Date: Sun, 25 Dec 2011 13:34:03 -0800 (PST)
From: Commander John <crazytvjohn@yahoo.com>
Subject: Re: [Amps] Fwd: Linear Amplifier Tuning---PROPERLY!
I fail to see how having spurious sidebands at -20, -30, -40?or whatever makes
the??????????????
Signal wider.? The sidebands are still there regardless of final?suppression
level.
### You are confusing sidebands with IMD. This is NOT FM. It's SSB.
IMD is caused by non linearity.
It is the receiving stations receiver having the rejection ability that
reduces received?interference.?
### wrong again! IF station XXX using his ICOM on TX....is 10 khz wide...
then he's 10 khz wide. If you are 3 khz away, you are now screwed, and there
is no filter on the the planet that's gonna do any good. He's Txing on your
RX passband, so his TX IMD is now overlapped with your RX passband.
Having adjacent sidebands that are stronger than necessary causes a receiving
station to hear these sidebands at a harmful signal?strength further away from
the transmitted frequency than if they had supression at a highter level
## It's adjacent IMD, not sidebands.
A legal limit station would have much stronger IMD because it is stronger not
wider.? It only is preceived as wider because they are stronger than from a 100
watt transmitter.?
## That all depends on how loud his IMD is to start with. But yes, if 2 x
stations have the same IMD... but one is 10db louder than the other [say a
bigger ant or amp].... then the station with the 10db syronger signal will also
have IMD that's also 10db stronger. Which is all the more reason to have a
cleaner signal when u have a big amp, and big towers' ants etc.
## No point in all these deluxe receiver's with 100db dynamic range. It's of
now use,and pointless on ssb. Not until the TX IMD gets improved on these
ham xcvr's. The Icom's are 10 khz wide when u stuff white noise into
them...and the yaesu 5000 in Class A is only 3.5 khz wide [both measured at
the -45db point]. The bands are NOT crowded . They are just jammed full of
sub standard xcvr's..which is most of them.. with junk TX portions. If
everybody got heir act together, you could easily double the number of ssb
signals on a given band. You could triple that if everybody had class A, or
the eq.
Jim VE7RF
john W9ZY
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