I went back to the review and the ARRL report was talking best IMD at a level
to drive a high gain amp such as an 8877 or 3CX800 so I figure they must have
been talking maybe 50 - 70 watts out. The third order was 28dB down and fifth
order was 40dB down at 100 watts out. The signal was described as "clean" at
the lower (50 or so w out) level so hopefully there the IMD would be okay.
What you describe with the grid driven amps is common on VHF. You get one or
two scenarios. One is the 50 watt 6 meter rig (like a TS690) backed down to 9
watts to drive a pair of 4CX250's.
Much better though, is the 50 watt rig backed down to 10 watts to underdrive a
solid state amp rated at 15 in to 160 out which in turns uses the 100 watts out
to drive a pair of 3-500Z's.
I know yoy can get strong signals on 160, but you haven't lived til you get a
bunch of those 6 meter setups coming through on a good Es opening.
Frank
W2FCA
"Tom Rauch" <w8ji@contesting.com> wrote:
>>Hi Frank,
>>While I have never specifically tested and 850, every radio I have
>>tested becomes pretty poor at low power. Radios go through an IM
>>minimum as power is increased from minimum, and eventually IM (as
>>compared to the desired signal) increases again at rated power.
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