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Re: [CQ-Contest] Impressive demonstration of one dB of signal strength i

To: "Bernie McClenny, W3UR" <bernie@dailydx.com>
Subject: Re: [CQ-Contest] Impressive demonstration of one dB of signal strength improvement
From: "Bob Shohet, KQ2M" <kq2m@kq2m.com>
Date: Wed, 21 Aug 2019 19:58:01 -0400
List-post: <mailto:cq-contest@contesting.com>
That’s Interesting Bernie.  For me it is dependent on how well I can hear them. 
 If they are strong enough for me to hear them reasonably well, then when I am 
dealing with heavy qrn with brief short bursts of relative quiet, (I think of 
it similar to meteor scatter) – you have maybe 2 seconds to get the call – 
faster is better; at higher speed you might get the whole call in one shot 
vs.with slower sending, fighting to get one letter or two repeatedly over 
perhaps a full minute or longer, or losing the station in qsb.  However, if 
they are weak and there is heavy qsb and/or qrn, then I agree with you that 
slower is usually better – more time to hear each individual character.

Sometimes if I am calling a DX station in high qrn cndx and they are reasonably 
loud, I will alternate the speeds in my calling for that reason, especially if 
I know the opr can copy cw at higher speeds.  I don’t know what the qrn sounds 
like on the other side but if there are brief windows in time between static 
crashes and they can hear a KQ2 calling, then at 35 wpm they likely already 
have my call; at 18 wpm they likely won’t.

73

Bob KQ2M



From: Bernie McClenny, W3UR 
Sent: Wednesday, August 21, 2019 6:11 PM
To: KQ2M Bob Shohet 
Cc: W3LPL Frank Donovan ; CQ Contest 
Subject: Re: [CQ-Contest] Impressive demonstration of one dB of signal strength 
improvement

For me, and I suspect for many other Topband ops, when QRN/QRM is involved 
slower is better than faster! 18-20 WPM is about the right speed. 

Bernie McClenny, W3UR

Editor of: The Daily DX (1997-2019)
   The Weekly DX (2001-2019)
   How's DX? (1999-2019)

Two week trial - 
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> On Aug 21, 2019, at 4:26 PM, Bob Shohet, KQ2M <kq2m@kq2m.com> wrote:
> 
> I have never had the opportunity before to hear differences in signal 
> strength by 1 db increments.  +1 db is clearly an advantage and a +2 db 
> difference nearly obliterates the weaker signal.  Remarkable.  I wish I had 
> heard this 20 years ago!    ;-)  
> 
> The differences in copy between different CW speeds is very interesting too.  
> I suspect that most contest ops will generally do better with the higher 
> speeds unless they are exhausted to the point of mental impairment, in which 
> case the slower speeds might work better.
> 
> Thanks for posting this Frank and a special thanks to AB7E for creating these 
> audio recordings with explanations!
> 
> 73
> 
> 
> Bob, KQ2M
> 
> 
> 
> From: donovanf@starpower.net 
> Sent: Wednesday, August 21, 2019 11:15 AM
> To: cq-contest@contesting.com 
> Subject: [CQ-Contest] Impressive demonstration of one dB of signal strength 
> improvement
> 
> These recordings are an impressive demonstration of the benefit of 
> one dB of signal strength improvement in a weak signal situation. 
> Click on the links on this website: 
> 
> 
> 
> www.ab7e.com/weak_signal/mdd.html 
> 
> 
> 73 
> Frank 
> W3LPL 
> 
> 
> ----- Original Message -----
> 
> From: "David Gilbert" <xdavid@cis-broadband.com> 
> To: elecraft@mailman.qth.net 
> Sent: Wednesday, August 21, 2019 7:02:21 AM 
> Subject: Re: [Elecraft] KPA500 Coax size requirements 
> 
> 
> That's not a universally true statement. 
> 
> Several years ago I was trying to decide which antenna to buy, and my 
> choice came down to two antennas that were 2 db apart. I created some 
> audio files by recording typical band noise and then overlaying them 
> with recorded CW messages at various strengths. The difference between 
> 1 dB above the noise level and 2 dB above the noise level can make the 
> difference between no copy and copy. The files and testing methodology 
> can be found here: 
> 
> http://www.ab7e.com/weak_signal/mdd.html 
> 
> If you're ragchewing it doesn't matter, but if you're trying to make a 
> contact and your signal is at the level of the mud it does. 
> 
> 73, 
> Dave AB7E 
> 
> On 8/20/2019 9:18 PM, Jim Danehy wrote: 
>> ONE DB loss is the LEAST DETECTABLE amount a human can detect. Hardly if not 
>> impossible to notice. 
>> 
>> Jim 
>> W9VNE/VA3VNE 
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