacitance. I bought a prototype "Schmart" board and tried to figure out how to use it, as this was MY FIRST TIME prototyping on a PCB!!! (I always cobbled stuff together before on a breadboard).Here's what I was thinking to do:So with both switches OFF (at the far right) and the trimmers all set to their lowest (8, 15, 15, 15), I have about 53 pF. The calculations also showed I have a distributed capacitance in the loop of 15 pF, so now I'm up to about 68 pF. So I figured if I add a 151 pF cap (the beige colored cap seen below) it will set the "floor" base capacitance to 219 pF.Now, when I am playing around with the trimmers I can go up to a maximum of 160 pF on the 3 larger green trimmers, and 40 pF on the smaller white one. So that gives me a range of about 520 pF of variability in the trimmers. So with all trimmers to full, I get up to 686 pF without invoking any of the "switchable" caps. So far so good?Now, I want to go into the next range, I dial all my trimmers back to the lowest values, switch in my 561 pF cap (the single blue one in the middle and you can see one of the switches is lined up with it), and now I am at 780 pF and can trim up to 1247 pF. Unfortunately this means I have a "dead spot" between 686 pF and 780 pF. I would need to add another trimmer in here to bridge the "gap" between my ranges. Either that or make the jump to the next range smaller (instead of 561 pF, I can get 2x221 pF or 442 pF jump). Either way, I would need components I didn't have. I can always modify later. Adding a trimmer (another 40-160 pF) in parallel to the circuit would solve this problem if I need, I would just lower the "base" floor cap down so compensate for the extra 40 pF on the lowest end of the newly added trimmer.In any case, if I turn off the 561 pF switch and invoke the other switch instead (hooked up to 2 parallel 561 pF or 1122 pF... you can see the pair of blue caps next to the other switch) then I can tune my next range from 1341 pF to 1808 pF. Then if I invoke BOTH switches, I'm basically now adding 1683 pF (3x561pF) so 1887 pF and reach a maximum of 2369 pF. So my ranges are as follows:219-686 pF780-1247 pF1341-1808 pF1887-2369 pFDead zones: 686-780, 1247-1341, 1808-1887. I can fix that by adding another trimmer or making my steps smaller and use another switch.So I started working on this and I apologize in advance for the dog-food appearance of the wiring on the back and solder joints. As I get more practice and proper wiring I'm sure I will be able to route the connections better and have a nicer layout and better soldering job. My soldering iron is also one of those pencil-style mini dollar-store pieces of crap and I'm using telephone wire to make the connections.Anyways, as long as it does the business that's good enough for now.You can see above the "base" cap in beige, and then the switchable either single blue cap, or the 2 blue-caps (associated with the switches, respectively at the far right edge of the board). My 3 green large trimmers and smaller white trimmer. The easiest way to compensate for the "dead" zones is to add another green trimmer and then take 40 pF off my beige cap (I can use a 68 pF instead of the 151 pF). If I do that, my low end will be 68 (floor)+15(loop)+8(small trimmer)+4x15(green trimmers)=151 pF. My highest end would be 68(floor)+15(loop)+40(small trimmer)+4x160(green trimmers)+1683(both switches on)=2446 pF. So I would improve my range 151 pF - 2446 pF and eliminate the dead zones!So once again I whipped out my LCR cheap-o eBay meter and tested it on my PCB and lo-and-behold I was able to tune in various ranges, from a low of about 216 pF to a high of about 2342 pF as you can see in the following photos:So I went ahead and tried searching for some signals in the LW tuning range of my Tecsun, which was 153 -513 kHz. Unfortunately all that work for next to nothing!There is not much activity in my area it seems, or at least I can't seem to find it. The loop antenna did help, I was able to find some signals but mostly just beeps and buzzes and strange noises. I found what I thought was MORSE CODE beeping at around 400-405 kHz and I tried to decode it:- - . . / - / - - - / _______Dash Dash Dot Dot (Space) Dash (Space) Dash Dash Dash (Space) ... a very very long Dash ...... repeats!I figured out it was morse code for "ZTO" and probably some kind of radio beacon. I don't know what the long beep at the end is, but probably to indicate end of the message, start again. I did a Google search for ZTO and it turns out it was listed onhttp://dxinfocentre.com/ndb.htmwith the following information:ZTO Frequency: 403 kHzCAN, ON, Toronto - WoodhillPower: 50Coordinates: 43°44'18", -79°42'11"So back on Google maps I went and look what I found!!!!!That must be what I was listening to! I'm only about 20 minutes drive away, about 20 km or so but barely could make it out on my radio (lots of static and was playing with the tuning). So far I'm not too impressed with the LW aspect of the radio. Seems like nothing interesting is coming in and I while I had fun doing it and learning, it was a lot of work building that antenna and tuner just to pick out a radio beacon 20 km away (and I had to turn my antenna to point to it also).Any ideas as to the state of LW signals in Toronto? Is that range fairly dead or am I just not having any luck with reception?

author: Lord of nothing
author_rank: Super Contributor
timestamp: December 25, 2019, 11:03:11 pm
content: HiI still looking for a good SW Radio for me at home.But sadly I could not found any who support:- DRM Radio or even a 10.100khz SSB Output- NFM on CB Channels

author: james_s
author_rank: Super Contributor
timestamp: December 26, 2019, 12:15:33 am
content: Most of what you'll find in that range are NDBshttps://en.wikipedia.org/wiki/Non-directional_beaconCanadian NDBs have a steady tone during the interval and US NDBs have a gap. Most aircraft navigation uses other means these days but a bunch of the beacons are still around.

author: edy
author_rank: Super Contributor
timestamp: December 26, 2019, 09:24:02 pm
content: Quote from: james_s on December 26, 2019, 12:15:33 amI picked up 3 NBD's so far... the furthest is 47 km away. They are ZTO, ZLP and OO. About 50 W transmitting power each as follows (according to the dxinfocentre site):403 kHz, ZTO, CAN, ON, Toronto - Woodhill, Power: 50, 43°44'18", -79°42'11" (21 km away)341 kHz, ZLP, CAN, ON, Toronto - Meadowvale, Power: 40, 43°37'40", -79°43'52" (30 km away)391 kHz, OO, CAN, ON, Toronto - Oshawa, Power: 50, 43°55'15",-78°54'1" (47 km away)They are barely audible but enough to pick up morse code and I can decode it. Lots of static but I get better reception turning antenna (very directional). Should I be getting stronger signals or is my antenna just too piss-poor to do the job?Other than that haven't found anything else interesting yet. Although with the SW mode I've been able to pick up Cuba (11760), Madagascar (11610 Chinese), Romania interfering with Algeria (7375) and I think even Greece (9420).... but I am just using the wire. Next I want to build the MAGLOOP out of coax and see if that improves reception.

author: edy
author_rank: Super Contributor
timestamp: December 27, 2019, 05:03:37 am
content: I just turned on the radio around 11pm Eastern Time and hit the ETM auto-programming button. After scanning the 2300-21950 kHz range it picked up 2 to 3 dozen stations! Basically the airwaves lit up like a Christmas tree!!!However, upon closer inspection I tuned through all the channels and it was actually the same program, in various states of clarity, with many frequencies seeming to be overlapping other stations in the background!Did my Tecsun have a stroke? Or was one of those religious stations (I believe it was WBCQ out of Monticello, Maine) spamming the entire spectrum and on top of almost every other station out there. I could hear nothing else but this ominous symphonic music!Is this something that you've seen before, or was I having a strange glitch on my radio? After I scanned again I still had this happening although it seems to have subsided somewhat after 11pm. Here are all the frequencies on which I was tuning and hear the exact same music and lady talking about religious stuff:31503170320532153330 (on top of the time signal in Canada... could hear it in the background)34103880405048405040508558305850589059105920593560006030609061056125628075059205926593909455116701170013575138201508515220152401526515330154351544517650178002167521875Was this some kind of Shortwave Armageddon?I couldn't hear any other station without this one on top of it. And there were probably a dozen other stations on the air that were faintly heard in the background. If this really happened (and not a glitch in my radio) how did it overlap all these stations by accident? And if it is a glitch in my radio, why this particular channel?

author: bob91343
author_rank: Super Contributor
timestamp: December 28, 2019, 06:17:47 am
content: Intermodulation could cause this. The offending station is very close and very strong and is modulating every signal you receive.That's why some radios include an rf attenuator, to reduce these very strong signals sufficiently to abate the problem.

author: james_s
author_rank: Super Contributor
timestamp: January 03, 2020, 04:48:00 am
content: I pulled out one of my radios several times over the last week or so and I've hardly been able to pick up any NDBs, usually I can hear at least 3 or 4 of them. I think atmospheric conditions are just not favorable right now for that band. Either that or they've decomissioned the beacons.

author: vwestlife
author_rank: Regular Contributor
timestamp: January 03, 2020, 02:03:56 pm
content: Quote from: edy on December 25, 2019, 02:40:28 amLongwave has never been used for broadcasting in North America, unlike Europe, Asia, and Africa. During the Cold War the U.S. government had plans to set up a network of longwave stations to broadcast warnings about incoming nuclear attacks to the public, but only one transmitter got built, and (luckily!) all it ever did was transmit time announcements:https://en.wikipedia.org/wiki/WGU-20But in the Very Low Frequency (VLF) range, you can pick up the signals from military transmitters communicating with submarines, using only a long piece of wire connected to your sound card's microphone input!

author: edy
author_rank: Super Contributor
timestamp: January 07, 2020, 04:18:14 am
content: That video was very interesting. I need to start downloading some of that software and get myself a SDR dongle. Meanwhile, I've been continuing to refine my antenna. I managed to add another trim pot so now I've got overlap between my capacitance "tuning" range and my steps (that I toggle using switches). Before my trimmers only gave me about 40-400 uF range, but I would be able to switch in groups of capacitors that jumped me 500, 1000, 1500 uF. As you can see, I would have a few "dead" spots because I couldn't fully tune up to the next range. I added another trimmer and now it is broader (50-600 uF range) than the steps, so I can actually overlap some regions with different settings (e.g. trimmers tuned all the way up, with no step, or trimmers tuned all the way down, with first step switched on will cover the same range which overlaps by about 50 uF).The other thing I did was added some wire "taps" to my loop at different numbers of turns. For example, at 1, 2, 3, 4, 6, 10 and 20 turns (and my full loop is 42 turns). Because of this, I have different inductances in my loop depending on which wire I hook into my capacitor-tuner. I made the calculations and printed up a table so I am now covering a large range of frequencies that should be able to resonate in my antenna depending on the "tap" I use, and the range of capacitance I tune in with my trimmer-cap/switch board. I've tried it and I feel that I do get some improvement with certain stations, but then I try my clip-on simple wire (strung across to the end of the backyard through my window) and get decent reception from that too without any fidgeting of capacitors and swapping of tap wires.However I know the antenna is doing something because I can hear the difference when I turn my trimmers or when I rotate as it is directional.The other thing I noticed that I may have mentioned previously is that the ETM function (Easy Tuning Mode) on the Tecsun is not picking up every station. It misses quite a few even moderately stations, definitely skips weak ones. I have built up a list and also slowly manually scanned through the frequency range and find other stations that I now dial into and find weak but obvious signals for, which ETM completely misses. For example, even 5000, 10000 and 15000 are clock signals which I pick up. Sometimes I'll find some HAM AM transmissions on 3885, and there are various other spots I've noticed signals that are weak but discernable. So while ETM is great at the beginning, once I am familiar with a few stations I should be able to dial them in and find them. There are also station lists that I am downloading from a DXing digest/forum that I've signed up for, so I am getting reports daily from others.Now I had the idea when the weather improves to fly up an antenna on a kite... I can just let out 100 foot easily and as long as the weight is not too great and the wind is good, it should hopefully pull up my wire along with the kite string and give me a big antenna. Has anyone tried flying up a wire antenna on a kite? Is there any advantage or more trouble than it helps?

author: Bud
author_rank: Super Contributor
timestamp: January 07, 2020, 06:55:06 am
content: Quote from: edy on January 07, 2020, 04:18:14 amMarconi did, 120 years agoGuess it gave him some advantage.

author: bsfeechannel
author_rank: Super Contributor
timestamp: January 07, 2020, 07:35:53 am
content: Quote from: vwestlife on January 03, 2020, 02:03:56 pmAmazing. The Tubular Bells VLF interference is quite a revelation to me. It reminded me of this sceneVery interesting channel by the way.

author: edy
author_rank: Super Contributor
timestamp: January 24, 2020, 05:18:11 pm
content: I finally got around to making a video of my Tecsun this morning and I think I picked up India on 11560 kHz! Is it really coming from that far away (I'm in Toronto), or am I being duped by a closer station or a repeater of some kind? Hopefully I'll have time to make a video of my loop antenna build in the upcoming weeks. I'm itching to work on more antennas but just didn't have any time.

author: fourfathom
author_rank: Super Contributor
timestamp: January 24, 2020, 07:10:55 pm
content: Quote from: edy on January 24, 2020, 05:18:11 pmThere's no reason to think that you weren't directly receiving the India station. When the conditions are right ham operators can talk to the other side of the planet (and sometimes further, via the long path), and they can do it with 100 Watts (or even 10 Watts), and using receivers that aren't any more sensitive than the Tecsun.I'm glad you're hanging in there!

author: Lord of nothing
author_rank: Super Contributor
timestamp: January 25, 2020, 03:13:52 pm
content: The Indian have a good Digital Radio. Hopefully when I can mount the Antenna Outside I get the with more power. Sadly the fad out often.You can try out Radio Romania to.

author: edy
author_rank: Super Contributor
timestamp: January 26, 2020, 12:19:06 am
content: Quote from: CJay on January 25, 2020, 02:53:37 pmIt was fairly choppy as you can hear in the video, and since then I haven't been able to receive that signal. I guess I need to wait until the proper time of day and conditions. I will try to listen longer to some stations to see if I can make out any repeater ID specs. I did use a site calledwww.short-wave.infoto ID the station. I need to work on a better antenna.Quote from: fourfathom on January 24, 2020, 07:10:55 pmThe conditions must have been just right because I didn't receive anything on that frequency before (at least using the auto-tune search function) and haven't since. I also don't typically listen at that time of day... so I may try tuning in again during the mornings and seeing if I get it again. The auto-tune does miss a lot of stations so I find myself also finding stuff using DXing logs (I am subscribed to one for my local area) and just sometimes manually scanning each frequency. I've picked up radio Romania and also Greece... but Europe is a lot closer than India! Once I picked up Chinese but it happened to be a repeat out of Cuba! That's why I was skeptical.Using manual tuning I stumbled upon fairly regular HAM shortwave AM activity which I can make out on 3885 kHz (and around there). The auto-tune search completely missed it. I haven't been able to figure out where they are though. They are audible and it is not using any SSB. Part of my limitation is I have a non-SSB capable radio, and I believe there is a lot of activity using weaker signals on SSB. I definitely need to work on my antenna options![ADDED:]I've included a couple of PDF's provided by my local group which gives listening guides by country and English broadcasts.

author: bob91343
author_rank: Super Contributor
timestamp: January 26, 2020, 04:43:40 am
content: You have found the AM nets on 75 meters. Here in Southern California there are AM nets on Monday and Wednesday around 8PM Pacific time on 3870 kHz. There are some on 40 meters also but I haven't listened; I think above 7200 kHz.Check out the SDR on the web; try first KFS. They offer great radios you can tune from your keyboard and listen to many modes. You select the frequency. I think KFS is near San Francisco bay. There is one in Arizona, and a few others. You only need a computer, not a radio or antenna. The display is selectable also.http://69.27.184.62:8901/http://websdr1.utahsdr.org:8901/http://www.i1wqrlinkradio.com/antype/ch121/chiave77.htm

author: vk6zgo
author_rank: Super Contributor
timestamp: January 26, 2020, 04:48:57 am
content: Quote from: edy on January 26, 2020, 12:19:06 amFor your information:-The slang term for Amateur Radio Operator is written either with a leading upper case letter ("Ham"), or in all lower case, ("ham").It isnotan acronym, so is not writen as "HAM".

author: edy
author_rank: Super Contributor
timestamp: January 31, 2020, 05:49:22 pm
content: I was on late last night ~2 am and found some strange signal of what sounded like a lady speaking numbers in Spanish on 9330 kHz followed by fax/modem noise!!!!! First time I've ever encountered this! I started looking it up on the web searching for "spanish lady numbers" and WOW! This is basically what I was hearing on my radio:Now, I have no idea how to decode the fax/modem noise. Is it possible to record it on an iPhone and run it through some software? Should I try recording straight to the computer? I doubt that the signal is regular or on the same frequency so chances I will encounter this again are probably slim and definitely will not have the right recording setup available when it happens. Anyways, thought I'd share as it was very strange! Anyone know how to decode this and why the lady says numbers followed by the "noise" (which I assume is some data signal although no idea how it is encoded).... and then repeats this over and over.

author: Lord of nothing
author_rank: Super Contributor
timestamp: January 31, 2020, 07:20:33 pm
content: Well you dont want to decode that much since its some Station for Spying and so on.

author: vwestlife
author_rank: Regular Contributor
timestamp: January 31, 2020, 07:54:52 pm
content: Quote from: edy on January 31, 2020, 05:49:22 pmWhatever you could decode would be meaningless anyway, because the data is encrypted.

author: edy
author_rank: Super Contributor
timestamp: January 31, 2020, 07:58:40 pm
content: OK I think I figured out it is HM01 and this page lists the schedule which would make sense:http://priyom.org/number-stations/digital/hm01/scheduleKind of odd to hear that with today's level of technology this is what spies use? I can't believe it. Must be something else surely!Wait... I found this article describing number stations. Fascinating!!!!http://priyom.org/number-stations

author: xrunner
author_rank: Super Contributor
timestamp: January 31, 2020, 08:37:41 pm
content: uno dos cinco ocho ochoseis siete uno dos tres...Been going on for decades on the shortwave bands.