Hi Folks,
My "travelling" station is a 555 Scout with one of those new Astron
switching power supplies. It's rated at 15A continuous, 18 A
intermittent. Although switching supplies are notorious for EMI, the
marketing hype faked me out and I bought one, since the spec sheet
actually said "High efficiency switching technology specifically
filtered for use with communications equipment, for all frequencies
including HF." The word "HF" is boldfaced and underlined.
Needless to say, the 80, 40, 30, and 20 meter bands are filled with S3
to S9 broadband pulses every 60 kHz or so that drift as the supply
heats up. The noise peaks on 40. I've kind of determined that it is a
combination of radiation, induction, and conduction (on the power
cable itself), but it is hard to tell (my scope is down at the
moment).
Question: Has anyone done any work to quiet these things down? Could
anybody using the Ten Tec switcher with their Scout comment as to the
quietness or noisiness of that particular power supply? Thanks very
much.
R,
Al W6LX
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