Re: [IRCA] ALA 100 and related thoughts

[Nick Hall-Patch <nhp@xxxxxxxx>]

At 06:42 1/29/2009, you wrote:

>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. *
>**
>My experience with the ALA100 has been that it picks up locally generated
>noise, close in and local just fine.   It is much less adept at picking up
>signals.  I purchased mine with the expectation that it could be a better
>performer on the LW BCB signals than any of my wires - which are certainly
>not of a length approaching a beverage at those frequencies.  It hasn't done
>that. My current loop is part of a former K9AY installation  - 30 high by
>30' wide triangle with fibreglass supports.   A 10' x 10' diamond loop
>configuration has also been tried.  Tonite, there was respectable audio on
>189, 171 and 153 khz on the 240 degree beverage (maybe 700' long).  Only on
>153khz were the wire and ALA in the same ballpark (10 db or so).
>
>For MW TA signals, the story is similar.  There, my wires could be
>considered of beverage length, albeit fairly short.  It hasn't been
>of enough merit here to even bother hooking it up since last winter, but I
>did so again today just to reconfirm my earlier observations.  For
>domestics, it seems generally ok.
>
>While it may be a good option where space is minimal, we are talking about
>Patrick's situation, and I am not all convinced that it would be a
>worthwhile cost effective answer for him.
>

Interesting observations, Don.   A couple of points though.   One is that Patrick's space situation to the north is very similar to that of any suburban DXer, not much room for anything (except that he can look at wide open spaces that aren't available for his antennas).   So, the comparison isn't with the Beverage (which isn't really a fair one for most small antennas most of the time), but with a random wire, active whip, or, as it turns out, maybe a Pennant or Ewe.  These last two may well be the better options with the direction he has available, because California will be roaring in on the back end on a bi-directional antenna.

Interesting that you have noise problems with the ALA100.  No argument that if you place one next to the house, you'll pick up noise, but it sounds like you're further away than that.  How does an active whip perform plonked down at the same location?    

I suspect a lot of the enthusiasm for the ALA100 is based on its working pretty well straight out of the box and in otherwise DXer unfriendly locations.   W8JI is probably quite right about doubting the "magic of magnetic", but even he spends more time questioning the efficacy of the shielded loop, which certainly has acquired a lot of magical claims over the years, many of them in the commercial market (such as RDF loops).

best wishes,

Nick









*****************************
Nick Hall-Patch
Victoria, BC
Canada 

_______________________________________________
IRCA mailing list
IRCA@xxxxxxxxxxxxxxxx
http://montreal.kotalampi.com/mailman/listinfo/irca

Opinions expressed in messages on this mailing list are those of the original contributors and do not necessarily reflect the opinion of the IRCA, its editors, publishing staff, or officers

For more information: http://www.ircaonline.org

To Post a message: irca@xxxxxxxxxxxxxxxx