I worked with Mike Kelley ( mpkelley at seco-systems.net) (be aware
there is another unrelated seco systems company). We worked out the
design of a dual coil (1/4" Cu tubing coils) center feed with about 12.5
turns per side to tune the EF180C. I used EZNEC to get the target uH
needed. The resulting coils have plenty of range to match the dipole
for the full 80m band and more. I replaced the linear loading with
phillystran guys and mechanically strengthened it in addition using the
Yagi-Mech (DXEng) analysis program.
As far as I know, Mike's company is unrelated to F12.
I haven't thought through how to use (number??) Tornado coils in a delta
loop. Two would exceed the cost of the SteppIR 40m vertical.
Grant KZ1W
On 11/22/2012 11:45 AM, Richard (Rick) Karlquist wrote:
On 11/22/2012 9:13 AM, Grant Saviers wrote:
with the antenna. An MFJ screwdriver controller provides 10 preset
turns counts, established at 20KHz steps by manually measuring swr. I
use the MFJ controller on my Tornado variable inductor tuned 80m
rotatable dipole (rebuilt EF-180C) for full band coverage and it has
been solid.
Why not use another Tornado to tune your 160m loop?
Does Force 12 sell the Tornado as a separate item?
Rick N6RK
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