[600MRG] A question on receiving loops.

[Kenneth G. Gordon]

On 10 Sep 2014 at 10:24, John Langridge wrote:

> 
> Ken,
> 
> I'm not familiar with your stoddard loop,

Hi, John: 

The "Stoddart Loop" is not a type of loop, but a make. See this URL for 
some interesting information on the company and its products.

http://online.sfsu.edu/hl/src.html

If you do a search for "Stoddart Aircraft Radio Company" you will get some 
very interesting hits.

> but I've used shielded loops on a
> number of occasions, both resonant and non-resonant, and for bidirectional loops
> they work fine.  The key is to decouple the feed line so you don't ruin the
> pattern.

OK. Interesting. These loops are fed with twin-ax...

> Mine were made of coax with a split at the top and tuned with a cap on
> the resonant models or fed with a preamp on the non-resonant models.

I have several preamps for these, but those preamps are for VLF, not MF. I'll 
have to modify them.

>  sometimes
> guys use transformers to isolate the feedpoint which I would recommend if you
> mount it very high off the ground.

About 4 feet, so far. I can extend the legs on the tripods so that the loop is 
about 5 feet above the ground, but that's about all.

>  A lot of decoupling is achieved by having
> the coax either on the ground or buried.  I don't see any value in getting them
> high off the ground.

OK. I wondered.

> I don't use those anymore, and recently replaced the K9AY loops (cardioid
> pattern) with the VE7SL multiturn resonant loop with the W1VD version of the
> W7IUV preamp.. bidirectional but works like a champ an I hear better on 475 than
> I have in a long time.

OK. Thanks. I'll investigate that too.

vy 73,

Ken W7EKB