SSB ops clear down to 7000 kHz on 40m, Grrrr
Glen Zook
gzook at YAHOO.COM
Fri Jan 20 11:54:08 EST 2006
I have yet to see an SSB signal from any of the
stations that are normally operating in the CW portion
that runs a true 40 dB over S-9 when the "old"
standard of S-9 = 50 microvolts is used.
That means the signal is at least 5000 microvolts and
that is "one heck of a signal". Now with the "modern"
equipment I have seen a lot of S-9 = less than 10
microvolts and "40 over" = under 100 microvolts. The
problem is that manufacturers have elevated the "S"
meter readings to claim that their equipment is more
sensitive than the next.
If you want to copy an S-3 CW signal through a strong
SSB signal you first have to turn off your
preamplifier (if you are using one). Next turn off
the AVC/AGC. Then run the audio gain basically wide
open. Finally, use your r.f. gain as the volume
control. With a narrow filter you can, in the vast
majority of cases, copy the CW signal through the SSB
without any problem.
Basically you need to keep the SSB signal from
"pumping" the AVC/AGC which it will do unless the
AVC/AGC is turned off. You also want to keep the SSB
signal from overwhelming the narrow filter. This is
the reason for cutting back on the r.f. gain.
Frankly, it is a matter of knowing your equipment and
knowing how to use it. Unfortunately, many amateur
radio operators today haven't taken time to use their
receivers in anything but the everything "wide open"
mode. It isn't what the "S" meter reads but the
signal to noise ratio of the signal that determines
whether or not the signal can be easily copied or not.
Cutting down the absolute signal level often is
rewarded with a signal that is easy to copy yet might
not even be moving the "S" meter.
Glen, K9STH
--- Brian Carling <bcarling at CFL.RR.COM> wrote:
LOL - let's see you try that when the CW signal is S3
with QSB and the SSB signal is 40dB over S9!
I SERIOUSLY doubt that your Collins is any better at
pulling them out than a modern rig with a narrow filter.
Glen, K9STH
Web sites
http://home.comcast.net/~k9sth
http://home.comcast.net/~zcomco
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