I am thinking of building up one of these balanced tuners and am wondering
if tapped inductors would suffice??
----- Original Message -----
From: "Ken Klinedinst" <kbk@conknet.com>
To: <tentec@contesting.com>
Sent: Tuesday, July 15, 2003 4:36 AM
Subject: [TenTec] More Info Balanced Tuners
> More info about the Measures balanced tuner I built.
>
> The Richard Measures 1990 article was followed for component values, the
> choke / balun and layout.
>
> 1. PVC pipe
> White, black has carbon, conductive. I pre-wound the coax to get the
> correct pipe length, which ended up at about 12" on an outside diameter
> of +/- 3 ?"
>
> 2. Coax
> RG8X with solid dielectric. Obtained from Radio Works (no commercial
> endorsement) The coax with foam may collapse. I started with 40' and
> most was used as the winding. I had one PL259 connected by the coax
> supplier.
>
> 3. For simplicity and individual adjustment of the rollers I eliminated
> the motors, belts and gears. The reason I wanted individual roller
> adjustment, my 234' dipole runs through trees which have leaves in the
> summer and in the winter we have ice and heavy snow here in NH. My
> concern was, I would have a antenna which at times could become
> unbalanced and I wanted to be able to compensate for this condition.
>
> 4. I used the tuner on a wooden board for several months before
> enclosing it in a wooden (Wine) box. I am sure the box, because of it's
> original use, gives the rig more power. Once in the box, I installed
> counter dials for ease of band changing.
>
> 5. The Measures design shows the capacitor being used either on the
> roller input or output, depending which configuration gives the lowest
> SWR. With my dipole 160-10 and my 20 meter 8JK, the tuner provides the
> best match with the capacitor on the roller output.
>
> 6. I have temporally installed RF ammeters in each side of the feedline.
> They read 1.75 RF amps, with key down, 800 watts DC input, on 40 meters.
> I have not measured the other bands because the meters have not been
> permanently installed. Frankly, I don't have a clue if 1.75 RF amps
> means anything, but I think it just another way to ensure a balanced
output.
>
> 7. QST April 2002, Pg 47 has another balanced tuner article, Feb 1990
> was Measures article with pictures. The author of the April article, has
> chose not to use the recommended capacitor value and the rollers he had
> purchased for some other tuner project and I don't find where he stated
> what their values they are. Point here is try to use the values which
> Measures uses. I don't have the tech background most of you have so I
> did not want to fiddle and diddle. There is an excellent picture of his
> layout on page 50. I followed this layout, except I placed the choke,
> perpendicular, in back of the rollers. I experimented with the choke
> location and this was were it fit best for my enclosure. There was no
> electrical effect if it was along side or in the rear of the rollers. I
> even considered locating it at a remote location from the tuner.
>
> 8. I used Johnson Cat. No. 229-020-001 18uh rollers these have the
> tapered output turns.
>
>
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