Sunday, 31 January 2010

The Enemy Within!

For some time I have been aware that one of the PCs in the shack does generate a little interference on the HF bands. However I have recently noticed that I have a constant carrier of the 2 metre band on 145.575 Mhz. The carrier is around S4 and always seems to be there.
Using my two metre handheld the other day I tracked down the source. Placing the handheld next to the power supply for my LCD monitor the carrier went up to full scale on the S-Meter. Unplugging the power the supply caused it to disappear.All is not lost as the monitor needs a 12 volt DC supply so if I make up a connector lead it should run quite happily from one of the shack supplies.
HF conditions do seem to be improving. Yesterday I worked several stations on PSK31 on the 18Mhz band which seemed very lively. Let us hope this is a sign of things to come.

I continue to be fairly impressed with the Wellbrook loop. From its temporary location I am able to rotate it using the famous "Armstrong" method. I have found it is possible by careful positioning to almost elimate the PLT i get on some bands. The loop also allows me to reduce a lot of local QRN. It is very directional below about 5Mhz or so. If you have two medium wave stations on the same frequency it is possible to null one out by rotating.


  1. I find the 2m band is full of carriers. There is one right on 144.333MHz which seems to be a favourite of SOTA operators, and one on the output of the GB3LA repeater. There are several in the 2m beacon segment. I haven't even tried to track them down - it would probably take forever.

  2. Hello Kevin, there are several things which produce interference. So is my computer and LCD TV. Without those two the HF is very quiet. 73 Paul