Wade, if your tuner spits and sputters on 15m, simply add 5 ft. more
feedline to it and it will straighten up and fly right.
On the coax loss, well unless you're using that cheap Rat Shack stuff, then
you are kind of exaggerating the amount of loss in the coax, assuming it is
connected to something like a dipole or OCFD (properly designed and
matched).
High loss comes from feeding higher SWR with coax. If your antenna's SWR is
less than 5:1 and your run of good quality coax is less than 100 ft., then
the loss is negligible. Confirm this in any ARRL Handbook in the chapter on
transmission lines, in the paragraph titled "SWR Myths".
73 - Rick, DJ0IP
(Nr. Frankfurt am Main)
-----Original Message-----
From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of Wade Staggs
Sent: Tuesday, October 20, 2015 7:48 PM
To: Discussion of Ten-Tec Equipment
Subject: Re: [TenTec] Open Wire Line - A CASE FOR OCFD
*It's just a plain old Center Fed Dipole. If I will need a Tuner anyway to
cover the Whole Band with an OCFD, we would rather just use the Window Line
(450 ohm)... And get rid of all the Coax Losses involved and also. Lose the
Common Mode Current ( RF ) that OCFD antenna's are Famous for. This is just
what I have done. That has worked just fine for me, for the past 29 years.
Just remember the issue with 15 Meters. Too much QRO and the Tuner Spits and
Sputters pretty bad on 15 Meters. *
* 73 from
Wade/KJ4WS*
On Tue, Oct 20, 2015 at 10:22 AM, Tony <va3dwi@gmail.com> wrote:
> Wade,
> Is your "antenna system" center or end fed. Just curious. 73, Tony VE3DWI.
>
>
> Sent from my BlackBerry 10 smartphone on the Bell network.
> Original Message
> From: Wade Staggs
> Sent: Tuesday, October 20, 2015 10:59
> To: Discussion of Ten-Tec Equipment
> Reply To: Discussion of Ten-Tec Equipment
> Subject: Re: [TenTec] Open Wire Line - A CASE FOR OCFD
>
> *Thank You Bob,*
> * An Antenna is a System. My Antenna System is
> 126 feet of #12 wire at 36 feet high. ( flat top ) With Window Line (
> 450 ohm ) running down to the eve of the house. We bring the feed line
> away as perpendicular as possible. The Ladder/Window Line ties
> directly to an Ugly Balun/Choke Balun which consists of 27 feet of
> RG-8 Coax wrapped around a 3 inch piece of PVC Pipe. Sixteen feet of
> the Coax wrapped around the pipe and the rest as short as we could
> make it into the Shack. With a good Tuner, we operate at Full Legal
> Limit when we Want Too. Only 15 Meters has any problems and we just
> learned not to Tax the Tuner by running QRO on 15 Meters. The Lobes
> and Nulls you speak of on 20 Meters. I find to be Gain in the favor of
> the Lobes. This has been my Antenna for over 25 years. Every year we
> put one up at Field Day with our Club. And Every year the station we
> provide is the Favored Station by the Field Day OP's. By comparison we
> beat the pants off of the various OCF and Inverted L stuff the others
> dream up. Not bragging here fellows just stating the facts. *
> * 73 from Wade/KJ4WS*
>
> On Tue, Oct 20, 2015 at 9:17 AM, Rob Atkinson <ranchorobbo@gmail.com>
> wrote:
>
> > >Perfect example. Another would be a full wave dipole. :)
> >
> > A full wave center fed dipole will be voltage fed and have a Z of
> > around 5K ohms and put a vswr on the line of around 10:1. The line
> > loss is negligible because it is a balanced line with an air
> > dielectric. I will go up against a horizontal 1/2 wave balun and
> > coax fed dipole on 40 m. with my balanced line fed horizontal 1 wave
> > center fed dipole on 40 any day of the week and I will come out
> > ahead across
> > 40 m. Both same height.
> >
> > >
> > >But more generally, I'm talking about putting up a single dipole,
> whether
> > center-fed or off-center fed, feeding it with open wire or window
> > line,
> and
> > loading it on all bands.
> > >
> >
> > Brown, you are off in your own world of open wire line hating and
> > you are free to be irrational about it to your heart's content but
> > you occasionally pop up in some on-line forum somewhere and I see
> > your dis-information. Perhaps you attempted the folly of feeding an
> > unbalanced (i.e. off center fed) dipole with balanced line as you
> > included it in your description above. Surely you understand the
> > concept of unbalanced load fed with unbalanced line and balanced
> > loads fed with balanced line. You don't feed an unbalanced load
> > directly with balanced line.
> >
> > A high dipole 1/2 wave on the lowest frequency of interest and fed
> > in the center with decent open wire line with a characteristic
> > impedance of at least 600 ohms and matched with a correctly designed
> > and constructed truly balanced link coupled matching network, will
> > run rings around any coax fed dipole, especially on 80 meters where
> > the band is 500 kc wide. You won't need a ridiculous ferrite core
> > balun at the feedpoint, sitting there adding to your losses with
> > heat reactance; you won't need a dozen dipoles to cover HF, and such
> > a system will deliver more power to the load on average on any HF
> > frequency than some hammy coax fed dipole will. If any ham wants to
> > be obsessed with feeding a balanced load with an unbalanced line he
> > is free to do so and live in denial (I work everyone I hear blah
> > blah) but professionally designed and constructed shortwave
> > broadcasting plants always use balanced antennas and feed them with
balanced line.
> > If they didn't work they wouldn't do it.
> >
> > To be objective, there is one problem with a low band dipole used on
> > the high bands, and that is the pattern you wind up with. An 80 m.
> > half wave dipole on 10 meters has many lobes going off in all
> > directions and even though the system in terms of power transfer is
> > efficient, the pattern is not reliable if the operator wants a good
> > idea of where is signal is going. For that reason, I employ a second
> > dipole, 1/2 w. on 20 meters to cover the high bands.
> >
> > 73
> >
> > Rob
> > K5UJ
> > _______________________________________________
> > TenTec mailing list
> > TenTec@contesting.com
> > http://lists.contesting.com/mailman/listinfo/tentec
> >
>
>
>
> --
> *Living one day at a time with Jesus as my Savior. But, still having
> Fun.* _______________________________________________
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--
*Living one day at a time with Jesus as my Savior. But, still having Fun.*
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