[Elecraft] JT65A output power variations.

[hb9ari]

Hello,

As i use principally JT65A (snice ~ 2years),
i've remarked transmit output power variations
depending where the audio is located in the waterfall,
as i'm not speaking English, it's difficult to explain correctly;
if i'm ~ in the middle of the waterfall (~ 1200Hz)
i get over 3dB in output power variations; for an expected
50W output power, between some tones of the JT65A
modulation, the output level can vary from 20W
to 60W; if i'm working away from the "middle",
variations are lower and acceptable but most
of time, "central" frequencies are used...
I've always worked with this "problem" as i
expect some AGC effect by the receiving side...
I would appreciate to have an explanation
of this effect.

Many TNX for an answer.

73 QRO de Rudolf, HB9ARI

PS With the same sound card and software,
using my "old" FT857 (non D) TX/RX, the
output power variation is well under 1dB
until the audio band edges.