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[Amps] TX IMD

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Subject: [Amps] TX IMD
From: "Jim Thomson" <>
Date: Wed, 18 Nov 2015 09:01:56 -0800
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The ARRL  uses  db below pep instead of db below one tone  ( of a 2 tone 
signal) .
Thats fine  with me.   S meters  are  PEAK reading devices.  So if ur IMD is 
say  30 db below pep,
that’s like  30db below the fellows S meter reading.   IE:  say station A is  
30 db over S9. 
His splatter  will then be  S9.   That’s nothing to write home about.  If he is 
40 db over S9,
then his splatter will be  10 db over S9.   Are you folks starting to get the 
point ? 
Lousy IMD is  semi ok on bands with lots of noise, but when noise is low... IMD 
rears its ugly

Most S meters  are NOT  6 db per s unit.... below  S9.   Even with an S9 
signal.... u will easily hear
splatter 30 db below that..or typ S1- S2.  ( in the case of lousy TX IMD, like  
-30db pep. ).

It’s the higher order IMD  u gotta worry the IMD 7-13 products. 

Jim  VE7RF

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