"Bill Turner" wrote in message
...
ORIGINAL MESSAGE:

On Wed, 2 Aug 2006 11:11:08 -0400, "Jimmie D"
wrote:

Hi Bill, can you tell m something about your setup with the roller
inductor.
I tried it and was not very happy with it. I guess I could have tried a
slower motor and it seemed like it require cleaning a couple of times a
month. I still have the old stuff around and may try it again if I thought
I
could get it to work better.

------------ REPLY SEPARATOR ------------

At the time I lived in the Seattle area so waterproofing was a must. I
built a plywood box with a plexiglas front and sealed it with
silicone. I used it for a couple of years and never had to clean the
roller inductor. One thing I didn't mention but should have is to have
most of the loading inductance in a separate high Q coil, and use the
roller only for tuning. IOW, don't try to use the roller for the
entire loading coil or it will tune too fast and probably won't be
very high Q either. As with mobile antennas, a center coil is best, or
at least as high off the ground as practical. If you don't have an MFJ
SWR analyzer or the equivalent, buy or borrow one. I would not attempt
this kind of project without one!

The motor was one I got from All Electronics in California. They seem
to have lots of surplus ones available. Something around five RPM
would be about right. They call them "gearhead" or something like that
because they have the reduction gears built in.

Does that answer your questions?

Bill, W6WRT

Ok, that helped. My motor turned even slower than yours but I was using only
the roller inductor. The next time I try this I may use a stepper motor.