All this talk prompted me to take my storage scope home tonight and
have a look at the rigs I use. Here's what I saw at 3.5 MHz as
measured with a 2Gs/sec digital scope:
On my Icom IC-706Mk2G, approx 1 year old:
pwr spike overshoot
=== ===== =========
100w 100w 0%
75w 91w 21%
50w 73w 46%
25w 52w 108%
10w 26w 160%
On my 9 year old Kenwood TS-850SAT:
pwr spike overshoot
=== ===== =========
100w 109w 9%
50w 58w 16%
25w 30w 20%
I didn't check my Johnson Ranger :-) Anyway, the 850 looks pretty
good, about 20% is the worst case. The output power on the 706 returns
to nominal after about 2.5 mS. I took some pictures, and if there's
any interest I can put them on a web page for others to see.
It would seem to me that the IC-706 (and rigs like it) would mainly be
problematic with amps that require substantially less than 100w to
drive and that switch quickly. Is this correct?
73,
Doug, K4DSP
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