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I would like some way of measuring the Q of inductors up to at least 30 MHz - 150 MHz would be nice. I have an HP 4284A Précision LCR meter (20 Hz to 1 MHz 0.05% basic accuracy) and a 4285A (75 kHz to 30 MHz, 0.1% basic accuracy). However, although these figures of 0.05% m n My mmand 0.1% might sound impressive, these are only achieved at a very limited set of circumstances. There’s an example in the 4285A manual of a measurement the Q on an inductor. I forgot the exact numbers, but they are similar to these * 220 nH * 25 MHz * indicated Q = 30 Measurement uncertainty +107/-13. So all it really says is that the Q id somewhere between 17! and 137. So I was looking for ideas on building a Q meter.. Dave, G8WRB -- Dr. David Kirkby, Kirkby Microwave Ltd, drkirkby@... https://www.kirkbymicrowave.co.uk/ Telephone 01621-680100./ +44 1621 680100 Registered in England & Wales, company number 08914892. Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United Kingdom

I've recently acquired a Tek 284 that seems to need some TLC. Before I start snooping around in it, I'm wondering if there are any "usual suspects" that I should consider. Besides all the electrolytic capacitors. They're already on my hit list. Thanks - Dave

This is a double post I also made on the tinySA group. It was intended to be posted here but groups.io switched to the wrong group for some reason. Anyway Has anyone of you had a look at this chip from semtech? Since Si4432 has become obsolete I browsed for a chip that can take its place as a platform for RF tools. It has continous frequency span from 150MHz to 960MHz and comparable phase noise as Si4432 with the disclaimer that it is frequency dependant. For me, fast sweep time is beneficial as I often scan wide chunks of spectrum and this chip have a pll settling time of 30us. It’s quite good , is it? Have I missed something that makes this chip a dead end to persue further? Link SX1261

Hi group members I have about 15 years as an EE developer, mostly conumer stuff. My main interest for test equipment is for debugging rf-emissions and pre-compliance testing and not amateur radio. If it is OK to discuss equipment from that perspective I am happy to join and if not I am perfectly fine with that and just keep lurking. :) /edit I want to add that ideas I have does not necessarily have to do with emission probing. I just like to build testgear as a hobby and learning exercise.

Hi, I am starting to build a 'specan' (https://hfsignals.blogspot.com/p/specan-reboot-of-w7zoi.html ) Mainly because I have a prototyping shield spare I will be using one. It also has an SOIC 14 footprint. I was wondering whether I could put the AD8307 on the shield. Would that introduce too much noise from the MCU? What about if I were to shield the area of the board that contains the log detector? Second Question: Ashhar Farhan used an external 5v regulator for the arduino (separate from the regulator for the AD8307) but the arduino has a regulator on board. Is there a good reason for by-passing the arduino's regulator? thanks & 73 Ellis G7SAI

Does anyone have a recommended source for 9MHz crystals for a crystal ladder filter? Plenty offered on E-bay but no way of telling how good they are. Thanks, Mike K5ESS

I'm trying to run Erik Kaashoeks code for the 10 MHz reference. The problem seems to be that the LCD is stuck while the code seems to achieve lock. The code is from 3 Dec 2021: https://github.com/erikkaashoek/Arduino_SI5351_GPSDO My hardware is a SI5351 with a TCXO at 25 MHz and a 16x2 LCD, and no phase detector. Judging from the serial output on the Arduino monitor, it seems to be running OK. But hardly anything shows on the LCD, only the second line which says " F2DC V.5.2"., no lock information and no clock. Here is the output on the serial monitor for the first 5 minutes: 0:00:05 dur=4 acount=25263408 dcount=-6480 calfact=0 acount=25263408 mincorr=10.0e-8 corr=1.5e0 xtal=26000000000 0:00:11 dur=5 acount=32043408 dcount=13680 calfact=0 acount=32043408 mincorr=8.0e-8 corr=1.6e0 xtal=26000000000 0:00:17 dur=5 acount=32043394 dcount=13666 calfact=0 acount=32043394 mincorr=8.0e-8 corr=1.6e0 xtal=26000000000 0:00:23 dur=5 acount=32043405 dcount=13677 calfact=0 acount=32043405 mincorr=8.0e-8 corr=1.6e0 xtal=66650276864 0:00:29 dur=5 acount=18754610 dcount=28690 calfact=0 acount=18754610 mincorr=8.0e-8 corr=5.0e-1 xtal=99999992832 0:00:35 dur=5 acount=12500001 dcount=1 calfact=0 acount=12500001 mincorr=8.0e-8 corr=8.0e-8 xtal=100000000831 Lock 0:00:46 dur=10 acount=24999998 dcount=-2 calfact=0 acount=24999998 mincorr=4.0e-8 corr=-4.0e-8 xtal=99999996831 Lock 0:01:07 dur=20 acount=49999998 dcount=-2 calfact=0 acount=49999998 mincorr=2.0e-8 corr=-2.0e-8 xtal=99999994831 Lock 0:01:48 dur=40 acount=100000000 dcount=0 calfact=0 acount=100000000 mincorr=10.0e-9 corr=0.0e0 xtal=99999994831 Lock 0:03:09 dur=80 acount=200000000 dcount=0 calfact=0 acount=200000000 mincorr=5.0e-9 corr=0.0e0 xtal=99999994831 Lock 0:05:50 dur=160 acount=400000001 dcount=1 calfact=0 acount=400000001 mincorr=2.5e-9 corr=2.5e-9 xtal=99999995081 Lock I would appreciate it if I could compare outputs with someone else -- Sverre LA3ZA http://la3za.blogspot.com

The following files and folders have been updated in the Files area of the [email protected] group. /Q&D GPSDO/GPS_Si_52.ino By: Bill Buoy <bill@...> Description: updated sketch for the GPSDO

Bill Buoy <bill@...> added folder /Q&D GPSDO

I have ordered a limited batch of boards from JLCPCB for the QEX September/October 2021 “Miniature SMA Step Attenuator” pp 9-21 by Tom Alldred VA7TA. If you are interested in a board, at $3.00 ppd CONUS, please reply off line [click the “Private” button]. I expect to receive the boards in the first week of October and will have 8 spare boards available. If there is sufficient additional interest, I would be willing to make a second order. See attached for some additional info. Dick K9IVB

Hello to all, I bought used an AR-60A (AccuBeat) and a Datum LPRO (I think it's from Efratom) and they both work. I have no experience with these Rubidium frequency standards and would like clarification regarding the optimal operating temperature, i.e. if they need a heatsink and how large it should be (or how many ° C / W). Currently without the heat sink the temperature rises to about 50 ° C then stabilizes. Thanks for the attention. -- Cheers Attilio

SPARKFUN? ARDUINO COMPONENT TESTER RE-PACKAGED I recently came across an Arduino based, Component Tester project by SPARKFUN?. Arduino Component Tester ( https://www.sparkfun.com/news/3909 ) Following the directions in the article, I bread-boarded the circuit, using an Arduino UNO, and found it to be a potential, useful addition to my test bench. However, the form factor left something to be desired. So, I flashed the firmware into an Arduino Nano and found no difference in the operation. Now I had a way to make a smaller, permanent tester. I found some small, project boxes in my stock that fit the bill perfectly - 58MM wide x 35MM high x 15MM thick. I entered the schematic into the FRITZING program and created a PCB to fit into the box. UNFORTUNATELY I forgot to rotate the NANO on the layout and the boards are useless. I have reverted to point-to-point wiring. I am posting a short PDF describing the build in the files section. Dennis KG4RUL

Dennis Zabawa <kg4rul@...> added folder /Honey I Shrunk The Component Tester - Build Description The following files have been uploaded to the Files area of the [email protected] group. /Honey I Shrunk The Component Tester - Build Description/ComponentTesterRepackaged.pdf By: Dennis Zabawa <kg4rul@...> Description: A description of the Sparkfun Arduino Component Tester down-sized to fit in a small package using a Nano is place of a UNO.

In the May 2021 edition of QST Magazine, Stan Johnson (W0SJ) published an article describing a device one can hook to an oscilloscope to turn it into a time domain reflectometer (TDR). Stan built his basically out of parts from the junque box for which he deserves kudos! I hate hand wiring stuff so I decided to design a printed circuit board for it. My board makes a few changes in Stan’s design which made the PCB layout a bit neater and added a couple of features, but otherwise it is basically the same as his design. With a lot of help from Glenn (VK3PE), the PCB can be built using either through-hole components or SMD components or a combination of both. The Gerber files for the PCB along with a document describing the PCB and some more information on it's use can be found on GitHub ( https://github.com/WA2FZW/A-PCB-for-the-W0SJ-TDR-by-WA2FZW ). Also available there are two Android apps developed by Roderick Wall (VK3YC). One allows you to calculate the length of a piece of coax and the other allows you to compute the velocity factor of a known length of coax. I have a few extra circuit boards available should anyone want one. You can have them for $5 each (free shipping to the USA). If you'd like one, please email me (good on QRZ.com). -- John P. WA2FZW

The following files have been uploaded to the Files area of the [email protected] group. /iw5bsf adf4351 pll spurios/adf4351 spuriosa.jpg By: Roberto <iw5bsf@...> Description: original out adf4351 pll spurios