[DavGoodlin]

One item that I found important to note is that built-in any kind of loop antenna will be affected if near a switch-mode power supply. This includes PCs and many power supplies in commonly found stuff around the house. Anything that should, but does not have a transformer is suspect!

I have transplanted into some radios the M-derived line voltage filters (from scrapped monitors) using common-mode inductors found in SMPS, ironically the same equipment causing interference. Its pretty hard to put filters on all the suspects, why a portable radio is key to sniffing them out.

On a radio requiring an external wire antenna, this extra step helps especially if already using an X2 or if a transformer set, two Y2-rated safety caps plus a grounded cord. Night DX reception at the office then was actually possible.

This worked better than expected on late 30s radios - a Philco 37-650 and a Zenith 5R135, where a 20 foot antenna placed under a rug in an otherwise noisy environement, pulled in the same stations as my GE "superadio" portable but with LESS noise.