Topband: Desktop power supplies
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 lifebut 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
Topband: BOG Rx antennas
I have a couple of those here, about 150 feet long and they have at times surprised the heck out of me. My best one is made with very fine wire...2 strands of #26 I think it is, maybe #24, telco crosscut wire it was. It is about 150 feet long and has given better results than those I have had made with heavier wire. My reference is a K9AY loop, which I have been using for years. Soil conductivity here is about as bad as it gets. I have to replace the wire every year or so when something breaks it. All the BOG's have very low signal output, require braid breakers to keep the power line away, and fail to work at all if the ground is snow covered or very wet. I have a theory: I think the fine wire works better because of less capacity to the soil. I also think that if the fine wire were installed in a plastic tube, say thin-walled water tubing, the things would work even better. That would put the wire, on average, say a half-inch above ground. I have never tried that design, but maybe I will some day. de K8RYU ___ Stew Perry Topband Distance Challenge coming on December 29th.
