[Elecraft] Parts for compact loop antenna - toroid help

[G3VVT at aol.com]

To confuse the matter of toroids further, the catalogs I have show the iron  
dust toroid T50-2 made by Micrometals as working in the mid to low HF, 0.25 -  
10MHz range and identified by a red color.
 
The T50-6 seems the best for all round HF use with a listing of 2 - 30Mhz  
and identified by a yellow color. Have used these in home  constructed HF radios 
in the past with good success.
 
For VHF there are several listed: T50-12 (green/white), T50-17  (blue/yellow) 
and the -22 version (green/orange) seems to be available in the  smaller 
sizes. All cover 20 - 200MHz with varying temperature stability.
 
Bob, G3VVT