On Oct 4, 6:36 pm, "Seeing-I-dawg" wrote:
Terry,
Please read the last paragraph of this 1991 paper:http://www.kongsfjord.no/dl/Antennas...ensitivity.pdf

Yep, the directivity of a loop is what the "magic" is all about.

Dallas' active dipole exhibited better, as in a better null,
directivity from 100KHz (loran)
to CB. A good buddy ratchet mouth about 3 miles from me makes a great
far field test
signal.

The Feb 1955 "Wireless Engineer" paper by J.S.Belrose gives some very
usefull
info on loop. I am not saying loops have no place. Jeff, the guy I
traded the wellbrook
to, loves it. In his RF hell it works better then anyother antenna he
has tried. Once I
get the shack rebuilt I intend to take my latest version of Dallas'
active dipole there to
see if the tighter null will help. I plan on building the WL1030 that
RHF mentioned.
Martinn Hagg's design look workable. I have major doubts about wide
band OpAmps
in a harsh RF task, but I am willing to give it a try.

I suspect that Dallas' Ultra Linear Amplifier will work as well as the
Wellbrook loop maker.
And it would be a lot less expensive. The Kiwa amp version 2, should
also work. It will
need a ?1:! broadband transformer but it is a pretty good amp.

The Belrose paper explained why the 2 different heads I have for my
McKay-Dymek DA5
behave so differently under temperature extremes. The unit that
performs the best under
wide, 100F to -20F temperature swings has a slot lengthwise to the
hollow center.

I have been in a heated conversation with some SWL aquantances here in
the central
KY area about how long a "long wire" should be. And at what length does
it start degrading
radio performance. Most SWL or hams, or even professional RF engineers,
either don' know,
or refuse to think about, the effects too much signal can cause. Front
ends and first mixers
behave very badly with 1dB to many. I envy DXace becuase he clearly has
a superior RF
location with a low enough background RF to degrade his R8B. Sadly
around here, anything
over 100' is more likely to cause problems then help you dig out the
really weak DX.

Jeff, he lives in a downtown Lexington condo, has had nasty experiences
with out of band
overload causing all sorts of receiver misbehavoir. And he has an
AOR7030, not the plus
version.

Terry