Hi Dan,
> The winding cores were then tested for frequency response. The #43 core
> had the lowest response and the least loss, the #61 was second, and the
> #67 poorest. The #43 had a loss of .4 to 1 db between 160 and 6 meters,
> the #67 had a loss of 1.5 to 2.4 db.
These loss figures seem very high. And I cannot make much sense of the
test setup you describe. It would be interesting to know how you
measured the loss, in terms of which configuration you used (1:1
transformer, 4:1 autotransformer, or common mode choke), and at what
impedance levels.
> There is a small response glitch in response
> at about 25 MHz, for about a MHz. This is common on all toroids. The
> question is: What is the cause of this glitch?
It cannot be the cores, if you get that glitch with all of them. It's
unlikely that it's the winding, because such short wires in that
configuration can hardly exhibit any resonance effects at that
frequency. That only leaves the test setup. Maybe the network analyser
has that problem, or maybe some stray signal around 25MHz was picked up.
Anyway, try again using a longer section of wires, to see if that glitch
moves down in frequency!
Manfred.
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