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Old October 25th 03, 02:44 PM
Alan P. Biddle
 
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Default Balanced Tuner for Balanced Antennas?

Hi,

Any recommendations on a good, or bad, tuner for use with balanced
antennas? That is, one which does not use a balun? It doesn't need
to be an auto-tuner. There are a few from small suppliers, and I see
the MFJ in their latest catalog has what is touted as a modernized
Johnson Matchbox.



--
Alan
WA4SCA
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Old October 25th 03, 06:31 PM
T.E.O
 
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You'll need at least a choke type balun to get from the unbalanced tx output
condition to the balanced antenna load unless you go with a link-coupled
tuner. Link coupling removes the necessity of using a balun since there is
no "direct" connection between the unbalanced tx output & the balanced
antenna load.



"Alan P. Biddle" wrote in message
...
Hi,

Any recommendations on a good, or bad, tuner for use with balanced
antennas? That is, one which does not use a balun? It doesn't need
to be an auto-tuner. There are a few from small suppliers, and I see
the MFJ in their latest catalog has what is touted as a modernized
Johnson Matchbox.



--
Alan
WA4SCA



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Old October 25th 03, 07:29 PM
J. McLaughlin
 
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MFJ's description of their "balanced" tuner might be describing a
conventional unbalanced tuner with an effective choke. Does anyone know
what is inside? 73 Mac N8TT

--
J. Mc Laughlin - Michigan USA


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Old October 25th 03, 09:43 PM
Dan Richardson
 
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On Sat, 25 Oct 2003 13:44:12 GMT, Alan P. Biddle
wrote:

Hi,

Any recommendations on a good, or bad, tuner for use with balanced
antennas? That is, one which does not use a balun? It doesn't need
to be an auto-tuner. There are a few from small suppliers, and I see
the MFJ in their latest catalog has what is touted as a modernized
Johnson Matchbox.



You can download the manual he
http://www.mfjenterprises.com/man/pdf/MFJ-974H.pdf

Danny. K6MHE

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Old October 25th 03, 10:30 PM
Cecil Moore
 
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T.E.O wrote:
These are fairly easy to build. Basically 2 homebrew coils, a variable
capacitor & a choke balun made of coax.


FYI, this is an ASCII newsgroup - no binaries allowed.
--
73, Cecil http://www.qsl.net/w5dxp



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Old October 26th 03, 03:36 AM
Bob Miller
 
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On Sat, 25 Oct 2003 13:44:12 GMT, Alan P. Biddle
wrote:

Hi,

Any recommendations on a good, or bad, tuner for use with balanced
antennas? That is, one which does not use a balun? It doesn't need
to be an auto-tuner. There are a few from small suppliers, and I see
the MFJ in their latest catalog has what is touted as a modernized
Johnson Matchbox.


I'm having good luck using an unbalanced tuner, an mfj989c, with an
external choke balun (a few turns of coiled coax), to transition to a
dipole fed with 450 ohm line. I can tune my 44-ft. dipole on all
bands, 30 thru 10.

As far as balanced tuners go, Palstar and Bliss make real expensive
ones, in addition to the mjf model you just mentioned. Don't know of
any others currently being marketed.

Bob
k5qwg


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Old October 26th 03, 09:04 PM
J. McLaughlin
 
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A look at the published schematic for the MFJ974H (Revision 7, dated
10/24/03) shows a balanced topology fed by a "choked" piece of coax (on
the transmitter side).
One might call it a Capital I arrangement. The vertical is a step
adjustable inductance. Two ganged capacitors (four sets of plates, each
nominally 10-208 pF) are on each side of the inductor. (one gang on the
left and the other on the right) Choked transmitter comes in on the
left and antenna is connected on the right. No means for discharging
accumulated charge appears to be provided. [ I would place something
like a 470 k ohm resistor to common from each of the antenna terminals.]
It will be interesting to learn how this unit performs in the field.
73 Mac N8TT

--
J. Mc Laughlin - Michigan USA



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Old October 26th 03, 09:07 PM
Niittymaa Family
 
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Check out the following URL for lots of "candid" comments about Tuners and
other amateur radio equipment:

http://www.eham.net/reviews/?ehamsid...4beaaa31ac6ce6

VA3KAI, Al


"Alan P. Biddle" wrote in message
...
Hi,

Any recommendations on a good, or bad, tuner for use with balanced
antennas? That is, one which does not use a balun? It doesn't need
to be an auto-tuner. There are a few from small suppliers, and I see
the MFJ in their latest catalog has what is touted as a modernized
Johnson Matchbox.



--
Alan
WA4SCA



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Old October 28th 03, 09:46 PM
Michalkun
 
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Alan P. Biddle wrote in
:

Any recommendations on a good, or bad, tuner for use with balanced
antennas? That is, one which does not use a balun? It doesn't need
to be an auto-tuner. There are a few from small suppliers, and I see
the MFJ in their latest catalog has what is touted as a modernized
Johnson Matchbox.


I thought if your antenna is balanced then you don't need a tuner or balun.
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Old October 28th 03, 11:19 PM
Dan Richardson
 
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On 28 Oct 2003 21:46:17 GMT, Michalkun wrote:

I thought if your antenna is balanced then you don't need a tuner or balun.


How do you suggest to connect your transmitter's unbalance output to a
balanced antenna system?

Danny
K6MHE


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