hybridfree/eevblog-posts huggingface dataset:
Kirkbymicrowave SMA calkit gender on HP8753C - Page 1
Forum section: electronics / rf-microwave

author: izsurk
author_rank: Newbie
timestamp: November 05, 2018, 05:03:40 pm
content: Hi guys,I've got the 7GHz SMA calkit by kirkbymicrowave. Unfortunately, I can not remember the correct selection for the gender during calibration. I know there was a little "specialty" regarding the gender on HP instruments. There was a section on the kirkbymicrowave website on this topic but I can not find this either. Can anyone help me out?Thanks

author: TheSteve
author_rank: Unknown
timestamp: November 05, 2018, 05:29:58 pm
content: Check this link:https://www.kirkbymicrowave.co.uk/Support/vector-network-analyzers/HP-Agilent-Keysight/8753/And a quote from that link:"the gender on the HP menus refers to the test port, and not the calibration standard."

author: izsurk
author_rank: Newbie
timestamp: November 06, 2018, 01:41:30 pm
content: "Testport" by the means of the connectors on the HP8753C (N female) or on the S-Parameter-Testset (APC7 = genderless?). I don't get it ...SMA calibration std female -> select male or female at the softkeys of the calibration menu?SMA calibration std male-> select male or female at the softkeys of the calibration menu?

author: SpencerTC
author_rank: Contributor
timestamp: November 06, 2018, 02:00:03 pm
content: I have an 8753ES and when I'm using a calkit with female standards, I configure the VNA for "male". It is very counter-intuitive.If you would like I could take a photo of the page/section in the 8753's manual that refers to this (assuming that I can find it), I read it a year or so ago and it removed the uncertainty that I had about the issue.Regards,Trent Spencer - KM4YTU

author: izsurk
author_rank: Newbie
timestamp: November 06, 2018, 04:52:05 pm
content: Hi,thanks for all your replies.It sounds kind of familiar to me ->using the female calibration std you need to select the male std in the VNA. (And vice versa)Thanks for your help

author: hendorog
author_rank: Super Contributor
timestamp: November 06, 2018, 06:38:40 pm
content: Quote from: izsurk on November 06, 2018, 01:41:30 pmTest port in this context means 'whatever you attach the calibration standards to'.So you might have an APC-7 to N adapter on the VNA, then an N cable, then an N to SMA male adapter. The test port is the SMA male and you use the SMA female cal standards.The best accuracy is achieved by testing APC-7 devices with no adapters and an APC-7 cal kit of course, but in real life you won't be doing that and will need to use adapters and cables. The calibration process compensates for the effect the adapters have on the measurement. (with limitations but that's another subject)

author: TheSteve
author_rank: Unknown
timestamp: November 06, 2018, 06:49:16 pm
content: And newer units are the opposite of course, they also show a picture on the screen to help avoid confusion.
Designing (broadband) RF transformers? - Page 1
Forum section: electronics / rf-microwave

author: cdev
author_rank: Super Contributor
timestamp: November 08, 2018, 01:46:07 pm
content: Can anybody suggest some reading on this thats got the basic math but which is not so math heavy my eyes glaze over?Or software? I have a bunch of magnetics and know what the various parameters are for most of them, although some of the magnetics I have are ferrites of unknown type.It would be great to know how to test them and be able to understand what kind of core they were and why.I'd like to know how to design baluns parametrically, rather than by trial and error.

author: babysitter
author_rank: Frequent Contributor
timestamp: November 08, 2018, 07:20:57 pm
content: Nice tool:http://www.dl0hst.de/mini-ringkern-rechner.htm(scroll down, there is a localized version for almost everybody.)

author: CJay
author_rank: Super Contributor
timestamp: November 08, 2018, 08:03:42 pm
content: Quote from: babysitter on November 08, 2018, 07:20:57 pmOhh, looks good.

author: cdev
author_rank: Super Contributor
timestamp: November 08, 2018, 11:22:40 pm
content: wow, looks like a keeper.. This is exactly what I needed,Thank you-

author: babysitter
author_rank: Frequent Contributor
timestamp: November 09, 2018, 07:34:30 am
content: I cant vouch for it but ISBN 3934350739 is the book "trilogy of inductors" by wuerth elektronik. Might be the right thing for you, might be not.

author: JohnPen
author_rank: Regular Contributor
timestamp: November 09, 2018, 09:36:04 am
content: I attempted to load the mini toroid program into Win 10 but it does not install despite saying it has installed. I have run as administrator but it never appears in the Program X86 directory. The various boxes during the install process are all in German so I have guessed a couple of answers. I have tried all the compatibility modes for the install process.What am I doing wrong?EDIT:Just realised I did not unpack the CAB file as well it all works now.

author: kerrsmith
author_rank: Regular Contributor
timestamp: November 09, 2018, 10:20:39 am
content: Quote from: JohnPen on November 09, 2018, 09:36:04 amI had the same issue in Windows 7, I tired several different ways to install but it would not work. In the end I just copied the files from the CAB file to a directory in my home folder and ran minirk13.exe directly and it worked fine.To update to the latest version I just unpacked the zip file and moved its contents to the folder I made and overwrote the files that were there.
DIY RF splitter? - Page 1
Forum section: electronics / rf-microwave

author: awallin
author_rank: Frequent Contributor
timestamp: November 03, 2018, 11:39:29 am
content: Hi all, is it possible to DIY RF-splitters with decent isolation?I would guess a splitter with just three resistors in Y or Delta configuration provides very little isolation between input-ports (e.g. when used as a combiner)!?https://www.radio-electronics.com/info/rf-technology-design/coupler-combiner-splitter/rf-resistive-splitter-combiner-divider.phpmini-circuits has lots of splitters for 30-60eur/piece - so I guess the trade-off is how much tinkering one has to do to DIY a splitter with similar performance (I would be looking at 10-100 MHz, not GHz!)

author: TheUnnamedNewbie
author_rank: Super Contributor
timestamp: November 03, 2018, 12:55:02 pm
content: A resistive type is going to provide little isolation by design - even with ideal components it just wont pull it off. What you need for high isolation is something like a Wilkinson power combiner/splitter. This requires one resistor (100 ohm in the case of 50 ohm transmission lines) and a number of transmission line sections of various impedance. If space is an issue, you can also do it with inductors and capacitors (done on chip sometimes).

author: awallin
author_rank: Frequent Contributor
timestamp: November 03, 2018, 01:50:20 pm
content: Quote from: TheUnnamedNewbie on November 03, 2018, 12:55:02 pmhm, ok, although the mini-circ connectorized ones are a bit pricey there are SMD splitters with good specs for about 10eur/pcs. maybe that's the way to go, e.g.https://ww2.minicircuits.com/pdfs/LRPS-2-1.pdffor $9.35 I guess DIY tinkering to get 30dB isolation is not worth it..

author: Wolfgang
author_rank: Super Contributor
timestamp: November 03, 2018, 08:40:43 pm
content: Quote from: awallin on November 03, 2018, 11:39:29 amI would say that a frequency range from DC to 100MHz is uncritical. You could easily homebrew this.https://electronicprojectsforfun.wordpress.com/rf-module-gallery/the-rf-splitter-and-combiner-gallery/a-resistive-combiner-for-imd-measurements/What you could try is a 19.5dB splitter if you need more isolation. I have made a lot of BNC/leaded resistor stuff and measured them on a VNA.Up to 100MHz results are quite good (30) if you keep leads really short:https://electronicprojectsforfun.wordpress.com/measuring-a-picotest-j2111a-current-injector/verification-of-some-homebrew-bnc-calibration-standards/When you try SMA connectors and chip resistors on transmission line PCBs you could easily go up to 500MHz.Above that I would buy some Mini Circuits stuff because homebrewing gets too tricky at several GHz.
Looking for RF  design engineer for 900MHz design : Melbourne - Page 1
Forum section: electronics / rf-microwave

author: JoeyG
author_rank: Regular Contributor
timestamp: October 31, 2018, 10:27:17 am
content: I'm on a quest to find an RF engineer available for some contract work, in Melbourne Australia(I hope).I think most of these engineers are already well employed and it may be difficult to find in this location.Requirement900MHz front end RF front end PCB design <200mW Tx to meet ACMA and FCC 15.247 requirements.ACMA LIPD requirements to AS / NZS 4268 :2017.I will touch base with Sepo at RF Designs in QLD , but hoping for some one in Melbourne.The engineer should already have access to the required RF test equipment , Spec Ana, Vector nwk analyser, signal generators etc.The 900MHz front end is not overly complicated but a Rx sensitivity in the -130dBm is required (the associated silicon can already achieves this on reference designs)RegsJoe
Is it possible to use the same trasnsceiver for Wi-Sun and NB-IoT ? - Page 1
Forum section: electronics / rf-microwave

author: sangar
author_rank: Regular Contributor
timestamp: October 28, 2018, 04:33:58 pm
content: Hi,We have an RF transceiver and looking that it is possible to use that in both Wi-Sun and NB-IoT applications. The main thing is that both fall in the Sub-GHz band 800 ~ 900 MHz.So, no need to look at RF synthesizer as it generates both Wi-SUN and NB-IoT transmission frequencies...What else ,I really need to look at? Suggest if anything you have...Thanks,sangar
Microwave 101: Identify rat-race parts (GHz LNB satellite TV EchoStar) - Page 1
Forum section: electronics / rf-microwave

author: RoGeorge
author_rank: Super Contributor
timestamp: October 26, 2018, 03:11:46 pm
content: Microwave SideRF SideAnnotated Rat-Race Mixer1 - stub2 - Bandpass filter3 - RF out connector (F type)4 - ?? trapezoidal structures ??5 - ?? half bow tie ??6 - ?? what is this for ??7 - ?? inductance ??8 - stub9 - ?? coupler or filter ??10 - capacitance11 - ?? double diode ??A, B, C, D - ports for the rat-raceLNA arrow - signal input from the Low Noise AmplifierOUT arrow - RF out, F type connector, to set top boxIF arrow - ?? output from the rat-race mixer ??LDO arrow - typo, my bad, it's DRO - output from the Dielectric Resonator OscillatorAlready Googled a lot, and overwhelmed with too much at once. I'm an absolute beginner in microwave.- Is that a mixer, or something else?- Are those annotations correct?- Any critical parts missed and not annotated?Can anybody help me understand how does that that "ring" works, please?Any good links to a concise microwave 101 will be appreciated, too.

author: rfeecs
author_rank: Frequent Contributor
timestamp: October 26, 2018, 04:56:17 pm
content: Looks like you got everything about right.4 - just contact pads for the diodes5 - an open stub, ideally around quarter wave to short out the RF and LO signal6 - probably a tuning pad9 - blocking cap11 - diode pairThe Signal Path described a similar mixer in one of his videos:https://youtu.be/5vqSX40seqA?t=516The "ring" as you said is a rat race coupler or combiner. It is feeding the RF from the LNA to the diodes in-phase. The LO is fed to the diodes 180 degrees out of phase. This gives better LO-RF isolation.So it is a 180 degree hybrid coupler or combiner. You wanted Microwaves101, so:https://www.microwaves101.com/encyclopedias/hybrid-couplersIt might be nice to see inside the DRO and to see what the waveguide to microstrip transition looks like.

author: RoGeorge
author_rank: Super Contributor
timestamp: October 27, 2018, 12:05:26 am
content: Thank you for your guidance.Here are two draft pics with the inside of the DRO, and the Waveguide to microstrip transition. The golden pin from the inside of the waveguide seems soldered straight to the LNA input. I'll try to make better pics tomorrow, with natural light, and also measure the sizes.Inside DROWaveguide to LNA
How do you get rid of the ghost signal always on the center on the SDRPlay? - Page 1
Forum section: electronics / rf-microwave

author: Beamin
author_rank: Super Contributor
timestamp: October 13, 2018, 07:16:00 pm
content: So this is strange I just got another new in box corei7 lap top also HP. Installed SDRUno and now I have the problem of a spike of signal on what ever you tune to right in the middle of the band. Say you type 333mhz hit enter and it looks like you found your signal. Scroll the freq up and down and you tune off of it. But its not real. I think this does have to do with the LO frequency being too close to something or too far. I know I had this problem before but I have no idea what you would call this to even search on google. "strange peak signal on sdrplay when new but not really a signal but looks like.com"?The other computer doesn't have this problem both are i7 just this one is a touch screen. Only windows can repeat the same thing with different results, a true random generator the military should use, better then factors of prime.The SDR seems to run a lot smoother on the i7 vs my old i3 from 3 years ago.

author: 9aplus
author_rank: Regular Contributor
timestamp: October 13, 2018, 09:15:09 pm
content: https://www.tapr.org/~n5eg/index_files/SDR%20from%20DC%20to%20Daylight.pdfslide 23and the rest is also good read

author: Beamin
author_rank: Super Contributor
timestamp: October 14, 2018, 10:31:39 pm
content: Quote from: 9aplus on October 13, 2018, 09:15:09 pmSo which applies to mine digital front end? Whats the setting I'm looking for called?Very interesting post BTW did not know that and the chart is so simple even I can read it!

author: TheBay
author_rank: Unknown
timestamp: October 16, 2018, 11:01:04 pm
content: Turn off "LO Lock" in SDRuno if its highlighted and move the LO outside of that area if it doesn't automatically do that for you.
ERASynth user experience - Page 1
Forum section: electronics / rf-microwave

author: 9aplus
author_rank: Regular Contributor
timestamp: September 07, 2018, 03:11:23 pm
content: There are no known virtual space like forum or group regarding above title,only one topic here ->https://www.eevblog.com/forum/crowd-funded-projects/erasynth-open-source-rf-signal-generator-request-for-feedback/25/andGit place here ->https://github.com/erainstrumentsAny other?User experience?Alternative SW interfaces?Or the number of sold units are not enough to be supported by community?

author: jhenderson0107
author_rank: Regular Contributor
timestamp: September 07, 2018, 09:00:29 pm
content: I have one of these units and it is useful. However, I have the following criticisms:1. While jitter performance is excellent, harmonic distortion is significant. Use of an external filter is often required (in my applications).2. EraSynth uses a non-standard programming API. I would have preferred the programming API be based on SCPI. With the current firmware, the unit cannot be conveniently detected and controlled like (most) other standard test equipment using the National or Keysight VISA libraries.

author: 9aplus
author_rank: Regular Contributor
timestamp: September 08, 2018, 11:15:23 am
content: Thank you.Agree on both 1. & 2.I am using only command line over the USB and virtual 232 interface becausethe web command firmware is still not fully functional even after firmware upgrade.

author: jhenderson0107
author_rank: Regular Contributor
timestamp: September 08, 2018, 07:08:23 pm
content: I have a Nexus 7" tablet near my electronics bench. A bookmarked ink on its desktop to the EraSynth provides a handy user-interface to the instrument.

author: 9aplus
author_rank: Regular Contributor
timestamp: September 08, 2018, 07:20:36 pm
content: You are able to use sweep option through wi-fi control panel?

author: 9aplus
author_rank: Regular Contributor
timestamp: October 21, 2018, 08:22:00 am
content: BUMPSo far no firmware update. Even development branch is quiet.Here still forced to use only via terminal commands...The only recent update is data sheethttps://github.com/erainstruments/erasynth-docs/blob/master/erasynth-datasheet.pdf
cheap Bluetooth jammer? - Page 1
Forum section: electronics / rf-microwave

author: FrankBuss
author_rank: Unknown
timestamp: October 16, 2018, 03:55:53 pm
content: For testing the reliability of my BLE device, I'm searching a Bluetooth jammer (for the new BLE standard, but I guess it is the same 2.4 GHz frequency band). Needs to be only very short range, I can use it very closely to the device. A quick search on eBay results only in > 400 EUR devices, which look very long range and which are probably very illegal as well.Or maybe I can shield it somehow? But an electronic jammer would be easier.

author: ahbushnell
author_rank: Frequent Contributor
timestamp: October 18, 2018, 01:17:52 pm
content: Quote from: FrankBuss on October 16, 2018, 03:55:53 pmPut it in a microwave oven.I guess I'm not much help.

author: FrankBuss
author_rank: Unknown
timestamp: October 18, 2018, 01:37:38 pm
content: Might work, even if you don't turn on the ovenbut a single button push solution would be better.

author: DaJMasta
author_rank: Super Contributor
timestamp: October 18, 2018, 01:50:34 pm
content: If shielding is an option, have you tried just sticking it in an antistatic (metallized) bag?

author: FrankBuss
author_rank: Unknown
timestamp: October 18, 2018, 02:05:54 pm
content: Quote from: DaJMasta on October 18, 2018, 01:50:34 pmThanks, this works! I put it inside a plastic bag, and this inside one of those Digikey antistatic bags. Then I can just press down on the opening to shield it. If I do this for less than a second, the Bluetooth transfer just stops, when longer the connection is closed.

author: coppercone2
author_rank: Super Contributor
timestamp: October 18, 2018, 09:31:50 pm
content: i wonder if this has to do anything (I mean lack of good testing) with why my laptop won't fucking work at all when wifi is connected together with blue tooth. It keeps freezing youtube and all sorts of shit.I wonder if its a cross talk related problem or just bad software.
50ohm RF VGA 3db - 18db(or more) low noise 12v 450 - 750mhz  - Page 1
Forum section: electronics / rf-microwave

author: benyB
author_rank: Newbie
timestamp: October 17, 2018, 03:49:39 pm
content: Hi, i'm looking for VGA modules with these specs and was hoping to avoid having to make my own. any ideas?I found loads of high gain low noise 50ohm modules but no variable. I need to tune the gain to the receivers..450mhz - 750mhz or larger12v or 5v ( pref 12v )adjustable gain 3db - 18db or higher50ohm input/output ( not differential )low noiselow powerI'm really needing a duel channel since i want to use in a diversity system but can live with 2 x modules.i'm looking at increasing gain from a diversity Log Periodic Dipole Array antenna before it goes into a 1 - 4 splitter. basically an antenna distribution amplifier.I'm assuming its best to put the amplifier modules at the antenna(s) and then split the signal at the multiple receivers end as to not amplify the noise from cable ?
Measurement of "Q"? - Page 1
Forum section: electronics / rf-microwave

author: cdev
author_rank: Super Contributor
timestamp: October 17, 2018, 02:25:27 am
content: I am trying to build a better HF preselector for the cold long winter nights and am experimenting with different designs, it has been especially helpful shielding the two portions of it from one another.I think I have a good design now, its very simple. Putting some flashing (with a hole in it) between the two sections seems to be the trick.
Strange antennas ... ??? - Page 1
Forum section: electronics / rf-microwave

author: Beamin
author_rank: Super Contributor
timestamp: October 16, 2018, 03:58:36 pm
content: What type of antenna is this? This is a screen shot from a video that has nothing to do with this. Antenna. It's on a hill over looking SF next to RF controlled air raid sirens, but those use a different antenna.The MSpaint, I mean photoshop creation I made is of other antennas I saw a long time ago on a mountain top 10-20 miles over looking a small city. Each unit was on top 30-50 ft tower and seemed to be maybe one of two feet tall. The ones on the left looked like old two school black telephone head sets positioned perpendicular 180' not pointing up like in the drawing(two half links of chain chained together), and the ones on the right were red and I'm guessing the cylinders had coils of wire in them. This was in the 90's but they looked much older. In all these years I have never seen ones like these anywhere else. This was the biggest hill for miles and littered with all kinds of microwave, cell and other gov and private antenna masts. This site wasn't part of the att long lines links, that actually shot past this hill an amazing distance away basically connecting a town next to Vermont with central NH and the next stop went all the way to the seacoast. One house sat on top and if those people leased out that land they are very rich by now. Really want to know what they are for or how they work.

author: tkamiya
author_rank: Super Contributor
timestamp: October 16, 2018, 06:08:24 pm
content: It looks like a collinear ground plane.The vertical part is the radiating element. Each section is 1/4 wave length and fat part stops that part from radiating. That makes radiating element in phase - compressing vertical radiation pattern and producing gain.
Looking for a MURS radio recommendation - Page 1
Forum section: electronics / rf-microwave

author: Tony_G
author_rank: Super Contributor
timestamp: October 14, 2018, 09:33:24 pm
content: Hey All,Our cabin is in a very wooded area with a lot of reentrants and so I'm thinking that a VHF based radio might be a better choice than the UHF FRS/GMRS ones (like those Motorola jobbies). The last time I used a VHF radio was back on an AN/PRC-77 set so I don't have any modern experience with these devices.Anyone have any recommendations for MURS devices?Or should I consider getting a GMRS license and using the 5W option?Thoughts?TonyG
Could anyone explain NB2-IoT subcarrier spacing ? - Page 1
Forum section: electronics / rf-microwave

author: sangar
author_rank: Regular Contributor
timestamp: October 26, 2018, 10:31:04 am
content: Hi,I am reading about NB2-IoT and want to know that how it exploits cellular spectrum...I am seeing that there are 3.75 and 15 KHz sub carrier spacing for data transmission and reception. Could anyone explain in detail?Thanks,Muthu

author: rf-fil
author_rank: Regular Contributor
timestamp: October 31, 2018, 11:51:13 pm
content: LTE is complex. If you are really interested, start reading the 3GPP TS36.1xx and 36.2xx series of specs. They are not a light read though.
Are all/most I-PEX MHF connectors compatible with one another? - Page 1
Forum section: electronics / rf-microwave

author: SlowBro
author_rank: Regular Contributor
timestamp: October 09, 2018, 01:59:29 pm
content: I am thinking of integrating this Wi-Fi adapter into my product, which needs an antenna which connects via an I-PEX socket. I was told by a manufacturer's rep that it uses an I-PEX MHF II. So I looked around the I-PEX website but the documentation was very unclear about the sizes of the pin and socket. Hence my question to you: Are all/most I-PEX MHF connectors compatible with one another? Can I for example mate an MHF4 plug into an MHF II socket?http://www.skylabmodule.com/usb-wifi-module-wg209/https://www.i-pex.com/Products/advanced_search/all
Cassegrain offset dish antenna : where is the beam ? - Page 1
Forum section: electronics / rf-microwave

author: jujun
author_rank: Regular Contributor
timestamp: September 29, 2018, 09:56:42 am
content: Hello,I just got for free a cassegrain offset dish antenna. So I am mounting it on my antenna rotator.But I am facing a problem, it's not obvious at all to understand where the beam is in the vertical axis.A picture of the different beam possibility, witch one is the good one ?I must say that mechanicaly it would be easier if it was the blue or the yellow.Also If you have any advice on this thing, I would love to hear them. (I'am thinking to add a focus motor)Thank you

author: VK5RC
author_rank: Unknown
timestamp: September 29, 2018, 10:23:43 am
content: When I was mucking about with a 10GHz using an off centre fed dish (satellite dish) I used a weak signal source at about 30m away and found it experimentally - rather interestingly I also had a bit of a sideways squint as well !!!

author: jujun
author_rank: Regular Contributor
timestamp: October 05, 2018, 12:17:24 pm
content: I will build a massive attenuator, and try. Thank you
Uniden UH-001 UHF Radio - Page 1
Forum section: electronics / rf-microwave

author: Ashhhhh
author_rank: Contributor
timestamp: October 02, 2018, 11:07:46 pm
content: Hey all,I've picked up one of these for free and am attempting a repair.The main issue ive found so far is that the typical old corrosive/conductive glue had damaged some diodes, which ive replaced.I've also replaced the main filter caps which were massively out of spec and leaky.The current situation is that it wont go into transmit mode when pressing the mic button. Pressing the "tone send" button does light the transmit button and it outputs power.Looking inside, its almost like its been modified. For what end, im not sure. There is daughter board which doesnt look factory with a wiring header that looks hacked about.Does anyone have one of these that they could photograph for me? Alternatively a high quality schematic would be great, the one I have is too grainy to be of any use.CheersAsh
Why does the air hum/buzz around the WWV transmitter site? - Page 1
Forum section: electronics / rf-microwave

author: Beamin
author_rank: Super Contributor
timestamp: September 27, 2018, 06:58:38 am
content: I can't find the video but there were some ham radio people that recorded a tour of the Colorado 5.0MHz site.When they stood under the huge antenna the air made a really strange sound not just a hum like you might expect but another sound I can't really describe. Do the antenna wires vibrate at some harmonic? It didn't sound like electricity either. Strange.

author: ogden
author_rank: Super Contributor
timestamp: September 27, 2018, 07:19:22 am
content: Quote from: Beamin on September 27, 2018, 06:58:38 amWe shall put effort into answering your question but you can't even find video you have question about? - Try harder.QuoteIt'shigh frequencyelectric field. Reason why sound differs from high voltage (AC) electric power transmission line - it'shigh frequency.

author: drussell
author_rank: Super Contributor
timestamp: September 27, 2018, 07:47:08 am
content: High power transmitter antennas usually buzz. It's not just WWV.

author: In Vacuo Veritas
author_rank: Frequent Contributor
timestamp: September 27, 2018, 07:50:15 pm
content: Don't do this

author: German_EE
author_rank: Super Contributor
timestamp: September 29, 2018, 08:02:06 am
content: Given the power of the WWV transmission it's possible that the RF could be interfering with the audio circuits in the camera.

author: ahbushnell
author_rank: Frequent Contributor
timestamp: September 29, 2018, 10:44:52 pm
content: It may be caused by corona?

author: Seekonk
author_rank: Super Contributor
timestamp: September 30, 2018, 07:03:10 pm
content: A friend lived near a transmitter. His electric stove would play music.

author: LaserSteve
author_rank: Super Contributor
timestamp: September 30, 2018, 08:07:17 pm
content: corona, rectification by rust, induction.. Pick one or more.Steve
ADS Layout simulation from schematic problem - Page 1
Forum section: electronics / rf-microwave

author: jujun
author_rank: Regular Contributor
timestamp: September 26, 2018, 09:58:44 pm
content: Hello,In ADS (keysight), I want to do a simulation of the layout of a schematic with the real model of the SMD coils and capacitors I use, instead of the default perfect components.So I open the schematic, swap the component to the SMD component from the built in library "RF passive SMT" with right click on the component, then "Componement=>Swap" then I generate a Layout with "Layout=>Generate/Update Layout"The problem is that I can no longer make electrical connection with these news components, the little dash line that mean "electrical connexion needed" appear, but if I connect it, it doses not disappear.Of course, if I don't swap the component to SMD component, everything works, when the connexion is made the little dash disappear.Do you know what I am missing ?Sorry for the noob question.Thank you for your helpJ

author: TheUnnamedNewbie
author_rank: Super Contributor
timestamp: September 27, 2018, 11:51:29 am
content: could you show a screenshot of what you mean?

author: jujun
author_rank: Regular Contributor
timestamp: September 28, 2018, 11:03:52 am
content: So I click on the blue item of the input port, and then to the blue item of the SMD pad.(I have to double click, or wont end)And you can see that there is no electrical connection.

author: KJDS
author_rank: Super Contributor
timestamp: September 29, 2018, 12:58:09 pm
content: I'll take a guess atYou either need to put a port on the end of the line for the component to connect toorThere's something needs to be added to the substrate model so that ADS know's which drawing layers are on the top of the substrate and so will connect when overlaid.

author: jujun
author_rank: Regular Contributor
timestamp: September 30, 2018, 01:32:30 pm
content: Thank you, it was a layer problem.Because when you use a SMD componement, if you dont define a SMD Pad, the default are that the conductor pad is on another layer than cond.
Regional antenna matching switch - Page 1
Forum section: electronics / rf-microwave

author: Koen
author_rank: Frequent Contributor
timestamp: September 30, 2018, 05:21:11 am
content: Hello,I received some interest from Australia for my products.But I'd have to move the ISM 14dBm radio link from 869 to 915MHz.According to the transceiver manufacturer references, the RF path is identical for 869/915MHz. Great.And the antenna matching is as-easy as changing one single inductor. Great too.But I would like an Australian on 915 to be able to use it in Europe on 868 and vice-versa when visiting.Could I simply put an RF-Switch to dynamically decide the matching inductor depending on location ? Something like one of these :Thank you very much,Koen

author: Koen
author_rank: Frequent Contributor
timestamp: September 30, 2018, 05:27:07 am
content: The other RF-Switch (to choose between TX/RX) is Peregrine PE4259 :https://www.psemi.com/pdf/datasheets/pe4259ds.pdfI would like to use the same switch if possible. It ties the unused path to ground.Thank you,Koen
Radio Noob Q:   Airband Radio Receiver Antenna - Page 1
Forum section: electronics / rf-microwave

author: Jebnor
author_rank: Regular Contributor
timestamp: September 27, 2018, 12:48:09 am
content: Hello all,I'm a total radio noob with enough info to be dangerous.I bought an Airband Radio Receiver kit from eBay, based on the "HMOOABRA_4.6" board . It's everywhere. My question is about Antennas to "Get it to work". ie, can I use a wire as an aeriel antenna? What is the easiest way to get a signal into my new receiver? A Yagi would be nice. A J-antenna would be cool too, I can make them, in time.https://www.ebay.ca/itm/DIY-KITs-Airband-Radio-Receiver-Aviation-Band-Receiver-manual-Al-Case/172748677141If you're brave, here is the "manual" -- Warning, Chinglish incoming! --https://www.adrive.com/public/gD2kv3/%E8%88%AA%E7%A9%BA%E6%B3%A2%E6%AE%B5%E6%8E%A5%E6%94%B6%E6%9C%BA%E5%A5%97%E4%BB%B6%E8%AF%B4%E6%98%8E%E4%B9%A6%E8%8B%B1%E6%96%87%E7%89%88V3.1.pdf

author: tkamiya
author_rank: Super Contributor
timestamp: September 27, 2018, 01:36:45 am
content: I use a discone antenna. Not only would it receive air-band, it will do anything from 25Mhz to 1300Mhz. (receive only) I use a hefty coax but you can get away with rg58 or rg8x if your run is short.

author: German_EE
author_rank: Super Contributor
timestamp: September 29, 2018, 08:16:48 am
content: The formula for a quarter wavelength is (234/MHz) feet so in your case assuming a center frequency of 125 MHz the answer is 1.87 feet / 22.5 inches / 57cm.So........1) Grab some scrap wire coathangers and cut down five of them to the correct length2) Solder one of them to the center pin of an SO239 socket3) Using solder tabs or crimped connections fix the other four wires to the base of the SO239, it should look something like this:https://farm8.staticflickr.com/7011/13637883585_a14f79a4fa_z.jpg4) Finally, bend the wires at the bottom downwards by about thirty degrees. This will give a better match to 50 ohms and let your new antenna stand up straight.Connect using a standard SO239 to SO239 cable and have fun.
Plotting Smith Chart Data in 3-D - Page 1
Forum section: electronics / rf-microwave

author: jca1955
author_rank: Newbie
timestamp: September 28, 2018, 12:04:58 pm
content: I don't know if this is of interest to anyone, but I had a need for plotting Smith Chart data in 3-D (to visually display power dissipation of an antenna tuning network versus load impedance).A friend who also worked many years in the Mathworks Applications Engineering group came up with a way to do it using an enhanced Smith Chart plotting routine he wrote for MATLAB. I found it very useful, and I thought I would share it in case it might be helpful for others.Here are some examples of the plots one can make:If interested, I describe the MATLAB code in greater detail (and how to download it from MATLAB Central) in a blog post of mine:http://k6jca.blogspot.com/2018/09/plotting-3-d-smith-charts-with-matlab.html- Jeff

author: Sparky49
author_rank: Regular Contributor
timestamp: September 28, 2018, 03:54:01 pm
content: This is very interesting, thanks for your post - I look forward to reading more about it on your website!
rf oscillator circuit  - Page 1
Forum section: electronics / rf-microwave

author: yalect
author_rank: Regular Contributor
timestamp: September 17, 2018, 08:45:23 am
content: Hello,I would like to ask you how this oscillator works? and crystal has to shift phase 180 degree to pevent negative feedback?thank you

author: paul@yahrprobert.com
author_rank: Regular Contributor
timestamp: September 18, 2018, 04:02:47 am
content: No, the crystal run in series resonance mode. That is, at a particular frequency it has a purely resistive impedance. The transistor provides the 180 degree phase shift, that is the collector voltage drops when the base current rises.

author: yalect
author_rank: Regular Contributor
timestamp: September 18, 2018, 08:31:31 am
content: Hi,thank youbut how that oscillator works where must it has positive feedback and phase shift, maybe quertz has phase shift and what is it?thanks

author: iMo
author_rank: Super Contributor
timestamp: September 19, 2018, 10:08:21 am
content: It is the Pierce oscillator. The crystal and parasitic capacitances create the 180deg phase shift. Near its resonance freq the crystal in that circuit is equivalent to a C-L-C (pi network) resonant tank.

author: yalect
author_rank: Regular Contributor
timestamp: September 22, 2018, 06:24:48 am
content: Thank youphase shift is 180 degree? And Crystal make it ?Thanks

author: lordvader88
author_rank: Frequent Contributor
timestamp: September 23, 2018, 09:40:21 pm
content: Here's what I studied todayI need to try the AC analysis on a metal I'm made today
wifi and wireless Exchange - Page 1
Forum section: electronics / rf-microwave

author: yalect
author_rank: Regular Contributor
timestamp: September 22, 2018, 10:44:26 am
content: Hi,I would like to ask you if I can use wireless mouse or keyboard reciever as wifi adaptor espcially both have same frequency 2.4Ghz, maybe the matter is softwar to deal with protocol of wifi?Regards

author: TheUnnamedNewbie
author_rank: Super Contributor
timestamp: September 22, 2018, 11:46:03 am
content: Quote from: yalect on September 22, 2018, 10:44:26 amMy microwave also operates at 2.4 GHz, but I cannot make that into a wifi system in any way. There is a lot more to the protocol than just the band it operates in. Likely your adapter is either some flavour of bluetooth, or a in-house protocol (like logitec's stuff). It could even be that your dongle is only a receiver, and wifi needs both parties to have a transmitter and receiver.

author: bob225
author_rank: Frequent Contributor
timestamp: September 22, 2018, 12:58:13 pm
content: It may be the same frequency but that's it, the power output is minuscule on a keyboard/mouse/receiver, the bandwidth will be much narrower and it will also use its own protocolThe basic keyboards are just use receiver dongles anywaytbh its not worth messing about as wifi dongles are cheap (what ever connection you require) a no name one is 2-3 dollars or a Belkin n300 adapter for $8
Spherical spiral antennas for HF? - Page 1
Forum section: electronics / rf-microwave

author: rhb
author_rank: Super Contributor
timestamp: September 16, 2018, 07:46:31 pm
content: Does anyone know of work on building a broadband HF antenna based on the spiral on the surface of a sphere design? Both Balanis, 2016, and Stutzman & Theile, 2012, show spiral examples.It looks as if with a program to account for catenary and stretch it would be a reasonable tree supported insulated wire antenna. Not as simple as a trap dipole, but not too much more complex other than threading all the wires through the support strings with enough strings to adequately approximate a sphere.

author: hagster
author_rank: Frequent Contributor
timestamp: September 17, 2018, 07:32:16 pm
content: I have never seen one. Looks like you could be the first.

author: 2N3055
author_rank: Super Contributor
timestamp: September 18, 2018, 06:41:49 am
content: Look for term "loxodromic antenna"..

author: hagster
author_rank: Frequent Contributor
timestamp: September 18, 2018, 07:31:50 am
content: To qualify my statement. I have never seen one at HF.This is s similar,but conical version.https://www.tcibr.com/product/tci-model-570-multimode-spiral-antenna/

author: rhb
author_rank: Super Contributor
timestamp: September 18, 2018, 02:26:49 pm
content: Thanks. They sell some very interesting antennas. I rather fear they are "no such agency" priced as you must send them your info to get a datasheet :-(But they have multiple models which cover 2-30 MHz which is precisely what I'm after.A cone has more gain along the axis of the cone, but I think it is related to the aspect ratio. So a short cone or pyramid should be very similar to a hemisphere and much easier to construct.

author: hagster
author_rank: Frequent Contributor
timestamp: September 18, 2018, 06:55:15 pm
content: Well at 2MHz it would be about 50m in diameter and 25m tall. That would never be cheap.20MHz and up is probably in the range of a DIY setup.I havent modelled it, but I guess peak gain would be straight up. So good for skywave stuff.

author: rhb
author_rank: Super Contributor
timestamp: September 18, 2018, 08:55:30 pm
content: I was able to get the data sheets for some. The 545 spiral pyramid is 40 ft tall and 85 ft on a side. However these all run in the $50-100K range. The circular spiral is around 340 ft in diameter.Generally they all have a VSWR of 2:1 or less from 2-30 MHz. An interesting aspect is that several models support multiple modes, so as many as 3 transmitters can share a single antenna. They have pretty good low angle radiation in a couple of modes.

author: cdev
author_rank: Super Contributor
timestamp: September 21, 2018, 12:36:16 pm
content: You might do better with a "43 foot vertical". And much cheaper, especially if you are owned by a tree.
Feeding signal generator into IF to get subcarrier radio? - Page 1
Forum section: electronics / rf-microwave

author: Beamin
author_rank: Super Contributor
timestamp: September 05, 2018, 10:58:30 pm
content: Normally I understand all these guys videos. I learned how tube amps work and how to test for leaky caps by feeding in old Mrs. Miller Records thru them and seeing how much your ears bleed for high/low frequency leakage. But whats he doing here with 50MHz signals in the IF? I thought the subcarriers were off by only KHz like he feeds in other stations with 88-108 MHz and they work. But he picks up the chinese stations at the end with 50 some MHz.https://youtu.be/VCDn-ONqQ7oHe has a point with really not wanting to integrate to be desperate enough to listen to that Chinese subcarrier music station. On a unrelated note don't use google translate to try and speak Chinese to your new land lords parents. They will start talking to you in Chinese and I'm pretty sure it messed up the translation because half my stuff is now sitting on the porch of their house and they really want it to stay there, I think it seemed to make them happy and like me too...Bonus points if you can translate the Arabic under the Shango66 logo in his videos.

author: ogden
author_rank: Super Contributor
timestamp: September 05, 2018, 11:29:49 pm
content: Quote from: Beamin on September 05, 2018, 10:58:30 pmHe is doing nothing with IF which is at 10.7 MHz. He replaced 45.6 MHz crystal (of local oscillator) with generator signal to tune that radio that does not have any tuning controls. Note LO frequency (re)calculation using mobile phone.

author: Beamin
author_rank: Super Contributor
timestamp: September 13, 2018, 02:25:42 am
content: Quote from: ogden on September 05, 2018, 11:29:49 pmSo does he have to physically cut the IF stage out, out of the radios circuit or can the signal generator over drive the radios own IF signal?

author: ogden
author_rank: Super Contributor
timestamp: September 13, 2018, 09:17:50 am
content: Quote from: Beamin on September 13, 2018, 02:25:42 amWhich part of "He is doing nothing with IF which is at 10.7 MHz" you did not understand? Seriously.He is connecting signal generator to crystal generator part of LO (local oscillator) circuit.IF stays unchanged and is operating as designed.

author: vk4ffab
author_rank: Frequent Contributor
timestamp: September 15, 2018, 11:39:02 pm
content: Quote from: Beamin on September 13, 2018, 02:25:42 amDesired Signal PLUS or MINUS the Local Oscillator Frequency = Intermediate FrequencyAs the poster above pointed out, he is doing nothing to the IF, he has changed the Local Oscillator from being Crystal controlled on a fixed frequency to VFO controlled via a signal generator. The 45mhz xtal must be going into a Doubler to get it to LO to 90Mhz, which is why he is feeding 45mhz into it.

author: Beamin
author_rank: Super Contributor
timestamp: September 16, 2018, 02:36:10 pm
content: Quote from: vk4ffab on September 15, 2018, 11:39:02 pmNow I understand. the doubler was throwing me off.
Can someone look over -> Russian RTL-SDR USB Filter Video Review - Page 1
Forum section: electronics / rf-microwave

author: Lord of nothing
author_rank: Super Contributor
timestamp: September 14, 2018, 02:49:17 pm
content: https://www.rtl-sdr.com/russian-rtl-sdr-usb-filter-video-review/So from an Technician Perspective usefull or Fontus Style?

author: HB9EVI
author_rank: Frequent Contributor
timestamp: September 14, 2018, 03:47:39 pm
content: I'm missing a common mode choke in that setup; just some random inductors in the + and - rail won't block all possible noise from the PCs SMPS

author: coppercone2
author_rank: Super Contributor
timestamp: September 14, 2018, 07:37:37 pm
content: I got a corning optically isolated USB cable that I was going to mod to have an isolated linear battery power supply to power the thing, but I was still worried about laser-driver noise feed through. I also wondered what effect the shitty PSU computer has on the laser demodulator, if it might send a nasty pulse that needs some kind of digital filter block to be used or such that can generate a noise spike on decoding.I am not sure what you can do to clean up the digital signal other then lowpass filtering it outside its bandwidth, since destroying its edge might have an effect.All I can think of is schmitt triggers with high isolation after the rise, a few in series at least so the noise of the rising edge gets attenuated, but it would need to be a fast trigger.Any idea what schmitt triggers are appropriate for USB 3 isolation to follow up with laser isolation, if you don't trust the feedthrough from demodulation on the digital pulse?Also does anyone have any ideas if you can make yourself a fiber adapter to use with those corning connectors, so that you can make a variable length fiber channel and get rid of the isolated ground?Also do you think the corning cable has attenuators or laser power which are configured per cable length? I am worried if I made a short fiber adapter it might fry the recievers.I think there would need to be some signal delay block to prevent the HF noise burst from the demodulator to go through the triggers though, so they should delay by like 1/8th - 1/6th of a clock cycle I think?I do think that buying this would be a better idea:http://spec.go4fiber.com/networking/gusb-xx-xxxx_20151120.pdfDoes anyone know what chips are used and stuff so you can maybe make it with a more solid ground plane part of a unit that has a nice linear regulator and some batteries etc so you can make your own thats real nice and does not have power going into the plug?

author: Lord of nothing
author_rank: Super Contributor
timestamp: September 14, 2018, 08:35:15 pm
content: @coppercone2 If you wait ~2 Weeks (quite) everything I ordered should be arrived and I will make a review.
Kenwood TK-852/892 service manual - Page 1
Forum section: electronics / rf-microwave

author: CJay
author_rank: Super Contributor
timestamp: September 11, 2018, 06:08:05 pm
content: I picked up a Kenwood TK-852 at a rally recently but haven't been able to find the service manual, can anyone help?I'm trying to work out which CPU it has and will be pulling the flash to read shortly as I want to see if there's scope for adding a few features, I *think* from the appearance of the chip it's some kind of Renesas device, possibly a H8 ROMless variant?
Any experiences with PDLUX from China? - Page 1
Forum section: electronics / rf-microwave

author: Kirkhaan
author_rank: Frequent Contributor
timestamp: September 04, 2018, 07:00:39 pm
content: For a local project in China I am consideringthis 5.8GHz Doppler modulefrom PDLUX.Does anyone here happen to have any experience with this supplier?Are they any good with respect to quality (reliability) and performance?They seem to be pretty western oriented because some of their sensors have FCC modular approval (https://fccid.io/2AIWW)Anyhow, look forward to your experiences.P.s. I know that if I want to be sure I should stick to a reputable supplier like InnoSent or RFbeam. But thats not the question now...

author: Kirkhaan
author_rank: Frequent Contributor
timestamp: September 07, 2018, 02:23:22 pm
content: I got hold on one of their modules. It appears that they use a dot of glue on the LO for frequency tuning...What to think about that with respect to stability over temperature and lifetime?

author: Kirkhaan
author_rank: Frequent Contributor
timestamp: September 10, 2018, 05:51:09 pm
content: I've seen designs where a trace is scratched with a knife to tune the LO frequency.Also laser trimming I have seen before, but such a dot of glue not. I doubt the reliability of it!