Hein ten Horn wrote:

Michael A. Terrell wrote:
isw wrote:

That particular receiver doesn't have much of a "front end"; diodes
(with protection) and straight into the first mixer. No RF stage, tuned
or otherwise.

It can exceed the PIV of the protection diodes and cause them to
short, or explode. That crappy Sony design is where the harmonics came
from. The diodes, (or any other semiconductor) with enough RF can
generate a lot of spurious signals. It can even come from a rusty joint
in the area.

Is the ICF-SW7600GR significantly better performing
than the ICF-7600D on this?

gr, Hein

I haven't seen the schematics of either model, but most portable SW
recievers suffer from no filtering on the front end, so are susceptible
to overload. A properly designed front end is expensive. Most
manufacturers would rather spend the money on eye candy to make it
attractive to those who don't know what they really need. This is
crossposted to: news:rec.radio.shortwave where the relative merits of
different SW radios are discussed.

I tend to use older, rack mounted equipment that I've restored and
when I have the time, I like to design my own equipment. I only have
one portable receiver, the RS DX-375, which is kept in my hurricane
emergency kit. It was bought on price, alone when it was discontinued
for $50, about eight or nine years ago. The power line and ignition
noise is so high around here that a portable is almost useless. After
the last hurricane, the nearest electricity was over 5 miles away for
about two weeks, and I was picking up stations from all over the world.
It reminded me of visits to my grandparent's farm back in the early
'60s, when their farm was the last one on their road with electricity.
They had nothing that generated noise, other that a few light switches,
when they were flipped on or off. I didn't have a shortwave radio, but
I could pick up AM DX from all over the country, late at night.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida