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[TenTec] 238 tuner on 160? (long)

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Subject: [TenTec] 238 tuner on 160? (long)
From: pagel@wi-net.com (Lara & Mike Pagel)
Date: Sun, 18 Jan 1998 17:04:30 -0600
Hello all:

I'm looking for a tuner, one that will enable me to cover more of 160
meters with my dipole and CTSVR antennas.  I have been thinking about
pouncing on one of the #238 tuners that pop up here from time to time.

While waiting, I dug up the review of tuners in the March '97 QST.  No
TenTec there, but coverage on 160 seemed to be a problem for most of the
commercial products reviewed, unless you were willing to spend a grand or
so.  Frankly, I was hoping to spend much less.

I then reviewed the archive for the TOPBAND reflector and read messages
associated with that same QST tuner review.  There seemed to be a strong
anti-MFJ sentiment, but significant disagreement about what was better. 
Someone favorably mentioned the #238, and that message was answered by
another ham who offered an unfavorable analysis - mostly about the

Here is a portion of his message about the #238:
I don't like:
* the anemic range (capacitor) switch--a conventional ceramic wafer easily
destroyed by a hotswitch at moderate power.
* the roller inductor--the coil form is ceramic, and the coil has a
variable pitch, but the end plates are epoxy/glass PC board, and the roller
tap wheel is skimpy. I wore mine out (the tap wheel literally wobbled on
the shaft) and replaced it with a roller inductor and counter mechanism
from a BC375E.
* the sliderule dial mechanism--I repaired it countless times until I just
threw it away, and it was not readable without the dial lights--nor was the
* the SWR/power meter--very inaccurate and nonlinear. Good for relative
indication only.
* the case--typical TenTec. Frequent disassembly lunched the end trim
pieces--I threw them away. Coax connectors were pop-riveted, but worked
loose over time, creating intermittent ground connections. Replaced all
rivets with screws, starwashers and nuts.
* the balun, a 4:1 unit. Most baluns in single-ended tuners---if not
all--are useless unless operated near the design center. This one smoked
early on, and I tore it out. If you want to use balanced line, build a
balanced-line tuner.

General construction reminds one of a homebrew project--useable but
cheaply-made couplings, shafts. knobs and other components. In short: good
electrical concepts, mediocre execution. This unit has helped dissuade me
from buying other TenTec gear.

My question is - are these comments valid?  

Are any of you running the #238 on 160?  What are your experiences?  I'm
running only 100 watts but have managed to work 31 countries from the RF
sinkhole that is the upper midwest, and a good tuner might help me work a
few more.  Someday I might even buy an amp!

I'm told that Ameritron builds a good tuner, but the skimpy literature I
find seems to imply that it lacks a roller inductor and I'm assuming that
I'd prefer the roller type to the tapped variety.  Dentron, according to
local legend, also built a good tuner but no one I've spoken to actually
owned one.


73, de Mike, K9UW
Amherst, WI

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