Topband: Core for K9AY loop transformer

[RFD]

After some encouragement from Eddy VE3CUI I am mobilizing to erect a K9AY loop.   Just as soon as the meter of snow that is left in the back forty melts !   The 9:1 Transformer required is recommended to be wound on a 0.75 to 1.00 inch toroid of type 43 material.    In looking on the FAIR RITE web page I see that type 43 material is spec'd for freq range 25-300 Mhz.  So why use a material for that range...what gives?...I guess its not all that critical. 

Secondly is there anyone on the list with one of these toroids available?

I have been using a coax loop for about 5 years now and its time to move on! .....  

73 Frank VO1HP
160M DXCC#1259
www.vo1hp.ca