Re: [IRCA] ALA 100 and related thoughts

[Guy Atkins <dx@xxxxxxxxxxxxx>]

Don,

I'd been thinking along the same line also, regarding W8JI's wisdom on this
subject and some of the claims about "magnetic loops" that are just too
glowing to be true.

Although I own a pair of ALA100s and love their versatility and ease of use,
any time I've had them close to noise sources like houses the results have
been disappointing. The rotating ALA100 I have is at 40 feet from the corner
of our house, which I consider right at the edge of the minimum distance.
Rotating the loop can null noise sources but I mainly use the antenna to
help determine whether a 9 kHz signal is coming in on a DU, TP, or TA path.

My more recently installed antenna, a 35 x 30 foot terminated ("Conti")
loop, unamplified, aimed northwest hears TPs a lot better than the ALA100
oriented in the same direction. The s/n ratio is simply better and makes the
difference between just a het on the ALA100 and audio on the Conti loop. The
directionality of Conti loops, EWEs, Flags, and Pennant antennas is what
makes the difference I think, as the rear beam of the figure-8 ALA100 aims
at houses, noise, and stateside signals when it's oriented northwest for
TPs.

Patrick-- in my opinion your first move (after trying the borrowed
ALA100) should be to build a small EWE oriented exactly on the TA bearing
you want, and get it as far from the house if you can. If you don't have
convenient trees or supports, try 20 or 30 foot telescoping fiberglas poles
such as some of us use on DXpeditions. (I can give you some good pointers on
pricing, sources, and usage offline.)

73,

Guy Atkins
Puyallup, WA'
www.perseus-sdr.blogspot.com




> Date: Thu, 29 Jan 2009 06:42:24 +0000
> From: Don Moman VE6JY <ve6jy.1@xxxxxxxxx>
> Subject: Re: [IRCA] ALA 100 and related thoughts
> To: Mailing list for the International Radio Club of America
>        <irca@xxxxxxxxxxxxxxxx>
>
> As Nick alluded to earlier, not all would agree with that assessment....
> what I consider to be a wealth of knowledge on this and other subjects
> exists at:
>
> http://www.w8ji.com/magnetic_receiving_loops.htm
> **
> and an excerpt from that page:
> **
> *Small loops are often referred to as "magnetic radiators". Folklore claims
> a small "shielded" loop antenna behaves like a sieve, sorting "good
> magnetic
> signals" from "bad electrical noise". *
> *Nothing is further from the truth! At relatively small distances a small
> magnetic loop is more sensitive to electric fields than a small electric
> field probe. *
>
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