LF Engineering H-800 antenna
 

Maybe you should ask that sassy gal to help set up your vertical whip!

LF Engineering H-800 antenna
 

HFguy wrote:
Mark S. Holden wrote:

I use an active whip for camping trips and vacations - largely because
they're easy to transport and set up. The one I'm using now is a 3
meter whip that folds like a tent pole with an impedance matching
transformer, and a milspec Avantek low noise high gain amp.


What model Avantek amp' are you using?

It's an AMG-502M. It's a 15v preamp, but I run it (and my 7030+) on
14.4v nimh battery packs.

Gain is 30db. It's rated for 5-500mhz but I generally dial in some
attenuation on the radio below about 5mhz because it's still got more
gain than you need (or want) down there.

LF Engineering H-800 antenna
 

I've run my radio from a gelcell where the closest noise source is the
farting of one of those poor cows that live in the high desert. I've
done the long wire, long wire plus Palomar magentic balun, and the
Wellbrook, all in the same "dxpedition." It's not even a contest. The
Wellbrook is much quieter. Finding trees worth a damn to string an
antenna in the high desert isn't easy. I had to go to a spot that had
those junipers you see around the 6000ft level. BTW, I used ceramic
insulators for both long wire setups.

Somewhere around 40 to 60ft of wire on the Wellbrook ALA 100 is the
magic spot.


wrote:
Or maybe you have the space for, say, a 100 ft wire? The Wellbrook is a
great antenna, so long as you find a quiet spot for it. In general,
though, I would trade it for 100 ft of wire in a quiet location.

LF Engineering H-800 antenna
 

Ah, the ALA-100...I don't have any first hand experience with the 100.
I would expect it to be a better performer than the 330S, though, since
it's Wellbrook's "large aperture" antenna. I suspect it would be better
than an ordinary random wire. Sounds like fun.

wrote:
I've run my radio from a gelcell where the closest noise source is the
farting of one of those poor cows that live in the high desert. I've
done the long wire, long wire plus Palomar magentic balun, and the
Wellbrook, all in the same "dxpedition." It's not even a contest. The
Wellbrook is much quieter. Finding trees worth a damn to string an
antenna in the high desert isn't easy. I had to go to a spot that had
those junipers you see around the 6000ft level. BTW, I used ceramic
insulators for both long wire setups.

Somewhere around 40 to 60ft of wire on the Wellbrook ALA 100 is the
magic spot.


wrote:
Or maybe you have the space for, say, a 100 ft wire? The Wellbrook is a
great antenna, so long as you find a quiet spot for it. In general,
though, I would trade it for 100 ft of wire in a quiet location.

LF Engineering H-800 antenna
 

The ALA100 is a roll your own Wellbrook. They sell the amp, you come up
with the wire.

I've run one ALA 100 scheme with a suare loop 11ft on the diagonal.
Obviously not suitable for indoor use. I have a wire holding scheme now
that uses a 5 ft on the diagonal form with 3 loops of wire. The
performance is quite good. This seems to be all the inductance the ALA
100 can handle. I think you get a LC filter with the ALA100, with the C
of the amp and the L of the wire. Too much inductance will put the
resonance in the HF band.

This 3 loop scheme gets good perfrmance on AFN out of Hawaii, though
the noise is higher than I care for. I think another turn or two would
do the trick, but I have to compute the requires "depth" of the coil to
keep the inductance the same as the 3 loop scheme. A larger loop is
generally the best solution if you have the space as it has the least
self inductance (no mutual term).

I had thought the null woould be worse with multiple turns. I don't
believe this is the case. In fact, the null is sharper, which actually
makes it harder to find the null.


wrote:
Ah, the ALA-100...I don't have any first hand experience with the 100.
I would expect it to be a better performer than the 330S, though, since
it's Wellbrook's "large aperture" antenna. I suspect it would be better
than an ordinary random wire. Sounds like fun.

wrote:
I've run my radio from a gelcell where the closest noise source is the
farting of one of those poor cows that live in the high desert. I've
done the long wire, long wire plus Palomar magentic balun, and the
Wellbrook, all in the same "dxpedition." It's not even a contest. The
Wellbrook is much quieter. Finding trees worth a damn to string an
antenna in the high desert isn't easy. I had to go to a spot that had
those junipers you see around the 6000ft level. BTW, I used ceramic
insulators for both long wire setups.

Somewhere around 40 to 60ft of wire on the Wellbrook ALA 100 is the
magic spot.


wrote:
Or maybe you have the space for, say, a 100 ft wire? The Wellbrook is a
great antenna, so long as you find a quiet spot for it. In general,
though, I would trade it for 100 ft of wire in a quiet location.