[Elecraft] Astron RS-35M - Problem Related to RF !!!

[Ron D'Eau Claire]

No doubt you can change the behavior - even stop the shut-down - by =
messing
with the antenna, but antennas do not "cause" these issues.=20

The smart fix is to keep the RF out of the power supply using =
suppressors on
the AC mains line (clamp on type) or a choke on the DC line to the rig =
as
others have mentioned. Also, make sure your AC mains ground is good. =
It's
not a particularly good RF ground under most conditions, but does a lot =
to
keep RF out of the current-monitoring circuits in the Astron.=20

Sure, you can change the antenna in a way that might cause a little less
pick-up of RF into the mains wiring or wherever it is getting into the =
Power
Supply, but there's no reason you shouldn't be able to run a random wire
around the shack and load it up at 100 watts out without having that =
problem
- if the power supply is working properly.

That said, unsoldered or corroded antenna connections need fixing for
efficient operation. =20

FWIW, I run an Astron 20 with an end fed wire on 80 through 30 meters at =
100
watts output with no problems. The Astron is about 3 feet from the rig =
and
the end of the wire, which is very "hot" with RF on some bands.=20

You mentioned that the supply delivers 16 amps on CW key-down. An Astron =
35M
should do more than twice that without the crowbar circuit shutting it =
down.
The current demand of most rigs, including the K2, varies widely with =
the
load and band used because of the way the RF power amp behaves. =
"Perfect"
loads, like a good dummy load, usually demand the least current. So
measuring the current into a dummy load is not a good indication of the
current required when hooked to an antenna or operating on other bands. =
The
current might be higher. Be sure the crowbar circuit isn't mis-adjusted =
to
trip at too low a current. You should be able to get a full 35 amps out =
of
that supply - enough to run TWO K2/100's at full output - without it
shutting down.

If you don't have a LARGE operating desk, you'll want that power supply =
on
the floor. The K2 is sensitive to the huge magnetic field it creates and
that can produce hum on your sig and other issues. I keep my K2 at least
three feet from a much-smaller Astron 20M.=20

Ron AC7AC=20

-----Original Message-----
Looks like the problem is RF.  I put a dummy load on the rig & the power =

supply works fine.....delivers 16 amps on CW key-down.  I discovered the =

problem when I was operating 40 meters, so today, I checked out 75 mtr. =
&=20
20 mtr. & the rig works fine.  Power supply still shuts down on 40 =
meters=20
so I will make the RF mods I have found & see how that works.

No problem on my K2 but my TS 440S shuts power supply down.  I'm in the=20
final stages of finishing up the KPA100 so I'm stopping to fix the PS=20
before proceeding.  (Antenna is a G5RV)  Wish I had the K2/100 ready to =
go=20
so I could see if it has the same problem.

(...I did check my antenna about 2 weeks ago & I was alarmed at=20
the degree of corrosion on the twin lead bolted connection to coax/balun =

connector.  Think I'd better redo that connection & wrap it with duct =
seal=20
to keep the mosture out.

Guess another easy options are to relocate the power supply to the =
floor.=20
Also rig is not grounded.