The far end is high impedance voltage, and has minimum horizontal current
radiation. The inverted L is a good trade off signal vs available
height. Not an expensive antenna to build.
73
Bruce-k1fz
On Sun, 18 Nov 2018 12:31:38 -0700, Wes Stewart wrote:
That also drives up the current in the horizontal wire with attendant increased
horizontal radiation.
I chose for a couple of reason to do the opposite; shorten the wire to make the
feedpoint capacitive and use a shunt inductor to get a 50-ohm match. This
really doesn't improve the 2:1 VSWR, that I consider acceptable, however.
Wes N7WS
On 11/18/2018 8:55 AM, F Z_Bruce wrote:
> That sounds about right. As you put a good ground system under it, that
value will come down, and the efficiency will come up.
>
> Many add extra antenna wire that pushes the current up the wire, this also
raises the impedance, hopefully to near 50 ohms with the right length.
> A capacitor (variable, then fixed) in series at the feed point can cancel
the added inductance.
>
> 73
> Bruce-k1fz
> https://www.qsl.net/k1fz/beverage_antenna.html
>
>
> On Sun, 18 Nov 2018 10:41:36 -0500, WW3S wrote:
>
> What should the Z be for a 1/4 wave inv l, with the radials attached to a
radial plate? Mine seems to be 60 ohms or so....
>
> Sent from my iPad
> _________________
> Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
>
> _________________
> Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
>
_________________
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
_________________
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
|