[Elecraft] Parts for compact loop antenna - toroid help

[Charles Greene]

Daniel,

The small powered iron toroids like the T-50-2 and T-50-6 are used for 
tuned circuits, as their loss is less.  The -2 is used for VHF and the high 
end of the HF band; the -6 is used for the mid and low end of the HF 
band.  The ferrite cores, which begin with F do not work well in tuned 
circuits.  They begin with an F, like F-50-61 or F-50-43.  The latter are 
used for baluns, RFI chokes and other than tuned circuits.  Most any 
electronics supply house carries  full line of powered iron 
toroids.  Amidon which sometimes advertises in QST is a source.

Chas, W1CG

At 02:18 PM 10/6/2004, 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