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Old April 27th 09, 01:40 PM posted to rec.radio.amateur.homebrew
David[_9_] David[_9_] is offline
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First recorded activity by RadioBanter: Apr 2009
Posts: 9
Default Experimenting with Coils for Crystal Sets

On Apr 26, 10:31*pm, Bill Janssen wrote:
Bob wrote:
David wrote:


Was just wandering if anyone has used or experimented with television
IF, Video and Detector coils, most are slug tuned coils that have a
few uh to several hundred uh, some are sheilded some are not, i have
about 500 that i bought years ago, a lot of them look very close too
the old loopstick type coils, looking for
ideas.


Unfortunately, the *Q* of those coils will be much too low for effective use
in crystal receivers. *The best results I've had with "no power" receivers
involved the use of FET detectors and /very/ High-Q coils. *The inductors
usually have to be large diameter air-cored, but you can get away with toroid
or ferrite rod types if you can accept poorer results. *It's quite
illuminating to browse the offerings on the web.


Bob


How about making an Air Core Toroid. That can be made using a wax core.
Then after winding it,
some QDope or something in strips to hold the windings and then melting
the wax. Or maybe a foam
plastic core.

Bill K7NOM- Hide quoted text -

- Show quoted text -


Have used glue from a hot glue gun before, the coils will never move
once the glue sets.