john battin wrote:
> ----- Original Message -----
>
>
> I'm looking for suggestions for improving the efficiency of a short
> vertical antenna on 160M.
>
> At present I have top loaded this 35 ft. vertical with four
> 25ft. long wires. They run down at a 45 degree angle. I'd appreciate any
> suggestions that would help improve the efficiency of this antenna system,
> keeping in mind the 35ft. height limitation.
>
> John,
>
If you connect around the top hat wires together before the insulator
(wire to wire to wire) you should be able to bring the base impedeance
up a few more ohms by creating a bigger hat in the process. (Maybe even
double the present value of the very low base impedence.) Also you may
want to shorten the top hat wires to 20 or 18 feet as with a 45 down
slope there could be more cancelation without giving you any additional
top loading. Here modeling or by cut and measure is the only way to be
sure. Also you can squeeze out some more efficiency with a properly
constructed ground screen under the vertical. Every little bit of
improvement should help in your case.
Herb Schoenbohm, KV4FZ
>
>
>
_______________________________________________
Topband mailing list
Topband@contesting.com
http://lists.contesting.com/mailman/listinfo/topband
|