You pretty much nailed it. No antenna is ideal. The fun is finding one,
two, three... that work respectably with your gear, your particular RF
environment, and your listening goals. That could be anything from a
beverage to a rubber duck :-)

IM - yech! Outboard filter(s) to knock down the offending station(s)
perhaps?

Regarding longwires; Why? It will have peaks and valleys in reception
across the RF spectrum. Join the ends to make a horizontal loop and that
will disappear - linear response.

I respect Guy Atkins remarks regarding his dissappointment with the
Wellbrook 1530. I have never owned a loop of that size and type and have
always been apprehensive about trying it. Noise isn't a huge problem here.
If I can replace my 450 ohm ladder-line feed to my horizontal loop with coax
(using the ALA100 amp) I may be able to eliminate most of the remaining
noise and pick up a db or two (except I can no longer transmit into it).

I no longer am a DYI with electronics. I just don't have the time or
patience to gather the parts, solder the board and cross my fingers. If
someone sells an assembled Dallas amplifier I may bite.

I am really getting excited about the software defined radio Guy Atkins
uses. After listening to his sound bites on his SDR-1000 blog I have to
lock up the credit cards. I would really enjoy attending one of his
DXpeditions.

EOM


wrote in message
ups.com...


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