I did a quick model of your proposed antenna with EZNEC assuming #14
wire and it said that you'd need about 52 uh to make the system resonate
at 1.83 MHz. The resulting feedpoint impedance would be about 22 ohms.
If you put the coil at the base (higher current point) it only requires
about 22 uH, but the feedpoint impedance would be less as well ... more
like 16 ohms.
Please consider these results to be approximate only, since my model
wouldn't necessarily match your system or your environment.
73,
Dave AB7E
k3hx@juno.com wrote:
> I wish to put up a top-loaded vertical for 160m (1.83 MHz.)
>
> I can go 60 feet up and the top-loading "T" wire can be only 46'
> long overall.
>
> I'd be grateful for suggested values for a loading coil between the top
> of the vertical element and the middle of the horizontal "T" wire.
>
>
> Once I get the thing to operate properly on 160m, I'd like to use the
> same antenna on 80m (3.56MHz) and would appreciate suggested circuitry
> and values.
>
> Thanks.
>
> 72,
>
> Tim
>
> Shameless plug:
>
> Michigan QRP Club Sprint
> 25 May 2009 2300Z - 26 May 2009 0300Z
> Google: MI-QRP for contest details
>
>
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