[TowerTalk] RE :Mosley TA34XL

[Gary]

On my TA33 the tell you to put a strap from one side of the driven
element to the boom. Connect the shield of the coax there. The center of
the coax to the other side of the driven element. I tried it that way
and found a very wide swr bandwidth. It actually had two dips. One a few
hundred kc below the band and the other near the higher end of each band.

I asked Mosley about why I was seeing that and got no answer other than
"send us all the measurements". Never did get an answer.

I took the strap off and put a coax balun on. Now I get a very clean
single dip in swr and less bandwidth but about what you would expect to
see rather than the extreme that they advertise.

73
Gary  K4FMX


Dudley Chapman wrote:
 > Jim,
 >     The Mosley faq at the link you provided sheds no light on why they
 > recommend no balun.  It's as unscientific as their inability to 
explain that
 > advice over the phone.  That business about gain and f/b with the same
 > tuning may be true, but it has no bearing on the balun discussion.  I 
think
 > they just don't really understand why and when baluns are needed.
 >     On the other hand, it's not surprising that most installations of
 > tribanders from any vendor seem to work ok without a balun, since the
 > feedline comes off along the boom and down the tower in a way that 
preserves
 > symmetry with the E field of the antenna.
 >     So the real question is how unique is the Mosley design compared to
 > other tribanders that make a balun unnecessary or detrimental? I bet the
 > answer is that it is not unique in that regard.  So that puts us back 
into
 > the age old balun vs no balun for any antennas in general.  Is that 
the way
 > you see it?
 >
 > Dudley - WA1X
 >
 >
 > Jim wrote.......
 >
 > Message: 2
 > Date: Fri, 29 Apr 2005 23:19:14 EDT
 > From: Jamesnf at aol.com
 > Subject: Re: [TowerTalk] Mosley TA34XL
 > To: k3cc at fast.net, towertalk at contesting.com
 > Message-ID: <191.3e58dd3b.2fa45332 at aol.com>
 > Content-Type: text/plain; charset="US-ASCII"
 >
 > In a message dated 4/29/2005 9:54:28 PM Central Standard Time, 
k3cc at fast.net
 >
 > writes:
 > I called Mosley after I read the instructions and they said don't use a
 > Balun but couldn't give me a gud explanation
 > Try reading the material at 
http://www.mosley-electronics.com/faq.htm#baluns
 >
 > I've used a couple of the smaller Mosley tribanders over the years 
and they
 > worked fine with the insulated, split dipole driven element fed directly
 > with
 > coax.
 >
 > Jim W9TM
 >
 >
 > _______________________________________________
 >
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