Theoretically, a TH3 boom can be matched on 40M
with somewhat less bandwidth than a 24 ft boom tribander.
The further out on the boom, the higher the resistive component
of the feed impedance. An OMEGA match can be used to raise
the resistive component when tapped below the 50 ohm point,
probably with less bandwidth.
It may be worth while using the full boom length to maximize
the resistive component. Two matches could be installed,
one to each end, for 30 and 40M, using separate feedlines
or relay switching to one feedline. NEVER connect separate
radios to the separate feedlines (unless you enjoy replacing
front end components in receivers).
de Tom N4KG
On Wed, 23 Dec 1998 16:27:42 -0800 Tom Osborne <w7why@harborside.com>
writes:
>
>Hi all
>Has anyone ever used a TH-3 for a rotary dipole on 30 meters? If
>so, how long should the gamma match be? I think it would be too
>short for 40 meters. Thanks and Happy Holidays.
>Tom W7WHY
>
>--
>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
>
>
___________________________________________________________________
You don't need to buy Internet access to use free Internet e-mail.
Get completely free e-mail from Juno at http://www.juno.com/getjuno.html
or call Juno at (800) 654-JUNO [654-5866]
--
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
|