hybridfree/eevblog-posts huggingface dataset:
433MHz  transmitter in USA to meet FCC - Page 1
Forum section: electronics / rf-microwave

author: JoeyG
author_rank: Regular Contributor
timestamp: May 10, 2021, 12:10:34 am
content: I'm hoping some can confirm my calculations and method.It seems the FCC acceptable standard for 433MHz is FCC 15.231 at 433MHz this equates to 10,000uV/m at 3 metressee herehttps://www.edn.com/using-433-mhz-for-wireless-connectivity-in-the-internet-of-things/10,000 uV/m ~ 60dBuV/mNow to covert to a power in dbm I used this calculatorhttps://www.compeng.com.au/radiated-power-calculator/60dbuV/m ~ -35dBmAm I missing something?Thanks in advance Joe

author: ahbushnell
author_rank: Frequent Contributor
timestamp: May 10, 2021, 12:27:28 am
content: Quote from: JoeyG on May 10, 2021, 12:10:34 amdBm is power 10*log(power/mW)uV/m is electric field. two different animals.

author: JoeyG
author_rank: Regular Contributor
timestamp: May 10, 2021, 12:33:50 am
content: I seem to be close according tohttps://www.yorkemc.com/wp-content/uploads/How_to_-_EIRP.pdfHow would you convert 10,000uV/m at 3 metres to dBm ?P = VI or IIR or VV/R and if the impedance is known eg 377ohm then a voltage developed across an impedance and a power can be calculated.

author: radiolistener
author_rank: Super Contributor
timestamp: May 10, 2021, 10:59:28 am
content: Quote from: JoeyG on May 10, 2021, 12:33:50 amThere is no simple conversion between field strength and power. It depends on antenna properties such as directivity, efficiency wavelength and distance.For isotropic radiator antenna power is distributed over the area of the sphere. But real antenna has directivity, so it will have some gain in the main lobe.For near field region of antenna it become even more complicated, because there is also reactive field of antenna.Here is Field Strength and Power Estimator app from Rohde & Schwarz:https://www.rohde-schwarz.com/us/applications/field-strength-and-power-estimator-application-note_56280-15837.htmlit also include app note with formulas used for such estimation:https://scdn.rohde-schwarz.com/ur/pws/dl_downloads/dl_application/application_notes/1ma85/1MA85_7e_Estimator.pdf
WSPR used to serach for MH370 - Page 1
Forum section: electronics / rf-microwave

author: NiHaoMike
author_rank: Super Contributor
timestamp: April 24, 2021, 04:57:07 pm
content: https://hackaday.com/2021/04/24/wspr-may-hold-the-key-to-mh370-final-position/Could this be the biggest radar system unintentionally built by amateurs?

author: fourfathom
author_rank: Super Contributor
timestamp: April 24, 2021, 05:44:06 pm
content: WSPR is a very interesting mode. I was at a friend's house and we were looking at VHF WSPR being bounced off jet vapor trails. We could see the FM caused by the exhaust vortices, so it's pretty sensitive. The premise of that hackaday article seems quite optimistic, but I suppose it could be barely possible.

author: vk3yedotcom
author_rank: Frequent Contributor
timestamp: May 09, 2021, 12:33:56 pm
content: Another view is presented in this video from VK7HH:
magnetic fields and medical (magsafe) - Page 1
Forum section: electronics / rf-microwave

author: coppercone2
author_rank: Super Contributor
timestamp: June 03, 2021, 10:28:05 pm
content: https://apple.slashdot.org/story/21/06/03/1957244/new-study-backs-up-finding-that-magsafe-can-interfere-with-medical-devicesNot really a AC field but something to keep in mind for older hams
SVA1000X Spectrum & Vector Network Analyzer by Siglent - Page 1
Forum section: electronics / rf-microwave

author: ahbushnell
author_rank: Frequent Contributor
timestamp: May 05, 2021, 02:34:25 pm
content: Hi,Does anyone have experience with the SVA1000X Spectrum & Vector Network Analyzer by Siglent. I'm thinking of buying this.ThanksAndy

author: Bicurico
author_rank: Super Contributor
timestamp: May 05, 2021, 05:19:14 pm
content: Take a look at the Test Equipment forum here. There is a whole thread just dedicated to this device - enjoy the threads regarding the SSA models, too.

author: ahbushnell
author_rank: Frequent Contributor
timestamp: May 05, 2021, 05:26:48 pm
content: Quote from: Bicurico on May 05, 2021, 05:19:14 pmDo you mean on this forum? I don't see a test equipment area.

author: Electro Fan
author_rank: Super Contributor
timestamp: May 06, 2021, 01:27:09 am
content: Quote from: ahbushnell on May 05, 2021, 05:26:48 pmwww.eevblog.com/forum/testgear/

author: tautech
author_rank: Super Contributor
timestamp: May 07, 2021, 09:24:41 am
content: Quote from: ahbushnell on May 05, 2021, 02:34:25 pmMy demo SVA1032X is one of my fav instruments.The first model in this series was SVA1015X and all later models use slightly different HW for better TG and VNA performance. Study of the datasheet reveals these differences.Ask me most anything about them.The SVA1000X thread:https://www.eevblog.com/forum/testgear/siglent-sva1015x-1-5ghz-spectrum-vector-network-analyzer-(coming)/
YAESU FT-817ND WITH STRANGE PROBLEM (MENU IS CRAZY)  - Page 1
Forum section: electronics / rf-microwave

author: bachtoon
author_rank: Newbie
timestamp: May 05, 2021, 07:40:42 am
content: Hi all.Sorry for my English.I have a mission for you, should you accept it?I have an 817ND with a unique problem in the world :-(after a few years in its box, i turned on the device and the menu and the values ​​change on their own ...At each restart, -the contract is at full or very low with a value of 255 !, the beeps are very loud, the frequency has changed to 1.8mhz, mic gain at 0, rf gain mode activated,the led screen light off (COLO writed in menu choice !).Has it gone completely crazy? But once fixed it works fine. When I turn it off, then turn it on, again change everything ...I have done multiple reset and hard reset, always the same problem.Is it possible to put the original program back into the device chip?Have you seen and repaired this kind of problem please? Could you help me ? Thank you so much.Best regards from Belgium.

author: A.Z.
author_rank: Super Contributor
timestamp: May 05, 2021, 07:59:01 am
content: Quote from: bachtoon on May 05, 2021, 07:40:42 amShooting in the dark, but... I suspect the internal battery may be totally off-duty and isn't charging, in such a case the settings will reset to hw defaults upon each power up, if that's the case, then replacing the battery with a new one (and fully charging it) should probably solve the issue; for further infos, see the rig manualhereand in particular, the infos about storing the rig for more than 10 days; also notice that if the rig was stored with batteries installed, the batteries may have leaked and damaged the circuitry

author: DC1MC
author_rank: Super Contributor
timestamp: May 05, 2021, 08:24:58 am
content: Quote from: A.Z. on May 05, 2021, 07:59:01 amThe battery leaking part is valid but for FT-817ND the settings are stored in an EEPROM, there is no internal battery.Cheers,DC1MC

author: bachtoon
author_rank: Newbie
timestamp: May 05, 2021, 03:20:24 pm
content: I just ordered an 818nd .. I am selling the 817nd...
WTB: Yaesu FT-690rii display  - Page 1
Forum section: electronics / rf-microwave

author: christopher iles
author_rank: Regular Contributor
timestamp: May 04, 2021, 04:26:17 am
content: Hello,My display has cracked and I can't source a new one.I'm hoping that someone reading this may have a spare display (same as the ft-790) or maybe a non-working donor radio.Any help greatly appreciated, thankyou.73,Chris. G0VOE, Somerset.
Low freq EMF op amp input stage - inverting vs non-inverting? - Page 1
Forum section: electronics / rf-microwave

author: cape zoloh
author_rank: Contributor
timestamp: May 01, 2021, 03:22:48 am
content: I'm building a EMF preamp circuit which uses an op amp on the input. In fact, it uses two in series, so the phase is corrected.There is 100k on the input and 10M in the feedback loop. As I'm concerned with noise, I would like to use a non-inverting stage on the input, to get rid of the extra current noise added by lowering the values of these resistors. Would this be a bad idea?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: May 01, 2021, 08:01:58 am
content: 100k doesn't sound very RF... what frequency and application?Tim

author: cape zoloh
author_rank: Contributor
timestamp: May 01, 2021, 12:57:49 pm
content: Sorry, I meant to say EMF! Very low such frequencies as well.

author: TimFox
author_rank: Super Contributor
timestamp: May 01, 2021, 02:39:36 pm
content: Adding a resistor in series with the signal, as in the inverting op-amp feedback circuit, will always degrade the SNR. This is why the non-inverting circuit is preferred for low-noise applications, since the resistors in the feedback network can be much lower than what is typically required for the inverting case. Your example has a very large resistor (100k) in series with the signal. For the non-inverting option, you could use 10k feedback and 100 ohms to ground, with far lower effective series resistance and the same gain.For high-frequency circuits, sometimes a capacitive divider can be used for the non-inverting circuit's feedback, where the capacitors do not have thermal noise. For specialized applications, the feedback can be through a transformer network. (DC stability with an op amp requires an additional DC feedback path.)
Need help identifying coupler - MC7205-15 - Page 1
Forum section: electronics / rf-microwave

author: EE-digger
author_rank: Frequent Contributor
timestamp: April 26, 2021, 10:11:24 pm
content: I have a new, three port coupler which I believe is a directional coupler, that I bought and used 5 or 6 years ago for a project. I'd like to put it to use again and would rather not have to characterize it.Not one to live or die by Google search results but I was surprised when a search turned up nothing, zilch.Part Number: MC7205-15Other text: 080616003I seem to recall that it was from a small Texas company ... maybe.If you can ID or have a datasheet for this part, it would be a big help

author: EE-digger
author_rank: Frequent Contributor
timestamp: April 29, 2021, 03:18:39 am
content: It turned out to be a Fairview Microwave part whose PN no longer exists in the wild (of the web).It's a 1 to 1000 MHz SMA directional coupler.Thanks to a helpful Fairview Microwave sales guy for the info and he also dug up a data sheet.
AOR Filter trace - Page 1
Forum section: electronics / rf-microwave

author: veedub565
author_rank: Frequent Contributor
timestamp: May 24, 2021, 07:33:42 am
content: I bought an AOR ABF-128 Airband filter, tested it on the network analyser, and thought people might like to see (attached)marker 1 = peak (2dB of insertion loss)markers 2&3 are (roughly) the 3dB points
Phase Noise - A Basic Tutorial - Page 1
Forum section: electronics / rf-microwave

author: ElizatronicWarfare
author_rank: Contributor
timestamp: April 14, 2021, 11:22:07 am
content: Hey y'all, this is a phase noise tutorial I wrote last year as training material for the phase noise measurement system I use at work. Hopefully this helps illustrate the broad strokes of a concept that is often seen as "black magic". Note that this tutorial doesn't go into the nitty-gritty of things like dBc/Hz, selecting oscillator amplitudes, AM noise, cross-correlation methods, etc. - this was originally for beginners.

author: Melt-O-Tronic
author_rank: Frequent Contributor
timestamp: April 14, 2021, 02:08:46 pm
content: Very well presented!!! I've been devouring everything I can about phase noise for reinforcement learning. I understand these concepts, but am fuzzy on the more advanced aspects. So I've been frequently re-reading different material to take it in from various perspectives.I'dloveto have this as a PDF. I'd especially like to encourage you to go deeper with the material. This is a terrific grounding and a very effective style.Edited to add: OMG, your sine waves even look like sine waves instead of semicircular humps & valleys!

author: Grandchuck
author_rank: Super Contributor
timestamp: April 14, 2021, 05:05:23 pm
content: +1 for a PDF

author: ElizatronicWarfare
author_rank: Contributor
timestamp: April 15, 2021, 04:09:41 am
content: Thankyou, I will see what I can do about putting this into a PDF but it was always designed to be a slideshow so the size/proportions might be a challenge.As for going deeper into the topic, unfortunately I am not quite there on the more esoteric points of phase noise (wtf is a lorenz factor??) but hopefully one day I will be in a position to publish a more complete Phase Noise tutorial.

author: K4FMH
author_rank: Newbie
timestamp: April 26, 2021, 12:17:13 am
content: Here’s the PDF...

author: SilverSolder
author_rank: Super Contributor
timestamp: April 26, 2021, 12:35:27 am
content: Very clear explanation, liked it a lot!

author: joeqsmith
author_rank: Super Contributor
timestamp: April 26, 2021, 12:00:52 pm
content: If you are interested in more details HP had published several papers that may be found here:https://www.hpmemoryproject.org/news/3048/hp3048_01.htmI had ran some experiments like this at home. The problem was getting a good delay line. I ended up buying some old test equipment that had one built in and then built my discriminator into that chassis. You can see it in operation here.My old DSO has some support to make simple measurements as well.
what is the conductor in LMR400 cable? *nomenclature* - Page 1
Forum section: electronics / rf-microwave

author: coppercone2
author_rank: Super Contributor
timestamp: April 28, 2021, 08:56:58 am
content: So I have a LMR400 cable I got on ebay.When I cut the copper center conductor it looks like a copper tube thats filled with something silver when looking at the cross section. When I got it real hot with a soldering iron the stuff inside did not want to melt. The datasheet says solid BCCAI whatever that means.I suppose I can try to melt it out, but it won't really give me a clue as to what is in there.Is this copper clad aluminum? what does BCCAI stand for? can someone fill me in on the nomenclature? I thought it was Oxygen Free Copper. I heard of OFC. Never of BCC.Never mind, I got it, its BCCAL, they wrote it as Al for the metal I guess, Weird mixture of chemical name and whatever BCC is.

author: richard.cs
author_rank: Super Contributor
timestamp: April 28, 2021, 10:00:02 am
content: Yes, I think the CCAL is probably Copper Clad ALuminium, but no idea what the B means. Could refer to the cladding process or something.

author: nali
author_rank: Frequent Contributor
timestamp: April 28, 2021, 10:14:55 am
content: Bare...https://www.fccable.com/pdf/lmr/Materials%20and%20Equation%20Legend.pdf

author: Stray Electron
author_rank: Super Contributor
timestamp: April 28, 2021, 03:10:52 pm
content: Doesn't your LMR have the manufacturer's name and model number printed or engraved on the jacket? If so then you should look up the specs on their site. If there's no markings then that stuff is very old or is probably some kind of Chinese knock-off but if that's the case, then all bets are off, regardless of what itsaysthat it is.

author: coppercone2
author_rank: Super Contributor
timestamp: April 28, 2021, 07:47:10 pm
content: yeah, the datasheet says BCCAlBare makes sense

author: TimFox
author_rank: Super Contributor
timestamp: April 28, 2021, 09:30:52 pm
content: I assume that “bare” = “B” means that there is no plating (Ag or Sn) on the outer surface of the Cu.

author: coppercone2
author_rank: Super Contributor
timestamp: April 29, 2021, 12:29:35 am
content: They should have named it BCuCAl? But I suppose you have problems with boron and carbon
E/H field to RF level in coaxial cable conversion (DON'T BOTHER) - Page 1
Forum section: electronics / rf-microwave

author: Neomys Sapiens
author_rank: Super Contributor
timestamp: April 20, 2021, 10:12:05 pm
content: Does someone have the law or conversion formula ready which can be used to determine which level of interference in a shielded/coaxial transmission line will result from an external field as it appears in radiated susceptibility tests? Of course, the screen attenuation goes into it, but how to calculate that?

author: radiolistener
author_rank: Super Contributor
timestamp: April 20, 2021, 10:36:39 pm
content: Quote from: Neomys Sapiens on April 20, 2021, 10:12:05 pmAt a glance you can use classic shielding attenuation formulas and calculate it from the coax cable insulation size (between braid and the center wire), braid conductor thickness and magnetic permeability. But I think the things may be a bit complicated, because the result will depends on cable orientation against field polarization and direction vector.You will get at least 3 attenuation values:- for plane wave far field (when RFI source is at distance more than lambda/2)- for E near field component (electrical field)- for H near field component (magnetic field)In short, more thick coax cable with more thick braid provide you with better shielding.

author: Neomys Sapiens
author_rank: Super Contributor
timestamp: April 20, 2021, 10:58:45 pm
content: Sorry - such is the kind of stupidity resulting from a frantic workload. Basically, I have to treat the center conductor as an antenna. Orientation, length, diameter etc - with the screen attenuation in front.
Sourcing a reasonably priced 1-3W microwave amplifier in the 2-4GHz range - Page 1
Forum section: electronics / rf-microwave

author: SMB784
author_rank: Frequent Contributor
timestamp: April 16, 2021, 12:43:22 pm
content: As the title implies, I am looking to acquire a 1-3 W microwave amplifier in the 2-4GHz range for a fun project in quantum optics. I have a Mini Circuits ZHL-42W (not the + version) that can output almost 1 W, but in my experience that wont be quite enough for this particular application. The datasheet says don't supply it with more than 0 dBm, so I'm not super excited to push the input power beyond 0 dBm in order to squeeze more power out of the unit unless someone here knows that its likely to be safe to do so.Almost everything I see on ebay for this power and frequency range is more than $400, and I was curious if anyone here might know of a good place to get one for cheaper than that. Any ideas are much appreciated.

author: syau
author_rank: Frequent Contributor
timestamp: April 18, 2021, 12:31:39 am
content: Quote from: SMB784 on April 16, 2021, 12:43:22 pmBought 1 from Aliexpress which market as amplifier for WiFi jammer, good frequency response. May be you can search for similar device in Amazon / Aliexpress.SZM2166 2.4Ghz RF power amplifier 2400MHz 2W 33dBm 8-23V DC for 2.4G wifi Bluetooth Ham Radiohttps://a.aliexpress.com/_mtdKa1N

author: bob91343
author_rank: Super Contributor
timestamp: April 18, 2021, 01:25:24 am
content: I have seen some interesting amplifiers on ebay. I am looking at one or two to enhance the output of a signal generator but I keep wondering why a half Volt isn't enough output as it is. All are inexpensive, under maybe $30.
HF ground plane antenna with elevated radials - Page 1
Forum section: electronics / rf-microwave

author: cleanworkbench
author_rank: Regular Contributor
timestamp: May 05, 2021, 09:34:44 am
content: A home brew 1/4 wave ground plane, the base is 3 metres above ground here with good swr but break through on audio whilst portable from the vehicle . Is this the old problem of common mode currents.Fed with rg58.

author: A.Z.
author_rank: Super Contributor
timestamp: May 05, 2021, 01:30:52 pm
content: Quote from: cleanworkbench on May 05, 2021, 09:34:44 amWould you please be so kind to clarify ? You wrote that you have a 1/4 wave GP antenna sitting at 3m above ground; fine till then, but then you wrote about "portable" and "audio issues", and sincerely I can't understand what's the supposed connection and what's your issue, so please, add more details

author: A.Z.
author_rank: Super Contributor
timestamp: May 05, 2021, 05:05:49 pm
content: I still can't understand what the "mobile" has to do with your issue; if it's due to CMC and RF in the shack, then some good chokes along the feedline and good RF grounding in the shack will help for sure, yet, your original post is unclear and you didn't care explaining your issue, so... if you prefer talking to yourself, I'm offand just in case, a groundplane isn't a bad antenna at all, given it's properly installed, any (reasonable) antenna will work well if one takes the time to understand some basic notions
10GHz+ PCB design questions - Page 1
Forum section: electronics / rf-microwave

author: prutser
author_rank: Regular Contributor
timestamp: April 15, 2021, 06:16:46 pm
content: For a hobby project I plan to build a frequency counter prescaler, which preferably extends over 12GHz. I have no experience with PCB design > 1GHz, so I hope someone could give me some insights or hints.Most prescaler IC's require an input level > -10dBm, my target is < -25dBm, so a preamp is required.Rogers PCB is very expensive for prototypes, not really interesting for a hobby project. So the most obvious option seems to be Oshpark, which has 4 layer Isola FR408 for a reasonable price and which is better than the 'standard' FR4 in terms of losses.Losses depends on transmission line length, so to minimize the losses it sounds logical to keep the transmission lines short. So the first I woould do is place the pre-amp (MMIC ?)almost directly to the SMA connector and the prescaler input maybe within 5-10mm from the preamp output.When I look to evaluation board designs, usually the transmission line from the IC to the SMA connector has a length of a couple of cm. Does this has a particular reason, or is is just to keep the eval board at a reasonable size ?Any idea if it would be feasible a > 10GHz preamp followed by a prescaler on 4 layer FR408 ?I expect any microstrip filters > 3GHz are out of the question on FR408 ?Thanks,

author: dcarr
author_rank: Regular Contributor
timestamp: April 15, 2021, 06:29:12 pm
content: I've used the OSH Park FR408 at 10GHz+ without issues including (microstrip) distributed element filters. The loss at 10GHz is about 1dB per inch.To answer your other question, you shouldn't need to put "extra" line between the connector and your preamp. I think that's mostly done to keep the eval boards from being super tiny.

author: David Hess
author_rank: Super Contributor
timestamp: April 16, 2021, 03:28:30 am
content: In a less critical design, the loss of FR4 and similar can be an advantage in preventing spurious responses or even oscillation.
CMU 200 basic  informations - Page 1
Forum section: electronics / rf-microwave

author: jean françois
author_rank: Contributor
timestamp: April 13, 2021, 04:13:18 pm
content: Bonjour,quelle est l'option qui utilise le petit haut parleur en façade ?ou est ce que c'est une option qui n'a jamais existée ou aboutie ! !d'avance merci,Jean François.

author: Ice-Tea
author_rank: Super Contributor
timestamp: April 13, 2021, 04:32:55 pm
content: It's connected to the B41 audio analyzer module if/when equiped I think. Not sure how usefull it is for it, though.

author: Bicurico
author_rank: Super Contributor
timestamp: April 13, 2021, 06:27:29 pm
content: The speaker was fitted for future applications but was never used by any FW revision or option.
rohde & schwarz CMU200 SPAN - Page 1
Forum section: electronics / rf-microwave

author: jean françois
author_rank: Contributor
timestamp: March 07, 2021, 09:19:49 am
content: Hello,I am offered a CMU200, R & S measurement benchcan a user of this device provide me with some information regarding the spectrum analyzer "SPAN"is the "ZERO SPAN" function possible?Is the "FULL SPAN" 100khz at 2.7ghz possible?I ask the question because I have an E4406A (it's not really a real A S), but the SPAN function only allows 10mhz.the seller is coming on Tuesday,thank you in advance for your answers.jean françoi

author: xmo
author_rank: Regular Contributor
timestamp: March 07, 2021, 05:07:45 pm
content: The answers are "yes" and "yes"You can download the CMU brochures, datasheets, and manuals from R&S.From the datasheet:

author: jean françois
author_rank: Contributor
timestamp: March 09, 2021, 01:54:09 pm
content: Hello ,thank you for your answers. I had a doubt about the SPAN, full or zero is absolutely perfect.thanks again.When I received the device, I would probably come back to ask you for more information.Regards,Jean Francois

author: Ice-Tea
author_rank: Super Contributor
timestamp: March 09, 2021, 01:57:16 pm
content: Make sure to check the internal and external loop tests. Some of these unit have been run into the ground by years of service and fail those tests.

author: jean françois
author_rank: Contributor
timestamp: April 13, 2021, 04:08:07 pm
content: Bonjour, desolé de vous repondre avec beaucoup de retard,j'ai la chance que le modele que je possede est relativement recent du plus l'etiuellette de calibration R&S est de 06_08-2016.Merci pour tout.
Description of Pulse Train FM Detector on Github - Page 1
Forum section: electronics / rf-microwave

author: kvd
author_rank: Contributor
timestamp: April 13, 2021, 11:29:51 am
content: Hi,On Github I published a project with a detailed description of the workings of a Pulse Train FM Detector. This is accompanied by a mathematical model, implemented in a Jupyter notebook with which experiments can be done. In the pdf document also a possible improvement is mentioned, together with some preliminary experimental results.The project can be found athttps://github.com/kvdijken/Pulse-Train-FM-Detector.The main document (pdf) of this project is attached to this message.This FM detector is also used in an actual FM receiver designed and built by myself. There is a github project for the receiver, athttps://github.com/kvdijken/FM-Receiver.I have a demonstration video of this FM receiver on youtube:https://www.youtube.com/watch?v=TlIiLwKdwg0&t=1s.Greetings and have fun, Koen
Small transmitting loop article with dozens of useful references - Page 1
Forum section: electronics / rf-microwave

author: cdev
author_rank: Super Contributor
timestamp: April 12, 2021, 02:17:25 pm
content: This web article is not only loaded with useful info about building your own remotely tuned loop it also has a huge number of links to tons more.https://www.nonstopsystems.com/radio/frank_radio_antenna_magloop.htm<<<<As the loop antenna is one of the best antennas of any size, is tons of fun to use, and it seems many hams have restrictions on the kinds of antennas and size especially matters a lot in overcoming them, the transmitting loop is an antenna for all in a big way.Note that they also often make spectacularly good receiving antennas - particularly well suited for SDR use because they are inherently preselectors. (with the exception of the one here, theslinky hulawhich seems to be kind of broadband (for a loop) and performs well...I am very interested in all aspects of mag loops and have had some amazing results using them to receive, mostly using a cheap USB dongle+upconverter as a receiver, usually with a cheap CATV L-pad attenuator on the input to prevent front end overload..

author: sab
author_rank: Contributor
timestamp: April 12, 2021, 08:46:58 pm
content: Looks interesting, cdev. Did you mean to include a link in addition to the slinky hula?Sanjay

author: cdev
author_rank: Super Contributor
timestamp: April 12, 2021, 10:16:00 pm
content: I thought that I did, it was near the top but it seems like its not there now, hope that SMF lets me add it properly. Thanks for pointing its non-presence out.Herehttps://www.nonstopsystems.com/radio/frank_radio_antenna_magloop.htm
nanoVNA Smith Chart reading - Page 1
Forum section: electronics / rf-microwave

author: Electro Fan
author_rank: Super Contributor
timestamp: April 04, 2021, 09:16:10 pm
content: Just checking to see if the reason the Smith Chart doesn't match the demo board diagram is because while the nanoVNA is set for the specified 50kHz to 600MHz the connection is through a N connector with a SMA adapter rather than just a SMA adapter? Or is there something else at play? Thx

author: E Kafeman
author_rank: Regular Contributor
timestamp: April 08, 2021, 07:20:20 pm
content: Correct done calibration and port forwarding?

author: Electro Fan
author_rank: Super Contributor
timestamp: April 09, 2021, 04:12:47 am
content: Yes, pretty sure the calibration was done correctly but please say more about port forwarding. Thx
Custom Crystal Filter - Page 1
Forum section: electronics / rf-microwave

author: DeepLink
author_rank: Regular Contributor
timestamp: April 23, 2021, 11:04:32 am
content: HiI'm looking into a custom made crystal filterGoogle reveals several suppliersAnybody has knowledge about this?I'm thinking about minimum orders and pricingData:Center frequency: 13.69MHzBW: +/- 6KHz8 pole design/Hans

author: purpose
author_rank: Frequent Contributor
timestamp: April 23, 2021, 10:15:13 pm
content: Evening,Making your own is simplicity itself, until consulting experts.A giant can of worms is opened, but learning about this stuff is fun.Sorry I can't point you in any other direction.Peter
R&S CMU200 1->4/3->2 RF Loop Path 1 Test failed. Why does this error occurs ?  - Page 1
Forum section: electronics / rf-microwave

author: electronic_guy
author_rank: Regular Contributor
timestamp: April 08, 2021, 04:25:59 am
content: Hi,I have a CMU200 with 1->4/3->2 RF Loop Path 1 test failure (see picture). What causes this test failure ?Is there a component failure inside the equipment ?Should I do some repair to correct this ?

author: capt bullshot
author_rank: Super Contributor
timestamp: April 08, 2021, 05:31:33 am
content: It's an external loop back test. Did you connect port 1->4 / 2->3 with a proper cable while running the test?

author: electronic_guy
author_rank: Regular Contributor
timestamp: April 08, 2021, 05:45:43 am
content: No. I did not connect it. I thought some internal module is missing.Can I connect those with a N-type RF cable ? I have this one :https://www.mouser.com/ProductDetail/523-175101-07-48.00

author: capt bullshot
author_rank: Super Contributor
timestamp: April 08, 2021, 06:41:25 am
content: Quote from: electronic_guy on April 08, 2021, 05:45:43 amYes, that'll do the job.
E4406A / VSA 89601A Measurement Behavior - Page 1
Forum section: electronics / rf-microwave

author: colorado.rob
author_rank: Frequent Contributor
timestamp: April 11, 2021, 01:01:25 am
content: I am trying to measure the modulation quality of low-speed, low-bandwidth (4.8ksps/12kHz) 4-FSK modulation using the E4406A and VSA 89601A software. The 4-FSK baseband generator i am using does not have a very accurate clock. It is rated for 250ppm, enough for USB, and it is well within that range. When measuring the signal quality with the software, and changing only the symbol clock rate, I find the software reports better modulation characteristics (lower FSK error) when the clock is slightly slow than when it it slightly fast. In this case the difference is between running the clock at about +100ppm vs -100ppm from the reference frequency. The FSK error reported more than doubles when running faster. Even when running significantly slower (-500ppm) the FSK error does not really change from -100ppm.This seems rather odd to me. I am hoping someone with more experience in this area can shed some light on what I am seeing, whether it would be considered normal, and, if so, maybe explain why.The baseband generator, for those curious, uses an STM32L4 with a 20ppm 32.768kHz LSE. The system clock is based on the MSI at 48MHz running in PLL mode (slaved to the LSE).
R&S CMU200 Checksum error CMOS. What should I do ?  - Page 1
Forum section: electronics / rf-microwave

author: electronic_guy
author_rank: Regular Contributor
timestamp: April 08, 2021, 03:57:47 am
content: Hi,I'm keep getting CMOS checksum error in CMU200 I bought (see the picture). What is the cause of this error ?If I did not correct this what would happen to the equipment ?

author: gnif
author_rank: Unknown
timestamp: April 08, 2021, 04:00:33 am
content: Just reconfigure the BIOS... it simply has a flat CMOS battery

author: electronic_guy
author_rank: Regular Contributor
timestamp: April 08, 2021, 04:17:27 am
content: Do I need to replace the CMOS battery ?
Interpretation of the Change of Inductance - Page 1
Forum section: electronics / rf-microwave

author: snoozy
author_rank: Contributor
timestamp: April 02, 2021, 11:08:34 am
content: I'm looking for the theortical explanation of the following phenomenon:I have two coils with each 50 winidings.The first has 10 Windings per layer and the second 5 Windings.So, the first one has 5 layers and the second one 10.Both have an inductance of 19.9 µH.Now I'm measuring the inductance while an aluminium object is brought close to the coil.The influence to the inductance of the first one is stronger than on the second one at the same distance to the object.I was expecting the oposite, because the windings of the "flat" coil with more layers are slightly closer to the object.

author: radiolistener
author_rank: Super Contributor
timestamp: April 02, 2021, 12:34:48 pm
content: I think there is no simple answer, because coupling between the coil and core depends on the coil and core geometry, material, exact location, distance and working frequency. There is needs to use electromagnetic simulator in order to see what happens exactly.

author: snoozy
author_rank: Contributor
timestamp: April 02, 2021, 02:34:10 pm
content: Thanks for your comment.I run two simulations now.The results are different to my measurements.I thought there might be a something about the field lines inside of the coil, if the coil dimensions changes.Like they concentrate better.Well I'm still thinking about how to interpretate. And probably there is something wrong with my measurements.

author: ahbushnell
author_rank: Frequent Contributor
timestamp: April 02, 2021, 05:11:06 pm
content: What frequency did you use in the simulation? It's going to change with frequency.

author: snoozy
author_rank: Contributor
timestamp: April 04, 2021, 07:54:13 am
content: The frequency is 1 MHz. Since there is no core, the influence of the frequeny shouldn't do so much.I discovered, that the diameter of the coil has quite an influnce.By changing the height of the coil, I was changing the width, too.That seems to have quite an impact on the inductance.
What is the purpose of the summing block in this SA? - Page 1
Forum section: electronics / rf-microwave

author: RoGeorge
author_rank: Super Contributor
timestamp: April 02, 2021, 07:28:14 pm
content: Found it in a Chauvin Arnaux (Metrix) instruments catalogue from 2017.https://www.chauvin-arnoux.com/sites/default/files/documents/cat-metrix-2017_gb.pdfI don't understand what is it the summing block for, looks like a drawing mistake.Is there some purpose in adding the LO after the mixer?

author: radiolistener
author_rank: Super Contributor
timestamp: April 03, 2021, 07:06:11 am
content: At a glance it produce sum with shifted phase LO to eliminate LO component on the output and improve dynamic range

author: xmo
author_rank: Regular Contributor
timestamp: April 03, 2021, 02:35:06 pm
content: I think it is somewhat confusing.I believe this block diagram is better at illustrating the basic spectrum analyzer:
R&S CMU200 Multiple B-21 options. How to know which one is installed ?  - Page 1
Forum section: electronics / rf-microwave

author: electronic_guy
author_rank: Regular Contributor
timestamp: April 08, 2021, 06:04:27 am
content: Hi,I saw that there are two B21 options in the official CMU200 options document (https://cdn.rohde-schwarz.com/pws/dl_downloads/dl_common_library/dl_brochures_and_datasheets/pdf_1/CMU200_Options_and_accessories.pdf)(see the picture)How to know which one is installed in the CMU200 I have (picture attached) ? I need to know if I have the AMPS option so I can use the external modulation signal to modulate the RF carrier.
TV modulator circuit analysis - Page 1
Forum section: electronics / rf-microwave

author: hermitengineer
author_rank: Regular Contributor
timestamp: March 25, 2021, 03:49:17 am
content: Hi all,I'm curious how this modulator handles the channel switching. It appears to only affect the audio modulation (at least directly). I see an FM modulator for the audio, and 2 additional modulators, one to mix the audio with the VHF base signal and one to mix the video. Any insights on this?

author: Ultrapurple
author_rank: Super Contributor
timestamp: March 25, 2021, 09:17:29 am
content: As far as I recall the UM1286 was a UHF modulator that output on channel 36 (~591.25MHz). That channel was deliberately left spare by the broadcasters so that VCRs, games, computers and so on could all operate on the same frequency.Of course, if you had a VCR and a computer and no baseband input for the latter, things got messy.I'm pretty sure the 'fine tune' was just for the audio subcarrier. Audio input is AC coupled to Q1; the 'tweak' voltage is DC coupled to Q2. Both connect to the sound ocsillator via 82p caps so I guess they're acting as varicaps.

author: Ultrapurple
author_rank: Super Contributor
timestamp: March 25, 2021, 09:21:16 am
content: I found a copy of theshortform datasheet here

author: hermitengineer
author_rank: Regular Contributor
timestamp: March 25, 2021, 08:00:33 pm
content: Ah, so that makes more sense then.This particular one is mounted on a board that has "3/4" silkscreened on the channel input pin. But my particular console did not have that switch circuit populated. I guess they used the same basic daughter PCB for the UHF version as well as for the VHF 3/4 switchable one then, and apparently used a different modulator.So that's one mystery solved.Now, there are 4 adjustments on this board, which was the main reason I reverse-engineered it--the documentation about what those adjustments were for seems to have been lost to time.The ones for tuning the carrier oscillators are obvious. The other two are in the final mixing. I guess (?) that the other 2 separately control the strength of the signals as they are finally summed?

author: Ultrapurple
author_rank: Super Contributor
timestamp: March 30, 2021, 07:51:10 am
content: If you're talking about L6 and L7, those tweakers are to resonate the coil precisely on the desired frequency, which will have an effect on the output amplitude.More technically, 'tune for maximum smoke'.
What data is sendt on a DMR datapacket. - Page 1
Forum section: electronics / rf-microwave

author: geggi1
author_rank: Frequent Contributor
timestamp: March 27, 2021, 02:15:48 pm
content: Does anybody know if a DMR datapacket contain RSSI data?It it contains this and posisioning data it would be possible to autogenerate repeater coveage maps.The posisioning data can come with the APRS function that is buildt in to many brands of radios.
Noise Figure Analysis Mode in Spike™ - Page 1
Forum section: electronics / rf-microwave

author: rfclown
author_rank: Frequent Contributor
timestamp: March 26, 2021, 08:20:55 pm
content: Lose the background music; very distracting. I used a USB-SA44B at a previous job and used the API with LabVIEW. Do routines exist in the API to make this easy to do remotely so that the remote program could turn the source on and off?
Does anyone use, own, have,... a xiegu Radio? - Page 1
Forum section: electronics / rf-microwave

author: Lord of nothing
author_rank: Super Contributor
timestamp: November 17, 2020, 09:18:09 pm
content: HiI am intend to buy a xiegu for myself if there is a Blackfriday Offer this year.Does anyone own a X5105?Thanks

author: bobsdr
author_rank: Newbie
timestamp: November 21, 2020, 12:50:14 pm
content: Sorry no - but I do have the G90, which I can thoroughly recommend if that's any help.It has a 20W output. I use it at home with an EndFed via a home-made balun. Mainly used for SSB but also set it up for FT8 and it's able to reach 2000km on 40m. There is an excellent user support group on Google groups.Good luckMM0MMQ

author: Lord of nothing
author_rank: Super Contributor
timestamp: November 21, 2020, 12:54:02 pm
content: Perfect do you have the frequency extention?If you know if its just Software or Hardware to?

author: frankmhowell
author_rank: Newbie
timestamp: December 06, 2020, 12:05:50 am
content: Hmm. I have both an X5105 and a G90. What are you referring to when you say “frequency extension”? I’m unfamiliar with it and I communicate directly with Xiegu.FrankK4FMH

author: Lord of nothing
author_rank: Super Contributor
timestamp: December 06, 2020, 09:01:14 am
content: https://xiegu.eu/product/frequency-extension/

author: frankmhowell
author_rank: Newbie
timestamp: December 08, 2020, 02:12:34 am
content: Ok, I was unaware of what that meant. No idea...Frank

author: noreply
author_rank: Frequent Contributor
timestamp: December 08, 2020, 06:44:08 pm
content: I think the 'frequency extension' as referred to the link above is a simple 'mod' - removing a diode (clearly marked on the PCB with a white arrow pointing to it) - this will enable the full 10M band allowing the G90 to tune and Tx on the North American CB frequencies (MARS).If you are not a licensed amateur - this might have some appeal to you

author: Lord of nothing
author_rank: Super Contributor
timestamp: December 08, 2020, 07:33:47 pm
content: Well I looking for a Radio who is capable to use them as Emergency Radio only.I know some People who we have "our" Freq and Times when we would start to send a Message out with our status. Sadly I could not find any commercial Radio.

author: kb2won
author_rank: Newbie
timestamp: March 11, 2021, 03:21:33 am
content: Does anyone know how to setup the xiegu g90 for FT-8 operations?

author: K4FMH
author_rank: Newbie
timestamp: March 26, 2021, 10:22:19 pm
content: Join the G90 group at groups.io. Plenty of details there.
getting a little ridiclous with the radio tracking - Page 1
Forum section: electronics / rf-microwave

author: coppercone2
author_rank: Super Contributor
timestamp: March 19, 2021, 05:46:01 am
content: https://yro.slashdot.org/story/21/03/18/2056245/surveillance-company-wants-to-sell-over-15-billion-car-locations-to-the-us-militarySo, given the great opportunities you get after you finish service with the US military, reenacting 'gone in 60 seconds' appears to be a potentially viable career optionI wonder where those Bugatti's are parked. I am waiting for Guy Fieri to post about building a faraday cage

author: cdev
author_rank: Super Contributor
timestamp: March 26, 2021, 09:12:13 pm
content: That info is a huge asset and trade agreements carve in stone corporations rights to use it for any purpose they want. They own it and any other information they collect voluntarily from you. They own it forever. Suppose you are a debtor, a fugitive from the law. Don't they have a right to recover their money any way they can? The future is digital. Where else are all the jobs supposed to come from besides the terrible crimes revealed by the Omnipresence and its Youniverse of Ugly Data.Resistance is futile, you and all your data will be assimilated.
microwave oven deltawaves - Page 1
Forum section: electronics / rf-microwave

author: m3vuv
author_rank: Super Contributor
timestamp: March 25, 2021, 09:14:39 pm
content: does anyone know what a deltawave is in the context of microwave ovens?,or is it just marketing b.s?

author: coppercone2
author_rank: Super Contributor
timestamp: March 26, 2021, 03:50:19 am
content: it sounds how much the wave moves around in the cavity so your food does not get hot spots (normally it rotates or there is a metal spinning reflector)

author: radiolistener
author_rank: Super Contributor
timestamp: March 26, 2021, 12:26:00 pm
content: Toshiba Deltawave? Looks like popular model name of microwave oven
Please help me find the datasheet - Page 1
Forum section: electronics / rf-microwave

author: un7gk
author_rank: Newbie
timestamp: March 26, 2021, 05:50:30 pm
content: Hello,Please help me find the datasheetThis is a 23GHz MMIC IQ UP-CONVERTER.Manufacturer and type are not known.Used in the Ericsson-23GHz radio linkI would be grateful for any information.Vladimir

author: A.Z.
author_rank: Super Contributor
timestamp: March 26, 2021, 06:26:01 pm
content: seeking for ericcson rop101 found thishttps://kaizerpowerelectronics.dk/teardown/ericsson-radio-base-station-rbs3206-teardown/hth
Fully Digital Bluetooth Receiver (Antenna connected directly to an FPGA) - Page 1
Forum section: electronics / rf-microwave

author: benzn
author_rank: Newbie
timestamp: March 26, 2021, 01:32:24 am
content: Hi folks,Thought this forum might find this project amusing/interesting:https://github.com/newhouseb/onebitbtTL;DR is that I built a "radio" that can receive nearby Bluetooth advertising packets on an FPGA, except there's no mixer, AGC, filtering, LNA or ADC: I've just connected an antenna directly to (one half) of a SERDES RX port and am sampling bits at 5GHz.There's a lot that can be improved, but it's passable as a proof of concept. I've also built a transmitter (https://twitter.com/newhouseb/status/1352796299700162560) but am reworking some of the (digital) DSP before I open source that part.I've documented/explained a ton of the building blocks in various python notebooks:In the onebitbt repository (Transmission is WIP, ignore that):https://github.com/newhouseb/onebitbt/tree/master/researchIn the alldigitalradio repository:https://github.com/newhouseb/alldigitalradio/tree/master/researchI've never built a radio before, so open to feedback/criticism! (I know my filtering and decimation is a joke though) Original twitter thread:https://twitter.com/newhouseb/status/1369468611430088712 Twitter thread with screenshots of notebooks:https://twitter.com/newhouseb/status/1374183128785387528
SI473x based radios? - Page 1
Forum section: electronics / rf-microwave

author: cdev
author_rank: Super Contributor
timestamp: February 26, 2021, 08:47:02 pm
content: Has anybody had any experience with these SI473x devices, which enable a wide range of receive functionality with a single chip.https://www.silabs.com/documents/public/data-sheets/Si4730-31-34-35-D60.pdfThere also is a breakout board/kit on ebay for around $40. The chip costs around $10 from the manufacturer..

author: 9aplus
author_rank: Regular Contributor
timestamp: February 28, 2021, 06:33:15 pm
content: Please see here:https://github.com/pu2clr/SI4735Also 1,5 k members group on FBhttps://www.facebook.com/groups/532613604253401/about

author: cdev
author_rank: Super Contributor
timestamp: February 28, 2021, 07:21:51 pm
content: Thanks! There is an interesting story behind this. The performance looks decent on SSB. The author also sells his version of the ssb radio and it includes his thumb size full color OLED display. (!) He needs a bigger knob for this receiver, with a hole for finger spinning.

author: 9aplus
author_rank: Regular Contributor
timestamp: February 28, 2021, 10:41:19 pm
content: Quite few of available kits or ready PCB-s are available.Personally like the one with mixer stage in front, because do notlike clicking sound of kHz frequency change on Si437x chipset.Have here at hand one chip and pcb adapter and few arduino-s,but no free time to start experimenting.

author: cdev
author_rank: Super Contributor
timestamp: March 01, 2021, 01:38:36 am
content: Quality of receive seems typical of a decent communications receiver which is surprising. I want one for the bedroom for when I wake up in the middle of the night. Or maybe set up a web SDR for use with laptop.

author: 9aplus
author_rank: Regular Contributor
timestamp: March 01, 2021, 08:38:42 am
content: I already have something, built during the first Covid lockuphttps://hackaday.io/project/171415-sdr-limetogo

author: cdev
author_rank: Super Contributor
timestamp: March 01, 2021, 02:41:56 pm
content: I like those pelican cases and the Harbor Freight knockoffs. Ideal for any small SDR or small RTK-GPS installation.

author: 9aplus
author_rank: Regular Contributor
timestamp: March 09, 2021, 07:34:53 am
content: Si473x Printed Circuit Boardavailable with or without chiphttps://www.pi4raz.nl/index.php/products-page/EU shipment possible, for WW check with OM FrankRegardsDjani

author: 9aplus
author_rank: Regular Contributor
timestamp: March 24, 2021, 07:48:51 pm
content: Was in great temptation with above PCB-s,finally ordered two.One with Si4732 and other empty,because here already have one 4735The boards arrived within 10 days from payment.Assembly manual is here ->https://github.com/pe0mgb/SI4735-Radio-ESP32-Touchscreen-Arduino/blob/master/Assembly%20instructions%20SI4732-35.pdfNow just to find some spare time to make them...