Topband: Beverage transformers tht work down to 630 m

[Mike Waters]

Yup! Amidon BN-73-202 (Fair-rite 2873000202) is good stuff! Very high
permeability.
W8JI himself kindly introduced me to 73 material back in the 1980s. Back
then we just used Beverage antenna transformers made from stacked ferrite
beads made from that that stuff, but those binocular cores were far
superior.

630m is ~475 kHz, and 73 material works (to a degree) down to 100 KHz.
www.w0btu.com/Beverage_antennas.html#Beverage_Antenna_Transformers

I just bought 100 of those cores from Newark. Cheap! I still have to test
them (as I always do) but I've never run into those that didn't meet specs.

FYI, Chuck Hutton has a better grasp on the technical  aspects of ferrite
that I do.

73, Mike
www.w0btu.com