[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

stacked primary \ winding direction bobs message attached this time

sorry forgot bob's message of Feb 99 (below)


Bob said
hi all,
        I have been playing around with the  stacked primary idea and
have some
figures to throw about for those that are interested. I started with 12
turns on each coil with a total of 45 uh on each one. I then laid one of

the primarys on top of the other with the turns opposing each other
made the total inductance 115 uH. I then turned the top coil over so
it is like a slice though the centre of the bottom coil, ie they are
images of each other. the minimum spacing between the two coils is
MM) this results in a inductance of 30 uH. I then added 1 1/2"(38) of
spacing . This brought the inductance up to 45uH. I then checked how
turns this equated to and found it worked out at 3 turns. If my maths is

correct with a 0.01 cap this should give a tuning range of about 50 kHz.
useful range of tuning for 1.1/2" of movement. I don't know what to do
about finding the best position for coupling, and of course it might all

change when it is in the tank circuit rather than with 9 volts at 1 kc's

from my bridge. Any feedback most welcome. hope this makes sense.

bob golding

Reach me by ICQ. My ICQ# is 27867352 or,
* Page me online through my Personal Communication Center:
http://wwp.mirabilis-dot-com/27867352 (go there and try it!) or,
* Send me E-mail Express directly to my computer screen
For downloading ICQ at http://www.icq-dot-com/
For adding similar signatures to your e-mail go to: