I believe he is talking about a half sloper fed at the top. The tower
becomes a radiator which can cause varying results so it should be included
in the model.
John KK9A
Jim Brown K9YC wrote:
Hi Art,
If you're talking about a sloping vertical fed from the base against
radials. it's a fairly easy antenna to design in NEC. I had that dipole
using components I'd purchased, and the lengths you're thinking about
are in the ballpark. I did measure the loading coils at least 15 years
ago. I'll see if I can find them.
The way to design it is to build a model with those approximate lengths
and start playing with variables until VSWR plots on both bands look
good on both bands.
Yes, SWR bandwidth will be very narrow on 160, but coax loss is quite
low on that band if you're using RG8.
73, Jim K9YC
On 11/19/2025 9:22 PM, ARTHUR BERNSTEIN via TowerTalk wrote:
> With roughly 65 ft for 80 could I resonate it on 160 with wire added after
the coil? I realize if doable will likely be narrowband which I don't care
as I use primarily CW or ft8 on those bands. Inductance of coil and length
could be tricky.
> Art., N2KA
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