[Amps] AM mode

[Bill, W6WRT]

ORIGINAL MESSAGE:

On Fri, 11 Sep 2009 17:57:44 -0600, Tomas Hood <nw7us.heliophile at gmail.com>
wrote:

>
>If I set my Power Output level to 25% of the maximum carrier power
>rated for my amp (85 watts) (25% is 21 watts on my Icom IC-7000),
>then, if my mic gain is modulating well, I will not run over the peak
>of 85 input to the Amp.  Is that correct? 

REPLY:

The peak power of an AM signal is approximately four times the carrier power. To
prevent your amp from flat-topping, you should tune it up at four times the
carrier you plan to run at. 

If you are going to run 85 watts of carrier, you should tune it up at 340 watts,
because your voice peaks are going to hit 340 watts. If you tune up with less,
the amp will flat-top while trying to reach 340 and it will cause splatter. 

If our TX has an audio compressor you can probably get away with a lower tune-up
power, but in that case you really should use a scope to monitor the output and
verify that you are not flat-topping. Watching a meter only can be very
misleading. 

73, Bill W6WRT