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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