I've not heard the term "accordian" applied, but the Tornado Tuner
expands and compresses a coil inside some pvc pipe to change L about
2:1. I have one (split) to tune the full 80m band at the center of an
86ft rotatable dipole. Your choice of Al or Cu coil tubing with a small
Portescap gearhead motor driving a delrin (I think) leadscrew screw and
reed switch for turns counting.
JKantennas makes an yagi with a Tornado. Rumor has it a 3L 80m was
built with them for full band coverage.
Originally, mostly used for tuning/loading verticals. No sliding
contacts makes it quiet and reliable. I used an MFJ screwdriver control
with 10 pushbutton 50KHz spaced presets for 80m but now have a RT21dc
automatically tracking frequency to preset coil positions. GHeverywhere
does the mapping.
Grant KZ1W
On 9/14/2021 12:54, Mark - N5OT wrote:
Wait. There's such a thing as an "accodion inductor"? I thought I knew
everything.
I'll be glad when mowing season is over, too.
73 - Mark N5OT
On 9/14/2021 2:44 PM, W3HKK@roadrunner.com wrote:
Been reading the encouraging posts. So, I got up and heard good
activity, working:
VK3HJ - ZL1AZ - VK2WR at Ohio SR and up to 20 minutes after, when the
band faded out.
Gud to hear Luke, Dennis and Adrian coming through so well, through
moderate QRN. Unusually warm temps here for mid Sep. ( 85-88F) I took
an hour last week to tweak the 52' tall 1/4 wave INV-L. All 26 radials
are still coiled up and hanging from the walnut tree, until lawn
mowing season ends in mid Oct. Then I will uncurl them and retune
accordion inductor.
Heard AA1K this morning as well.
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