[Elecraft] Parts for compact loop antenna - toroid help

[Larry Phipps]

I haven't built a loop like this, but here is some general info about 
ferrite vs. powdered iron...

If  the toroid will be used only as a transformer and not as a coil, 
then you can use either ferrite or powdered iron. For low-band only work 
you could use FT-50-43 or -61. For all bands, I would use -61. FT-50 
should be good up to about 50W. The -61 core will require more turns on 
gthe secondary. If you use powdered iron, T-50-2 is a far better choice 
than -6, especially at lower frequencies.

If you need a coil instead of a xfmr, forget ferrite... it saturates too 
easily.

73,
Larry N8LP


Daniel Reynolds wrote:

>I'm thinking about building a non-tunable compact loop for 40m (7040) using
>RG-8. If I have good success, I'll be making other loops for 20m and 30m
>(mono-band / tuned to the CW-QRP frequency). I need some help figuring out
>which toroid to buy to build a portable compact loop like is shown here:
>
>http://www.qsl.net/aa5tb/loop.html
>
>It looks like I can buy the cable, toroid, and even the banana plug/bnc adapter
>at Ocean State Electronics. My only question is - which toroid core should I
>buy for this application? I've seen comments on the web about using a T-50-2
>for the Rock Loop, and I've seen other vendors selling a T-50-6 which
>supposedly covers the entire HF band. But I cannot find either one at Ocean
>State Electronics. For 40m, should I buy a T-50-61? What about 30m? T-50-61 or
>-67?
>
>Thanks for your help,
>Daniel / AA0NI
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