Hi Pat and group,
FWIW, I have just built an HF Packer Amp and have exactly the same problem with
marked audio distortion on SSB when driving it with my FT 817nd. Maybe the
problem isn't the K2?
I have discovered others with the same problem, but no-one with a solution to
this Amp's non-linear
That sounds like the amp is not running linear. First make sure the
bias is set correctly.
Then do a test in CW mode -
Put a small amount of drive to the amp (measure it), and measure the
output. Compute the gain.
Increase the drive by a small amount, and again compute the gain.
Continue in
If the input impedance of the amplifier is changing with drive level,
that can be cured with an attenuator at the input - the driver will
then see a more constant impedance.
The schematic in the HF Packer amplifier manual shows different input
attenuators for the K3 (3 db), FT-817 (4 dB)
Don,
Shortly after I sent my comment earlier today I received an email telling me
that the HF Packer amp was intended to be used for CW (Class C?) not SSB,
and that a modification was necessary for its use as a linear amplifier for
SSB - presumably at least a change in the amplifier's standing
Hi Don and Geoffrey,
The manual doesn't discuss biasing the amp for Class C, just for
linear operation. This is a 2nd Gen amp with only a single-turn pot
for bias adjustment which makes the adjustment tricky but doable (3rd
Gen has a ten-turn pot) but I'm pretty sure I set the bias correctly
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