[Elecraft] K2 proximity to power supply

[Ron D'Eau Claire]

It probably varies with he orientation since the intensity of the =
magnetic
field around the power transformer varies according to direction as well =
as
distance.=20

I don't have any trouble with my 20 amp Astron sitting under the =
operating
desk. It's about 3-feet away. When I first put my K2 on the air running
without the KPA100, I set it directly on top of a 10 amp linear supply =
and
got tons of hum <G>. I did NOT hear it in the receiver. I only became =
aware
of it when someone mentioned hearing it on my transmitted signal. =
Naturally,
I pulled the K2 off of its perch on the supply and connected it to a =
dummy
load and found a perfectly clean signal on my auxiliary receiver. It =
took
doing that several times to connect the fact that moving the K2 off of =
the
supply cleaned up the hum. It was clean sitting only six inches or so in
front of the supply in that case.=20

With the bigger Astron, I'm happy to keep it off of the operating desk. =
It's
sitting on a small step-stool under the desk so it doesn't get kicked =
and I
can reach the power switch easily sitting in my chair.=20

Ron AC7AC

-----Original Message-----
When I first got my K2 (a few weeks back), I discovered the problem that =
can
be caused by proximity to the AC supply (in my case, Astron RS-30M) when =
I
noted a rough CW note on received stations.  I moved the supply about 18
inches away from the K2 and considered my problem solved.  Received CW
sounded pure, and there was no trace of hum on my CW signal.  This =
weekend,
I played around for a short time in the SS, and immediately got a couple =
of
reports of "rough audio".  When I listened on my other transceiver, sure
enough there was the AC hum on my SSB signal.  I reverted to the =
switching
supply and all was well.  I'm not sure just how far away from the K2 you
have to get a supply like the Astron in order to eliminate the hum, but =
it's
sure more than 18-20 inches.  Once the hum problem was gone, I began =
getting
"beautiful signal" reports again.

73, Floyd - K8AC