Re: NDB - Airspy HF+ DIscovery versus Hermes Lite 2

Allan Isaacs

Sorry you lost your beam YL. It must have been a really traumatic experience.

I did buy a box of dual gate mosfets many moons ago with the aim of transistorising my R206. I got as far as changing the EF50 oscillator and eliminated oscillator pulling when using it with a nuvistor converter on 2m but reverted to a valve when overcome with guilt but I admit to leaving in place the tiny FM TDA chip for 2m as it was so small to be almost unnoticeable.


The goodish news is I just repaired a broken earth lead that a visitor had tripped over. This connects to the unun and I can now report the LW Polish station on 225KHz has shot up from -92dBm to -75dBm and is now intelligible on the Andrus SDR. In fact I counted eight AM LW broadcast stations. Radio 4 went from -47dBm to -32.5dBm and I had to insert 20dB attenuation to eliminate spurii.


I met my very understanding wife G3SGL on 80m SSB back in the 60s.

Allan G3PIY

From: [] On Behalf Of jdow
Sent: 24 December 2021 10:53
Subject: Re: [SDR-Radio] NDB - Airspy HF+ DIscovery versus Hermes Lite 2


Heh, me be injuneer. Alas not hairy chested for some reason. So MY R390A has been tweaked a little. It goes down into that frequency range. I used it a little. I moved back to 20 meters SSB talking with folks in Oz after dinner here. (nice folks.) At that time I had a TH6DXX at 70'. Gone with the divorce. And I still think I won.

I also built in a hang AGC system and rewired the demodulation processes so that for SSB and CW I used a 7360 tube.  Heaven forbid you'd think I'd leave it unmodified. Hm, I also had a nice vernier knob on it. I forget the exact ratio. I get something like 2 kHz to 5 kHz per revolution. It has an PLL synchronous AM demodulator that I'm not fond of. It needs tweaking and was not worth it. Its a superb SSB receiver. I used it in actual communications service rather than SWL.


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