SDR? Bear with me I'm a radio noob!!! - Page 1
Forum section: electronics / rf-microwave

author: biotron345
author_rank: Contributor
timestamp: November 15, 2016, 09:22:03 pm
content: Greetings!Always liked the idea of ham radio and recently met a enthusiast who told me about the SDR dongle things on eBay for around £10-£15. He reckons they're great. What's your opinions? Is there one particular model I should avoid? I'd like to listen to ham stuff and anything else interesting. Advice greatly appreciated!!!

author: voltz
author_rank: Frequent Contributor
timestamp: November 15, 2016, 09:59:51 pm
content: If you just want to listen about, try one of the Web SDR links on the net for free. Like this one:http://hackgreensdr.org:8901The cheap SDR dongles (on Ebay) are a great start but there are limits with them. The cheap RTL DVB dongles you see usually start at around 25Mhz and go up from there. So not much use at the lower HF bands. Some can be converted though.Other more expensive dongles do cover the lower bands.The main problem with SDR dongles seems to be the lack of signal dynamic range. So large signals can swamp, or pull down, the whole band you're listening to. The 40m band at 7.200 Mhz is a real problem because of the massive AM broadcasts there. These generally kill reception with a cheap SDR RTL dongle.Better more expensive dongles have band filtering, higher resolution ADCs (12 bit instead of 8 bit) and other goodies. So as usual, you get what you pay for.

author: w2aew
author_rank: Super Contributor
timestamp: November 16, 2016, 01:16:08 am
content: Another good site ishttp://www.globaltuners.com/Lots of online rigs to pick from, all over the world. Nice way to listen when you don't have your own equipment, or can't put up a decent antenna, etc.

author: biotron345
author_rank: Contributor
timestamp: November 16, 2016, 08:27:40 am
content: Thanks guys! I never heard of these. Something to play with whilst I look into SDR

author: TheBay
author_rank: Unknown
timestamp: November 16, 2016, 02:28:28 pm
content: If you do get bitten by the SDR bug I highly recommend the SDRPlay RSP1, for the money it can't be beaten and will do HF and Below which the cheap sticks can't do properly/natively.

author: Towger
author_rank: Super Contributor
timestamp: November 16, 2016, 02:57:47 pm
content: One the same topic, is the Funcube Pro a good dongle to get?I already have an eBay special and an ageing Sony ICF-SW55 and Yaesu FR101, which have not seen much used in recent years.

author: TheBay
author_rank: Unknown
timestamp: November 16, 2016, 07:04:56 pm
content: Quote from: Towger on November 16, 2016, 02:57:47 pmDepends what you want to use it for, the SDR Play has more bandwidth.

author: Towger
author_rank: Super Contributor
timestamp: November 16, 2016, 08:44:49 pm
content: Mainly SW listening, but I suspect I may suffer from a high level of interface where I now live. I have a tramline at the end of the back garden fed with 750VDC overhead lines. Maybe I should put up a long wire and digout my old radios first.

author: rwgast_lowlevellogicdesin
author_rank: Frequent Contributor
timestamp: November 17, 2016, 07:12:46 am
content: Im an SDR fanatic, im currently working on a down conversion design for microwaves, an 800-2700mhz sdr using an analog devices chip, and ive started building LNA to sell on tindie until my other design are done. I was really in to robotics and then I got an RTL dongle and got bit, inspired me to get my licence.The RTL cant do SWL out of the box but it can do all kinds of fun stuff! I am mostly in to satcom and reverse engineering devices. For HF I use a Ham-it-Up but honestly the mixer on it sucks and I bought it more for the noise source it has on board. Usually I use an 8 dollar shortwave radio with a BNC jack hacked in to it so I can connect a real antenna. I would suggest this route to you...Buy RTL dongle, a10 dollar e-bay RTL-R820T2 based dongle(AVOID Rt820T LIKE THE PLAGUE), dont waste your money on an upgraded one from NooElec or the like its not worth the cash.If you like it and want SW then buySV1AFN H Mode UpConverteror get aSpyVerterwhich is also an H-Mode design. If you need to get down to VLF SV1AFN sells another UpConverter which uses the ADE-1 mixer like the Ham It Up, the difference is his is wired different to get reception at 1hz and up, its also a much better filter design.If you want to go further your next best bets go in this order AirSpy ~$200, AirSpy Mini ~$100, Funcube+ ~200. I own the AirSpy Mini and my only regret is as a developer I didnt get the bigger model, the only difference is some bells and whistles for developers and 4mhz more instantaneous bandwidth. The SDRPlay cant touch an airspys dynamic range, linearity or noise floor, and most importantly software support sucks out side it main SDRuno program. The main argument is the SDRPlay has HF, but if you have an H-Mode mixer with an AirSpy model or FunCube you will have a much better receiver.Then the only other SDR systems I would spend money on is the LimeSDR or USRP, $400 and $700 respectively. There is also the HackRF its Rx is about as good as an RTL but it has 20mhz bandwidth at 1mhz-6ghz(1mhz isnt advertised but the developer confirms it on his site) and it can also transmit at very low power between 1Mhz-6Ghz. Its ~300 i think and I think its acually the best choice if you are just trying to hack gadgets. or you NEED tx and know enough to amplify its output and overcome its Rx limitations.

author: tronde
author_rank: Frequent Contributor
timestamp: November 17, 2016, 05:44:43 pm
content: Quote from: rwgast_lowlevellogicdesin on November 17, 2016, 07:12:46 amCan you clarify?Do yo mean that RTL2832U+R820T2is OK and RTL2832U+R820Tis bad?If so, what is the difference?

author: Towger
author_rank: Super Contributor
timestamp: November 17, 2016, 05:50:20 pm
content: The T2 is the second version. Can't remember the exact difference off the top of my head, but think it is more sensitive.

author: rwgast_lowlevellogicdesin
author_rank: Frequent Contributor
timestamp: November 17, 2016, 05:56:18 pm
content: T2 is more sensitive, it doesn't lock up in the l band, and it has way less noise/harmonics/spurs the original dongles are junk now and still being sold for 20+.The upgraded dongles from noodles and rtl-sdr blog are a decent upgrade but now with the airsoft mini at 90 bucks there a waste of money. Although there is a new RTL upgraded dongle called thumbnet which appears to be worth paying 30 bucks instead of 10 for. The thing is you may not get a lot of use out of sdr, if that's the case the low noise floor of the thumbnet is kind of a waste for a marginaly better RTL dongle that collects dust.

author: Bicurico
author_rank: Super Contributor
timestamp: November 17, 2016, 10:04:49 pm
content: I own several scanners, among them:Uniden Bearcat UBC9000XLTUniden Bearcat BCT15XIcom IC-R3...Also, I have an amateur radio license, but only purchased two ridiculous cheap radios (which I use for example to produce faults in DVB-T transponders when doing test reports on TV field meter):Baofeng UV-3RBaofeng UV-5RSo, while I am not the traditional amateur radio addict with an expensive Yaesu/Icom/you name it transciever sitting in my shack, I do have some equipment... (apart from all my satellite gear, which is my real hobby).I can confirm that the 10 Euro/Pound/Dollar SDR dongles are ***GREAT***! For so little money you do get a full band receiver with real time spectrum analyser. You can demodulate analogue and digital signals. Come on, a traditional radio capable of all this would cost several thousands! Sure, for 10 bucks you cannot expect great sensibility and all the wistles, but the main thing is: it does work!And you will NEVER regret that purchase, even if you later on buy something more expensive.Not sure about it? Heck go ahead and buy one at eBay for a tenner. What's the worst possible loss?Now the real problems are:If you want to receive frequencies under 20MHz, you need a low band converter. These are available at little money - no sweat. But what people often fail to realize is the size of the required antenna!!! We are talking about antennas which consist of a wire which is tens of meters long! I don't have any space to mount them, so I am stuck at the higher frequencies.And even for those freqeuncies from 20MHz up to 2500MHz you need SEVERAL antennas! Some are big, most need to be mounted on the roof, the cables may not be too long and these antennas cost much more than the SDR USB receiver!In fact, if you just hook up the silly antenna included with the SDR USB dongle (which is actually a regular USB DVB-T or DVB-T/T2 receiver), then the reception results will be really disappointing!So, for a propper reception and acceptable results, you need to consider the required frequency range and puchase a suitable antenna (or build your own).Here is the next problem: what can you actually receive?In Europe:- Air traffic: which is nice, including the 1080MHz ADS-B Aircraft signals- Taxi services- Analogue amateur bands- Analogue PMR bands- Eventually some naval communications if you happen to be close to the seaI guess that is mostly it!Face it: regular amateur radio is dead (it is not, but for the more common radio amateurs it kind of is), nothing interesting is happening on the ether and in Europe, all public services (police, firefighters, ambulances, etc.) switched to the digital TETRA system, which is similar to GSM and of course encrypted. This is less depressing in the USA, where analogue communications are still very popular.Hence why I think it is the best option to actually get such a USB dongle for almost no money and take a peek into the radio communications, to evaluate if any further investment makes sense (it probably doesn't).Cheers,Vitor

author: Seekonk
author_rank: Super Contributor
timestamp: November 17, 2016, 10:47:20 pm
content: I wouldn't mind getting one just for the TV recording. They all say RTL2832U+R820T2, whether that are $9 or $29. Anything special about the more expensive one? Are the TV and FM ones capable of the other frequencies or are they peaked for those bands?

author: Bicurico
author_rank: Super Contributor
timestamp: November 17, 2016, 11:00:19 pm
content: These dongle use mainly two IC's: the RTL2832U (which is mandatory) and different tuners:Elonics E4000: 52 - 2200 MHz with a gap from 1100 MHz to 1250 MHz (varies)Rafael Micro R820T: 24 - 1766 MHzRafael Micro R828D: 24 - 1766 MHzFitipower FC0013: 22 - 1100 MHz (FC0013B/C, FC0013G has a separate L-band input, which is unconnected on most sticks)Fitipower FC0012: 22 - 948.6 MHzFCI FC2580: 146 - 308 MHz and 438 - 924 MHz (gap in between)(Source:http://sdr.osmocom.org/trac/wiki/rtl-sdr)Depending on the application, you may prefer a USB dongle with one or the other tuner (I have several, with different tuners).Apparently, the R820T is famous for frequent lockups.Regards,Vitor

author: rwgast_lowlevellogicdesin
author_rank: Frequent Contributor
timestamp: November 17, 2016, 11:51:00 pm
content: And in the r820T section above isR820T - original dongleR820T2 - new tuner revision works much betterAll dongles that are listed as r80t2 weather they are 10 or 30 are the same, unless they are branded by RTL-SDR, NooElec, ThumbNet, these dongles are basically a 10 dollar dongle with a better crystal and nice case. The ThumbNet has some more going for it than a crystal though. If you dont know the difference between a TCXO and a Crystal, you will be fine with a blue $10 dollar dongle like I linked to. The unbranded $30 dollar ones in blue/black plastic cases are 100% the same item as the $10 model. I suggest the cheap ones until you get conformable building/buying antennas and know why and what parts of your SDR need to be upgraded. By that time you will realize spending 20 bucks for a case is dumb when 100 wil get you a 12bit adc with 6mhz bandwidth and crazy good decimation!The 10 dollar ones are great! I still use four, I just JB welded heay sinks on the chips, used a TI 3.3v/1.8v dual low noise linear regulator, some usb chokes and an aluminum case, and if need be a low pass filtered TCXO. This gets you better than thumbNet for cheap. When you have a specific use case for a dongle an LNA along with lots of BP filtering will get the job done on an RTL. For new experiments weak signal hunts, and things like that I use the Airspy.As a side node my 10 dollar non modded dongle gets better recption on the same antenna as a Baofeng.

author: metrologist
author_rank: Super Contributor
timestamp: November 18, 2016, 12:07:25 am
content: Interesting results between the R820T and T2

author: rwgast_lowlevellogicdesin
author_rank: Frequent Contributor
timestamp: November 18, 2016, 12:29:16 am
content: And here is a comparison of the 10 blue dongle, a 3o dollar RTL-SDR Blog dongle, and a $30 dollar Thumbnet. As you can see the noise figure between them isnt worth 20 bucks for you first purchase..and here is a good article which compares the AirSpy, HackRF, SDRPlay, the AirSpy mini is the exact same as the AirSpy r2 reception wise, only some features a developer would want are limited in the mini. The AirSpys also use the r820T2 as a front end tuner, other than that they have nothing in common with an RTL-SDR dongle, or any of its modded versions, the CPU and Analog to Digital are totally different along with the way the r820T2 is setup. So if you want to spend money the mini is your best bet!http://www.rtl-sdr.com/review-airspy-vs-sdrplay-rsp-vs-hackrf/

author: raspberrypi
author_rank: Frequent Contributor
timestamp: November 22, 2016, 12:28:44 am
content: Dongles are cool, but there is not much to listen to on VHF and above, They do a poor job below 50 mhz. I bought an SDRPlay for 120 bucks from hamuniverse.com and it goes all the way down to DC (almost). Worth hours of listening and messing about making hf, uhf, and vhf antennas. If you want to hear below 30 MHz you NEED a 9:1 balum and a long wire. I now have a closet full of antennas and yard full of long wire antennas. My first was the sdr with the rafael chip for 20 using sdr#, really just gives you a tease as you get frustrated with lower signals. Cool for 20 bucks but I should have just bought the sdrPlay. Also rated best receiver under 300 bucks USD.

author: rwgast_lowlevellogicdesin
author_rank: Frequent Contributor
timestamp: December 03, 2016, 07:15:57 pm
content: Sorry to bump this but.... Nothing to listen to at VHF and above!!! Almost all of is just SW broadcast or amateur gab. HF is one place to be if you wanna gab about nothing important with strangers, and obviously the only way to DX radio to radio across continents. In my town you will hear more ham gab on 2m/70cm with a rubber duck than you'll get on HF with a long wire under 100ft.Tune up above the hairband , get some Yagi's and a sat dish, you will hear more and DX farther than HF. Hell there's even ham tv. Saying there's nothing at vhf+ to listen to is preference!

author: ebclr
author_rank: Super Contributor
timestamp: December 04, 2016, 01:59:34 am
content: I would love to buy this one when they are availablehttps://www.crowdsupply.com/lime-micro/limesdr

author: Bicurico
author_rank: Super Contributor
timestamp: December 04, 2016, 05:16:09 am
content: Perhaps, in the meantime, you want to look at Dektec products.www.dektec.comhttp://www.dektec.com/products/PCIe/DTA-2115B/Regards,Vitor

author: Lord of nothing
author_rank: Super Contributor
timestamp: December 12, 2016, 11:36:08 pm
content: QuoteThat is wrong.I have 20 of the Dongle at Home I would use it for ADSB.The dont go up to 1Ghz!!!!

author: raspberrypi
author_rank: Frequent Contributor
timestamp: December 13, 2016, 01:30:22 am
content: I recommend the SDRPlay. Its 120USD but come with awesome software called SDR uno that looks Like a real ham radio. The SDRPlay is the best receiver for 100-300$ price range. The dongles are cool for converting the VHF UHF signal, like tracking air planes, but below 50MHzthey suck if not work at all.Things you NEED to listen to HAMs with an SDR are:- longwire antenna- balun (I got one off ebay for 10 bucks 9:1 or 11:1) to convert 450~to 50for the SDR, It will only pick up >50MHz without this-A real grounding rod-If you have a really good antenna you may need an AM trap if you are close to an AM Broad cast station. These cost 30-70$ USD and keep the AM from swamping out all the faint signals the SDRPlay is really sensitive so there is no easy way around this.

author: Towger
author_rank: Super Contributor
timestamp: December 13, 2016, 08:30:23 am
content: I got the new SDRplay RSP2 last week. I have not had a chance to test it properly yet. Ill give it to the kids to give to me for Christmas, along with an end fed antenna, coax etc...Just using a couple of meters of cat5 at work in the office the difference between the RSP2 and an ebay dongle is between light and day. It has far better filtering of all the local hash from computers and florescent tubes. This was using a generic USB cable, but I still might buy one with built in ferrite filters.The SDRUno software is nice. Just plug and play, no messing with drivers. I have seen reports it is too complicated, certainly if you have no previous experience with proper rigs it might be. But it only took a minute or two to work out how to turn on, tune in a broadcast FM station, select Wide FM modulation, play around with the RF gain, change the sample rate etc.

author: Lord of nothing
author_rank: Super Contributor
timestamp: December 13, 2016, 06:29:36 pm
content: Quote130.44GBP -> ~157€So where I could get it for 120USD (113€) ?

author: Towger
author_rank: Super Contributor
timestamp: December 13, 2016, 07:30:29 pm
content: Several RSP1s have appeared on eBay in the last couple of weeks, now that version 2 is out.

author: Lord of nothing
author_rank: Super Contributor
timestamp: December 13, 2016, 07:44:42 pm
content: EUR 150,46 + EUR 6,57 Shipping

author: Towger
author_rank: Super Contributor
timestamp: December 13, 2016, 08:43:03 pm
content: When I was young an Icom icr9000 was only a dream. Even today about 30 years later they can fetch $1000 on eBay.They run hot, suffer from bad capacitors, screen burn and general old age related problems. They are probably more sensitive and have better filtering, but apart from that a decent SRD at a fraction of the price has much more capabilities.In saying all that I still want one... Have to get the SWMBO used to the SDR first. ..