Topband: FT-240-77 Toroid Impedance R + jX Components

[Chuck Hutton]

Mike:

When I compare your plots to those from Fair-Rite (
http://www.fair-rite.com/fr_catalog-14thed_rev3.pdf , page 173, Figure 4),
the difference is quite notable. Fair-Rite shows that the impedance for a 73
(not a 77 like you measured, but not too different either) has no peak
around 2 MHz and their transformer primary impedance goes up with frequency
over the range you measured. Your charts show a decrease in impedance as
frequency increases.

I've seen a peak like yours when sweeping cores, but can't reconcile the
Fair-Rite charts with that. I think their chart doesn't mean what I think it
means. Can you explain?


Chuck

-----Original Message-----
From: topband-bounces at contesting.com [mailto:topband-bounces at contesting.com]
On Behalf Of Michael Tope
<CLIP>
A while back I posted impedance vs frequency vs # of turns 
data for the Amidon FT-240-77 toroid (Fair-Rite Products 
P/N 5977003801). I have updated my website to include 
plots of the real (R) and imaginary  (jX) components of the 
impedance:

http://FT-240-77.notlong.com

<CLIP>
Mike, W4EF......................



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