In article 1119208556.bdf46749713b734146fe6f29f1b9f3b9@megan etnews2,
"Wannabe DXer" wrote:

"Joe Analssandrini" wrote in message
oups.com...
Hello,

I just finished reading all the posts here to date (June 16, 2005 at
2040 UTC) and I must say that most of the replies to you are
well-reasoned and thought out. I think that if you follow many of the
suggestions that have been written, you will be pleased with the
results you obtain.

May I make my suggestion for a good receiver/antenna combination? Go on
to the Universal site and look at ther AOR AR7030 Plus receiver. I have
had one for over a year now and each day I am more impressed with it.
In addition to being a superb receiver, one of the finest ever
designed, it can also be controlled from your computer via a free
computer program called RxWings, if you are interested in that sort of
thing. I've been using this computer program for almost as long as I
have owned the receiver and it is, in my opinion, first-rate.

I would recommend buying the NB7030 Noise Blanker/Notch Filter option
for the radio.

I've gone to Universal Radio's website and read about the AOR AR7030+
reciever and did a google search for reviews on it as well. It would seem
that it would be a great pick for a top-notch DXing setup!

As for an antenna, it seems that you, like me, live in an
electrically-noisy location. Yes those power lines 250 meters away from
your location are going to cause problems (as you have already
discovered). The solution? A Wellbrook ALA 330S Active Loop Antenna, in
my opinion the finest shortwave antenna currently on the market. You
can go to Wellbrook's website to view all the particulars; you would
buy it from THE SHORTWAVE SHOP in the UK (Wellbrook's only dealer) if
you want to use a credit card. The results achievable with this antenna
in an electrically-noisy location are nothing short of astounding. A TV
rotator is helpful as the antenna, like all loops, exhibits
directionality especially at lower frequencies and you might as well
take advantage of this functionality.

Actually, I now think some if not most of the noise problems are internal to
my house rather than external. I poked around in my backyard last night with
my portable radio, and to my surprise most of the noise was gone. I also
checked out my front yard and found it was somewhat noisier, but it's also
the side closest to the power substation, so perhaps my house is providing a
bit of shielding from it? I'm wondering if some sort of low mounted outdoor
antenna might be my best bet. I'm thinking that if I get it too high up in
the air then it would be more line-of-sight to the power substation and
might be noisy again. (Maybe I ought to take my portable up on the roof and
see what I get up there?)

That combination, the AOR AR7030 Plus (with the NB7030) and the
Wellbrook ALA 330S is not cheap. Nor is the antenna "convenient" to
buy. And, especially, the installation of the antenna is quite a
precise affair - you must be willing to carefully read and follow (to
the letter) the quite-clear installation instructions (with one
exception: placement of the antenna is not at all critical as the
instructions suggest; I have mine mounted in my attic on a Radio Shack
rotator where it performs superbly; it can be mounted outdoors, high or
low - even on a deck rail or fence post).

I've also read some reviews on this antenna, and most if not all gave it
rave reviews. He's a review that I found interesting and helpful.
http://www.radiointel.com/review-wellbrook.htm

The learning curve of the AOR AR7030 Plus, though nowhere nearly as
difficult as PASSPORT purports, is still something that must be
mastered. (Of course this applies to any communications receiver; it's
not enough to know what buttons to press; you have to know when and
under what circumstances to press them! This comes only with
experience.)

All that notwithstanding, if you can afford it (and apparently you
can), the results obtainable with the AR7030 Plus and the Wellbrook ALA
330S are well-worth the money!!

I wish you the very best of luck with whatever you purchase.

Joe

Thanks Joe. Your post was very helpful to this shortwave newbie!

I came to the conclusion years ago that loop type antennas are the best
bet for most people. The amplified loops can be made smaller and due to
size you have more options where to locate it but they are more
expensive than the passive loops.

You can build a shielded passive loop out of coax. A general purpose one
of 40 to 60 foot circumference should be electrically balanced and the
smaller ones ( 20 foot) can be non-balanced for more gain. The small
non-balanced ones pickup both the E and M fields of a passing EM wave
where the balanced one picks up the M part only.

The difference between the balanced and unbalanced is where the shield
is split. Say you take a 50 foot piece and loop it back on itself ten
feet from one end. At that point you solder the center conductor of the
end of the cable to the shield. The the outer shield of the cable is not
connected and floats. The 10 foot section behaves as a transmission line
to the radio in this example. This will probably be to much antenna on
the lower bands for most table top or any sensitive radio. This is not a
shielded loop. This loop is high output and responds to both the E and M
fields, which is why you have a larger output.

To make a balanced loop at that 10 foot point you solder both the center
conductor and shield of the cable end to the coax shield. Then half way
around the loop you cut the outer insulator and shield only. Now you
have a balanced loop that only responds to the M field. The output will
be less but so will the local noise that is limiting your reception. The
balanced loop is shielded against local common mode E field noise.

This balanced loop will be the most like the Wellbrook if you can manage
to get it some distance from local noise sources. You need it to be some
distance away from the local noise sources so the noise field is equal
over the area of the loop so it can be canceled. Here a small 1 meter
loop like the Wellbrook has the advantage. It can be much closer to
local noise sources and cancel them out. Another advantage the Wellbrook
has is flatter response over the 3 to 30MHz range. The response of the
passive loop will change over that range depending on its size but not a
lot. Another advantage the Wellbrook has is that you can turn it but you
can always build two passive loops at right angles to each other and
switch between them. This is good for all except nulling of course.

I think the Wellbrook is worth the money but if you don't want to spend
that much or if you like to make your own passive loop its easy. The
noisiest locations will probably still do better with the Wellbrook
though. I don't think you can beat a well designed small amplified loop
for a poor receiving location.

--
Telamon
Ventura, California