Hi Reid -
Mosley owners are some of our best customers for the W2DU current baluns
for beams that we have made for years, in spite of the maker's insistance
that a random coil of coax is all that is needed. They have also violated
customary standards for bend radius in their advice, although I have
heard that they've changed some instruction points recently.
We've advocated that the current balun is the best, simplest, and most
cost effective solution where a problem exists due to the unbalanced to
balanced mismatch. The problem, however, is feedline radiation, and in
most cases it is no problem where RFI is not manifested in nearby
electronic devices.
The old saw that involves a diagram around a balanced feed point showing
a big half wave on one side and a small one on the other is simply ad
hype. When a balun is added, the only detectable improvement is likely to
be the RFI removal from the phones, TV, stereo, etc. - certainly not your
signal report from Tokyo.
A balun in this application is more of a peacemaker than an absolute
performance necessity.
The tight helix of touching but not overlapping coax is a great, and
inexpensive, test as to whether you need a balun in a given situation,
but it is sure an awkward and heavy eyesore to leave up there forever
when a low profile device will do the job if proven necessary!
73,
Press Jones, N8UG, The Wireman, Inc., Landrum, SC, 29356
Sales (800)727-WIRE(9473) or orders@thewireman.com
Tech help (864)895-4195 or n8ug@thewireman.com
www.thewireman.com and the WIRELINE bargain page
Our 21st year!
On Wed, 22 Jul 1998 08:04:59 -0500 "MAERTZ, ALLISON R" <amaertz@oppd.com>
writes:
>
>Hi:
>
>I am planning to reinstall a TA-33 which has been stored since 1975.
>The instructions (1970 dated) indicate to attach the coax directly to
>the driven element.
>
>My questions: should a 1:1 balun be used at the beam or is that not
>recommended? What alternatives should one consider in making the coax
>connection?
>
>73,
>Reid--W0FVR
>
>
>--
>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
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
|