> What happens, I think, is that the RF heats any ferrous metal, making it
> oxidize. That's
> why hardware in RF fields needs to be non-ferrous. I suspect it must be
> getting red-hot in
> order to do that. Wasted power that could be working DX!
Quick story: Back in college, I rebuilt the PA cavity of an RCA 5KW FM
transmitter. The owner of the station was an ex-CBS Radio engineer. When I
completed the hardware assembly, he asked what I used for hardware.
Puzzled, I told him I really didn't know. He then unscrewed a sample of
hardware, took them to the work bench and began testing the hardware for
magnetic attraction. He used the permanent magnet from a loudspeaker for
the test. I had previously wondered why he kept the speaker near a big
Maxwell House tin can loaded with hardware. He told me that in RF
applications, to try and use brass at every opportunity, and stainless steel
as less-preferred substitute. Neither metal is magnetic in low fields, but
perhaps stainless still retains some of its ferrous attributes depending on
it grade. To this day, I still have trouble sorting stainless from
nickel-plated brass hardware. I suppose the nickel hardware has a bit more
shine than does the duller appearance of stainless.
Paul, W9AC
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