LF: Care and feeding of a top-loaded vertical]
Tue, 09 Mar 1999 10:18:56 -0500
Toni Baertschi wrote:
> from HB9ASB
> Hello Bob,
> I'm using a helical vertical for more than a year and it works fine.
> The lower part (7m) is a PVC irrigation pipe (11cm Diameter) the upper
> part a Kevlar fishing pole (8m). I've wound about 350m of Liz wire on
> it. Top load is a 60m long wire going up to 18m and then down to 8m,
> zigzag over my 30*40m property. Self resonance of the whole thing is
> around 170 kHz and I match it to the coax via an autotransformer (abt.
> 1mH), wound on a plastic waste-paper basket.
> For comparison I've built exactly the same antenna a few meters away but
> with a straight wire instead of the helical. The helical was always 3 or
> more dB's better, on transmit and on reception.
> I think the helical is good for some more dB's if you can make the
> diameter larger (a handling problem, hi).
> 73 de Toni
> Bob RIESE schrieb:
> > Has anyone done anything with a continuously loaded vertical and top hat.
> > 40 Ft of large diameter plastic pipe wound with copper wire would be a
> > rubber duckie on LF, the only problem I see would to keep it from acting
> > like a Tesla Coil
> > Bob K3DJC
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