[Lowfer] 185 overnight

Fri, 21 Mar 2003 05:18:03 -0600

Yes the wire was wound very close on the outside of the ferrites. The
ferrites had a plastic tube inserted inside them to hold them together.

Mike>WE0H

www.we0h.us/lf

-----Original Message-----
From: [email protected]
[mailto:[email protected]]On Behalf Of Bill Ashlock
Sent: Friday, March 21, 2003 3:15 AM
To: [email protected]
Subject: RE: [Lowfer] 185 overnight

Mike R,

>>Awesome. I will look up my test data for the variable inductor I made
>> >>and post it on the reflector. I wrote it down in a notebook when I
>> >>did the tests.

>I was using #12 THHN insulated copper for my inductors. I achieved a
> >maximum change in inductance of .584uh by using two turns of #12 and >two
>Steward (Digi P/N 240-2081-ND) ferrite beads being movable inside >the two
>wire turns.

Assume the two turns were larger than the diameter of the Steward cores?

This morning when the sun hit the test loop and final box the dip in current
was much less than the previous morning when the variable capacitor was
used.

We have been receiving light rain since about 8:00 this evening and there
was no consequential reduction in current for the test loop while there was
a 25% drop in the current for the big loop. This drop is almost totally
recoverable by changing the frequency so it is suspected that moisture in
the trimmer capacitor is the cause (similar to the way the old variable in
the final for the test loop behaved).

I'm beginning to subscribe to the theory that air-variables cannot be used
in outdoor high Q circuits. Moisture collecting on the plates apparently
causes a significant change in capacity (sometimes a lowering of Q as well).
A few nights ago, when it was 15 deg outside, I could blow on the VC and
lower the loop current by 15%. Another advantage for the variable inductor
replacement is that it will work far better in the 100w situation where the
voltage is 10 times higher.

More later.

Bill