Hi Carl,
Well I was speaking about two different antennas in that post:
- 1. the original trap vertical (don't recall who started this thread)
- 2. my own vertical dipole
Not sure which case you were referring to.
For the original trap vertical, I believe you could use a balun, probably a
4:1 to raise the impedance closer to that of the feedline. Whether you
place one at the matchbox or not depends on what kind of matchbox you have.
With a symmetrical matchbox then you needn't bother.
Somebody from this group told me long ago that he was doing just what you
propose. It might have been K4TAX. I've thought about this solution too,
but never tried it so I won't speculate on how well that would work. Sounds
like a good idea when you have long runs to the antenna.
As for my own vertical dipole, well it is a non-resonant doublet so I just
connect openwire directly to the feedpoint. I usually use a symmetrical
matchbox in the shack, so I don't use any balun at all.
73
Rick
-----Original Message-----
From: tentec-bounces@contesting.com [mailto:tentec-bounces@contesting.com]
On Behalf Of Carl Moreschi
Sent: Friday, January 27, 2012 1:59 PM
To: Discussion of Ten-Tec Equipment
Subject: Re: [TenTec] Re. [Ten Tec] --- and balanced fed verticals
What's wrong with another Balun at the vertical. There would then be
two baluns - one at each end of the open wire line.
Carl Moreschi N4PY
121 Little Bell Dr.
Hays, NC 28635
www.n4py.com
On 1/27/2012 12:19 AM, Rick - DJ0IP / NJ0IP wrote:
> I agree Jim, but are you implying that you cannot use openwire to feed an
> unbalanced antenna?
> What about the original Zepp?
> It was 100% unbalanced. One of the two lines was left open at the antenna
> end.
>
> The whole point (IMO) of using openwire these days is to reduce loss.
> Otherwise we would just use coax.
>
> Another Example: Vertical dipole, non-resonant, base about 5 ft. off the
> ground, center-fed with openwire.
> This is an antenna I've used for some 20 years.
> OBVIOUSLY, it is not 100% balanced because one side is so much closer to
the
> ground.
> Running this antenna on 80m from Oklahoma, I was easily working any
> continent in the world.
> I'm not sure I would have had those results using coax.
> (the dipole was only 9m per side).
>
> In my opinon, openwire is an excellent feedline to use, even when the
> antenna is not perfectly balanced.
>
> 73
> Rick, DJ0IP
>
>
>
>
> -----Original Message-----
> From: tentec-bounces@contesting.com [mailto:tentec-bounces@contesting.com]
> On Behalf Of Jim Brown
> Sent: Thursday, January 26, 2012 11:09 PM
> To: tentec@contesting.com
> Subject: Re: [TenTec] Re. [Ten Tec] --- and balanced fed verticals
>
> On 1/26/2012 12:36 PM, Stuart Rohre wrote:
>> I agree with you, but the original post defined a possibly balanced or
>> near balanced vertical system, a quarter wave antenna with at least two
>> radials. (This was the classic RCA design by Brown et al, when the
>> ground plane antenna as it came to be called was invented.) (Later the
>> marketing department wanted and added more radials
>> "to look more symmetrical".)
>
> But this antenna is NOT balanced -- the radials have a MUCH MUCH LOWER
> impedance to earth than the vertical element. It is a GOOD antenna, but
> it is NOT a BALANCED antenna.
>
> 73, Jim Brown K9YC
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