"Edmund H. Ramm" wrote in message
...
In "Ron Baker, Pluralitas!"
writes:
"DougSlug" wrote in message
...
While tuning through the 28.3 to 28.5 MHz portion of the 10m band in USB
mode, I get what sound like carrier tones very evenly spaced every 15
kHz
starting at about 28.3 MHz.
I am using an AOR AR8600MkII receiver with an AOR SA7000 antenna mounted
on a mast outside. I am located in central NJ in the Princeton/Trenton
area.
What is the source of these tones?
Thanks,
Doug
The horizontal sweep of television sets is 15750 Hz.
Switch mode power supplies operate anywhere from
10 kHz to 100 kHz.
It is not uncommon for either of them to ring and generate
harmonics in HF.
In the case of switch mode power supplies the spikes IMO would be
120Hz apart (100Hz where I live). And most of the rf energy is spilled
from abt. 1 to 7 MHz, with almost nothing left to be found on 28MHz.
73, Eddi ._._.
--
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Linux/m68k, the best U**x ever to hit an Atari!
The mains frequency has little to do with the noise
that a switcher can generate. A switcher rectifies and filters
the mains to DC then uses a switching transistor to
drive a transformer at a much higher frequency. Tens of
kHz typically. The higher frequency allows the "magnetics",
i.e. the tranformer, to be much smaller physically than
a 60 (50) Hz transformer. That plus the on-off and not
linear nature of the switch allows switching power supplies
to be smaller and more efficient than linear supplies.
It is the switching, with sharp edges, that generates
high frequency components. I've seen poorly designed
switchers generate harmonics into the hundreds of MHz.
--
rb