[CQ-Contest] Receiver adjustments in CW contest conditions

[Hans Brakob]

I expect that the answers to the question will be variable, to a large degree, on the individuals ears, and will be particularly related to the sweet spot in their auditory “curve”.

I have profound hearing loss above about 1000Hz, so I prefer a CW sidetone of about 300Hz.   Disregard RX filtering/offset/shift for the moment, and consider “percentage of separation”.

Using 300Hz sidetone, if another station fires up 100Hz away the percentage of separation is 33%.  Generally my wetware filter can easily reject that signal.  Naturally the judicious selection of hardware width, shift, and even RIT can improve this situation if needed.

Now consider if I used a sidetone of 800Hz (for an example).  The same fellow fires up 100Hz away.  Now the percentage of separation drops to 12.5% (from 33%) and my wetware will have a much more difficult time rejecting the interference.  Obviously I can still apply hardware-based rejection, but my awareness of the surrounding spectrum will suffer.

Thus I have found that using a lower sidetone is the single most effective tool in dealing with crowded band conditions.


73, de Hans, KØHB
“Just a Boy and his Radio”™
________________________________
From: CQ-Contest <cq-contest-bounces+kzerohb=gmail.com at contesting.com> on behalf of Pete Smith N4ZR <pete.n4zr at gmail.com>
Sent: Wednesday, December 15, 2021 10:56:04 AM
To: reflector cq-contest <CQ-Contest at Contesting.COM>
Subject: [CQ-Contest] Receiver adjustments in CW contest conditions

I'm curious to know - except maybe on 160 or VHF, most of my receiving
problems in CW contests seem to come from QRM. When I'm contesting, I
find that the only RX controls I use on my K-3 are the main tuning or
(when running) RIT - this despite having DSP control to shift and narrow
my passband.  I just go with my 500-Hz filter and my ears.

So what do you do?  What have you found useful - again, not in
weak-signal situations, but in QRM.

73, Pete N4ZR
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