Just to be clear - when there are very weak signals and QRM/QRN.
Bernie McClenny, W3UR
Editor of: The Daily DX (1997-2019)
The Weekly DX (2001-2019)
How's DX? (1999-2019)
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> On Aug 21, 2019, at 7:58 PM, Bob Shohet, KQ2M <kq2m@kq2m.com> wrote:
>
> 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 -
> http://www.dailydx.com/free-trial-request/
> https://twitter.com/dailydx
> 410-489-6518
>
> > 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
> > _______________________________________________
> > CQ-Contest mailing list
> > CQ-Contest@contesting.com
> > http://lists.contesting.com/mailman/listinfo/cq-contest
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