Gary @N8DMTMar 8
Phase Noise Test Set Parts? While looking for wire-wrap tools in the garage, ran across bag of the HP11729 phase noise test set modules saved from a scrapped unit. Have the Low Noise Amp, 640 MHz filter/driver-amp & comb generator, and IF Amplifier modules. Not enough to replicate the full features of the HP11729, but might be fun to fire them up and see what works. Starting tests with the 640 MHz bandpass filter. #TestEquipment #PhaseNoise #RFTest
Gary @N8DMTAug 12, 2025

You know its a slow work day when you’re cleaning RF connectors just to keep busy…

Some of them were pretty good — others were in desperate need of some attention by the cleaning cloth/brush.

#HamRadio #RFtest #ElectronicsTest

Gary @N8DMTJul 30, 2025
Completed testing of the home lab stock small RF amplifiers today with the goal of identifying (and fixing or getting rid of) any defective amps. Some of these cover up to 18 GHz although I can only test easily up to 6 GHz with the Pluto SDR and SATSAGEN. Found one bad ZFL-2000 amp amongst those tested (it has a bad stage and likely toast). Plan to test the lab’s larger RF amplifiers before the next local ham fest coming up in September. #HamRadio #TestEquipment #RFAmplifiers #RFTest
Gary @N8DMTJul 20, 2025

Who needs a 3D printer when an ARCHER Deluxe Project Case is awaiting easy installation of the DC/DC converter board with a BNC jack added to the case side wall?

Pondering adding an input-voltage-present LED indicator as well. (Maybe output LED too?) Hoping to wrap this project up in the near future.
#HamRadio #RFtest #NOS

Show threadGary @N8DMTJul 20, 2025
Recently found a LM2577 boost converter board that I’d been saving for years to use with my Yaesu VX-8DR radio chargers (wanted 12V out from a 5V USB battery pack). Today this converter is better purposed in providing +28 VDC output to the noise source from a 5V or 12V DC wall wart supply. Off to the lab storage totes to find an in-stock modular AC/DC supply (DC wall wart). Thereafter the dreaded “packaging element” of the project will come into play. No 3D printer here!
#HamRadio #RFtest
Show threadGary @N8DMTJul 20, 2025

The Noise Com noise source works! Enabled the LNA inside the TinySA-Ultra and was able to clearly see the noise increase when the on/off control (short to ground or open connection) was activated. Next step is to put together a small dedicated +28VDC supply for this item and finish part 2 of the blog posting on this topic.
#HamRadio #RFtest #TestEquipment #NoiseSource

Thanks to @miek for the “enable LNA?” tip!

Gary @N8DMTJul 19, 2025
RF Noise Source Part 1: Have had a surplus Noise Com source in the junk box for a few years without knowing if it was working or not. Did a quick disassembly, reassembly, and power off/on tests today. Item appears to be working, but can’t see its noise on the TinySA-Ultra (yet). May need to add amplifiers to see noise output. Inside unit photos and details are over on the blog posting. #HamRadio #RFTest #NoiseSource
https://qsl.net/n8dmt/rf-noise-source-part-1/index.html
Gary @N8DMTJun 30, 2025
Getting caught up with RF module tests to ensure they’re working properly. First up: Anzac (MA/COM) JH-131 90 deg hybrid. First time measuring phase with the NanoVNA-H4. TLDR: Both hybrid and NanoVNA appear to be working correctly. Next: A weird part number SMA connectorized DC-Block / High Pass filter that I’ve used for DC isolation in common antenna / multiple GPS receiver systems (limiting GPS DC antenna feed to only 1 RX supplying LNA power). It works as expected. #RFTest #NanoVNA
Gary @N8DMTMay 25, 2025
@hamchallenge HC46S Write a useful computer program. Created SW interface to read a Mini-Circuits ZX47-55 RF Detector using an Digilent AD3 interface module. Used free LabVIEW Community Edition for programming environment. SW provides a nice stable readout of the detector in dBm. Simple calibration values yield pretty-close output level & temp display. This will be a nice addition to the home lab (once the detector module is mounted onto an AD3 interface board). #HamRadio #RFTest #Digilent
Show threadGary @N8DMTMay 25, 2025
Last toot on the Mini-Circuits ZX47-55 RF Detector: Explore AM demodulation functionality. Setup detector with Digilent AD3 interface and Waveforms software with ADALM-Pluto SDR driven by SATSAGEN software to make a few AM demod measurements. Captures below show 50% and 90% modulation detected waveforms. SATSAGEN software has other Pluto modulation functions of interest including WFM, NFM, Ext, ASK, FSK, and NPR. #HamRadio #RFTest