[CQ-Contest] Reciprocity in signal strength

[Pete Smith N4ZR]

And this is, of course true.  Reciprocity is just a starting point.  
Yesterday in NAQPSSB I had an S9 noise level on 20-10 meters, where I 
also have directivity.  I had a hard time hearing anyone in the 
direction of the noise, but putting it at 90 degrees let me work at 
least a few.

73, Pete N4ZR

On 1/22/2023 10:26 AM, K9MA wrote:
> That's true, but only part of the story. On the HF bands, receiver 
> noise is almost always negligible, so absolute signal strength doesn't 
> matter much. If your random wire isn't matched, all bets are off. Even 
> modern radios have drastically different S-meter calibrations: 3 or 6 
> dB per S-unit. You may also have various lossy components in the 
> received signal path. Noise levels also vary enormously, so even at 
> the same absolute signal strength, S/N can be very different. And 
> then, of course, there's QRM and competition.
>
> 73,
> Scott K9MA
>
> On 1/22/2023 12:10 AM, Barry Jacobson wrote:
>> Hi guys, it seems that in a contest like NAQP where presumably almost
>> everyone is running the same 100 W power, you should be able to hear the
>> other guy at the same level he hears you. Even if the other guy has a
>> $25,000 dollar beam, and you have a simple 10 foot random wire, the
>> weakness in your transmission ability will also weaken your received 
>> signal
>> just as much in the other direction. So if you can hear him, it 
>> guarantees
>> he can hear you. (Unless one or both of you has separate receive and
>> transmit antennas, or the receivers you are using are of very different
>> quality.) Does that make any sense?
>>
>> Barry WA2VIU
>>
>> -- 
>> Barry Jacobson
>> WA2VIU
>> bdj at alum.mit.edu
>> @bdj_phd
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>
>