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

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:
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

Guy Atkins is very lucky to live in what must be one of the quitest RF
environments
around. My home RF level isn't as bad as I had thought, I know see what
real
bad RFI is, but at that there is very little I can hear on a AOR7030+,
R8B, or a R2000.
The first 2 recivers do a much beter job in very crowded band
conditions with very strong
signlas next to weak ones that I am intereted in.

On a "remote" mountain top in eastern KY I enjoyed pushing the AOR to
the limits.
That quite location showed the difference between a great receiver and
a much more
modest (R2000) receiver.

Perversly better locations deserve better recveivers. Since the local
noise floor sets
the limit to our reception it makes sense but it does feel odd. I have
been busy trying
to eliminate, or at least reduce, any unwanted RF noise. Sadly while I
have had great
success at eliminating the RF noise emitted by/within our home. We got
rid of our
desk top PCs, tossed the TV and similar steps have reduced my noise
floor as much
as I can. Too bad I can;t convine my nieghbors to limit thier RFI. I
had hoped the
Wellbrook ALA 1530 would reduce noise from nearby homes, but either
the whole
lopp concept is flawed, which I believe, or my in location all the
noise is "far field" and
a loop won't help.

Terry

wrote
I had hoped the
Wellbrook ALA 1530 would reduce noise from nearby homes, but either
the whole
lopp concept is flawed, which I believe, or my in location all the
noise is "far field" and
a loop won't help.

Curious that Wellbrook states that the 1530 will operate best when it is
about 30ft away from your home and for best MW reception mounted near the
ground. It alegedly performs better on SW when mounted up high at the cost
of MW reception.

Where's that credit card!? LOL

In article . com,
wrote:

Snip

Guy Atkins is very lucky to live in what must be one of the quitest
RF environments around. My home RF level isn't as bad as I had
thought, I know see what real bad RFI is, but at that there is very
little I can hear on a AOR7030+, R8B, or a R2000. The first 2
recivers do a much beter job in very crowded band conditions with
very strong signlas next to weak ones that I am intereted in.

On a "remote" mountain top in eastern KY I enjoyed pushing the AOR to
the limits. That quite location showed the difference between a great
receiver and a much more modest (R2000) receiver.

Perversly better locations deserve better recveivers. Since the local
noise floor sets the limit to our reception it makes sense but it
does feel odd. I have been busy trying to eliminate, or at least
reduce, any unwanted RF noise. Sadly while I have had great success
at eliminating the RF noise emitted by/within our home. We got rid of
our desk top PCs, tossed the TV and similar steps have reduced my
noise floor as much as I can. Too bad I can;t convine my nieghbors to
limit thier RFI. I had hoped the Wellbrook ALA 1530 would reduce
noise from nearby homes, but either the whole lopp concept is flawed,
which I believe, or my in location all the noise is "far field" and a
loop won't help.

I would believe the latter. The "whole loop concept" is not flawed.

--
Telamon
Ventura, California

wrote in message
ups.com...
Guy Atkins is very lucky to live in what must be one of the quitest RF
environments
around. My home RF level isn't as bad as I had thought, I know see what
real
bad RFI is, but at that there is very little I can hear on a AOR7030+,
R8B, or a R2000.

Yes, it's very quiet here in the Pacific NW, with the fewest "thunderstorm
days" of any place in the continental USA. In mid-winter, with a Western
Beverage antenna at dawn, aimed out over the Pacific Ocean, you'd swear your
receiver was defective, or the antenna broken. In these conditions,
extremely faint tropical band and foreign (TP) mediumwave signals have a
fighting chance to be heard (assuming a top-notch, low noise receiver like a
AR7030 or my current fave, the SDR-1000.

It was under these mid-winter, dawn enhancement conditions that I heard
tantalizing faint signals around 3174 kHz (variable) in the late 1990s,
which had all the clues of Indonesian "amatir" stations. Think: Indo college
kids back home on holiday or weekend breaks, playing non-stop Indo rock
music with flea-powered transmitters, no IDs, often distorted audio, no
official "RRI" news at the top of the hour, etc. I've heard enough of the
real RRI and RPD Indonesian stations to recognize the Indo amatir (pirate)
station. Similarly, I've logged very low power Australian x-band stations
such as Radio Brisvaani, the Hindi station on 1701 kHz (Brisbane,
Queensland). I'd never have a chance to hear this sort of DX, however, at
home in the suburban RF jungle near Seattle-Tacoma. These catches were on
coastal DXpeditions, under ideal conditions.

I do have pretty low noise levels of the RFI, hash-and-buzz sort at home,
due to the underground AC mains. The main problem are the dozen or so MW
stations registering S-9+40 to S-9+60 dB on the SDR's (calibrated) signal
meter. My local 1 kw'er, 1450 KSUH in Puyallup, is a bit over 1 mile from
home. When I had a 700 ft. Beverage antenna aimed at my Asian targets, the
antenna unfortunately was oriented right at KSUH, too. The signal on 1450
from that antenna registered -13 dBm, which is, I believe, around S-9+65 dB.
This is an example of what the trans-Pacific MW stations need to fight
through to be heard in a suburban location like this. So far, I'm finding
the Wellbrook ALA 100 on a rotator does just fine for snagging the foreign
MW DX that makes it through the RF jungle; a Beverage is no advantage.

73,

Guy Atkins
Puyallup, WA
www.sdr-1000.blogspot.com

Guy is so right about the joys of DXing in a very low noise environment,
such as the Pacific coast Grayland site. I takes a lot of research and
running around to find an "ideal" low noise DX site and on our crowded
planet they become harder and harder to find.

I found such a site in a remote part of our Atlantic coast,Seefontein, miles
from the nearest town and miles from the nearest powerline. It's just bliss
to have that phenomena that Guy describes: when the noise on the antenna's
is so low you start checking to see if in fact they are connected. It is
such a joy to hear stations thousand's of miles away waft in over the
airwaves as clear as a bell, yet the signal strength is so low it doesn't
even move your "S" meter. What a thrill!

That's why some of us serious DXer's travel long distances with considerable
effort in time and money to enjoy these most favourable DX conditions.

Try it = you'll love it..............
--
John Plimmer, Montagu, Western Cape Province, South Africa
South 33 d 47 m 32 s, East 20 d 07 m 32 s
RX Icom IC-756 PRO III with MW mods
Drake SW8 & ERGO software
Sony 7600D, GE SRIII, Redsun RP2100
BW XCR 30, Sangean 803A.
GE circa 50's radiogram
Antenna's RF Systems DX 1 Pro, Datong AD-270
Kiwa MW Loop, POARDT Roelof mini-whip
http://www.dxing.info/about/dxers/plimmer.dx

"Guy Atkins" wrote in message
. ..

Yes, it's very quiet here in the Pacific NW, with the fewest "thunderstorm
days" of any place in the continental USA. In mid-winter, with a Western
Beverage antenna at dawn, aimed out over the Pacific Ocean, you'd swear
your receiver was defective, or the antenna broken. In these conditions,
extremely faint tropical band and foreign (TP) mediumwave signals have a
fighting chance to be heard (assuming a top-notch, low noise receiver like
a AR7030 or my current fave, the SDR-1000.

It was under these mid-winter, dawn enhancement conditions that I heard
tantalizing faint signals around 3174 kHz (variable) in the late 1990s,
which had all the clues of Indonesian "amatir" stations. Think: Indo
college kids back home on holiday or weekend breaks, playing non-stop Indo
rock music with flea-powered transmitters, no IDs, often distorted audio,
no official "RRI" news at the top of the hour, etc. I've heard enough of
the real RRI and RPD Indonesian stations to recognize the Indo amatir
(pirate) station. Similarly, I've logged very low power Australian x-band
stations such as Radio Brisvaani, the Hindi station on 1701 kHz (Brisbane,
Queensland). I'd never have a chance to hear this sort of DX, however, at
home in the suburban RF jungle near Seattle-Tacoma. These catches were on
coastal DXpeditions, under ideal conditions.

I do have pretty low noise levels of the RFI, hash-and-buzz sort at home,
due to the underground AC mains. The main problem are the dozen or so MW
stations registering S-9+40 to S-9+60 dB on the SDR's (calibrated) signal
meter. My local 1 kw'er, 1450 KSUH in Puyallup, is a bit over 1 mile from
home. When I had a 700 ft. Beverage antenna aimed at my Asian targets, the
antenna unfortunately was oriented right at KSUH, too. The signal on 1450
from that antenna registered -13 dBm, which is, I believe, around S-9+65
dB. This is an example of what the trans-Pacific MW stations need to fight
through to be heard in a suburban location like this. So far, I'm finding
the Wellbrook ALA 100 on a rotator does just fine for snagging the foreign
MW DX that makes it through the RF jungle; a Beverage is no advantage.

73,

Guy Atkins
Puyallup, WA
www.sdr-1000.blogspot.com

John Plimmer wrote:
It's just bliss
to have that phenomena that Guy describes: when the noise on the antenna's
is so low you start checking to see if in fact they are connected. It is
such a joy to hear stations thousand's of miles away waft in over the
airwaves as clear as a bell, yet the signal strength is so low it doesn't
even move your "S" meter. What a thrill!


It's a pity these sorts of locations are so few and far between. In
most locations, atmospheric noise is significant *all by itself*.

I think it was Seein-I-Dawg who commented about the Wellbrook ALA-1530
being shielded....

As far as I can tell, having looked at their site several times,
Wellbrook makes no such claims and points to the loop configuration as
the reason why it rejects some near field RFI. This is also born out
by the fact that they also sell an Indoor version of the antenna which
is packaged in a sort of plastic hula hoop, rather than in Aluminum
tubing. Wellbrook does make a very nice preamp and I suspect that the
ALA-100 WILL outperform the ALA-1530 and the ALA-330s with 50 feet of
wire on it. (I currently have an ALA-1530 and hope to have an ALA-100
shortly so I'll let you know.)

Rob


Steve wrote:
John Plimmer wrote:
It's just bliss
to have that phenomena that Guy describes: when the noise on the antenna's
is so low you start checking to see if in fact they are connected. It is
such a joy to hear stations thousand's of miles away waft in over the
airwaves as clear as a bell, yet the signal strength is so low it doesn't
even move your "S" meter. What a thrill!


It's a pity these sorts of locations are so few and far between. In
most locations, atmospheric noise is significant *all by itself*.