hybridfree/eevblog-posts huggingface dataset:
SINGER SPA-100 SPECTRUM ALALYSER MANUAL PLEASE - Page 1
Forum section: electronics / rf-microwave

author: alanainslie
author_rank: Newbie
timestamp: September 14, 2022, 04:55:47 pm
content: I have a nice Singer SPA-100 Spectrum Analyser - the EHT has decided to die and I have no manuals.Can anyone assist plesase?Tried the usual sources (I think).ThanksAlan A

author: coppercone2
author_rank: Super Contributor
timestamp: September 15, 2022, 01:25:21 am
content: That looks like a nice unit that you might be able to trouble shoot even without knowing anything. Did you do a check for obviously burnt/damaged components, broken wires, etc?

author: coppercone2
author_rank: Super Contributor
timestamp: September 15, 2022, 01:28:55 am
content: https://www.ebay.com/itm/125141420223this might be a start for 15$. I see block diagrams at least.

author: coppercone2
author_rank: Super Contributor
timestamp: September 15, 2022, 01:32:40 am
content: https://emperoroftestequipment.weebly.com/QuoteSO that means what you might be looking for is a MF100 mainframe manual, presumable the scope EHT is part of the main frame. Also check for loose sockets for tubes, it could just be a damn socket, it sounds like that is powered by tubes. Can't hurt to just clean it through if you can't find a manual (look up tube socket cleaning guides).

author: wn1fju
author_rank: Frequent Contributor
timestamp: September 15, 2022, 09:03:14 pm
content: I've attached two schematics from my MF-100 mainframe manual concerning the CRT. One is for the HV power supply and the other is a general interconnect diagram. Hopefully that will get you started.I have the hardcopy manuals for the spectrum analyzer, but it is >100 pages and has a lot of fold-outs. The only thing I'm able to do is a quick photo of a page or two at a time.In a perfect world, I would lend you the manual. But the last time I tried that, the recipient was in Canada (I am in USA) and it got held up at a UPS store right near the border. Then Covid hit and border crossings were suspended. The poor guy never was able to get the UPS delivery and after well over a year, I contacted UPS and had them ship it back (at my expense). I've learned my lesson, no more manual lending!
looking for schematic for Motorola MTM700/MTM800/GM360 remote head PCB - Page 1
Forum section: electronics / rf-microwave

author: wkb
author_rank: Super Contributor
timestamp: July 16, 2018, 09:22:45 pm
content: I am in the process of fitting a remote head ("control unit") to my Motorola MTM800 Tetra mobole radio. On these radios youcan remove the head unit from the radio, add a interface box to the radio, another interface box to the head unit and fit a RJ50 (10 wire) cableto link them together.OK.. the problem at hand is that I have a remote head including the interface PCB. I lack the interface PCB that goes onto the radio body.Having borrowed a specimen of the latter I learned that both ends of the cable use the same base PCB. It is just that the module that goes ontothe radio body has more parts fitted, like for example a voltage regulator.Right.. I have some spare PCBs of the "remote head" variant, so the lesser populated version.What I lack are the schematics of the modules to determine which parts need to be fitted to morphe my "remote head module" into a "radio body module". I am specifically interested in the SOT23 parts.Who can help me to the schematics??NB1: GM360 analog radios use the same module type it seems.NB2: there are multiple variants of these modules, I found schematics for the other module types, just not for the ones I haveNB3: the MTM800 works fine with a straigh-through 8 wire cable with RJ45 plugs fitted. So standard UTP cable will do, just make sure it isa 1:1 cable.aNB4: where I live we have a DMO Tetra repeater operating in the Dutch 70cm ham band allocation.

author: TheSteve
author_rank: Unknown
timestamp: July 17, 2018, 01:26:29 am
content: If you haven't asked already I would also post to batlabs -http://batboard.batlabs.com

author: wkb
author_rank: Super Contributor
timestamp: July 17, 2018, 06:35:49 pm
content: Thanks, will try that angle. Can't seem to register there at the moment, their captcha thingy (hate them with a passion btw) appears broken

author: Scarparo
author_rank: Newbie
timestamp: September 09, 2022, 09:57:53 am
content: Dear Sir, do you have the schematics of these PCB ? If yes, could you send to me ? Thanks !
Charger and manual for HT - Page 1
Forum section: electronics / rf-microwave

author: bob91343
author_rank: Super Contributor
timestamp: June 15, 2022, 05:38:56 am
content: I was given a pair of Abbree Hts model AR-F6 but no charger or manual.Can anyone help?

author: MikeK
author_rank: Super Contributor
timestamp: June 15, 2022, 12:38:46 pm
content: Google found a PDF for me.http://kitelecharge.free.fr/Baofeng/pdf/manuel-abbree-ar-889g.pdf

author: bob91343
author_rank: Super Contributor
timestamp: June 15, 2022, 04:40:20 pm
content: That is a different model.

author: duckduck
author_rank: Frequent Contributor
timestamp: September 01, 2022, 04:48:08 pm
content: Quote from: bob91343 on June 15, 2022, 05:38:56 amDid you ask Abbree? info@abbree.com
How to compare the performance of atomic clock? - Page 1
Forum section: electronics / rf-microwave

author: poorren
author_rank: Newbie
timestamp: July 28, 2022, 02:00:23 am
content: Hello guys,My question comes from evaluate two rubidium clock sources, one is bought as used clock with nice price, another is disassembled from an old basestation. I don't know the detailed spec of two clocks. After reading some material on time source measurement, I found the methods on the table (commerial counter TIC or dual mixer time difference method) require to use a more stable clock to measure another one. Because all the methods above are relative measurement, the confidence is based on priori knowledge on standard performance. So, my curiosity drive me to ask how to compare two clock with unknow performance (short term jitter and long term stability)? Thanks for your time.

author: Geoff-AU
author_rank: Frequent Contributor
timestamp: July 28, 2022, 04:30:44 am
content: There's an old saying:A man with one clock knows what time it isA man with two clocks has no idea what time it isA man with 3 clocks has slightly more idea than the man with 2 clocks

author: ejeffrey
author_rank: Super Contributor
timestamp: July 28, 2022, 05:11:52 am
content: If you have two identical clocks you can use the allan variance to measure the relative error between them and then assign that 50/50 to each clock since they are supposed to be identical.If you have 3 clocks, you can use the "three corner hat" measurement to find the variance in each clock individually.Both of these methods require the clocks to be statistically uncorrelated with each other which is often extremely difficult to achieve in practice.

author: MikeK
author_rank: Super Contributor
timestamp: July 28, 2022, 01:23:45 pm
content: Compare to GPS time?

author: jmw
author_rank: Frequent Contributor
timestamp: July 28, 2022, 05:25:16 pm
content: If comparing the PPS signal is what you want, this might do the job:https://tapr.org/product/tapr-ticc/

author: poorren
author_rank: Newbie
timestamp: July 29, 2022, 03:18:34 am
content: excellent open source work, I have starred it.

author: poorren
author_rank: Newbie
timestamp: July 29, 2022, 03:22:06 am
content: the gps seems to be not good enough for this. the 1pps signal derived by receiver MAYBE only have good lone term performance. the jitter introduced by weather is too much for this application.

author: poorren
author_rank: Newbie
timestamp: July 29, 2022, 03:47:19 am
content: Hi ejeffrey, Thank you VERY MUCH! That's the one I am looking for.

author: ejeffrey
author_rank: Super Contributor
timestamp: July 29, 2022, 04:09:28 am
content: Take a look at the plot from Stanford Research at the bottom of this page:https://thinksrs.com/products/prs10.htmlThey show the allan variance of the Rb oscillator beating a GPS 1pps for intervals up to ~3 days.

author: coppercone2
author_rank: Super Contributor
timestamp: August 29, 2022, 12:11:45 am
content: what if you put them all into a logic gate so when one of them drifts there is a short glitch. I wonder how fast it would need to be.
finding alternatives for old part numbers? - Page 1
Forum section: electronics / rf-microwave

author: hostile
author_rank: Contributor
timestamp: August 20, 2022, 12:32:07 am
content: I have some old radios like IC-745 that reference Icom part numbers with no indication on what I could use as a supplement. I assume since these radios have long ago not been serviced by Icom that they can not supply the parts. Whats a guy to do? have lots of adjustable coils and chokes that corroded and falling apart.

author: mag_therm
author_rank: Frequent Contributor
timestamp: August 20, 2022, 08:16:33 pm
content: One item is to realize that old radios built after about 1978 are more difficult to restore than earlier ones with discrete components for the reasons you mention and others.I have restored a few tube and transistor units.The best age seems to be between 1958 and 1975.Substitution in those is mostly easy.However IF coils and IF filters are difficult to find now.

author: geggi1
author_rank: Frequent Contributor
timestamp: August 21, 2022, 08:43:49 am
content: First you have to find the data on the original component. Icom where back in the 70s and 80s often delivering pretty good documentationAs far as I remember they used the original partnumber form the manufacturer not like today when they are using the internal Icom partnumber.Then just start to use Google for substitute parts.In some cases you might also be able to find donor radios/cards for your radio. Back then the same parts where often used in several radios

author: hostile
author_rank: Contributor
timestamp: August 21, 2022, 05:52:24 pm
content: thats the problem, no data on the component. Icom parts that have long ago vanished.

author: geggi1
author_rank: Frequent Contributor
timestamp: August 23, 2022, 09:17:04 pm
content: start looking here.http://www.radiomanual.info/schemi/ICOM_HF/IC-745_serv.pdfYou will find information about the components in the back of the SM.Some parts will probably be hard to get especially intigrated circuits.

author: hostile
author_rank: Contributor
timestamp: August 24, 2022, 01:30:58 pm
content: Been using the service manual, but all of the inductors and chokes use IC part numbers and there is no information on them.

author: mag_therm
author_rank: Frequent Contributor
timestamp: August 24, 2022, 03:19:11 pm
content: I had a look at the service manual posted by geggi.It seems detailed enough however I can imagine it would be difficult and time consuming to trace to a particular failed component.With the "number" of radios you have, can you just focus on one which has the least faults, and or the least visible component deterioration ?At some stage you should consider write- off.I like restoring old stuff, but selectively by age and of simpler complexity.I have a new single board Hermes sdr transceiver on order, as it was only $350 I would not consider it worthwhile to try to restore an old Japanese one.

author: hostile
author_rank: Contributor
timestamp: August 24, 2022, 08:10:31 pm
content: For instance, PLL Uint, L8 (LS-162), PLL Sub-Unit LS201 ( LB-133 ). Where is there any information on these parts, What are the specs on them?
Any Value in Hanging Passive Metal Bow Ties in Trees on a Hill - Page 1
Forum section: electronics / rf-microwave

author: jonovid
author_rank: Super Contributor
timestamp: August 16, 2022, 11:42:39 pm
content: is there any value hanging dozens of metal bow ties in trees on a hillas passive UHF dipole antennas.one piecedipoles or strips of metal cut to size. Hzhanging them bynon conductivecord.for radio black spots? improved coverage over a hill.

author: vk3yedotcom
author_rank: Frequent Contributor
timestamp: August 16, 2022, 11:49:50 pm
content: Potentially.Haven't tried it seriously but as a proof of concept got some results from this demo:

author: vu2nan
author_rank: Contributor
timestamp: August 17, 2022, 04:32:05 pm
content: Here's a similar application.Some good commercial VHF handhelds have only one drawback - no external antenna connector.Modification is also a problem as the rubber ducky is either integral or screwed on to a threaded stud, with no access to ground.The result is a frustrated, repeater-bound ham. When a fellow ham in such a predicament set me pondering, realisation dawned that another rubber ducky could be used to couple the rig to an external antenna.My own rig (which has a BNC connector!) was used to check it out. The coupling rubber ducky was mounted on the input of a homebrew SWR meter, with a dial lamp loading the output.Rubber ducky coupling to a bulb loadThe glow of the dial lamp indicated a coupling efficiency of about 20% (2.5W to 0.5W).A 2m external antenna was then connected instead of the dial lamp.Rubber ducky coupling to an external antennaOn-the-air tests were successful. Comfortable simplex QSOs, not possible with the rubber ducky alone, were now possible.Nandu.

author: David Hess
author_rank: Super Contributor
timestamp: August 17, 2022, 05:13:12 pm
content: The bow ties could also be used as a reflector with low wind loading.
Help please! How to connect a 4 Pin DIN cable to the Oscilloscope? - Page 1
Forum section: electronics / rf-microwave

author: upbeat-pm
author_rank: Newbie
timestamp: August 11, 2022, 09:29:00 pm
content: Help please! I want to do TDR test on a 4 Pin DIN cable. How to connect it to the Oscilloscope? I have found this type of connector:https://www.amazon.com/gp/product/B09X181FZP/ref=ox_sc_act_title_1?smid=A2N4NU72MATLUW&th=1But looks like it's for audio applications? is this ok if I use it (even not sure it fits)

author: geggi1
author_rank: Frequent Contributor
timestamp: August 12, 2022, 08:38:41 am
content: Just get the opposite of the plug you got and solder on some wires to the recep

author: Jeff eelcr
author_rank: Frequent Contributor
timestamp: August 14, 2022, 12:08:22 pm
content: 4 pin DIN is not the same as 4 pin mini-DIN.Try Digi-key CUI stack connectors for both types.Jeff
Palomar Engineers ... are they defunct? - Page 1
Forum section: electronics / rf-microwave

author: Michael-VK2BEA
author_rank: Regular Contributor
timestamp: July 25, 2022, 02:37:41 am
content: Does anyone know if 'Palomar Engineers' is till in business ?I placed an order on their web site on July 5th and have heard nothing from them. When Iwasable to look at the order on-line it showed as "Awaiting Processing" (just now I tried and get a Wordpress login screen from the order link!).Emails over the last two weeks are unanswered and their phone answering system is now full and I can't leave a message. (I had left a message last week).Michael

author: Mark19960
author_rank: Regular Contributor
timestamp: July 26, 2022, 09:32:23 pm
content: Last time I ordered something from then was about a year ago.I did get an email from them with an advert for their 4 July sale.Not answering emails and having the messagebox full doesn't look good however.I hope they are still around. They have some good products.

author: xrunner
author_rank: Super Contributor
timestamp: July 27, 2022, 12:21:47 pm
content: Just interested in this. I've bought products from them years ago. I did call last night and got the voice mail overload message. Just for an experiment I tried to order a product and got well into the ordering process. I'm sure it would have accepted my credit card if I had wanted to follow-through. No sign of any trouble with the company on the website.Strange ...

author: edtyler
author_rank: Contributor
timestamp: August 05, 2022, 06:00:37 am
content: Palomar is a fairly small operation, but they have been reliable for many years. I had thought I saw Bob (AK6R) at the W6TRW swap meet at the end of July, but could be mistaken.I'd give them a little time, just in case there is a vacation or something else going on. If things don't work out you can always do a chargeback on your credit card.Dale

author: Michael-VK2BEA
author_rank: Regular Contributor
timestamp: August 06, 2022, 12:25:35 am
content: Quote from: edtyler on August 05, 2022, 06:00:37 amYes after an email directly to Bob, I got a response.I get the feeling that that is actually Palomar Engineer (singular)

author: Mark19960
author_rank: Regular Contributor
timestamp: August 09, 2022, 04:11:56 pm
content: So I take it all is well then?That's good to know.

author: Michael-VK2BEA
author_rank: Regular Contributor
timestamp: August 09, 2022, 04:50:30 pm
content: Quote from: Mark19960 on August 09, 2022, 04:11:56 pmYes, but the order took a month and the customer service was virtually non-existent.I would suggest not ordering directly but to go through a distributor like HRO.
cryatal calibrator - Page 1
Forum section: electronics / rf-microwave

author: bob91343
author_rank: Super Contributor
timestamp: August 09, 2022, 02:25:52 am
content: Anyone know a simple 100kHz crystal calibrator emulator?

author: A.Z.
author_rank: Super Contributor
timestamp: August 09, 2022, 05:29:34 am
content: check thishttp://qrp.gr/marker/will it fit ?

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: August 09, 2022, 10:25:06 pm
content: There are lots of old fashioned ham radios with xtal calibrators, like the Kenwood 520 and Yaesu 101 HybridsYou could look at their schematics and come up with one of your own pretty easily.All these things are is an oscillator with a lot of harmonics that feeds into you antenna input.The one AZ showed you is quite typical.There is one in the ARRL question book for HAM exams.

author: kc0ngu
author_rank: Contributor
timestamp: September 07, 2022, 02:47:15 am
content: You could try this:https://www.ebay.com/itm/153992327219Gets good reviews, made in USA.Regards,
ADF4351 LCD version missing software - any good soul? - Page 1
Forum section: electronics / rf-microwave

author: xardomain
author_rank: Contributor
timestamp: December 15, 2021, 05:37:13 pm
content: Hi,just bought an ADF4351 board (the one with LCD touch) but in the heat of the moment I selected a seller that does not list the software for optionally driving it.Now, I don't plan to use the software for the application I need (Oscar 100 sat transceiver, to downconvert the LNB into ham frequencies to skip the SDR rx) but I could in the future drive it using a pc.Since the seller is taking some time to address my request, could any good soul to share the software?I see that a serial port does show up, and somewhere there is a protocol description but just to not reinvent the wheel...Hope this does not break any rule, in this case please disregard.Thanks in advance.Giuseppe MarulloIW2JWW - JN45RQgiuseppe at marullo dot it

author: ledtester
author_rank: Super Contributor
timestamp: December 15, 2021, 07:00:37 pm
content: Have a look at this thread:https://www.eevblog.com/forum/rf-microwave/how-to-control-ltdz-max2870-23-5-6000mhz-signal-source/for some pointers to PC software and other tech info.

author: xardomain
author_rank: Contributor
timestamp: December 15, 2021, 10:07:14 pm
content: Hi Ledtester,I did already see some posts, but following your suggestion(Thanks!) I re-read them and after some fiddling, this is the link to the software:https://www.tonyplaza.nl/download/YT054/PLZ-PLL-435X.zipIt seems it is from Tony Albus, found the reference here:https://techymetrics.com/download/SUf2T9pSD3Y/054-adf4351-lcd-signal-generator-35-4400-mhz-with-sweepThere are other downloads related to ADF451, but I did not test them (yet).As always, use at your own risk, VirusTotal says ok (2/60 detection rate, no big AV complained)Thanks again for your suggestion, I would not have looked again there.Giuseppe MarulloIW2JWW - JN45RQ

author: ledtester
author_rank: Super Contributor
timestamp: December 15, 2021, 10:43:07 pm
content: Thanks for providing the link to the software you found - I'm sure it will help others!

author: tonyalbus
author_rank: Super Contributor
timestamp: August 04, 2022, 09:20:22 am
content: Its save.
Determining LO drive voltage for 13dBm mini-circuits mixer - Page 1
Forum section: electronics / rf-microwave

author: spacehen
author_rank: Contributor
timestamp: August 01, 2022, 05:49:29 pm
content: I am interested in using the following double balanced mixer by mini-circuits: RMS25-MH+. In the datasheet it is specified that the required LO drive power is 13dBm (level 13).As i understand it double balanced mixers use diodes and so are non-linear devices. I only have available a signal generator that I can set the peak voltage to. My question is how can I determine the required LO input voltage. Do I assume that the input impedance looking into the LO port is 50 ohms and calculate from there?

author: TimFox
author_rank: Super Contributor
timestamp: August 01, 2022, 06:17:47 pm
content: Yes, you want to calculate the AC voltage that gives +13 dBm = 20 mW into 50 ohms, which is 1 V rms = 1.4 V pk = 2.8 V pk-pk. This is technically the "available power" from the source.

author: Hamelec
author_rank: Regular Contributor
timestamp: August 02, 2022, 03:33:21 pm
content: (I have never seen an RF generator where you can set the peak voltage, normally in µVrms or dBm only)

author: TimFox
author_rank: Super Contributor
timestamp: August 02, 2022, 03:34:43 pm
content: He's probably using a "function generator", rather than an "RF generator".

author: radiolistener
author_rank: Super Contributor
timestamp: August 02, 2022, 04:36:59 pm
content: Usually dBm power is specified for 50 Ω impedance.13 dBm = 1.41 Vpk = 2.82 Vpk-pk for 50 ΩIf your signal generator displays peak-to-peak Voltage, then you're needs to setup 2.82 Vpk-pk.If your signal generator displays peak Voltage (amplitude), then you're needs to setup 1.41 Vpk

author: TimFox
author_rank: Super Contributor
timestamp: August 02, 2022, 04:50:29 pm
content: That's assuming the generator output is calibrated for voltage into a 50 ohm load.Reasonable assumption for an RF generator, but not a safe assumption for a function generator.
Trimble Mini-T and TBOLTMON - Page 1
Forum section: electronics / rf-microwave

author: WPXS472
author_rank: Regular Contributor
timestamp: February 27, 2022, 06:12:29 pm
content: I recently acquired a Trimble Mini T GPSDO, and when I hooked it up, It didn't appear to be locked to GPS. I say this because there is a frequency offset between it and my existing T-Bolt. I noticed that the correct software to use with it is DSPMON. I have looked, and can't find that anywhere. At one time, you could download such software from their website, but no more. I had TBOLTMON, so I connected up the Mini-T, and it seemed to be working. But, the survey progress never gets past 0%. Will TBOLTMON work with the Mini-T? Is there some place where I can download DSPMON? When I connected my T-bolt, TBOLTMON says it isn't communicating, but that is another issue entirely.

author: WPXS472
author_rank: Regular Contributor
timestamp: March 01, 2022, 02:01:43 pm
content: Well, no one has replied, but I see that some have at least read the post. So, I'll give an update. I was able to get the Mini-T to do a self survey. The 10 MHz still didn't match the TBolt. Even though TBOLTMON isn't the recommended software, it does seem to work. I then tried Lady Heather, and it worked as well. Seems my TBolt has an intermittent power connection. I fooled with it a bit, and it started communicating, and after a few minutes, the 10 MHz agreed with the Mini-T with just a slow phase drift. I would still like to find a copy of DSPMON. If anyone can point me in the right direction, I would be most grateful.

author: bin10
author_rank: Contributor
timestamp: May 18, 2022, 09:03:41 am
content: You can find it here:https://xdevs.com/doc/Trimble/

author: WPXS472
author_rank: Regular Contributor
timestamp: July 29, 2022, 02:20:31 pm
content: Thanks much!
Please, help me identify SMA adapter - Page 1
Forum section: electronics / rf-microwave

author: lz_linux
author_rank: Newbie
timestamp: July 21, 2022, 09:27:12 am
content: Hi All,Please help me to identify an SMA adapter which Taoglas and other manufacturers of ceramic patch elements are using for interfacing their test fixture patch antenna setups. I can't find is it something custom or something commercially available.I want to avoid SMD SMA connectors, and looking to couple directly to the patch antenna pin, same time solder to the ground plane PCB.here is an image from their datasheethttps://www.taoglas.com/wp-content/uploads/2015/04/GP.1575.25.4.A.02.pdfhere is datasheet, page 14

author: TheUnnamedNewbie
author_rank: Super Contributor
timestamp: July 22, 2022, 07:23:30 am
content: I'm sorry but it seems a bit unrealistic to expect someone to identify a connector adapter based on a technical drawing that shows the connector as 3 rectangles, and on top of that no sense of scale.

author: lz_linux
author_rank: Newbie
timestamp: July 22, 2022, 08:26:59 am
content: Quote from: TheUnnamedNewbie on July 22, 2022, 07:23:30 amSorry, that my initial question sounds that I specifically looking what Taoglas is using, but their datasheet was most graphical and convenient to present. I found another, better one.I'm observing that almost all manufacturers of ceramic patch elements mention or show some kind of similar adapter in their evaluation test setups. Probably some of their RF engeneers are in that forum and they would like to answer to my post/question. Somebody will know how we can couple coaxialy to the patch element pin and the ground plane.Here some sort of technical drawing of that SMA adapter, position #3

author: Kean
author_rank: Unknown
timestamp: July 22, 2022, 07:05:43 pm
content: If I am understanding what you want correctly, maybe you could use an SMA female to SMA female flanged/bulkhead connector.Something likehttps://www.amphenolrf.com/132340.htmlorhttps://www.amphenolrf.com/901-9986-rfx.htmlThis will accept the central pin of the patch antenna assuming it is near the size of an SMA pin (~0.9mm) although it is overall probably bit longer than ideal.

author: lz_linux
author_rank: Newbie
timestamp: July 22, 2022, 07:29:34 pm
content: Kean, you are very close as idea. Meanwile I found solution.It will be perfect if the teflon insulator protrude 1 mm (that is the thicknest of the GP) above the flange

author: Kean
author_rank: Unknown
timestamp: July 22, 2022, 08:19:08 pm
content: Quote from: lz_linux on July 22, 2022, 07:29:34 pmIf you have access to a lathe, you could remove some of the outer material on the SMA connector to expose the teflon. Then solder the connector to the back of the GP, or add nuts/tin plate to space it out as needed.I might actually try making one of these myself as I have the odd need to evaluate patch antennas. Element14 have some 901-9986-RFX on special, but I may try first with a cheap SMA-F to SMA-F adapter.
The Small Unidirectional Loop Antenna (SULA) - Page 1
Forum section: electronics / rf-microwave

author: A.Z.
author_rank: Super Contributor
timestamp: August 20, 2022, 02:23:10 pm
content: after some months of fiddling, simulating and field testing, this (receive only) antenna is finally ready for anyone willing to try ithttps://swling.com/blog/2022/08/introducing-the-amazing-sula-an-affordable-unidirectional-dx-grade-loop-antenna-that-you-can-build/no miracle antenna, mind me, just the result of an idea which became a NEC model, a real thing and got refined and improved through a process which started months ago; if someone is curious, the whole "evolution" of the idea can be found herehttps://swling.net/viewtopic.php?t=47again, no miracles, just a small unidirectional antenna covering the whole HF bands and pretty good on V/UHF too, for the ones willing to try it, the latest design (along with the NEC model) is herehttps://swling.net/viewtopic.php?p=411#p411notice that while we (me and Ollie) used off the shelf components, nothing forbids one from using homemade ones, just... if someone will decide to try it, some feedback will be welcome

author: mag_therm
author_rank: Frequent Contributor
timestamp: August 20, 2022, 04:33:57 pm
content: Neat job.I played with loops about that size at VLF, but multiturn and resonant.If I ever get on 630 m (5 W eirp limit) I will first try a loop like that.At that frequency , resonant ferrite rods are also usable , having sharp nulls.

author: A.Z.
author_rank: Super Contributor
timestamp: August 21, 2022, 10:32:52 am
content: the SULA is a RECEIVE only loop and it has ONE main (cardioid) lobe and ONE null, as opposite to regular loops which have an eight shape pattern, plus its vertical aperture shows a low angle good for DX signals

author: A.Z.
author_rank: Super Contributor
timestamp: September 02, 2022, 11:46:53 am
content: for the interested ones, the 3rd part is online, full infos about building the SULA can be found herehttps://swling.net/viewtopic.php?t=55
TX harmoic of AD9361/9363 - Page 1
Forum section: electronics / rf-microwave

author: zkf0100007
author_rank: Contributor
timestamp: July 20, 2022, 01:49:30 am
content: I made a board using zynq and AD9363.The TX is amplified by ADL5611.I set the tx_lo_freq=1500MHz，the TX output is as shown below.What's the matter?

author: jwet
author_rank: Frequent Contributor
timestamp: July 20, 2022, 11:23:41 am
content: Looks like reference frequency leakage of 15.8 Mhz. Have a look at the eval board for the 9363, they likely do somethings to help this. The datasheet is a bit vague on reference leakage with no specs at 1500 but it might just be what the part does. DDS are known to have various spurs and feedthroughs at odd frequencies. ADI used to have a simulator or tool for their DDS chips that let you put in your reference, accumulator width, DAC spec and it would predict where the spurs would show up. Some of the hotter DDS had a thing called "Spurkiller" that would somehow suppress spurs in the internal DDS algorithm. DDS's are amazing but they do have their quirks.
DSA815-TG tracking generator reads -30dbm for -20dbm output - Page 1
Forum section: electronics / rf-microwave

author: spacehen
author_rank: Contributor
timestamp: August 06, 2022, 06:39:51 am
content: Hi everyone this might be a noob question but I recently acquired a DSA815-TG which comes with a tracking generator option. I currently don't have coax because I am in the process of ordering. So I decided to just use a thin 13cm wire to connect my TG output (centre pin) to the RF input port (centre pin) and set the TG output power to -20dBm. I was subsequently horrified at what I saw with a sharp downwards peak after about 50 MHz which goes from -20dBm to -30dBm. The response seems to be correct up until 30MHzI have attached two screenshots from the device with the TG directly connected to the RF input port using a wire.You can see that the response if correct for 0-20MHzNow my question is: Is this because I am not using coax or is this unit defective? The specs for output flatness read +-/3dBYour help is greatly appreciated. I just want to make sure the unit is not defective.

author: wn1fju
author_rank: Frequent Contributor
timestamp: August 06, 2022, 11:38:35 am
content: Mine does exactly the same as your photos with a piece of wire. All will be fine with proper coax.

author: spacehen
author_rank: Contributor
timestamp: August 06, 2022, 12:42:08 pm
content: That's a relief, I suspect the wire's self inductance is the root cause. At low frequencies the wire acts as an ideal inductor (follows a linear trend). However at higher frequencies the behaviour becomes more complex I guess.Thanks though

author: geggi1
author_rank: Frequent Contributor
timestamp: August 07, 2022, 07:23:09 am
content: The straight wire will work as a tuned circuit and add attenuation as the frequency increases.
The SV4401A low cost VNA ($350 USD) - Page 1
Forum section: electronics / rf-microwave

author: joeqsmith
author_rank: Super Contributor
timestamp: July 11, 2022, 12:30:03 pm
content: https://usa.banggood.com/SV4401A-50KHz-4400MHz-Vector-Network-Analyzer-7-inch-Touch-Screen-100db-Dynamic-NanoVNA-Vector-Network-Analyzer-p-1953814.html?cur_warehouse=CNClaim 100dB dynamic range below 1.3GHz. 1001 data points at 400 data points per second and 25 averages. Very slow as we would expect.50kHz low end is nothing new.They claim the 6700mA/hr is a feature. I don't see where they talk about the run time.It looks like it may have a built in step attenuator for the output level w/ 1dB resolution.They don't mention the serial interface protocol and that would be a deal breaker for me.If you get one, post some data off it.

author: Grandchuck
author_rank: Super Contributor
timestamp: July 11, 2022, 09:12:00 pm
content: I wonder if it would support the design of crystal filters?

author: joeqsmith
author_rank: Super Contributor
timestamp: July 12, 2022, 12:35:09 am
content: Yes, measuring crystals and crystal filters would be a good one. I doubt it would work with that anti-gain, tuned amplifier I put together to demonstrate a case where the squarewave drives can cause a problem. If they cap the bottom end at 50kHz and it's closed source, the original may still out perform it on the lower end. Does the firmware crash after 10 minutes of use?

author: LM21
author_rank: Regular Contributor
timestamp: July 18, 2022, 04:04:28 pm
content: Clone of NanoVna2?
Decoding James Webb Space Telescope - Page 1
Forum section: electronics / rf-microwave

author: sarbog
author_rank: Contributor
timestamp: July 14, 2022, 04:05:57 am
content: Very interesting post by Daniel Estevez Seehttps://destevez.net/2021/12/decoding-james-webb-space-telescope/

author: sarbog
author_rank: Contributor
timestamp: July 16, 2022, 11:12:39 pm
content: Here is a screen shot of the baseband telemetry, provided by Daniel Estevez, being decoded. I'm running Ubuntu 22.04 with GNU Radio 3.10.xx on a 10 year old iMac. The raw IQ data was recorded using the Allen Telescope Array the day after JWST was launched.
NEC2,  2 Port Admittance card (NT) query. - Page 1
Forum section: electronics / rf-microwave

author: mag_therm
author_rank: Frequent Contributor
timestamp: July 10, 2022, 09:13:29 pm
content: I have a transmission line modeled as two parallel wires. It seems to solve correctly for the impedances of an excitation at the feed point.I need to simulate and adjust a series L or C equally in both sides of the transmission lineIt appears the only way is to add a lumped 2 port network (NT card) in between that transmission line and the EX.The NT card only has Y11, Y22, and Y12.Q1: Is that for an Balanced Ladder where Y12 = Y21 or an UNBalanced Ladder where Y21 would be infinity?Q2: If "Balanced", Is a value in Y12 DOUBLED and placed on each side?Note, Reading Manual Page 62 and Fig 17 ,If Y12 is set 0, that makes BOTH sides of the unbalanced ladder to be open circuited .Carrying that logically, it might mean answer to Q1 is "Balanced"Q3: Is there any way of adding the primary values (ie uHenry or pFarad) to get the solution in a frequency scan?Maybe someone here has done this before.Thanks
Shortwave Australia - Page 1
Forum section: electronics / rf-microwave

author: vk3yedotcom
author_rank: Frequent Contributor
timestamp: July 08, 2022, 12:53:28 pm
content: Something new to listen on shortwave, at least for those in south-east Australia.Transmitting from central Victoria 3pm - 8pm approx.4835 & 2310 kHz. With varied content.Started a couple of days ago.Approx 100-200w but signals in Melbourne can still be quite strong, especially on the higher frequency around 5 or 6pm.More:

author: mag_therm
author_rank: Frequent Contributor
timestamp: July 08, 2022, 05:56:26 pm
content: It seems a pity that Lyndhurst Time Signal and Radio Australia were shut down completely.Radio NZ (RNZI) to Michigan is ~ 15,000km from West.Sometimes S9 on 13840 kHz this year.The carrier on RNZI 5980 today was just audible above the noise after the path had closed.Last night swl on ft8 4:00 to 7:00 UTC, 20m about (20) of VK and ZL were logged. Trying 17m now & tonight.

author: Scherms
author_rank: Regular Contributor
timestamp: July 09, 2022, 04:34:44 pm
content: There is nothing to listen to on SW... as the internet superseded it years ago!

author: RoGeorge
author_rank: Super Contributor
timestamp: July 09, 2022, 05:51:28 pm
content: Around the world, if the radio signal is too weak but the Internet is good:http://radio.garden/

author: mag_therm
author_rank: Frequent Contributor
timestamp: July 10, 2022, 03:38:11 pm
content: 17 m Band ft8 swl to Michigan from VK was open UTC 1:00 to 9:00. Solar Flux Index 148 . Out of 194 DX, I only logged 2 from VK/ZL.https://app.box.com/s/tkgw0idqzoeqv78bb83zpzjnagtcsx3pOf course it depends on many VK are active on 17 as well as the band conditions.20m is packed with ft8, 18m is a lot less active.
Help identify device - Page 1
Forum section: electronics / rf-microwave

author: vk3gm
author_rank: Newbie
timestamp: July 06, 2022, 06:33:51 am
content: Hi All,First post.I have several VMMD-S1498-Q100-K100 devices. These are fantastic RF amplifiers/modulators.Spent some time characterising one unit based on the very limited information I could find.With out notice, this post is to see who may know more and has further explored other pin function?Any feedback is welcome.RegardsGerald
wide range analog VCO wanted  90-210Mhz - Page 1
Forum section: electronics / rf-microwave

author: bnevins
author_rank: Newbie
timestamp: March 23, 2021, 12:52:30 am
content: I would like an analog VCO or PLL-VCO that can voltage tune from 90MHz to 210MhzThe closest I found is TLC2934. It reaches 130MHz, and is "last time buy"I thought such chips were common, but they are going extinct.There are other solutions, but this is the easiest for my goal.

author: geggi1
author_rank: Frequent Contributor
timestamp: March 23, 2021, 03:11:37 am
content: There is a lot of digital ones if that can be used.The SI-5351 is hackable up to 225Mhz but its a square vave.

author: rfdave#gmail.com
author_rank: Contributor
timestamp: March 27, 2021, 10:28:40 pm
content: A PLL isn't generally voltage tuned. That frequency sweep is pretty aggressive for 90 to 230 MHz. How about sweeping 1.0 to 1.2 GHz, and mixing down to 90 to 210 MHz?

author: Joop
author_rank: Newbie
timestamp: April 02, 2021, 12:31:17 pm
content: Mini-Circuits POS-200. Also end of life, but you may find it here and there.

author: bnevins
author_rank: Newbie
timestamp: July 05, 2022, 11:35:56 am
content: Thank you for all the suggestions!
GNU Radio and APRS - Page 1
Forum section: electronics / rf-microwave

author: sarbog
author_rank: Contributor
timestamp: June 30, 2022, 09:32:32 pm
content: I made modifications to the project gr-APRS - A GNU Radio Block for Receiving APRS athttps://handiko.github.io/gr-APRS/to work with GNU-Radio 3.10.2.0 on Ubuntu 22.04Below are screenshots of the flow graph and output. The PDU vector contents are visible lower left and AX.25 packet on bottom.Note: A modification is needed to the software that converts from HDLC to AX.25 to avoid the error "Unexpected stop of address section"

author: sarbog
author_rank: Contributor
timestamp: June 30, 2022, 09:38:52 pm
content: The only file I modified was gr-APRS/Examples/APRS_RX_RTL.grc

author: sarbog
author_rank: Contributor
timestamp: July 03, 2022, 11:36:49 pm
content: Well...... the embedded HDLC to AX.25 blocks needs lots of work!
Need help identifying a 2.4Ghz antenna - Page 1
Forum section: electronics / rf-microwave

author: vamax
author_rank: Newbie
timestamp: July 03, 2022, 04:36:35 pm
content: Dear colleagues,I need help identifying what type is the antenna on the pictures and how it works!Maybe omni ground plane!?Thanks in advance!Dimiter

author: S57UUU
author_rank: Regular Contributor
timestamp: July 03, 2022, 06:31:15 pm
content: Without those screws, this would be an omnidirectional GP antenna. Not sure what those screws do, or where they connect - for an effective GP they should NOT be there, especially if grounded.The coaxial stub is probably an attempt at extending the bandwidth (matching).Marko Cebokli

author: vamax
author_rank: Newbie
timestamp: July 03, 2022, 07:01:57 pm
content: The M2,5 screws just hold the double side 1mm FR4 PCB attached to the aluminum body!For my it also looks like Omni GP antenna. What I don`t understand is this "stub" connected to the GND.The length of the brass tube - 27mm match for an 1/4 GP antenna for 2.7GHzBut the center RF of the device is 2.43GHz

author: S57UUU
author_rank: Regular Contributor
timestamp: July 03, 2022, 07:16:36 pm
content: The electrical length of the stub also depends on the dielectric within the tube. As I said, it's probably a kind of impedance compensator, to extend the bandwidth of the match.It could also be there just to ground the center pin, for receiver ESD protection. In that case lambda/4 would be best, because the short on top would transform into open at bottom.Do the screws have insulating washers below their heads? But why the strange pattern (not all at the same radius)?

author: vamax
author_rank: Newbie
timestamp: July 03, 2022, 07:26:04 pm
content: No insulation washers on the bolt heads!The threads in the aluminum body are also used to attach the RF board from the back side.I suppose the strange radius is because to match the board design!
REVISIT: Icom IC-7000    HF/VHF/UHF All Mode Transceiver - Page 1
Forum section: electronics / rf-microwave

author: Scherms
author_rank: Regular Contributor
timestamp: June 28, 2022, 05:09:06 pm
content: Icom IC-7000 HF/VHF/UHF All Mode TransceiverA revist on one of Icom's iconic and very popular pre SDR sets the IC-7000.https://icomuk.co.uk/files/icom/PDF/productLeaflet/IC-7000.pdfNOTE:If Craig had turned on the ANF 'auto notch filter' that interference would have been notched out!Quote

author: TheSteve
author_rank: Unknown
timestamp: June 28, 2022, 10:58:07 pm
content: Still have mine, bought it brand new years ago. It is my backup/portable rig.

author: Scherms
author_rank: Regular Contributor
timestamp: June 30, 2022, 07:03:47 am
content: http://www.qrz.com/ic-7000_review.htmlhttp://www.ad5x.com/images/Presentations/IC7KreviewRevA.pdf

author: iMo
author_rank: Super Contributor
timestamp: June 30, 2022, 07:43:30 am
content: @TheSteve: nice tactical holders.. In past I made myself a prototype (see below), but still not cut them off the aluminum (the cutting too expensive here)..

author: Scherms
author_rank: Regular Contributor
timestamp: July 01, 2022, 05:11:47 am
content: Quote from: imo on June 30, 2022, 07:43:30 amhttps://tac-comm.com

author: Scherms
author_rank: Regular Contributor
timestamp: July 02, 2022, 04:19:14 pm
content: Here is my Icom IC-7000, bought new and always run fan assisted...❤️
Low Frequency Mixer - Page 1
Forum section: electronics / rf-microwave

author: abquke
author_rank: Regular Contributor
timestamp: July 01, 2022, 09:11:14 pm
content: I've been looking around for chip mixers to implement a low frequency (100kHz-1MHz) lock in amplifier. Seems like in RF that 0GHz starts somewhere around 70MHz. The other way I can think to do it would be a dual-gate FET or the heavy-HAM way of a transistor-with-transformer circuit. Hopefully I'm not seeing the obvious?

author: BigBoss
author_rank: Regular Contributor
timestamp: July 01, 2022, 09:21:28 pm
content: There are very popular ICs here. Select a appropriate one.https://www.nxp.com/products/radio-frequency/rf-mixers:MC_71683

author: bd139
author_rank: Super Contributor
timestamp: July 01, 2022, 10:39:22 pm
content: AD633 multiplierhttps://www.analog.com/media/en/technical-documentation/data-sheets/ad633.pdfThink the MC1496 is still available. That's a gilbert cell so will go to DC. Also SA612.Depends what's driving it etc really.

author: David Hess
author_rank: Super Contributor
timestamp: July 01, 2022, 10:41:47 pm
content: Instead of a mixer look for an analog multiplier.

author: abquke
author_rank: Regular Contributor
timestamp: July 01, 2022, 10:55:39 pm
content: Heyyyy exactly what I needed. Thanks!

author: TimFox
author_rank: Super Contributor
timestamp: July 01, 2022, 10:58:07 pm
content: -hp- used the 1496 balanced modulator IC in their low-frequency spectrum analyzers and selective voltmeters.
SDR with LO input - Page 1
Forum section: electronics / rf-microwave

author: bnevins
author_rank: Newbie
timestamp: July 05, 2022, 11:40:36 am
content: Is there a way to apply a "local oscillator" input to an SDR, so that theSDR output is the down converted spectrum in the vicinity of the LO frequency?

author: A.Z.
author_rank: Super Contributor
timestamp: July 05, 2022, 12:10:19 pm
content: check out thishttps://www.rtl-sdr.com/hooking-up-an-si5351a-voltage-controlled-oscillator-to-the-local-oscillator-input-on-an-rtl-sdr/

author: radiolistener
author_rank: Super Contributor
timestamp: July 06, 2022, 01:27:15 pm
content: Quote from: bnevins on July 05, 2022, 11:40:36 amjust use some Chinese mixer, like that:https://www.aliexpress.com/item/1005004266323916.html
863-865MHz generation and detection - Page 1
Forum section: electronics / rf-microwave

author: Trotters_Independent2
author_rank: Contributor
timestamp: June 26, 2022, 08:49:05 pm
content: Hi allA brief explanation of my background: I am experienced in working with microcontrollers and power electronics but I'm not experienced in high frequency electronics where I have to worry about transmission line effects. In the past I have studied things like impedance matching and reflections so I have a rudimentary awareness of these things but I have absolutely no practical experience.What I am trying to do:I am working on a home project which, in order to implement my idea, would involve detection of standing waves in the 863-865MHz frequency range along varying lengths of transmission line - I was thinking of making a germanium diode RF peak-detector/de-modulator probe in conjunction with my oscilloscope to measure them, like in this video:But I am really not sure how to generate the wave:I am not trying to transmit any information by modulating it - I only want to detect its presence. I don't want any more than 25mW of transmission power and I want to be able to operate it in a burst-mode. Where I would transmit for maybe 1-10 micro-seconds at a time. When I started on this idea, I envisioned being able to find a simple chip that would cost a few £ (perhaps with a configurable output frequency and power) which I could just pulse an enable line with a microcontroller and it would simply output the desired frequency in the "burst" fashion that I want. But I am struggling to find what I want.Could anyone point me in the right direction? Is what I am trying to implement even realistic?Thanks a lot

author: Trotters_Independent2
author_rank: Contributor
timestamp: June 26, 2022, 10:11:45 pm
content: Thank you, very much appreciated. I shall have a look at these.

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: June 29, 2022, 11:36:16 pm
content: There are several different cell phone and cell tower service monitors that work very well in this freq range.I have two HP 89935 and Agilent 7495.I do not know anything about the burst detection issue however. Maybe there is a way to detect bursts with this type of equipment.Perhaps someone here might know?

author: themadhippy
author_rank: Super Contributor
timestamp: June 29, 2022, 11:57:01 pm
content: Fantasic ,more noise clogging up the the license exempt radio mic band here in the uk.

author: Trotters_Independent2
author_rank: Contributor
timestamp: June 30, 2022, 05:34:14 pm
content: Exactly! If my idea is successful, I am hoping to sell millions of these things. And you'll have to say goodbye to your precious radio mics, which will all be rendered totally useless across the whole country by my genius! You're gonna have to haul your stupid mics off to Timbuktu, mate.... if you still wanna use them. See ya, bye bye - now!
Witec Instruments Pulse Forced Mode any suggestions for testing it? - Page 1
Forum section: electronics / rf-microwave

author: jorgeh
author_rank: Regular Contributor
timestamp: July 07, 2022, 07:31:11 pm
content: Hi.I got a bunch of equipment from a decommisioned Atomic Force Microscope. and I wonder if there is a way I can test for basic functionality a Witec Instruments Pulse Forced Mode.It appears to work but I honestly dont know if its working correctly.TIA J