hybridfree/eevblog-posts huggingface dataset:
L-section impedance matching - spreadsheet / homepage - Page 1
Forum section: electronics / rf-microwave

author: hilper
author_rank: Contributor
timestamp: June 28, 2022, 12:47:51 pm
content: HiDo anybody has a spreadsheet (or know a homepage) which can calculate all the potential 8 combinations of matching topologies (using L & C components).

author: hilper
author_rank: Contributor
timestamp: June 28, 2022, 10:36:22 pm
content: Thanks a lot - evb149
URV55 repair - Page 1
Forum section: electronics / rf-microwave

author: mr_D
author_rank: Newbie
timestamp: February 17, 2022, 03:28:28 am
content: Hi everyone !I,ve problem with URV55 of R&S. But I don,t understand its.Can everyone help me !

author: radiolistener
author_rank: Super Contributor
timestamp: February 17, 2022, 03:58:33 am
content: looks like some issue with calibration

author: mr_D
author_rank: Newbie
timestamp: February 17, 2022, 04:20:05 am
content: cause out of battery 3.6 V. I replaced the battery with a new one but still no result

author: George Edmonds
author_rank: Frequent Contributor
timestamp: February 20, 2022, 09:49:21 am
content: HiI suspect that you now have a some electronic junk, If the battery goes flat or it is changed without the unit on power all the calibration information is lost.The instrument is calibrated over GPIB using unobtainable software.G Edmonds

author: rf-messkopf
author_rank: Regular Contributor
timestamp: February 20, 2022, 08:30:57 pm
content: Quote from: George Edmonds on February 20, 2022, 09:49:21 amIf I remember correctly, and if the URV55 is like the NRVD, the calibration procedure and the requisite GPIB commands are documented in the service manual. Without the R&S service software, you could do the procedure by hand for each range and write the cal constants via GPIB manually (or create your own script).The procedure requires a DC calibrator (also under GPIB control when using the R&S software) as well as a special pod that feeds the DC voltage from the calibrator into the instrument. You would have to reproduce that as well somehow.I think there also is a command that dumps all calibration values to GPIB, in case you want to save them.

author: Antonio Borda
author_rank: Newbie
timestamp: June 28, 2022, 07:01:31 am
content: Hello dear Om,Have you found a solution to recover the problem of error calibration, I recovered 2 MILLIVOLTETER URV55 with the same symptoms.Best regardsb.Antonio
weather science? - Page 1
Forum section: electronics / rf-microwave

author: coppercone2
author_rank: Super Contributor
timestamp: July 04, 2022, 06:34:09 am
content: Is there any interesting weather/climate/atmospheric related science that can be done with transmitters or receivers?Stuff like this:https://science.nasa.gov/science-news/citizenscience/ham-radio-operators-tune-in-to-giant-waves-in-the-earths-ionosphereHas anyone gathered any interesting data at home? (I mean without connecting to a satellite to download data). I read about upper atmosphere hydrogen reactions that make green house gasses, maybe those make some kind of emissions? (like maybe HF 'ambient' noise has some components, like has ambient noise changed in the last 50 years? we know the sun is a big contributor, but maybe other stuff can be identified?)

author: RoGeorge
author_rank: Super Contributor
timestamp: July 04, 2022, 01:42:15 pm
content: My understanding is right now (these days) it's a massive solar sunspot facing earth, so that's why I think the different ionospheric propagation in ham.Random search result:Quotesource:https://earthsky.org/sun/sun-activity-solar-flare-cme-aurora-updates/

author: coppercone2
author_rank: Super Contributor
timestamp: July 04, 2022, 08:50:15 pm
content: But has anyone actually managed to do any of this stuff? HAARP (first thing that came to mind really) is a gigantic government effort. Has anyone managed to do anything useful DIY that translated into some kind of data that had scientific impact?Like the worldwide lightning map is interesting I guess. I kinda wanted projects like that. Not sure if its all node based.
Large Antenna or multiple 1/n wave in parallel  for 868mhz - Page 1
Forum section: electronics / rf-microwave

author: imk
author_rank: Regular Contributor
timestamp: June 26, 2022, 11:58:18 am
content: HelloI am using some ZULU-2 Radio modems with a PC base station and a mobile device.For the mobile device i am pretty much stuck with 1/4 or 1/2 wave and or their variants because of it mobile nature.But for the base station I have a lot more flexibility with respect to type and size.So question is it better to have a single n times wave length antenna (long whip) or multiple say 1/4 wave in parallel?May seem a dumb question but i am not an RF person or have any test equipment that goes up to 868mhz so cant measure signal strengthmany thanks imk

author: geggi1
author_rank: Frequent Contributor
timestamp: June 26, 2022, 02:20:40 pm
content: Get a phased vertical if you need a omni directional antenna and a beam antenna if you can use a directional.

author: A.Z.
author_rank: Super Contributor
timestamp: June 26, 2022, 05:28:38 pm
content: Quote from: geggi1 on June 26, 2022, 02:20:40 pmor just build a h doublebay antennahttps://sites.google.com/site/wvfisher/hdoublebay
Trees (the backyard kind) as antennae link - Page 1
Forum section: electronics / rf-microwave

author: cdev
author_rank: Super Contributor
timestamp: May 19, 2022, 02:47:59 pm
content: I just noticed This thread on another site, its got a couple of links in it to other resources. Why not? They do help reception on my mini whip a lot when the two are put next to one another.https://www.eham.net/article/8916

author: Scherms
author_rank: Regular Contributor
timestamp: June 24, 2022, 03:35:41 pm
content: This might help...https://web.archive.org/web/20060507092526/http://www.comsistel.com/HAM%20documents/Trees01141017.pdfhttps://web.archive.org/web/20050219023326/http://www.comsistel.com/nuova_pagina_2.htm

author: coppercone2
author_rank: Super Contributor
timestamp: June 24, 2022, 05:56:46 pm
content: Is the capacitive collar just conductive tape wrapped around a tree?

author: Scherms
author_rank: Regular Contributor
timestamp: June 24, 2022, 09:56:21 pm
content: Quote from: coppercone2 on June 24, 2022, 05:56:46 pmSeems so...
Ham and Antarctica  - Page 1
Forum section: electronics / rf-microwave

author: coppercone2
author_rank: Super Contributor
timestamp: May 18, 2022, 04:46:34 pm
content: I found this interesting from a historical prospective m, it is about how ham operators allowed for improved communications with Antarctic expeditions many years agohttps://hackaday.com/2022/05/17/when-hams-helped-polar-researchers-come-in-from-the-cold/

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: May 18, 2022, 06:53:19 pm
content: My "Uncle" actually a second cousin,was the base chaplain during the IGY. It was really cool to get a Christmas card from Antarctica!!!!

author: cgroen
author_rank: Unknown
timestamp: June 14, 2022, 08:50:30 am
content: DP0GVN is active using QO-100, heard them just the other day doing QSO's and talking with (I think) a German schoolhttps://amsat-dl.org/category/dp0gvn/(probably not too interesting for US based Hams.....)

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: June 14, 2022, 11:30:47 am
content: I also know a local Ham who operated the base station in Antartica which was the primary way for the sailors to contact home.He says that the radio was a Kenwood 520. This was in the 70's

author: coppercone2
author_rank: Super Contributor
timestamp: June 23, 2022, 11:22:44 pm
content: I wanna see if I can receive that satellite one day, working on itgonna be busy servicing the 8015 for a while though, and again the rack buckled under weight, I really need to add a structural support. The theory that all the weight was on one side and a single reinforcement was enough was not correct.But TBH its worth taking them apart and putting some grease on the screws and whatnot, the chassis was like fused in some places, and I am sure the ground was not the best... and so much dust was removed. Damn corrosive primary cell chemistry.
matching, determination of microstrip line impedance - in the design - verificat - Page 1
Forum section: electronics / rf-microwave

author: max-bit
author_rank: Frequent Contributor
timestamp: June 22, 2022, 07:23:37 am
content: I want to verify the correctness of the project because something is wrong in this project (Or maybe I am wrong):This projekt:https://www.barbouri.com/2017/03/12/low-noise-amplifier-for-sdr-radio-ads-b-ver-2-3-with-1090mhz-ceramic-filter/parameters of tracks and laminate (dimensions):Laminate - FR-4 (?) 1,5mm (1.6mm)4 layers (3 layers of laminate (each 0.5mm thick))Type microstrip:- conductor width 18 mils- conductor height 20 mils (0,5mm)Er (Fr4) = 4.3Resulting impedance parameters of 70 Ohm- ERROR !correct track width (for FR-4, Er = 4.3) 36 milsWho is wrong, me or the author?The author did not provide the PCB thickness and PCB type (Rogers etc?)

author: max-bit
author_rank: Frequent Contributor
timestamp: June 22, 2022, 08:12:25 am
content: There are many factors that influence impedanceI checked on several "calculators" and on all of them, the ones on the original PCB come out of the design around 70 Ohm (+ -3) and not 50 Ohm. The thickness of the tin coating (not counted or soldermask) slightly affects the impedance.

author: max-bit
author_rank: Frequent Contributor
timestamp: June 22, 2022, 08:39:19 am
content: The frequency has been included.Maybe the manufacturer "ensured the impedance" of the line later.

author: max-bit
author_rank: Frequent Contributor
timestamp: June 22, 2022, 08:49:54 am
content: GCPW is probably not ...I don't think it's an advanced microstrip there is no indication of that.

author: ThomasDK
author_rank: Regular Contributor
timestamp: June 22, 2022, 10:00:16 am
content: Quote from: max-bit on June 22, 2022, 07:23:37 amThe author specifies OSH-PARK 4-layer boards, all your assumptions are wrong:https://docs.oshpark.com/services/four-layer/

author: max-bit
author_rank: Frequent Contributor
timestamp: June 22, 2022, 10:53:49 am
content: And it all fits.H - 8milsImpedance = 50 Ohm

author: rfclown
author_rank: Frequent Contributor
timestamp: June 22, 2022, 11:12:27 pm
content: I just made a 4 layer board with OSH Park. Go to their site and see the stackups. The one I used is H=8 mils (top to layer 2), er=3.68, thickness (plated)=1.7 mils. 16 mil microstrip width gives a 50 ohm line based on the calculators that I use (AppCAD and AWR TXLINE). I had ground 31 mils from the trace (grounded coplaner waveguide), so my trace was a little wider.
I have a question about this c-band LNBF - Page 1
Forum section: electronics / rf-microwave

author: Ben321
author_rank: Frequent Contributor
timestamp: June 20, 2022, 01:36:38 am
content: I notice it says that it is an LNB filter, not an LNB. Does that mean that this is a filter that is used in conjunction with an LNB, to filter out interference? Or is it actually itself an LNB, that just has a builtin filter for blocking interference?https://www.amazon.com/Titanium-Satellite-C238-5g-Interference-3800-4200MHz/dp/B09PTCXLCW/

author: Ben321
author_rank: Frequent Contributor
timestamp: June 20, 2022, 08:50:17 pm
content: Well, it does look like it's an actual LNB, as it has a local oscillator specification. Here's a picture I found on the Amazon page for it.https://m.media-amazon.com/images/I/51XdtmeGKYL._AC_.jpgWhat's really interesting though, is that the local oscillator frequency is just above the highest frequency in the intended receive band, rather than just below it. Not only will all of the transmissions be down-shifted into an easier to process frequency band (as an LNB is supposed to do), the result of the way that's being done with this specific LNB is that the output of this LNB will have all of its frequencies FLIPPED. This means that received transmissions at a higher frequency will be lower in output frequency than received transmissions at a lower frequency. This also meant that the frequencies will be flipped within a given RF channel. For example, if digital data was transmitted with FSK with mark being the higher tone and space being the lower tone, the output of this LNB will flip those so that mark will be the lower tone and space will be the higher tone. This makes actually receiving downshifted signals very complicated, because you will need to re-invert the frequencies in whatever receiver is using this LNB as its signal source, in order to make the signals appear correctly in the frequency space.

author: yl3akb
author_rank: Regular Contributor
timestamp: June 21, 2022, 11:30:32 am
content: Demodulation is usually done at baseband/dsp domain and flipping the baseband spectrum is as simple as inverting the sign of I or Q or swapping the I and Q, so not very complicated at all. On the other hand, with high-side LO, image band is at higher frequencies which is easier to filter out.

author: El Rubio
author_rank: Regular Contributor
timestamp: June 22, 2022, 12:49:43 pm
content: If you don’t mind my asking, are you getting interference from 5 G networks, or anticipating it? Is this for Satellite TV? Sometimes, and I don’t know this to be true with C-Band, wireless carriers are responsible for providing filters for interference caused by repurposed bands. It’s not always the case and I haven’t heard anything about this, but it’s worth looking into if you are having problems.
Zigbee or other "ready to use" Modulefor 433 or 868? - Page 1
Forum section: electronics / rf-microwave

author: Lord of nothing
author_rank: Super Contributor
timestamp: September 10, 2017, 01:34:32 pm
content: HiAre there any Ready to use Modules for 433, 868 to allow me to transfer any Data legally on one or both Bands?Maybe Zigbee?

author: imk
author_rank: Regular Contributor
timestamp: June 20, 2022, 07:49:27 pm
content: https://www.rfsolutions.co.uk/radio-modules-c10/zulu-wireless-serial-data-radio-modem-module-p390and other on same site
EMSCAN RFXpert Software? - Page 1
Forum section: electronics / rf-microwave

author: DaJMasta
author_rank: Super Contributor
timestamp: March 02, 2022, 04:27:39 am
content: I had the good fortune to get one of these neat devices, an RFXpert RFX2, but without operating software, and am wondering if anyone has a copy of it. From a little research, the company shut down in 2018 or so, and from the description in the manual and the archive of the old site, I don't believe the software was ever distributed online, just as a thumb drive that would normally have come with the unit. I also haven't been able to locate any signs of an open source driver or API that I could write my own stuff with, but I'd be happy to be proven otherwise.If you've got a copy or know something about it and are willing to share, I'd appreciate it. If you can point me in a direction where I could get a copy, for pay or otherwise, that would also be appreciated - I don't even know who bought the EMSCAN assets or who may have any rights to the software or technology now, though there's mention of a YIC Tec operating at least some support services for them at one point.

author: DaJMasta
author_rank: Super Contributor
timestamp: March 10, 2022, 06:46:34 am
content: Well a new search with slightly different terms yielded some results: the company that bought EMSCAN is YIC Technologies in the UK (https://yictechnologies.com/), not the Chinese YIC Tec, and that they are making newer versions and software beyond what EMSCAN made. I asked their contact line if software was available for the older units, and while they explicitly said the old units were not supported (there is some sort of trade in program on their site), they were also willing to send along a zip of the software, and I was able to get it installed and running with no issues!My extremely crude first test already points in some interesting directions:

author: caEMI
author_rank: Newbie
timestamp: March 15, 2022, 08:27:14 pm
content: Hi DaJMasta:We have an EMScan EHx and the software has somehow been misplaced. I contacted YIC and they are trying to sell me a new unit. Reluctant to provide the software.Any chance of getting it from you? Would be much appreciated. Would definitely buy you a beer or beverage of your choice in return if you are in the bay area.Thanks.

author: coldSolder
author_rank: Newbie
timestamp: June 21, 2022, 11:56:06 pm
content: Hello DaJMasta,I was also fortunate to acquire an EMSCAN system. However, mine is the EMSCAN NEXUS Plus or Nexus+. It didn't come with any control software either. Do you know if the .zip that you received supports multiple models? If so, would you be willing to share your copy?Best regards,coldSolder
FCC Waiver how hard? - Page 1
Forum section: electronics / rf-microwave

author: bugnate
author_rank: Regular Contributor
timestamp: June 15, 2022, 10:50:47 pm
content: I have a product in development which I intend to submit as a part 15 device to the FCC but will need waivers (more than one). I have the FCC filings for a very similar (but not identical) device which successfully navigated this and I don't see why I couldn't get the same treatment in principle. The thing is, previous filings were handled by a $600 per hour DC law firm. I'm not exactly cheap but I am loathe to do the same.Is the waiver process navigable by an engineer or two without legal experience, given that I have a pretty good blueprint to follow from the other filings? I'm not in a hurry. I understand that the "not identical" part could trip me up but I am taking that risk.If it is a bad idea or otherwise, I'd appreciate any suggestions / referrals / resources. I've had some feeler discussions with testing labs but frankly have left unimpressed or empty handed so far.

author: Gribo
author_rank: Frequent Contributor
timestamp: June 16, 2022, 04:47:05 pm
content: What sort of waiver? Which section of part 15?

author: bugnate
author_rank: Regular Contributor
timestamp: June 16, 2022, 07:22:27 pm
content: The waivers are for a variety of sections. Some for relatively minor EMI reasons, some for measurement/methodology tweaks, and some tweaking higher level rules. The other device I am looking at needed at least 5 waivers. So I know it can be done, it is just a question of effort.
Irobot virtual wall RF (MC13202FC) broken and obsolete. Replacement or source? - Page 1
Forum section: electronics / rf-microwave

author: jorgemef
author_rank: Regular Contributor
timestamp: June 16, 2022, 05:06:53 pm
content: Hello,One of the my virtual wall/lighthouse from my Irobot got broken.It contains R3MOD24A 2.4 GHz Module and RF chip seems damaged.https://fccid.io/UFE-R3MOD24A/External-Photos/Pix-Ext-7812062.4 GHz Low Power Transceiver for the IEEE® 802.15.4 StandardAfter debugging I traced it to MC13202FC. VDDINT and VDDD pins are showing low resistance to EP ( 5/6 ohms).The module interface are:Left:GPIO2GPIO1/RSTRXTXEN/ATTNCLKOGNDRight:VBATTGND/IRQ/CEMISOMOSISPICLKIt interfaces with a main board with MCU MC9S08QG8. Main board is in good shape.Unfortunately the chips seems to be obsolete now and not available anywhere. There are some merchants still with it but shipping price is almost the price of the virtual wall.Any alternative to this chip or RF board, or an affordable provider? Replacement indicated by NXP (JN5169 and JN5189) is not a direct fit. Even if I wire solder one of those not sure if it would work the same.Else I need to scrap it/purchase a chinese replacement. Maybe the original chip which is broken will came in.Cheers,Jorge

author: james_s
author_rank: Super Contributor
timestamp: June 16, 2022, 05:39:56 pm
content: Virtual walls can often be found pretty cheap on ebay, I don't think I've ever paid more than $15 for one. If the RF chip is not readily available that is probably your best bet. You can look for a beat up dirty one and put the board from it in yours.
Aim-TTI TGR2050 1.5Ghz RF Sig gen or the Rigol DSG821 - Page 1
Forum section: electronics / rf-microwave

author: gb243
author_rank: Contributor
timestamp: June 15, 2022, 03:49:22 pm
content: I am mulling over purchasing one of these two RF signal generators. Mostly for alignment of receiver IF stages and general learning and playing about with RF/filters. I have a soft spot for Aim-TTI and will probably add one of their PSUs to my lab soon. However Rigol is often quite good bang for the buck, and it comes with a free DSG-800 PUG option (pulse train generation). Has anyone experience of either of these two machines and have strong opinions as to the good and bad of each? Like my scope I will probably only use 5% of their capabilities but I still do not want to buy a donkey.

author: bd139
author_rank: Super Contributor
timestamp: June 15, 2022, 04:12:16 pm
content: Worth looking at an older HP unit from a reseller unless you need specific features or a Marconi 2019A if it goes high enough. They have a better specification and less capital expenditure for trivial cases.If the IF is under 100Mhz buy a Rigol DG811 and crack it and use that.

author: gb243
author_rank: Contributor
timestamp: June 15, 2022, 04:22:49 pm
content: Thanks for the reply. I already have a function generator and want to go to very low signal levels. Well below -100dBm. I know some older second hand kit can also be good value but knowing my luck I would have issues so a warranty would help.

author: bd139
author_rank: Super Contributor
timestamp: June 15, 2022, 04:31:53 pm
content: Use the FG and an external step attenuator. There will be some leakage but it’s probably cheaper.I like the Marconi units myself. If they break it’s a good learning exercise too

author: gb243
author_rank: Contributor
timestamp: June 15, 2022, 05:04:38 pm
content: You are 100% correct of course. There again I admit to being an idiot. This purchase is part of a lab revamp and all my cheap and cheerful (and often rubbish) ebay kit is going. There is an element of 'shiny' new kit here and cost is not too important. Apart from Rohde and Schwarz. I always thought they were expensive and good but now the price performance ratio is starting to look bad.

author: bd139
author_rank: Super Contributor
timestamp: June 15, 2022, 05:15:45 pm
content: Best to start with the problem you are solving and the budget and work back. One thing with expensive test gear is it depreciates faster than new cars do

author: gb243
author_rank: Contributor
timestamp: June 16, 2022, 10:05:16 am
content: Thing is I have never sold old test gear. If it works and is safe it goes to an electronics club of some kind or just gathers dust if it is rubbish. I do sell old Mac computers but PCs just sit until I can be bothered to put them in recycling. In the end I got the Rigol. Not quite a coin toss but it will do the job. Thanks for your thoughts.

author: bd139
author_rank: Super Contributor
timestamp: June 16, 2022, 10:47:51 am
content: Enjoy. Also please post a review on here
OSL calibration kit quality question - Page 1
Forum section: electronics / rf-microwave

author: antenna
author_rank: Frequent Contributor
timestamp: June 12, 2022, 06:17:44 pm
content: After seeing a video comparing the quality of various calibration loads, I am wondering what mine, which says it is good up to 4.5GHz, looks like compared to a much better load. The one I have is the Siglent F503ME kit, but I have nothing better to compare it to. Has anyone calibrated with a better load and then looked at the F503ME? I don't have a VNA that goes that high, I am just curious how accurate it is near the top end of what my equipment can measure, which is 3.2GHz.Thanks!

author: Andrey_irk
author_rank: Regular Contributor
timestamp: June 13, 2022, 11:15:49 am
content: In the F503ME's datasheet they say that the VSWR of the load is <=1.02, which is about -40dB of Return loss. It is pretty decent, especially considering the fact that the repeatability of precision coaxial connectors and cables is not that far off from this number.Can't tell you from the top of my head, but I saw cal kits with loads that have RL of -50dB in your frequency range, but these are very expensive and fragile. A better load than this one can potentially give a better residual directivity for your VNA, but you have to look closely to find whether it is going to make any sense considering the drift of your VNA, repeatability of your connectors and the VSWR you are going to measure.There is a nice table from Anritsu where you can find the uncertainty of your RL measurement from the difference between your directivity (which you can just take equal to the RL of the load) and the expected RL of the DUT. Find it, play around with it and see for yourself if that load is good enough for you. Personally, I would be pretty happy with it.

author: Joel_Dunsmore
author_rank: Regular Contributor
timestamp: June 15, 2022, 05:14:36 am
content: -40 dB load will give you almost exactly 1 dB ripple (error) on a -22 dB return loss measurement. Good Keysight loads are on the order 1.005 SWR (about -52 dB RL) up to a few GHz but the hard spec is something like -46 dB RL (in fact, they have to pass -52 dB to guarantee they are better than -42, at least back in the day). Above a couple of GHz, TRL standards are actually better for Return Loss than using fixed loads.
How to boost cellular test equipment output power? - Page 1
Forum section: electronics / rf-microwave

author: itsmescotty
author_rank: Newbie
timestamp: June 10, 2022, 04:49:16 am
content: Hey all, apologies in advance if I'm an idiot, but I'm looking for some help with an Anritsu MD8470A cellular signalling tester. I use this to test old cellphones, especially in frequencies no longer active like GSM900.Right now, I use a small Tescom antenna coupler held up against the back of the phone. The output signal from the Anritsu is clearly very weak by design I'm assuming for regulatory.Putting all regulatory issues aside, is there a simple way I can boost the power output out of this? In my early RF days, I used linear amplifiers, but I don't actually know if that would work for this device, especially since a lot of the power control is managed by the phone<>device handshake. I'm not looking to light up the neighborhood, just provide the ability to get a few extra meters range instead of ~10cm...Thanks for any tips you can provide!

author: El Rubio
author_rank: Regular Contributor
timestamp: June 12, 2022, 12:49:10 pm
content: Scotty, Your signature has an American flag so I assume you are in the US. GSM 900 was never used in the US. Most US phones would work because the device would have been functional if one would travel. When an older technology like GSM is phased out for newer tech like 3G, 4G, or5G, the frequencies are reused with those newer technologies. In the US, GSM900 would function where other services operate and increasing your test set’s range could infringe on their bands and cause interference. Why do you test old phones on an old technology?
A06 MMIC Identification - Page 1
Forum section: electronics / rf-microwave

author: komradebob
author_rank: Contributor
timestamp: June 09, 2022, 04:27:41 pm
content: I acquired a box full of components from a microwave product manufacturer who shut down. In the box was a bin full of HP 43035's 6GHz transistors, a ton of ATC caps, and a bin full of MMICs marked 'A06'.Short of mounting one up and trying to characterize it, any ideas what it might be?Thanks!Bob

author: gamalot
author_rank: Super Contributor
timestamp: June 09, 2022, 04:51:29 pm
content: Not even a picture?https://media.digikey.com/pdf/Data%20Sheets/Avago%20PDFs/MSA-0611.pdf

author: komradebob
author_rank: Contributor
timestamp: June 09, 2022, 05:15:50 pm
content: Of course! My apologies.

author: gamalot
author_rank: Super Contributor
timestamp: June 09, 2022, 05:33:22 pm
content: MAR-6SMhttps://pdf1.alldatasheet.com/datasheet-pdf/view/185930/MINI/MAR-6SM.html
Build RF test equipment for radio aligment - Page 1
Forum section: electronics / rf-microwave

author: MrWifiHifi
author_rank: Regular Contributor
timestamp: June 05, 2022, 01:35:19 pm
content: HiI'm begginer with RF, so I would be very thankful to anyone, who could help me and guid me with this.I stumbled across some older articels about rf test and measuring equipment, I also read some books and articels so I have some knowledge, but it is not very great. My main concern is about measuring probes, input/output circuits, rf compensation of probes, shielding of rf circuits and so on.I really want to learn to design and build rf equipment, not just in theory, but practically too.

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: June 07, 2022, 09:52:33 pm
content: If you are interested in starting out in HF rather than even higher frequencies:Sometimes you can pick up old test equipment at hamfests for almost nothing or free. Stuff like audio and RF generators. Heath and EICO and RCA stuff. Even if they do not work, you might find fixing them informative. You can get a lot of manuals on line.The good older HP test equipment (and Marconi and other brands) are complicated and harder to work on.I think getting a multimeter, even the cheap ones these days would help a lot, better ones are of course better but the $5 ones these days would have been very valuable in the 60'sI do not have one but I think starting out with a computer based spectrum analyzer would be very nice, they are quite inexpensive. Maybe ask someone who uses one to see which one is a good deal for you. SDR receivers can do the same things sometimes. A SA is most likely more versatile than a scope.Don't go out and buy a broken old scope, these take experience to repair. Wait till you think you can work on one. Even old working ones are of course prone to mishaps.If you are going to work on transistor circuits, look around for a triple power supply. No need to get the best, just has to work. Sometimes the older ones have less hash although they do not adjust very accurately. You can always check the voltage with your multimeter. Older ones are usually "linear" not switching and are simpler and heavier.
Exponential HF amplifier circuit needed - Page 1
Forum section: electronics / rf-microwave

author: sv3ora
author_rank: Regular Contributor
timestamp: June 04, 2022, 12:07:56 am
content: Hi,I need a circuit for an exponential anti-logarithmic amplifier. I.e. I need to amplify more the higher level signals and less the lower level signals.I want the circuit to work in HF spectrum.Could you suggest a way to do this (discrete components preferred).

author: rf-fil
author_rank: Regular Contributor
timestamp: June 09, 2022, 07:17:37 am
content: Do you understand that if the input to such an amplifier is anything other than CW (carrier), that it will cause spectrum growth? Even when you input a CW carrier, a circuit like that will generate harmonics.Anyway, a diode based circuit should be able to do what you want. A diode current is an exponential function of the voltage across the diode.
SMA cable assembly / connector 18 GHz vs 26.5 GHz - Page 1
Forum section: electronics / rf-microwave

author: matthuszagh
author_rank: Frequent Contributor
timestamp: May 31, 2022, 11:20:32 pm
content: What does it mean for one SMA connector or cable assembly to be rated to 18 GHz and another one to be rated to 26.5 GHz? This question can obviously be applied more broadly to a comparison of any 2 connectors or cable assemblies that use roughly the same construction but have different upper frequency ratings. What are the salient measurements considered by the manufacturer?For example, I expect VSWR plays a big part. Does the manufacturer set a maximum VSWR and say an assembly/connector operates over some frequency range if the VSWR is below that max over the full range? Is there any standardization for what this max VSWR is?Any other important parameters? I expect insertion loss isn't too important here since that depends on the length of the cable, though maybe it's considered for connectors?

author: Marsupilami
author_rank: Frequent Contributor
timestamp: June 01, 2022, 02:08:02 am
content: TLDR: Above a certain cutoff frequency there are additional modes of propagation through the coax medium and it causes a resonance. Advanced designs juggle with trying to keep the 50Ohm impedance while reducing the effective dielectric constant.https://www.microwavejournal.com/articles/5113-sma-connectors-with-extended-frequency-range

author: Joel_Dunsmore
author_rank: Regular Contributor
timestamp: June 03, 2022, 05:21:42 pm
content: It all has to do with the largest outer diameter and how/if it is loaded with a dielectric. SMA with teflon will have additional transmission modes (a circular waveguide mode) above 18 GHz which means part of the signal will transmit down the cable in TEM (normal) mode and some in waveguide mode, each having a different propagation speed, so at the end of the cable, at some frequencies above 18 GHz, the signals will be exactly out of phase and cancel, giving an null in the transmission response. If the waveguide mode energy is exactly equal to the TEM mode, they can cancel completely and give a deep null. Usually the higher-order mode is smaller so it only gives a dip in the S21 or transmission response.Super SMA uses a smaller outer (and inner) conductor that mates with normal SMA so can extend to higher frequencies. Many flex cables and many semi rigid cables use a smaller diameter cable that passes higher frequency, and only the connector is sized to SMA. In these cables the higher order modes in the connector are somewhat suppressed in the cable. 3.5 mm connectors use an air dielectric at the interface and so doesn't have dielectric, thus has a higher mode freq frequency, but is usually limited by the support bead, which causes some moding. 2.92 mm (aka K-connector) has an even smaller diameter, but still mates to the 3.5/SMA interface. Because of the smaller size, the female contact is much thinner so you need to be a bit more careful than with 3.5 mm or SMA.
Finding RF communication module! - Page 1
Forum section: electronics / rf-microwave

author: Swapnil
author_rank: Contributor
timestamp: May 30, 2022, 05:54:52 pm
content: Hello everyone! I am having a hard time finding the RF communication module for the following specificationsFrequency:902-928 MHzSpread Method:Frequency Hopping/ DTSLink rate:Up to 500 kbpsRange:Up to 10Km @ 500KbpsSensitivity:-108dBm @200 Kbps link rateInput voltage:24±6VDCDimensions:57mm x 98mm x 38mm(P.S - Mil Standard module preferred)I would appreciate it if you guys help me find out about this module. Looking forward to hearing from you guys!
stripping tool for UT141 hardline? - Page 1
Forum section: electronics / rf-microwave

author: paul@yahrprobert.com
author_rank: Regular Contributor
timestamp: May 18, 2022, 07:22:57 pm
content: Anybody know where to get a reasonably priced hand tool for cleanly stripping the solid outer copper jacket on UT141 hardline or semi-rigid coax? Or do you have a trick method using conventional tools? Thanks!

author: Grandchuck
author_rank: Super Contributor
timestamp: May 18, 2022, 07:41:05 pm
content: I wonder if the tubing cutters designed for copper tubing could work? They come in various sizes.https://www.tequipment.net/CPS/TC127/Tubing-Cutters/?Source=googleshopping&/?utm_content=small%20tubing%20cutter&utm_term=&utm_campaign=Shopping%20Campaign(BSC)&utm_source=Bing_Yahoo&utm_medium=cpc&mscl

author: paul@yahrprobert.com
author_rank: Regular Contributor
timestamp: May 18, 2022, 07:53:14 pm
content: the tubing cutters I've tried tend to reduce the ID a little at the cut, leaving a sharp burr pointing towards the center conductor. Probably also creating an impedance bump.

author: coppercone2
author_rank: Super Contributor
timestamp: May 18, 2022, 08:49:57 pm
content: the proper kit has a expensive tool for this but I forgot what its called

author: themadhippy
author_rank: Super Contributor
timestamp: May 18, 2022, 09:42:43 pm
content: If its anything like mineral insulated cablehttps://youtu.be/IujQEj8hQoc?t=949you can knock up a "key" with a length of rod, cut slot cut in one end and bend the other into a handle.

author: paul@yahrprobert.com
author_rank: Regular Contributor
timestamp: May 24, 2022, 05:39:43 pm
content: I didn't find anything to strip my coax, so I made a fixture for my dremel tool. See pictures. I used the plastic routing attachment that came with the tool and screwed on an aluminum assembly that supports the coax as I twist it. Also shown is the resulting stripped coax. It needs a little deburring with a needle file, but the result is pretty good. It takes a few practice cuts to get the depth set right.Pro tip: don't bend your coax before stripping it.

author: graybeard
author_rank: Frequent Contributor
timestamp: May 30, 2022, 02:50:19 am
content: The ones I have seen used at work just look like miniature tubing cutters. The bender looks like a miniature conduit bender.

author: coppercone2
author_rank: Super Contributor
timestamp: May 30, 2022, 03:28:00 am
content: I think what i saw was a metal jig with a carbide scribe that you rotate around the pipe, not a wheel. like a lathe cut.
Off the shelf transformer for DC-DC converter, 1W, 100kHz - Page 1
Forum section: electronics / rf-microwave

author: ivan747
author_rank: Super Contributor
timestamp: May 28, 2022, 07:17:18 pm
content: Hi everyone,I'm designing an isolated DC-DC converter circuit, for low volume manufacturing (1k to 5k units). It will step up 5V into +/-10V at 1W. I have some noise requirements to meet, so off-the-shelf DC-DC converter blocks are not an option. Isolation voltage is not super critical, probably won't exceed 60V. I'm having trouble finding transformers like this for my application, so maybe I'm not looking on the right places (maybe there are RF applications for a transformer like this). I saw some audio transformers but they seem too low power. Any hints? Thanks.

author: nctnico
author_rank: Super Contributor
timestamp: May 28, 2022, 07:28:21 pm
content: Wurth has a whole range of dc-dc converter transformers. But what makes you think you can design something better compared to off-the-shelve? You'll still need to deal with leakage between primary and secondary and getting rid of switching noise.A better route is likely to put filtering at the primary and secondary side of an off-the-shelve converter and make sure the HF leakage current can flow from secondary to primary inside a small loop area. There are also shielded DC-DC converters available for noise sensitive applications.
Dumb question: why EVB for chip antenna has 2 feed lines, one unpopulated - Page 1
Forum section: electronics / rf-microwave

author: uer166
author_rank: Super Contributor
timestamp: May 27, 2022, 10:54:43 pm
content: I'm in a process of looking at suitable chip antennas to play in the 2.4G ISM range, and this chip antenna seems to have exceptionally high gain for its' size:https://abracon.com/datasheets/ACAG0801-2450-T.pdf, EVB:https://abracon.com/datasheets/ACAG0801-2450-EVB.pdf.Looking at the EVB, they have 2 footprints on either end of PCBA, with only one populated. Question: wouldn't the unpopulated part cause unwanted reflections? Or maybe that is on purpose? Or maybe it's not connected at all? Can't tell from documentation. The idea of course is to copy the layout/stackup/FR4 material in own design.

author: Marsupilami
author_rank: Frequent Contributor
timestamp: May 27, 2022, 11:53:22 pm
content: The trace right at the SMA connector is cut, so I'm guessing there is a jumper to only one side and the other is not connected.The ground plane is part of the antenna so how the chip is placed in relation to it is important. What I'm guessing is they did the 2nd trace to give the user the ability to evaluate performance in the other orientation compared to the long edge of the board. (Educated guess only, listen to others if they know better.)
How to use `nickel powder` and `lime powder` to paint `faraday cage`? - Page 1
Forum section: electronics / rf-microwave

author: youta556
author_rank: Contributor
timestamp: May 19, 2022, 10:46:54 pm
content: I try to build `faraday cage` room for RF testing,this job is for shield low frequency RF radiation.I mix nickel powder,316 stanless steel powder and lime powder,add some water,that's my material of painting.Before I start painting,I ask for advices here.Any formula of ingredients?Is that enough paint only one time?What will happen if I leave floor unpainted?Anything I should notice based on your experience?

author: ahbushnell
author_rank: Frequent Contributor
timestamp: May 20, 2022, 02:11:32 pm
content: What frequencies?

author: youta556
author_rank: Contributor
timestamp: May 20, 2022, 09:43:29 pm
content: frequency band is 10hz-10Mhz.

author: ahbushnell
author_rank: Frequent Contributor
timestamp: May 21, 2022, 04:21:15 am
content: What do you want to shield against? Electric fields or magnetic?

author: youta556
author_rank: Contributor
timestamp: May 22, 2022, 02:24:44 pm
content: Electric fields.

author: jonpaul
author_rank: Super Contributor
timestamp: May 22, 2022, 02:33:46 pm
content: So called conductive paint has a relatively high resistance per squareA Faraday cage or screen room needs a copper screen with no gapsCost to buy or build a one man screen room is 10...100K$what is your goal?Jon

author: twospoons
author_rank: Frequent Contributor
timestamp: May 23, 2022, 01:28:56 am
content: Graphite paint would get you most of the way there, but if you really want to shield down to 10Hz you are going to need sheet metal. Sheet steel would be good enough, and a lot cheaper than copper. You will need to seal all the seams with conductive foil tape.And you need to do the floor too.What are you doing for the door? Any electrical gaps when the door is closed will leak RF.
1575Mhz 50Ohm patch antenna - Page 1
Forum section: electronics / rf-microwave

author: Alakis
author_rank: Newbie
timestamp: May 24, 2022, 06:25:54 pm
content: Hello,I need to design a 1575 MHz 50 Ohm input impedance patch antenna and don't know where to start. Some of the calculators I've tried give the dimensions of the antenna disregarding the input impedance. How could I match the input impedance? I've attached the calculations for the dimensions

author: antenna
author_rank: Frequent Contributor
timestamp: May 25, 2022, 12:45:58 am
content: That's a GPS frequency, I assume this is a receive-only project... The matching will probably be done with striplines rather than discrete components. Do you have a means to measure the impedance of the patch? I know it says 197Ω in the calculator, but is that purely resistive? Some antennas have a better pattern away from resonance so I wonder what that calculator is doing...
rf explorer upconverter mod? - Page 1
Forum section: electronics / rf-microwave

author: coppercone2
author_rank: Super Contributor
timestamp: May 07, 2022, 05:39:31 pm
content: https://www.seeedstudio.com/RF-Explorer-Upconverter-p-2991.html?gclid=Cj0KCQjwsdiTBhD5ARIsAIpW8CLGysHxApbQgSH_xgoxlBUTE9ZTimNf4FbGNuq1fRYbqM-TwWM_1gMaAnDmEALw_wcBSo this fits nicely in my chassis and it does what I want, which is to be able to get HF on my SDR. But my SDR (plutosdr) is 6GHz, and the bypass mode on that upconverter is 4GHz.Does anyone think that its possible to mod that upconverter to pass 6GHz ok in the bypass mode?Or does anyone know of a similar product that has a higher frequency range? Not really sure if its the LNA, the switch, the coupling capacitors or maybe the connectors.My auxiliary empty steel plate that would be used for mounting this is 18.5 x 14.5 cm. I thought it might be possible to do this with modules but its a tight fit.

author: arocholl
author_rank: Newbie
timestamp: May 20, 2022, 04:01:29 pm
content: Actually the bypass mode is 6GHz capable, it is designed for 4GHz but has only additional linear attenuation at higher frequencies so may work very well in your setup.

author: coppercone2
author_rank: Super Contributor
timestamp: May 20, 2022, 07:20:47 pm
content: Ok, it looks like a solid choice then. Might linear attenuation come from low quality passive components ?

author: arocholl
author_rank: Newbie
timestamp: May 20, 2022, 09:53:46 pm
content: If you check the circuit, there are two RF switches, typically adding this kind of linear attenuation
idea for wifi antenna - Page 1
Forum section: electronics / rf-microwave

author: OverlordCheese
author_rank: Contributor
timestamp: May 26, 2022, 01:21:23 pm
content: Now, I know that this is probably pretty stupid, so that's out of the way.I was wondering if it is feasible to have multiple wifi antennas, and using something like an opamp, combine their outputs so that we get the same signal but at a much higher strength, then feed it into a computer.Basically, I want to be able to combine wifi antennas, and I was wondering how i can do so

author: antenna
author_rank: Frequent Contributor
timestamp: June 03, 2022, 06:33:05 am
content: What you are describing is called a phased array. You'll have a little impedance matching to doOne of the problems is that, unless it is a router with just one antenna, most routers are mimo and use more than one antenna for communication with the target device. In that case, you will be looking at multiple phased arrays working together or you might end up with a router that really sucks at it's intended job and performs worse than a single-antenna router.

author: TheUnnamedNewbie
author_rank: Super Contributor
timestamp: June 03, 2022, 06:40:36 am
content: Another potential down-side for applications like WiFi is that an antenna array has higher gain. So you make it more sensitive in one direction, but at the same time, youlosesensitivity in every other direction. So it will only actually make things better provided that the other device you are communicating is in the direction you want.It is really quite similar to a lenses in optics. By getting a higher zoom lens, you see more clearly a small area, but the area you can see becomes larger. So that is great if what you want to see is in your field of view, but if you don't know, it will make it much harder than with a 'less zoomy' lens.