RadioBanter - View Single Post - how to wind 10mH inductor for AF diplexer?

March 9th 06, 01:08 PM posted to rec.radio.amateur.homebrew

wrote:
My question is: how on earth should I wind those 10mH inductors?

In years past I would pick up 88mH/22mH and like "phone company"
toroids at hamfests etc.

My understanding is that these were used to compensate for line loading
in long phone wire runs.

Windings were either used as-is (if 88 mH or 22mH was appropriate) or
were removed and rewound.

Don't know what the actual core material was, I'm sure it was
completely inappropriate for RF but did fine at audio (I used them in
RTTY demodulators).

Haven't seen these on the surplus market in many years now. Too bad,
just about every 70's-era ARRL handbook had a half-dozen projects based
around them. A quick look at Digikey turns up some 2 through 16 mH
toroids intended for use in switching power supplies (page 1619).

Tim.