[CQ-Contest] Impressive demonstration of one dB of signal strength improvement

Bob Shohet, KQ2M kq2m at kq2m.com
Wed Aug 21 16:26:17 EDT 2019

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!


Bob, KQ2M

From: donovanf at starpower.net 
Sent: Wednesday, August 21, 2019 11:15 AM
To: cq-contest at 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: 



----- Original Message -----

From: "David Gilbert" <xdavid at cis-broadband.com> 
To: elecraft at 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: 


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. 

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 

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