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Telamon · October 6th 06, 02:25 AM posted to rec.radio.shortwave

In article . com,
wrote:

I may have given the impression that I think that loops have no place
in a radio system.

I am also a ham, extra class, and for the last 18 months I have been
somewhat active using NVIS in a mobile setup. When you are using a
1991 Honda roof as your ground plane, a loop is the only thing that
works.

My negative comments about loops should be for broad band, untuned
loops.

My SWL mainly is utility and I often have 2 receivers tuned to very
different frequencies. For my SWL activities an antenna that must be
tuned is not very useful.

A friend pointed out that I had tared all loops with the same brush.

I will stand by the observation that in all of my tests, small,
fractional wavelength loops have no advantage over, and have proven
very inferrior to the Lankford active dipole. Even a north country
configured in a dipole array worked better then the Wellbrook.

I will be the first to admit that I have not experimented with larger
loops for broad band SWL reception. If I every get the time it would
be interesting to use a Dallas "ultra linear" amplifer with a 50'
square horizontal loop. For the time being I will concentrate my
energy on standard "long" wire antennas with a set of 2 vertical
Lankford active dipoles couple to a phaser with an additional and
rotatable horizontal active dipole. That should cover my foreseeable
needs.

A Langford "ultra linear amp" makes a very good buffer for ampifing a
signal prior to power division. In fact it works better, as in much
higher IP2, IP3 and simple harmonic distortion then the 40 year old
Nuvistor based unit I had been using for the last year or so.

FWIW we got the desk in place, stained and sealed between showers
today. And I was able to burry the copper tubing that will cary the
coax away from our home. You can't have too good a ground. The entry
bulkhead is ready to mount, and I am only a week behind on my planed
timeline.

What equipment are you using to make the IP2 and IP3 measurements?

Can you share the comparison data you took on the units?

--
Telamon
Ventura, California