It is my opinion that there are two kinds of switching power supplies---the kind that are messing up your radio today and the ones that will at a later time. I believe they are not compatible with HF radio at a fundamental level, thought we must learn to live with them.
Two instances...one noise related, the other not. A few years back I setup a packet node at a remote BC location, and was blessed with a high quality switching supply. Every time the radio was keyed, the supply would sense the load increase as a short and briefly pulse the DC output. This reset the packet controller, which created several trips to the site before I scoped the DC and figgered out what was going on. In the second instance, this past field day somebody managed to get a switcher hooked up to our 6M radio without my knowledge. When the radio was keyed, the noise from the normally quiet supply clobbered the adjacent SSB station. Reason: The supply did not like the square wave from our generator (rather than the utility sine wave) and the switcher would "panic" when the load was high. Problem not apparent on the 6M or HF radio while 6M was receiving...only a couple amps load. Never would have thought of those problems. Switching power supplies are very sneaky as well as potentially noisy. They work well with steady loads under ideal conditions. They work well when new when all the line-filter caps are in tact, but the quality of those little caps isn't always the best and they get popped at the worst time. Switchers are a fact of life....but any time you can avoid one on your operating table, I say do it. Same is true of the little curley-Q lightbulbs (with a switcher inside)... One man's opinion.... de K8RYU _________________ Topband Reflector