[Amps] Fwd: Linear Amplifier Tuning---PROPERLY!

[Commander John]

 That is about what I said.  But it doesn't make the signal any wider.
please read the previous posts as to what I was commenting on.
john W9ZY
 
 
  W9ZY
              .... Commander John ....
                        
 

--- On Tue, 12/27/11, Gary Schafer <garyschafer at comcast.net> wrote:


From: Gary Schafer <garyschafer at comcast.net>
Subject: RE: [Amps] Fwd: Linear Amplifier Tuning---PROPERLY!
To: "'Commander John'" <crazytvjohn at yahoo.com>, Amps at contesting.com
Date: Tuesday, December 27, 2011, 12:18 PM


Well John, think of it this way. The IM product being transmitted is like
sticking another station right beside the existing one when you are trying
to work there. The stronger the IM products the stronger that new station
is.

73
Gary  K4FMX

> -----Original Message-----
> From: amps-bounces at contesting.com [mailto:amps-bounces at contesting.com]
> On Behalf Of Commander John
> Sent: Sunday, December 25, 2011 4:34 PM
> To: Amps at contesting.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. It is the receiving stations receiver having
> the rejection ability that reduces received interference.  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.  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.
> john W9ZY
> 
> 
> 
> 
> > On 12/22/2011 10:32 AM, Frank wrote:
> > > I can see how you can improve IMD 2 or 3 db by
> > agonizing over the
> > > "proper way to tune" but your probably already at 20
> > to 30 db IMD to
> > > start with.  That 3 db will never be noticed by
> > anyone except the fellow
> > > looking at the lab equipment.
> >
> > IMD in the -30dB range means a LOT of RF trash in your
> > sidebands, both
> > from modulation and from the transients of your keying.
> > That means
> > you're TOO DAMNED BROAD!  Keeping our signals as clean
> > as possible DOES
> > matter.  When your signal is 20 over S9, sidebands
> > that are only 30dB
> > down are S7, and prevent me from working guys at that level
> > in your
> > sidebands.  Ten dB cleaner means S5. Have any hams as
> > neighbors?  How
> > would you like THEM to have -20dB
> > sidebands?   I had one, two miles away
> > with a big dirty amp, and he wiped out all of whatever
> > phone band he
> > worked a contest, and called CQ ALL the time.  Another
> > neighbor, only
> > 0.3 miles away with a clean amp, only burns about 10 kHz.
> >
> > 73, Jim K9YC
> >
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