Greg,

It looks like you forgot the link, but I have some comments anyway.

Pure sine inverters often provide power that's even "cleaner" than the juice
coming directly from the AC wall outlet, and this is great for sensitive
devices like computers and audio equipment.

I bought a new pure sine inverter at a good price on Ebay last year and put
it to extensive tests. My goal was to use it to power a Racal RA6790GM on
DC-only DXpeditions with my other equipment, and hopefully avoid the noise
and RFI present with garden-variety inverters.

Well, my friend Craig at Kiwa Electronics told me that pure sine inverters
can still be sources of radiated noise that interfere with radio reception,
and I found this to be sadly true. I had a deep cycle battery and the pure
sine inverter completely sealed in a metal box, and separated from my DXing
van by 35 feet of shielded, 3-conductor 16-ga cabling. The box was tried
grounded and ungrounded. I also added RFI surpression ferrite chokes inside
the pure sine inverter's enclosure on the input & output leads. My Beverage
antenna's feedline (with grounded shield) and isolated matching transformer
were in the opposite direction, as far as possible from the inverter &
battery box. I also used a high quality Bussman line conditioner between the
receiver and pure sine inverter's output.

Unfortunately no matter what arrangement I tried, I still had bothersome RFI
on most shortwave bands and throughout mediumwave. In this quiet DXpedition
location, *any* noise is noticeable. I had to give up on the Racal during
the DXpedition and use my modded R-75 on DC only.

I noted that all of the noise (in this case) was RADIATED noise, not
conducted through the Racal's power cord. When I disconnected the antennas,
the noise went away. I believe that the 3-conductor "shielded" cable and/or
metal box was the culprit; they radiated the RFI despite the grounding.

Bottom line: pure sine inverters are great for protecting delicate gear, but
they still create external noise that can be picked up by nearby antennas
:^(

Guy Atkins
Puyallup, WA USA



"Greg" wrote in message
...
Here's a line of power inverters marketed to photographers, but possibly
of
interest for use with radios. They offer "pure sine wave" inverters as
well
as cheaper switching power supplies.

What's the difference, in layman's terms, between sine wave and switching
power supplies? What are the pros & cons for practical applications?

I've always wondered if the switching power supplies, like the Radio Shack
models, that convert 120VAC to 13VDC, are appropriate for radios.

Thanks,

Greg