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

Seeing-I-dawg wrote:
wrote in message
oups.com...

Seeing-I-dawg wrote:

cut

My antenna goal is to have one antenna and to squeeze as much performance
out of it on as many frequencies (500KHz-30MHz) as possible. That, my
friend, can be most closely accomplished with a large loop. However, I am
intriqed by the 15ft vertical that is diagramed at the Kongsfjord noise
measurments link.

cut

An inverted L, 15 feet vertical and 30 feet horizontal, works fine too.
You can make it longer and higher, or amplify it if you want more
signal. Though more sensitive to horizontal polarization then the
vertical, the L still beats the ALA 100 by about 10 dB S/MMN in the
near field of power lines, just like the vertical. I used verticals
for the previous comparisons because those were what I am using
currently (verticals give me better phaser performance in the MW band
than L's).

Here's another idea:

Custom made, 5ft square, rotatable loop using Wellbrook ALA-100 amp

"...so far it looks to be a fine replacement for my 700 ft. NW Beverage
antenna..."

http://sdr-1000.blogspot.com/2006/07...0-antenna.html

__________________________________________________ ____________

"Seeing-I-dawg" wrote in message
...
Do you currently use a longwire or dipole or have the real estate for one?
Have you been considering the ALA1530+ instead?

I exchanged emails with Wellbrook about using the ALA100 with my current
70M
fullwave Horizontal loop.

About Horizontal loops
http://www.cebik.com/wire/hl.html
http://www.cebik.com/fdim/atl1.html
http://www.cebik.com/wire/horloop.html

About ALA100 http://www.wellbrook.uk.com/ALA100b.html

The ALA100 will allow me to use a coax feeder instead of the noise prone
450ohm ladder-line and dispense with the
antenna tuner/matchbox.

Per Wellbrook, "You may also find that a smaller vertical loop with
ALA100
will give better directivity for MW plus very high gain at HF. The ALA100
will out perform the ALA1530+ , because the loop area is much larger."

So if you are considering a ALA1530+ and are currently occupying real
estate
with a long-wire or dipole, you may consider joining the ends with the
ALA100 for a loop in either the horizontal or vertical plane.

Here's to the '06/'07 DXing season!
Post your logs and good luck.

Seeing-I-dawg wrote:
Here's another idea:

Custom made, 5ft square, rotatable loop using Wellbrook ALA-100 amp

"...so far it looks to be a fine replacement for my 700 ft. NW Beverage
antenna..."

http://sdr-1000.blogspot.com/2006/07...0-antenna.html

__________________________________________________ ____________

"Seeing-I-dawg" wrote in message
...
Do you currently use a longwire or dipole or have the real estate for one?
Have you been considering the ALA1530+ instead?

I exchanged emails with Wellbrook about using the ALA100 with my current
70M
fullwave Horizontal loop.

About Horizontal loops
http://www.cebik.com/wire/hl.html
http://www.cebik.com/fdim/atl1.html
http://www.cebik.com/wire/horloop.html

About ALA100 http://www.wellbrook.uk.com/ALA100b.html

The ALA100 will allow me to use a coax feeder instead of the noise prone
450ohm ladder-line and dispense with the
antenna tuner/matchbox.

Per Wellbrook, "You may also find that a smaller vertical loop with
ALA100
will give better directivity for MW plus very high gain at HF. The ALA100
will out perform the ALA1530+ , because the loop area is much larger."

So if you are considering a ALA1530+ and are currently occupying real
estate
with a long-wire or dipole, you may consider joining the ends with the
ALA100 for a loop in either the horizontal or vertical plane.

Here's to the '06/'07 DXing season!
Post your logs and good luck.



Once you have about 50ft on the ALA100, it really cranks. I have mine
in a multi-turn loop as well. With 50ft, myAR7030+ needs to switch in
the attenuator on local BCB.