My first thought is one should be using a 1:1 balun which would be a current
balun and not a 4:1 voltage balun. The described antenna would likely have
a feed point Z of about 75 ohms, based on length and height. Feeding with a
non resonant feed line the impedance would appear similar at the
transmitter/tuner end.
Based on your description the impedance seen by the tuner is some 18 ohms.
Fact is known, a tuner a very low Z load presents higher tuner loss. I also
suggest a common mode choke between the tuner and the balun.
73
Bob, K4TAX
----- Original Message -----
From: "Don Jones" <ko7i@comcast.net>
To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
Sent: Saturday, September 13, 2014 9:12 AM
Subject: Re: [TenTec] Zepp?
I am using a 34 ft doublet / zepp for 20M and above. I feed it with 100ft
of #16 420 ladder line that can be purchased from radio works. I am using a
4:1 DX Engineering 10kW-pk rated balun.
The antenna is 34 ft high and works pretty good. I am happy with my
shortened zepp.
One strange misbehavior I have found that my MFJ 929 auto tuner lockup if
placed near the 4:1 balun (i.e. using a 2 ft jumper of RG213). requiring
power to be cycled to regain its brain.
With a 12 ft length of RG213 (about a 1/4 wave long @ 20M) between the
remotely mounted tuner and balun, it works fine up to 28.3MHz. I have not
grounded the case of the balun yet, going to try that next.
The auto tuner is installed inside a spare 50 cal ammo can I had kicking
around to protect it from the elements. Come to think of it, a EMI gasket
vendor dropped off some rubberized EMI Gaskets at my lab, I think I will
install some of that stuff and see if that solves my problem.
73, Don KO7i
On 9/10/2014 8:59 AM, Joel Hallas wrote:
That's what I mean by "at the bottom," at the bottom of the feed line
rather
than at the top where the antenna is. The SWR is not improved, but the
loss
is reduced.
Regards, Joel Hallas, W1ZR
Westport, CT
-----Original Message-----
From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of Paul
Gates
via TenTec
Sent: Wednesday, September 10, 2014 11:29 AM
To: Discussion of Ten-Tec Equipment
Subject: Re: [TenTec] Zepp?
I do not know what you mean by putting Balun at bottom? I place my balun
between the openline and the tuner. 130 ft attenna then the SWR is 1:1 on
all bands.
Paul Gates KW4BD
On Wednesday, September 10, 2014 10:46 AM, Joel Hallas
<jrhallas@optonline.net> wrote:
Gents,
This is an interesting antenna idea, and I did a quick EZNEC/TLW look
on the
5 major HF bands. Unfortunately, the SWR ranges from a low of 5:1 (80
and 10
meters) to 11:1 on 40. 100 feet of RG-213 will have a loss of more than
2 dB on all bands, except about 1 dB on 80.
An alternative, and what I am using here, is to feed the 130 foot cf
antenna with lower loss window line and a balun at the bottom, with a
short length of coax to a tuner. Window line is lighter (less sag),
cheaper and has less loss than coax.
The same discussion about names could take place in the window line
realm <g>!
Regards, Joel Hallas, W1ZR
Westport, CT
-----Original Message-----
From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of John F.
Sent: Wednesday, September 10, 2014 10:16 AM
To: tentec@contesting.com; Jim Allen
Subject: [TenTec] Zepp?
Jim,
I like the sound of Zepp better than dipole. Actually it's probably a
matter of semantics, and I'm not going to argue how many angels will
fit on the head of a pin! ;>) There is a reason I called it a zepp,
and I think it was in the 95 or 98 Handbook. Terms many have changed by
now.
I actually think it's a dipole only on 80 meters, and technically a
doublet on the other bands! Ooops, I did it!
73,
John, K4AVX
Yes the balun, I think is a 9 to one. It will load and put out a
signal on all bands except 160 meters. Trying to work out an inverted
L again on that band - tricky.
Message: 3
Date: Tue, 9 Sep 2014 15:46:59 -0500
From: Jim Allen<jim.allen@longhornband.net>
To: Discussion of Ten-Tec Equipment<tentec@contesting.com>
Subject: Re: [TenTec] Eagle Tuner
Message-ID:
<CAO5v6iLk96Oi-DVfpCPLpO35MphtsfoFD7K4MUvGOP9wPokQEw@mail.gmail.com>
Content-Type: text/plain; charset=UTF-8
What makes a 130' center fed dipole a Zepp?
73 de W6OGC Jim Allen
On Tue, Sep 9, 2014 at 3:44 PM, Rick - DJ0IP / NJ0IP<Rick@dj0ip.de>
wrote:
That is an excellent setup, John. Nice choice.
I'm a friend of that antenna too and have used it most of the time
for the past 50 years.
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