Late message because I've been out of town. I use a home grown program
to calculate SRF and here's what I get, based on a winding factor [turns /
turns with no spaces] of 0.98:
Diameter = 4.5 "
Winding length = 18" [You didn't say whether the 18" was winding length or
total form length]
SRF = 555 kHz
Self capacitance = 7.6 uufd
Top load capacitance = 19.4 uufd
Loaded resonant frequency = 295 kHz
Turns = 653
DC resistance = 12.4 ohms
Not too far from what you got so your results don't sound strange to me.
Ed
Andrew Robinson wrote:
Does this sound strange to anyone. A 4" OD x 22" (windings) secondary
using 22 gauge wire with a 4.5" x 18" spun alum toroid having a self res
freq of around 515kHz? I ran the tests in the lab today and thats what im
getting. For some reason though, I had reason to believe it was going to
be much lower. I'm gonna resubmit this email next Thursday when I get a
chance to get back in the lab and im gonna take a video of myself taking
the measurements. Maybe im just doing something wrong.
------------------------
Regards,
Andrew Robinson
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