[Amps] TX IMD
Jim Thomson
jim.thom at telus.net
Wed Nov 18 12:01:56 EST 2015
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
head.
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 about....like the IMD 7-13 products.
Jim VE7RF
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