"Mark S. Holden" wrote in message
...

An alternative to the Amrad antenna is you can
connect a high quality rf preamplifier to a whip.

That's what I do for the antenna on my 7030+
"portable".

That's right up there with those that call the old
Hammarlunds and Hallicrafters boatanchors
portables because they had a handle. ;-)

The one I chose is an avantek 30db preamp that I
picked up at the flea at MIT for $5 or $10. (I expect
a new one with similar specs would sell for a few
hundred) The whip is connected to the input of the
amplifier with a 9:1 impedance matching transformer.

I often dial in some attenuation when I'm listening
below about 5mhz. Other makes for milspec RF
preamps include Aiken/Norlin/ACL/Applied
Communications (same company, different names)
and Watkins Johnson. I'm sure there are others
too - I'm just not familiar with them.

Okay, that brings up the question of the MFJ-1020
used as a preamp. Admittedly, you can't beat
and Avantek for $5-10, but is the MFJ-1020 worth
the price, or can you find schematics for decent
preamps lying around??

I'm not knocking the Amrad - if I had the time to
build one, I probably would.

As for the Dressler, and the Wellbrook, I think
between the two, I'd go for the Wellbrook. IIRC,
the Wellbrook has more dynamic range. Loops are
less likely to pick up RFI. I've also noticed numerous
favorable comments about it, and relatively few
comments (positive or negative) about the Dressler.

Actually, I've read a bit about the Wellbrook from replies
on lists and on the occasional webpage on it, but what
puzzles me is the spread that the Wellbrook claims that
the loop is good for. After all, it's not a tunable loop and
it looks like an aluminum hoop (about 1m diameter) with
a preamp and matching transformer attached. The best
I saw on a homebrewed magnetic loop after an hour
or so of perusing the web was about 5-17 MHz for
usability.

I figure that it looks simple enough of a design that
someone could build one at home (or at least emulate
one) easily enough, but some of the claims don't seem
to mesh with that people who have built these type
of loops have discovered.

--Mike L.