From: "Pete Smith" <n4zr@contesting.com>
Subject: Re: [CQ-Contest] Tip - Weak Signal Detection
>
> At 10:07 PM 2/25/01 -0600, Dan Weisenburger wrote:
> >As the band begins to sound dead, switch to wide filter.
>
> Boy, this sure doesn't work for me. It also doesn't seem to me to make
> theoretical sense, particularly on CW. Why would the noise floor drop?
The noise floor does NOT drop - and, of course, the noise power is larger
compared to the original cw signal. However....
There is a curious psycho-acoustical phenomena dealing with noise - a weak
signal that is "almost free of noise" is more difficult to hear than one
surrounded in a reasonable amount of broad band (white/pink etc) noise. The
noise provides a context that the brain needs to decipher the signal. Thus,
using the SSB filter in a CW contest may result in the ability to copy
signals that are difficult to copy using a narrow cw filter. Of course,
this is not a guarantee - it depends upon the quality of signal, noise, and
your personal ear/brain system.
There was an interesting article a few years ago in Scientific American that
describes effect.
tony (ve6yp)
--
CQ-Contest on WWW: http://lists.contesting.com/_cq-contest/
Administrative requests: cq-contest-REQUEST@contesting.com
>From K0HB@qwest.net" <K0HB@qwest.net Mon Feb 26 04:25:05 2001
From: K0HB@qwest.net" <K0HB@qwest.net (Hans K0HB)
Subject: [CQ-Contest] Field Day CW Exchanges
Message-ID: <01C09FAC.3489A0C0.K0HB@qwest.net>
John Aughey wrote:
> I'm writing some software that simulates a CW contest similar to
> the way CyberCW does. I want to be able to recognize and reply to all
> different kinds of responses. I would like to know from all of you want
> you would typically send for some of the standard exchanges. I'm
> looking at only Field Day exchanges right now.
> Calling out for contacts:
TEST K0HB or
CQ FD K0HB
> Calling to a CQ:
K0HB
> Replying to the calling station (if you are the CQer):
THEIRCALLSIGN exchange
> Replying to the calling station (you are the non CQer):
TU K0HB 1A MN
> Asking to repeat:
THEIRCALLSIGN AGN?
> Acknowleging:
TU K0HB FD
--
CQ-Contest on WWW: http://lists.contesting.com/_cq-contest/
Administrative requests: cq-contest-REQUEST@contesting.com
|