[Milsurplus] 800cps inverter on Craigslist in Portland

[Jack Antonio]

On 11/16/2017 10:53 AM, Dewayne Doud wrote:
> I have operated a GP-7 with this type of inverter and an autotransformer.
> It is limited, the GP-7 could only be ran at half power (around 40 watts out).
> But is an option if you don't have an 800-1 or PU-43/A
> It is loud too! A video of it running is here:
I  concur. I have run my GP-7 with a PE-206 (also an 80V/800 Hz 
inverter) and a variac. It
too is a 500W unit, so won't run a GP-7 at full power CW.

One thing I found in my experiments is that a 60 Hz variac did not 
function too well at the
current levels required by the GP. Up to the 100W or so load level, the 
variac performed as
it should, but increasing the load caused the output voltage to sag.

I wound up using a 400 Hz variac from Fair, which is no longer in their 
catalog, which did function,
but the whole combination was loud and a bit kludgy. And, the 
combination tended to be a bit chirpy on
CW, but OK for AM.  I never got the load compensation switches on the 
front of the GP to
reduce the voltage swing on transmit to a low level. Did I mention loud. 
The PE-206 isn't so much a screamer,
but sounded more like a heavy duty leaf blower. I started on building a 
sound proof
box, and was about half way finished with it, when.....

  I found a pair of Behlman ACM-750 AC power sources on eBay, at a 
decent price.
These are 750W units, and Behlman is pretty conservative, and one of 
them runs the GP nicely,
at a much reduced noise level. And the chirp is reduced to what I think 
is a fair level for the GP.

I've had the rig on the air a few times in the last few weeks.

Jack Antonio
WA7DIA