[Elecraft] Strange Interference

[G4GNX]

A bit late with this one (ill health) but I had a horrible teaser with a 
switcher. I was using a wall wart to power an MFJ Intellituner. It seemed OK 
at first and I didn't detect any RFI on any band from it, but after a short 
while I was getting a 10-20KHz wide spurious on 40 metres, and the center 
frequency moved around from time to time and always seemed to cover the part 
of the band that I wanted to use! I finally traced it back to the tuner, 
which every time it tuned to a different band segment, used a different 
internal relay array, which very slightly varied the load on the wall wart. 
This in turn caused it to change its frequency. Needless to say, the wall 
wart was replaced. Interference can indeed be strange.

73,

Alan. G4GNX

-----Original Message----- 
From: Terry
Sent: Saturday, July 23, 2016 7:43 PM
To: elecraft at mailman.qth.net
Subject: Re: [Elecraft] Strange Interference

Thanks to all for the advice. I found the issue. It is my Powerwerx SS30DV
Switching supply. I thought this supply was a good one to not create
problems like I am having. Not sure if it is fixable or If I need to send it
in for repair.

Very 73,

Terry
N7TB