[ARC5] ARC5 Digest, Vol 242, Issue 123

[sbjohnston at aol.com]

I was programming the ProgRock2 for the local oscillator frequencies for reception of local aviation channels.  I don't recall them specifically right now, but they were in the aviation band 118 and 137 MHz.  The noise was on the operating frequencies not the LO frequencies and seemed to be coming out of the microcontroller itself (not harmonically-related to the outputs).  All the interesting frequencies (example 123.45 MHz) that I tried had some interference - but of course my most desired local airport frequencies seemed to be the worst (thanks Murphy).
I tried putting it in a shielded box and bypassing the power wire, but the interfering signals still got out of the box on the output line (along with the desired LO signal).  I added a low-pass filter but without a tight-fitting shield on that it still radiated lots of interference.  At that point I remembered I could just turn on a scanner and I gave up. 

Self-interference can be a significant problem for receivers since the desired signals are so weak.  Another irritating example is how the Czech Telsa RF-10 radios PLL sometimes interferes with reception on 51.0 MHz - the one frequency I want to use them on!


Steve WD8DAS   

sbjohnston at aol.com   
http://www.wd8das.net/   http://af4k-crystals.com/   
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Today's Topics:

  1. Re: A crystal Substitute (Hubert Miller)


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Message: 1
Date: Tue, 26 Mar 2024 01:13:55 +0000
From: Hubert Miller <Kargo_cult at msn.com>
To: "arc5 at mailman.qth.net" <arc5 at mailman.qth.net>
Subject: Re: [ARC5] A crystal Substitute
Message-ID:
    <CO6PR19MB5434640A4B6127DD4135F657E4352 at CO6PR19MB5434.namprd19.prod.outlook.com>
    
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Steve, what frequency were you using the rock substitute on ?
Just curious. 
No one seems to have reported big noise problems on HF receive.
-Hue Miller 


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End of ARC5 Digest, Vol 242, Issue 123
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