Hello Brian:
> The stubs are not insulated from the tower. They are "decoupling" stubs
> which essentially make the tower above them electrically disappear.
> They form an antenna which is resonant the desired frequency.
>
> At 20 meters the antenna is a 3/4 antenna (tower only) naturally. The
> 40 meter "stub" essentially lengthens it to be 1/4 wave on that band.
> Note that the lower band stubs are placed progressively lower on the
> tower and make it operate as 1/4 wave or 3/4 wave on the higher freq
> bands.
I kinda suspected that was the way it worked but I needed someone to
confirm it.
Regards 20m, the distance from the base to the top of the tower is 24',
3/8th
wavelength. From the base to the top of the antenna somewhere between
3/4 and
one wavelength. Oh well, the point is it works - after a fashion.
Cheers & thanks.
Glenn
--
Glenn Wiebe...Box 1563...Beausejour...MB...Canada...R0E 0C0
Email: gswiebe@mb.sympatico.ca.....ham radio call sign: VE4GN
Packet address: ve4gn@ve4ua.#wpg.mb.ca.noam
--
FAQ on WWW: http://www.contesting.com/towertalkfaq.html
Submissions: towertalk@contesting.com
Administrative requests: towertalk-REQUEST@contesting.com
Problems: owner-towertalk@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|