hybridfree/eevblog-posts huggingface dataset:
Network Analyzer Transmission Response Calibration question - Page 1
Forum section: electronics / rf-microwave

author: barrds
author_rank: Contributor
timestamp: September 19, 2025, 09:23:46 am
content: Hi all,A question on just a plain Transmission Response meas. (without one port or two port calibration):On figures 10 and 11 of the Agilent application note "Applying Error Correction to Network Analyzer Measurements", why a 1 is added/subtracted to calculate the Calibration and Measurements Uncertainties when performing a transmission response??Calibration Uncertainty = (1 +/- rS.rL)rS = network analyzer Source matchrL = network analyzer Load matchMany thankshttps://anlage.umd.edu/Microwave%20Measurements%20for%20Personal%20Web%20Site/5965-7709E.pdf

author: rf-messkopf
author_rank: Regular Contributor
timestamp: September 22, 2025, 10:34:50 pm
content: In figure 10, the 1 is the relative amplitude of the wave traveling directly through the ideal "thru" connection towards the VNA load port. Due to mismatch, a portion rL of this wave is reflected at the load port, travels back through the "thru" towards the source port, where a portion rS is reflected, which then travels back towards the load, where it interferes with the other wave. Now in the worst case the amplitude at the load port is 1 + rL*rS or 1 - rL*rS when the waves are in phase or 180° out of phase.The same applies to figure 11.

author: barrds
author_rank: Contributor
timestamp: September 25, 2025, 09:31:17 am
content: Excellent explanation.Many thanks !
Looking for some help identifying some Texas Instruments Microwave transistors - Page 1
Forum section: electronics / rf-microwave

author: Johnny10
author_rank: Frequent Contributor
timestamp: September 27, 2025, 01:59:34 am
content: Looking for some help identifying some Texas Instruments Microwave transistors.Sorting through some of my salvage buys I found a box of components containing various new sealed parts.I am not finding identification of these items.Any help would be appreciated.Also HP device

author: fant
author_rank: Contributor
timestamp: September 27, 2025, 08:21:06 am
content: I have seen some similar FET on microwave amplifiers, mostly on 1,5 - 1,8 GHz and 3 - 4 GHz.If are FET, consider that the gate negative voltage MUST be applied before the DRAIN voltage, otherwise destruction immediate.Even mine are without any sign, some are with the number 21 on top.On some working amplifiers I had the following DC characteristics:- Gate voltage : from - 1,5 to -2 V- Drain Voltage : from 4 to 7 V- Drain current : around 10 - 12 mAGain about 10 dB per active unit.No other characteristics, we were repairing the amplifiers just replacing the FET and adjusting for the correct drain current.Mandi
VK2ZJ SINAD Measurement App - Page 1
Forum section: electronics / rf-microwave

author: rf-fil
author_rank: Regular Contributor
timestamp: October 09, 2025, 11:14:31 am
content: I've written a little app that uses the PC sound input to measure SINAD (Signal to Noise Distortion ratio) in real time, as typically used for testing receiver sensitivity.Grab the app and its documentation fromhttps://github.com/VK2ZJ/VK2ZJ_SINAD_Meter.The sound card / app combo has some limitations compared to a proper piece of test equipment, but should mostly work for testing radios. It has worked for me pretty well, so far.There is also a little command line program that will process a pre-recorded wav file and plot the SINAD over time.Any feedback is welcome and I hope people find it useful.

author: Roger Need
author_rank: Regular Contributor
timestamp: October 10, 2025, 05:46:22 pm
content: I downloaded your app and found it very useful for testing the sensitivity of several SDR radios. I used a virtual audio cable to pipe the audio to your program. The program uses the default sound device in Windows for the input. The calculated SINAD "bounces" a fair bit due to the frequent updates.I made several changes to the program with the assistance of Perplexity AI. The first was to implement a drop down menu to select from available sound inputs. The second was another dropdown menu to do average over a number of SINAD calculated values. I will contact you via PM to send you a copy of the modified code.Roger

author: rf-fil
author_rank: Regular Contributor
timestamp: October 11, 2025, 06:10:33 am
content: Thanks - I've improved the bouncing now. I've also added a bunch of other improvements.
Controlling RF Attenuator PE43703 - Page 1
Forum section: electronics / rf-microwave

author: space
author_rank: Newbie
timestamp: September 23, 2025, 01:53:38 pm
content: Hello,I'm trying to control a RF Attenuator PE43703. I hoping to do this via serial interface using Raspberry Pi Pico and ISP.Code:from machine import Pin, SPIimport time# --- SPI setup (Raspberry Pi Pico, hardware SPI0) ---spi = SPI(0, baudrate=1_000_000, polarity=0, phase=0,sck=Pin(18), mosi=Pin(19), miso=Pin(16))# --- Latch Enable pin for attenuator A1 ---A1_LE = Pin(17, Pin.OUT, value=1) # keep high when idleword = 0b0000001100011110data = bytes([(word >> 8) & 0xFF, word & 0xFF])print(data)# --- Send over SPI ---A1_LE.value(0) # keep LE low while shifting in dataspi.write(data)time.sleep_us(10)A1_LE.value(1) # rising edge latches new wordWhile using this code and changing the attenuation word (word = 0b0000001100011110) I'm not able to change it as I want in the software. Using the datasheet, I've checked the address bytes and hardware pins - all fine.
VNA Calibration Kit Design - Page 1
Forum section: electronics / rf-microwave

author: M3K33L
author_rank: Contributor
timestamp: September 18, 2025, 01:22:23 pm
content: Hello!Recently, I posted about getting my calibration to work properly on my VNA. This post is related, but not the same topic, so I decided to make a new post.Currently, I am trying to design a calibration kit based on measurements of on-wafer TRL standards that I've designed. I have seen a handful of people using METAS VNA Tools to do this, but I have not seen a good guide on how to actually get the calibration coefficients from the software. I have between 2-4 measurements of each of the T,R, and L standards that I've made and imported them into METAS. They line up pretty well with my simulations. Regarding those, the subcircuit is a representation of a CPW launcher. I just don't know how to take the optimization of the collected data. It seems like METAS wants me to have an existing calibration definition for this, but I'm a bit unsure as to how I create that. Should I use my simulations?Looking forward to hearing your answers.
Components for a 433.92MHz key fob? From JLCPCB? - Page 1
Forum section: electronics / rf-microwave

author: LM21
author_rank: Regular Contributor
timestamp: September 09, 2025, 04:24:24 pm
content: I need a gate opener for the 433.92MHz ISM band. JLCPCB has a 433M-TO39 SAW resonator for that frequency, but the datasheet has no component values. A Murata app note gives some values for some SAW resonators. That is, for the common base oscillator which drives the SAWHas anyone built these kind of devices, or does anyone know a good resonator or oscillator for that band. Resonators can be tricky to solder at home, so I prefer something which JLCPCB has.I think I'll put a small CPU on the board to to give modulation data. What I have heard, modulation is often on off keying.Edit: TO-39 is not hard to solder.

author: tszaboo
author_rank: Super Contributor
timestamp: September 09, 2025, 04:37:49 pm
content: That's not how you make radio devices, not in the 21st century anyway.Choose a SO8 or similar Chinese OOK RF transmitters and build a simple circuit around that. HopeRF sells parts like that

author: Uunoctium
author_rank: Frequent Contributor
timestamp: September 09, 2025, 05:20:48 pm
content: Why not using a single chip ASK/FSK solution? Melexis MLX72013 is 1.66$ @ Digikey.In Fig.12 a complete transmitter with 50Ohms RF out is shown w BOM. It's Crystal stabilized and his 866 counterpart is wideley used in European wireless heat cost allocators.https://mm.digikey.com/Volume0/opasdata/d220001/medias/docus/524/MLX72013_DS.pdfEdit: image shows Brunata/Metrona 866 TX,

author: LM21
author_rank: Regular Contributor
timestamp: September 09, 2025, 08:43:16 pm
content: HopeRF sells interesting products. I ordered a couple of RFM110 from Aliexpress. If that does not open the gate, I'll buy MLX72013 next time I buy from Digikey.Postage and handling has rosen again. Who broke free postage from China.

author: ftg
author_rank: Frequent Contributor
timestamp: September 10, 2025, 12:14:52 pm
content: JLCPCB assembly has multiple SOT23-6 sized OOK transmitter chips.Just add a 13.56 MHz crystal for 433.92 MHz output.Some examples:PT4455 - €0.2139F113 - €0.1414MICRF113 - €0.8274VI8805H - €0.1277T117 - €0.0594VI4455 - €0.0911LR690L - €0.1611WS4455 - €0.1321JT2309 - €0.0939VG4455 - €0.0811Prices in 1 pcs qty.So there's tons of these for next to nothing and many are pin compatible with each other.I should design some boards for these to measure how widely they tune and how bad the phase noise truly is.Edit: Re-read your initial post about having a microcontroller, then there's also the option of using CMT2110A or CMT2119A as well.CMT2119A does (G)FSK in addition to the usual ASK/OOK.

author: LM21
author_rank: Regular Contributor
timestamp: September 10, 2025, 01:50:30 pm
content: RFM110-433S1 from HopeRf is widely available. I even could have bought them here locally, but bought themfrom Aliexpress.Thank you ftg, MICRF113 is somehow familiar, I'll look them up. Yes there probably is some code to open the gate. Some small Arduino clone is good for that
What is the purpose of Q2? - Page 1
Forum section: electronics / rf-microwave

author: honorasm
author_rank: Newbie
timestamp: August 29, 2025, 10:25:00 am
content: It is a RF amp taken from the OrCAD simulation examples. What is the purpose of Q2, D1 and C1? I think Q2 is biasing Q1, but can not find out how it works. I don't know why D1 and C1 is needed, either.

author: Andy Watson
author_rank: Super Contributor
timestamp: August 29, 2025, 10:49:56 am
content: Focusing on R6, Q2 and D1 + R2. This is the basis of a constant current source - the current being determined by the voltage across R6. D1 compensates for the temperature variations of Q2's Vbe. Q1 is brought into the loop via the connection R6-R7. What you have is a feedback loop that detemines the DC current through Q1. Essentially, Q2 is providing a automatic bias for Q1.

author: honorasm
author_rank: Newbie
timestamp: August 30, 2025, 09:55:28 am
content: The operating point of Q1 is:Ic(Q1)=[Vcc-Ve(Q2)]/R6={Vcc-[(Vcc-V(D1))*R3/(R2+R3)+Vbe(Q2)]}/R6={Vcc*R2/(R2+R3)+[V(D1)*R3/(R2+R3)-Vbe(Q2)]}/R6={0.3Vcc+[0.7V(D1)-Vbe(Q2)]}/R6Assume V(D1)=Vbe(Q2) and they varies over the temperature the same amount, [0.7V(D1)-Vbe(Q2)] is still not zero and varies over temperature. Is it still cancellation? Or did I misunderstand it?

author: tchicago
author_rank: Regular Contributor
timestamp: September 05, 2025, 03:11:10 pm
content: Quote from: Andy Watson on August 29, 2025, 10:49:56 am.. and the C1 is to make sure the Q2 does not interfere with the RF functionality of the amplifier, i.e. excluding the RF from the feedback loop.

author: TimFox
author_rank: Super Contributor
timestamp: September 05, 2025, 03:50:12 pm
content: The circuit section with Q2 senses the voltage across R6 to measure the DC collector current in Q1, for negative feedback to the base voltage of Q1 to establish the quiescent current in Q1.

author: Andy Watson
author_rank: Super Contributor
timestamp: September 05, 2025, 08:33:05 pm
content: Quote from: honorasm on September 04, 2025, 03:53:22 pmI agree, it is not a perfect cancelation. But it is better than no cancelation.Quote from: honorasm on September 04, 2025, 03:53:22 pmI think I would call it "compensation" (partial compensation). As with most discrete analogue designs, it is a compromise. I am not the designer of this circuit; I can only guess what their intentions were. However, my guess is that the required outcome is to put Q1 in "operating" conditions, regardless of temperature variations. As a thought experiment, consider how you would bias Q1 using only fixed resistors. It is operating into a load impedance of 50- to attain some voltage gain will require the emitter resistance (3.8plus the re of the transistor) to be substantially less. To achieve low re requires the collector current to be maintained at a relatively high level (mA). With a fixed bias voltage, changes in Vbe of Q1 (due to temperature) are going to have a significant effect on the collector current. In comparison, the changes due to the temperatire of D1 and Q2 will be negligible (I hope - I've not run the figures).
LDOs on power RF amps - Page 1
Forum section: electronics / rf-microwave

author: ezalys
author_rank: Frequent Contributor
timestamp: September 05, 2025, 05:52:23 am
content: In the HMC1099 dev boards, nobody shows any LDOs to pre-regulate the supply voltage. The HMC1099 also doesn't show any kind of PSRR specs. How do I decide whether or not I want to pre-regulate?

author: ejeffrey
author_rank: Super Contributor
timestamp: September 05, 2025, 09:42:45 am
content: The HMC1099 is effectively a single transistor amplifier. It is powered through the output pin. That means it effectively has 0 dB PSRR. Only your external bias network provides filtering of power supply noise.

author: mtwieg
author_rank: Frequent Contributor
timestamp: September 05, 2025, 12:58:54 pm
content: Yeah, the HMC1099 itself provides no PSRR. Power supply noise/ripple will pass to the output through the drain bias and output matching network, should be easy to calculate.Care should be taken to attenute noise/ripple on the RFIN pins, as that will be amplified.Depending on your application and required bandwidth, it might be find to operate this directly from a switching DCDC with no preregulator.
Compression mount SMA on PCB - Page 1
Forum section: electronics / rf-microwave

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: August 28, 2025, 02:40:21 pm
content: So I've seen compression mounted SMAs on microwave hybrids that are made of alumina or something equally as tough.But are they meant for permanent PCB mount?https://www.digikey.ca/en/products/detail/amphenol-sv-microwave/SF2921-61345-1S/6716278Doesn't fiberglass and epoxy PCB material flow under pressure? Or are the SMAs designed to apply only the pressure required for contact and doesn't deform the PCB enough to flow? It is a tiny area after all.Question is, are these meant for permanent FR-4 type PCB mounting?I'm just a dabbler in RF so maybe it's obvious. Beats me.

author: shabaz
author_rank: Frequent Contributor
timestamp: August 28, 2025, 03:24:11 pm
content: Quote from: Alex Eisenhut on August 28, 2025, 02:40:21 pmHi,It's discussed on page 2 of thisSV Microwave PDF doc.Also, a discussion thread here:https://www.eevblog.com/forum/rf-microwave/how-to-properly-use-these-sma-connectors/msg5987743/?topicseen#msg5987743
What happened to  www.g3ynh.info site? - Page 1
Forum section: electronics / rf-microwave

author: LM21
author_rank: Regular Contributor
timestamp: August 04, 2025, 04:35:50 pm
content: The whole site is down. Owner of the site died years ago, but the site was up without updates. It was a good place to read about inductor making and other RF issues.

author: szoftveres
author_rank: Regular Contributor
timestamp: August 04, 2025, 04:46:46 pm
content: It's archived, the links seem to be workinghttps://web.archive.org/web/20241005233337/https://www.g3ynh.info/

author: RoGeorge
author_rank: Super Contributor
timestamp: August 04, 2025, 05:37:55 pm
content: Internet websites do not last more than a few years. This is true even for big companies who constantly redo their website, or get acquired, and render useless all the links posted anywhere else online.When I find something interesting, but don't have the time to read it right away, I save that page. Not just a link to it, but I save the webpage entirely, with pictures and all. There are browser plugins that can save an entire webpage and put all that in a single file, that you can store locally on your computer. Together with the local copy, it saves a link to the real page, too. An example of such a browser plugin/addon/extension isSingleFile(for Firefox).

author: LM21
author_rank: Regular Contributor
timestamp: August 04, 2025, 05:59:06 pm
content: I have copied some articles and spreadsheets from that site here. But didn't copy all. Is there a plug-in for copying the whole site. Firefox is quite good at printing webpages/making PDFs.That page from wayback machine seems to work well.

author: rainbow
author_rank: Contributor
timestamp: August 28, 2025, 01:50:27 pm
content: Few years ago, I made a full backup. Here the archivehttps://www.dropbox.com/scl/fi/8vr5ns1t2gskjim1yg7jo/G3YNH.zip?rlkey=vkhazfc13hrvk2x7qrpjrkvw4&st=be0ivfss&dl=0
Unexpected Spurs in the LMX2572LP - Page 1
Forum section: electronics / rf-microwave

author: armaganergin
author_rank: Newbie
timestamp: August 18, 2025, 07:38:40 am
content: There are spurs I observe which isn’t predicted by PLLatinum SimThere are some spurs that I couldn't find the root causes. I simulated on PLLatinum Sim, I used same registers as TICs Pro software says but I m getting unexpected results. For example, when I configured the PLL to output frequency is 240.02 MHz there are spurs at100 kHzaway from carrier frequency but PLLatium says there is aprimary fractional spur at 160 kHzaway from carrier frequency if MASH clock distortion is enabled.My observation is that after the PLL, in the second stage, a spur appears at half of whatever is set after the decimal point.For example, when it is set to 240.02 MHz, the spur shows up 100 kHz away; when it is set to 240.01 MHz, the spur shows up 50 kHz away — that is, at 5 times the value after the decimal point.However, this is not the same for every frequency. For instance, at 210.01 MHz the spur is 100 kHz away, while at 215.01 MHz no spur appears. At 220.01 MHz more serious spurs appeared.What I triedI tried to see significant difference in PLLatium Sim for different output frequencies but I can't see any. 215.01 MHz and 220.01 MHz are almost the same configuration only the fractional N-div values are changing.I tried different register configurations with different MASH orders, MASH seeds and different fractional N-div values. All gave the same result nothing has changed. Only lowering the charge pump current improved the spur level by 6 dBc.Different LMX2572LP gave the same results too.Thanks for helping.

author: dobsonr741
author_rank: Frequent Contributor
timestamp: August 27, 2025, 01:55:17 pm
content: The simulation is being honest about the fractional N dividers. It’s math, and expected. Think about the divider in the PLL, sometimes dividing with N, then N+1 to get the averaged division ratio. You can consider it as phase noise injected. Your loop filter needs to be hard at work to attenuate, if possible. -60dB is not bad, but what budget do you have for the spurs?
NRAO Fortran code TCHEBx.F - does anybody have a copy? - Page 1
Forum section: electronics / rf-microwave

author: OscarM
author_rank: Newbie
timestamp: September 03, 2025, 11:16:14 pm
content: E. Wollack at NRAO created a fortran code TCHEBx.F to calculate Homogenous Stepped Waveguide Transformers.It is discussed in a technical note No. 176 (Nov 1995)Does anybody have any suggestions where I could find a copy?It appears to do exactly what I want I just can't find it anywhere.TYIA

author: radiolistener
author_rank: Super Contributor
timestamp: September 04, 2025, 03:06:13 am
content: Here is the original article, which describes the algorithm:https://library.nrao.edu/public/memos/edtn/EDTN_176.pdfThe code itself is not included, but you can implement it yourself - for example, in Octave, based on the algorithm outlined in the paper.If you want to see the original code, I think the most practical approach would likely be to contact NRAO directly and request it, they should be able to locate it in their archives.
Expot cvs and json data from namovna usn liteVNA64 - Page 1
Forum section: electronics / rf-microwave

author: markus_jlrb
author_rank: Regular Contributor
timestamp: August 12, 2025, 02:23:32 pm
content: Dears,FYI,found an interesting link to sw onhttps://groups.io/g/liteVNA/topic/114658929thanks to Julio Alvarez.https://github.com/jcziviani/litevnaserver/blob/main/README.mdThis SW is capable to communicate with the mentioned VNA and fetch thevalues and export them as json format that could be easy converted to csvand other useful formats for further usage.>curl -s 'http://localhost:8888/litevna?start=30000000&step=1000000&points=30'| jq -r '.result[] | [ .freq , .s11[] , .s21[] ] | @csv'30000000,-26.4765,170.91,1.09961,-94.9591,82.427831000000,-26.5099,171.691,1.09921,-90.4226,126.52932000000,-26.5082,172.427,1.09923,-82.9833,-81.7755Markus
Why Your Antennas Are Fighting Each Other — And How to Stop It? - Page 1
Forum section: electronics / rf-microwave

author: Thinkingliferf
author_rank: Newbie
timestamp: August 07, 2025, 08:39:11 am
content: If you have antenna isolation issue, you may watch this:You also can download the excel tool for your antenna isolation calculation with the link in the description. If you like the tool, do remember to like, subscribe and share.Thank you!

author: LM21
author_rank: Regular Contributor
timestamp: August 10, 2025, 06:56:14 pm
content: The sound volume is a bit low.
quensheng uv-k6 mod board mystery ic - Page 1
Forum section: electronics / rf-microwave

author: ME
author_rank: Frequent Contributor
timestamp: September 06, 2025, 01:39:09 pm
content: I have a mod board for my k6,It says v5 but also there is an ic included that looks to be marked as "24m02rd K433k,can anyone tell me what it is? Thanks.
BG7TBL OC8-ADJ - Does anyone have the manual or the rs-232 commands? - Page 1
Forum section: electronics / rf-microwave

author: lb7pj
author_rank: Newbie
timestamp: August 08, 2025, 09:35:10 pm
content: Looking for the RS-232 commands to change the frequency of the outputs... Seems impossible to get it from the sellerAnyone ?
ICOM IC-745, LSB mode - Page 1
Forum section: electronics / rf-microwave

author: Zolive974
author_rank: Newbie
timestamp: April 22, 2024, 10:46:11 am
content: Hello,I have a little problem with an IC-745 which prevents me from going to LSB mode, let me explain:Initially the radio was sold for parts as non-functional, I managed to repair it by flashing the SRAM module (thanks to your forum) and performing an alignment using the service manual.The radio works well on all bands and I can listen when there is modulation on the bands.However, when I press the "MODE-SEL" button to change modes, it works fine and I have in order "USB, CW, RTTY, AM, FM" and normally, pressing again this same button, I should reach LSB mode, but impossible, it automatically brings me back to USB mode, and so on, I cannot access LSB mode.The only way to enter LSB mode is to press the "VFO A/B" button in order to switch to VFO B which at the moment is magically set to LSB.On this VFO B I can therefore go in all bands (from 0 to 30Mhz) in LSB only, and if I press the "MODE-SEL" button nothing happens, I remain stuck in LSB mode.To return to the other modes, you have to switch to VFO A, but once there I would have access to all the other modes except LSB.Do you have any idea of ​​the origin of this problem?I searched a bit on the internet and it seems that it might be a fault in the SRAM module but not much information on this subject.Knowing that I do not have another replacement SRAM module to test, I am therefore turning to you to guide me in researching this problem.Thanks for your help.

author: s-petersen
author_rank: Contributor
timestamp: July 29, 2025, 02:06:23 am
content: Although this is old, and you already likely solved the issue, you have an issue with the data stored in the memory module. it is the only thing that controls the mode settings. Maybe this helps the next person
Anyone knows what happened to www.opengd77.com - Page 1
Forum section: electronics / rf-microwave

author: bingo600
author_rank: Super Contributor
timestamp: July 22, 2025, 06:22:25 pm
content: For the last couple of dayswww.opengd77.comhas given me a 403 answer.Anyone knows what happened ?

author: oPossum
author_rank: Super Contributor
timestamp: July 22, 2025, 06:51:08 pm
content: denial of service attack

author: bingo600
author_rank: Super Contributor
timestamp: July 23, 2025, 01:33:50 pm
content: @opossumThnxWhere did you get that info (page) ??
Square Halo antenna - Page 1
Forum section: electronics / rf-microwave

author: A.Z.
author_rank: Super Contributor
timestamp: July 16, 2025, 04:10:47 pm
content: I am interested in such an antenna ( the single one, not the cobweb) but can't find the formulas to calculate itany help ?

author: Geoff-AU
author_rank: Frequent Contributor
timestamp: July 17, 2025, 06:40:08 am
content: the hobby refers to them as "Squalo antenna" so that will no doubt turn up many sites

author: A.Z.
author_rank: Super Contributor
timestamp: July 23, 2025, 09:40:43 am
content: Quote from: Geoff-AU on July 17, 2025, 06:40:08 amWell, I knew that and did my homework, but I was unable to fiind the calcs needed, I don't want the size, but the calc formulas which are different from the vanilla dipole

author: A.Z.
author_rank: Super Contributor
timestamp: July 23, 2025, 10:05:50 am
content: No sweat, figured it out by myself with the help of 4nec2here's the modelCode:CM square halo (squalo) antennaCM impedance is around 12.5 OhmCM use an 1:4 transformer andCM a current balun (choke)CE' symbolsSY freq=28.800 ' design frequencySY wire=0.00075 ' wire radiusSY fact=1.0003 ' length factorSY wave=(300/freq) ' wavelength (lambda)sy cgap=0.058 ' arms gapSY sgap=cgap/2 ' half gapSY tlen=(wave*fact)/2 ' wire lenSY peri=tlen+cgap ' perimeterSY side=peri/4 ' sideSY half=side/2 ' half sideSY leng=wave*fact ' total wire lengthSY arms=(leng/4) ' dipole arm lengthSY hght=(wave*0.60) ' height from groundSY segs=21 ' segments in wires' geometry of wiresGW 1 segs 0 0 hght 0 -half hght wireGW 2 segs 0 0 hght 0 half hght wireGW 3 segs 0 -half hght -side -half hght wireGW 4 segs 0 half hght -side half hght wireGW 5 segs -side -half hght -side -sgap hght wireGW 6 segs -side half hght -side sgap hght wire' groundGE 1GN 2 0 0 0 13 0.005LD 7 0 0 0 2.1 wire ' teflonLD 5 0 0 0 58000000 ' copper' enable extended kernelEK' feedpointEX 0 1 1 0 1.0 0 0' test frequencyFR 0 0 0 0 freq 0' end of modelENI still need to find the "gap" formula but the calcs seem right; feedpoint impedance is around 13Ohm so a 1:4 like this onehttps://www.m0pzt.com/blog/4to1-current-balun/will fit and allow to feed it using coax, gain is above 6 dBi with good low angles and analmost(3dB difference) omnidirectional pattern so no real need to rotate the antennaas for gain, like most horizontally polarized antennas, raise this one to 0.60 Lambda to squeeze out max gain and low angles, as explained herehttps://www.voacap.com/2023/antennas/squeezing-decibels-out-of-dipole/for further details run the NEC model and see the attached imageNote: the model uses metric units
Sonnet Lite: is it possible to import DXF? - Page 1
Forum section: electronics / rf-microwave

author: SiliconWizard
author_rank: Super Contributor
timestamp: July 24, 2025, 11:01:09 pm
content: Using Sonnet Lite (latest version). My goal is to model a NFC antenna that I designed on PCB.Apparently, Sonnet Lite doesn't support importing Gerber (says so when attempting to). But it lets you import DXF, so I exported my antenna layout as DXF and tried to import it in Sonnet Lite.The import wizard lets me go up to the end but once I validate it, nothing happens. Nothing gets imported and my metal layer remains empty.Has anyone tried it or can tell me how to proceed? As we say, can't complain, it's free. But would be great if it worked.

author: G0HZU
author_rank: Super Contributor
timestamp: July 25, 2025, 02:36:27 pm
content: I haven't used Sonnet Lite in a while but the attached files in the zip file below are for a basic 1680 MHz Interdigital bandpass filter I've just designed to be built on Rogers 4003C 0.032" thick. It includes a DXF file that I exported from Keysight Genesys.I tried importing the DXF to Sonnet and it did seem to accept it and display it. However, the actual artwork for the .son project file below was imported direct from Genesys. I think that if you want to recreate the project below using just the DXF file you would have to get the scaling right and then tell it the PCB substrate info and where the via holes are etc.The fingers in the filter are about 28mm long and the DXF was exported as a metric DXF file in mm. Importing and exporting DXF files is always a bit clunky so let me know if you need me to export it again (in case I missed something).It should all be in the attached zip file below.

author: SiliconWizard
author_rank: Super Contributor
timestamp: July 25, 2025, 03:16:54 pm
content: I'll have a closer look at this project - after more attempts, I think the problem may be with what kind of DXF features Sonnet accepts. I did export DXF from KiCad. From a few, sort of cryptic diagnostics shown on the last import wizard page, I think it's unable to find any polygon, so must be the way KiCad exports PCB Layers to DXF.

author: SiliconWizard
author_rank: Super Contributor
timestamp: July 25, 2025, 03:32:59 pm
content: Ok, your project file opens fine, but if I try importing the DXF file, it also fails.And... finally found out what's wrong. Turns out that importing a DXF in an existing project just doesn't work. But if importing it to a new project, it works. Not sure if this is a bug in Sonnet, Sonnet Lite in particular, or something else.
RAK3172 LoRa Module – Range Problem at 500m (Non Line-of-Sight) - Page 1
Forum section: electronics / rf-microwave

author: blnc
author_rank: Newbie
timestamp: July 22, 2025, 11:26:30 am
content: Hi,I'm relatively new to LoRa, and I'm experiencing some issues with the achievable range when there is no clear line of sight.I'm trying to communicate between two nodes in a simple P2P setup (without setting up a full LoRaWAN network). I'm using the LR 14 Click board from MikroE, which integrates an RAK3172 module and uses an external antenna. The communication is handled via AT commands: one node sends data every 10 seconds, and the other node remains in listening mode. On the receiving side, I'm monitoring RSSI, SNR, and packet loss.The nodes are installed in a photovoltaic (PV) solar plant environment. The transmitting node is mounted on one of the solar panel structures at approximately 4 meters height, and the receiving node is on a tower about 2 meters above ground level. The distance between these two points is around 540 meters, but there are numerous solar panels obstructing direct line-of-sight.Previously, I used DigiMesh modules under the same phisical conditions, and it seems like switching to LoRa has not significantly improved the situation. I had expected better performance with LoRa.I'd like to ask: Are these range issues normal for LoRa at around 500 meters with obstacles such as solar panels? What improvements or adjustments could I make to enhance communication quality and reduce packet loss?Any insights or suggestions would be greatly appreciated. Thank you!

author: whollender
author_rank: Regular Contributor
timestamp: July 22, 2025, 04:29:52 pm
content: I think your best approach would be to find a way to get line of sight.A couple things you could try are a lower frequency band or directional antennas.The LORA modules I've seen are generally either ~900MHz or ~430MHz, but the lower frequency should have better propagation in your conditions.I'm not sure directional antennas will help without line of sight, but it may be worth trying if you just need a bit more power.The Lora modules I've used before have configurable transmit power and modulation rate, so you could also try using the max transmit power at the lowest rate to get the best link budget.
How does Anaren works? - Page 1
Forum section: electronics / rf-microwave

author: u666sa
author_rank: Frequent Contributor
timestamp: July 17, 2025, 02:51:05 pm
content: Can someone explain how it works?How it rotates signal 90 degrees?

author: radiolistener
author_rank: Super Contributor
timestamp: July 17, 2025, 03:36:14 pm
content: This is microstrip coupler.It’s based on coupled microstrip lines, where part of the energy transfers from one line to the other due to electromagnetic coupling. When signal enters the IN port, half the power goes directly to the 0° port, and half couples to the other line, delayed by 90°, reaching the -90° port. The phase shift appears because energy coupled into the adjacent line travels a slightly longer electromagnetic path, introducing a phase difference. The geometry - spacing between lines, length of coupling section, defines both the coupling ratio (here, 3 dB split) and the phase shift (here, 90° delay).In simple terms:- Direct path: IN => 0°, -3 dB- Coupled path: IN => -90°, -3 dBThe ISOL port absorbs any leftover energy not coupled efficiently, improving isolation.

author: TimFox
author_rank: Super Contributor
timestamp: July 17, 2025, 04:03:33 pm
content: Notice that the phase error (+/- 2o) and amplitude error (+/- 0.5 dB) are specified over a frequency range of 0.85 to 1.45 GHz.
Rf module 433mhz- led blinking unwanted - Page 1
Forum section: electronics / rf-microwave

author: theocid10
author_rank: Newbie
timestamp: July 20, 2025, 11:17:19 am
content: HIi have a circuiot of remote control with the RF module 433mhz with pt2262 and pt2272-m4. the transmitter has 4 butttons and the receiver has 4 leds as output plus an led that indicates the connection between the transmitter and the receiver. the power supply is 5v (transmitter) and four AA batteries (receiver)The problem is that all the leds instead of being on they blink constinuosly and it doenst depends on the distance between both circuit and the delay between the bliks are always the same.thanks in advance!theo
Dissolve foam? - Page 1
Forum section: electronics / rf-microwave

author: Dave92F1
author_rank: Contributor
timestamp: August 14, 2025, 01:02:22 am
content: Here is a King KA42B ADF (Automatic Direction Finding) antenna, circa 1972. (From eBay but before that it was on an airplane). It seems to be potted in brown crumbly foam. I was hoping to see what was inside.(I have a couple of ADFs too...may try to hook one up someday just for fun.)Any suggestions on dissolving the foam? Without destroying it?

author: Stray Electron
author_rank: Super Contributor
timestamp: August 14, 2025, 01:53:49 am
content: Acetone or MEK?

author: jpanhalt
author_rank: Super Contributor
timestamp: August 14, 2025, 05:50:28 am
content: I disassembled a KA428 or similar antenna years ago and probably used acetone and picking. Under the plastic cover is a copper sheet with fingers and a bunch of wires in a rectilinear grid (top to bottom and side to side). The foam keeps them separated and organized.The picture is what I pulled out of another antenna, except for the copper sheet and wires. The BNC is attached to another potted thing (shown). The antenna underneath is a KA428. I also have is a KR86. It was fun to listen too

author: Dave92F1
author_rank: Contributor
timestamp: August 14, 2025, 02:03:49 pm
content: Sounds like I should be careful not to move that rectilinear array around. Thanks!

author: jpanhalt
author_rank: Super Contributor
timestamp: August 14, 2025, 05:55:52 pm
content: I know NOTHING about antennas. Here's a link you may find interesting:https://longview.be/king-ka-42b-adf-antenna-system.html(t appears I misread the "B" as an 8 ). Flying an ADF/NDB approach used to be required for an instrument rating. I don't know if it still is. It can be challenging with a cross-wind and an engine out (simulated).

author: Dave92F1
author_rank: Contributor
timestamp: August 15, 2025, 04:54:06 pm
content: Thanks. I'm not entirely sure what that guy was trying to do with it - use it as an antenna for a home-made HF receiver? Anyway interesting.

author: jpanhalt
author_rank: Super Contributor
timestamp: August 15, 2025, 06:02:55 pm
content: Don't know about that guy. I got two antennas off eBay when I was playing with lightning detection (roughly 500 kHz). The ADF receiver came as a package with one. That's pretty outdated equipment, but it still works.
Hallicrafters SX-28 Finally Finished! - Page 1
Forum section: electronics / rf-microwave

author: Peithojr
author_rank: Contributor
timestamp: July 13, 2025, 03:32:16 am
content: Hey everyone,Finally finished my Hallicrafters SX-28!https://youtu.be/9oUieWJvnjs

author: RoGeorge
author_rank: Super Contributor
timestamp: July 13, 2025, 07:27:48 am
content: That must have took forever, to restore it so beautifully, nice work!Never seen such a large tuning capacitor.

author: Peithojr
author_rank: Contributor
timestamp: July 13, 2025, 05:20:24 pm
content: Thank you!
Extremely Simple Doherty Amplifier LTspice Simulation - Page 1
Forum section: electronics / rf-microwave

author: bb1
author_rank: Regular Contributor
timestamp: July 16, 2025, 09:35:34 pm
content: Doherty invented his amplifier in 1936 to improve efficiency of linear (such as SSB as opposed to CW) RF power amplifiers.His idea is so good that nowadays it is used everywhere, even including smartphones.Despite that, it was difficult to find simple free simulation model demonstrating all the important features of the Doherty amplifier.So I created such an LTspice model, which is attached.Doherty amp actually consists of two amps.They are modeled by current sources B1 and B2. B1 is the main amp, and B2 is the peak amp.Both amps are modulated by increasing voltage from V3.Output current of B1 increases from very small value to the maximum amplitude of 10A.Output current of B2 is zero for the first half of the modulation time, then cuts off less and less of the carrier signal,so at the end the output of B2 also has 10 A amplitude.For simplicity, to avoid RF complications not related to the Doherty idea,I1) used 1 Hz sinusoidal carrier signal.2) used 0.25 sec (quarter wavelength) delay lines with 1 ohm impedanceStandard doubling of the output impedance R1 is not simulatedRemarkable feature of the Doherty amp is that while the current of B1 is increasing all the time,the output voltage of B1 stops increasing just below 10V at the half of the simulation.V5 and V6 10V sources with diodes are added tosimulate possible B1 saturation, which never happens due to the Doherty great idea.At the end of the simulation both B1 and B2 contributeequal 10 A currents via the R1 load.LTSpice permits to see all the details of what is happening in the Doherty amp.I also attach the screenshot of the simulation environment.You can see time dependence of B1 (out1) voltage as well as B2 (out2) voltage.Another screenshot shows B1 and B2 currents.

author: bb1
author_rank: Regular Contributor
timestamp: July 16, 2025, 09:36:53 pm
content: More attached
High precision inductors for RF - Page 1
Forum section: electronics / rf-microwave

author: fluxgate
author_rank: Contributor
timestamp: July 10, 2025, 08:46:00 am
content: Hi, for a Z=50 Ohm filter in an adc frontend I need very stable inductors for frequencies from around 5 to 50 MHz in the range of 40nH to 300nH and 10mA max. current.Unfortunately while there's a lot of info in datasheets about capacitors, there's virtually none about inductors.My approach for choosing components was to just use these with the lowest tolerance and avoid ferrite core ones.Also besides from temperature stability, do these also some kind of 1/f noise?Thank you for your input!

author: ftg
author_rank: Frequent Contributor
timestamp: July 10, 2025, 09:15:17 am
content: If you go with air core inductors from Coilcraft or Wurth, I don't really see how there would be noise outside of the Johnson noise from the resistance of the wire used in the coil and stray EMI coupling into the inductors.But I'm always open to learn new things about noise.Shielded inductors would ofc then be shielded by metal cans or ferrite.

author: Uunoctium
author_rank: Frequent Contributor
timestamp: July 10, 2025, 09:40:10 am
content: tl;drThe usual ones eg muRata, Coilcraft have a lot of basics in their knowledge base.Coilcraft points to their 'higest Q series' for RF applications:https://www.coilcraft.com/en-us/products/rf/ceramic-core-chip-inductors/0402-(1005)/0402dc/and most of them offering Spice data/models.Sagami-Elec:https://www.sagami-elec.co.jp/en/news/index.php?dno=SPICE_1https://www.coilcraft.com/en-us/products/rf/https://www.murata.com/en-global/products/inductor/chip
SMP to PCB transition layout question - Page 1
Forum section: electronics / rf-microwave

author: raz2701
author_rank: Newbie
timestamp: July 11, 2025, 04:42:02 am
content: I'm making an RF thru with SMP connectors. The recommended layout is in this datasheet and also attached a screenshot of the relevant bit:https://www.te.com/commerce/DocumentDelivery/DDEController?Action=srchrtrv&DocNm=consmp001-smd-g-t-ds&DocType=Data+Sheet&DocLang=English&DocFormat=pdf&PartCntxt=CONSMP001-SMD-G-TMy first iteration of the board I had ground copper everywhere except 0.3mm away from the trace because I was trying to do a coplanar waveguide design. So I had ground copper under the center pin of the SMP connector, separated by the soldermask. This is a mistake right? My board is very sensitive to touch and being moved around, it's very capacitively coupled I guess would be the better term, too much parasitic capacitance.I should have a no fill zone in that circle correct? Like shown in the second picture? That picture only shows the top copper layer, in the second layer I have continuous ground plane. I've seen other people cutout a bit off the ground in the second layer, but for now I just want to make sure that indeed my mistake was mainly in the top layer having copper underneath the SMP's center pin.Thanks!

author: Marsupilami
author_rank: Frequent Contributor
timestamp: July 13, 2025, 11:44:15 pm
content: That would likely make it significantly better but it’s not guaranteed to be good. What’s your target?If you have something appropriate that’s solderable and you can cut it to the shape of the ground pads you could use it as a shim and bend the center conductor down to touch the pad on the trace. That’s a messy but relatively still easy experiment before respinning the board.
Rate the antennae for omnidirectionality and loss - Page 1
Forum section: electronics / rf-microwave

author: kellogs
author_rank: Regular Contributor
timestamp: June 26, 2025, 07:37:35 pm
content: The bowtie is printed on standard FR4, 1.6 mm thick, 1 oz copper. 434 MHz, all are in between 6-8 cm long.NMHA1: 1 cm per turn,support material is unknown and has 13 mm diameter,1 mm copper wire diameterNMHA2: 2 mm per turn,support material is nylon and has 20 mm diameter,0.5 mm copper wire diameterThanks
Trying to understand the AD9248 ADC module - Page 1
Forum section: electronics / rf-microwave

author: Amish_Fighter_Pilot
author_rank: Regular Contributor
timestamp: June 26, 2025, 10:54:33 am
content: Hello. I am interested in using the AD9248 module pictured below to function as an ADC in a system that will be sampling the output from AD831 mixers. I will be sampling frequencies that are mostly under 300KHz.So I understand that it outputs offset binary and two's compliment that can be selected by jumper, but I am not clear on the output data load. The chip seems to have three data speed modes(20,40,65 megasamples/s), but I don't know how to select those. Does the ADC stream that exact amount of data constantly or does it depend on what signals it has coming through the inputs? What is the best way to initially process this at this stage to reduce it's size without losing detail? AI claims these don't need an MCU to operate, but can I output each channel to a separate MCU for initial processing to cut down the data load and remove unneeded data so it's small enough to transfer to the control device for final review(Android OTG device or PC via USB)? Can I use a sort of virtual bandpass filter to focus on a smaller portion of the spectral data and thus reduce the load that is then passed forward across the slow USB from the MCU?This device seems to have a 22 pin bank on it. It just says it is "Parallel", but it isn't clear at all to me what that is. I thought parallel ports were 25 pin. There are basically two banks vertically that seem to be the same; so is it wrong of me to assume that each row represents the output of one channel? Does anyone know what this connector pinout standard is called? How would one interface this with an MCU's GPIO? Sorry for all the ignorance, but I've only been studying all this stuff for a short time and have no formal training.

author: iMo
author_rank: Super Contributor
timestamp: June 26, 2025, 12:27:43 pm
content: The chip itself can do 2x14b output or a muxed 1x14b. Your module has 1x14b output so you have to go muxed.I would recommend you to search for existing examples (hw wiring, sw - speedy MCUs and/or FPGAs) for that particular module (or the chip itself) on the github or somewhere else, as the messing with the 65MSps data rates requires some experience, imho..

author: Amish_Fighter_Pilot
author_rank: Regular Contributor
timestamp: June 26, 2025, 04:41:18 pm
content: Thank you for the reply. I did find a project very similar to what I am building, but it uses the AD9226(which uses more power and has only one channel, but has the same per channel sampling rate as the AD9248). I am considering similar, but I would like to do a first step of processing on the RP2350-plus boards to reduce the data load and get rid of junk I don't want or need from the stream. Otherwise i have to find a way to get that port adapted so I can go straight from the ADC to the Android device and bypass the MCU entirely. It's disappointing that the Pi Pico 2 has such limited USB speeds though.Anyway... here's that project:https://github.com/steve-m/hsdaoh-rp2350
Help with SNA and Sig Gen testing attenuation - Page 1
Forum section: electronics / rf-microwave

author: staticshock
author_rank: Contributor
timestamp: June 25, 2025, 08:43:16 pm
content: The test setup requires a Scalar Network Analyzer and Signal Generator to measure attenuation of a 3dB attenuator inserted into the Measurement Plane, as defined in the attached figure, from 0.8GHz to 18GHz.The SNA B and C path reference are established prior. However, when the attenuator is inserted into the measurement plane, the readings are very sporadic. I’ll see inconsistent readings that are not even nominally close to the attenuator’s value. The measurements for the 3dB attenuation displayed on the SNA is in the attached picture.The GPIB Addresses are correctly setup, which I can confirm since the Signal Generator amplitude changes accordingly when the power level on the SNA is altered. I’ve checked all cabling and made sure they are correct and secure. The SNA and components recently passed calibration. Are there any possible issues with the test setup that is causing the inconsistent readings?
high res microwave antenna canceled - Page 1
Forum section: electronics / rf-microwave

author: coppercone2
author_rank: Super Contributor
timestamp: July 12, 2025, 01:00:10 am
content: https://www.science.org/content/article/u-s-abandons-hunt-signal-cosmic-inflationIt looks like the current administrations are taking a very 'practical' approach to science. The idea was to look at the large scale effect of gravitational waves on CMBR.I think its a big let down because they developed LIGO, which very much proved gravitational waves, so this experiment had a very high chance in detecting something. So either the experiment is deemed useless because it has too low a chance of success or useless because it has a too high chance in success.Not to mention such high density microwave receiver arrays would undoubtably bring some major information to radar tech.