I wonder if you guys could give us a description of your antenna and feed
line? Once I burned up a torroid coil in a TS-940's tuner trying to load
an 80m dipole on 160m. The tuner was seeing a very low impedance thus the
current through the little coil was quite high. With a big tuner, you
would not notice the heat but those little torroids will get blazing hot,
change value and the swr will creep up as you transmit.
Maybe next time it starts acting up, remove the lid and check for hot
parts. If you find this to be true, try adding a quarter wave length of
feedline and see what happens.
I would like to see some efficiency measurements on those little tuners.
Reading the review of various tuners in the new QST, you can see some of
the large tuners have 20% or more loss and that loss translates to heat.
I'll bet those little autotuners have losses twice as high and 50 watts
of heat on a coil wound with 20ga wire will surely get hot!
73 N4LQ Steve
-----Original Message-----
From: "Lee Groce" <n4aad@yadtel.net>
To: <tentec@contesting.com>
To: <tentec@contesting.com>
Date: Wed, 8 Jan 2003 00:59:08 -0500
Subject: Re: [TenTec] Jupiter/LDG AT-11MP Tuner
>
> ----- Original Message -----
> From: <WmLB@attbi.com>
> To: <tentec@contesting.com>
> Sent: Tuesday, January 07, 2003 23:35
> Subject: [TenTec] Jupiter/LDG AT-11MP Tuner
>
> Hi Bill,
> I bought a Jupiter with the internal antenna tuner in early April
> 2002.
> It has acted strange at times too. TT told me as long as swr did not
> exceed 2:1 I would be ok.
>
> Last Saturday, a friend dropped by and I showed him my Jupiter.
> I had the power at about 40 per cent and noticed as he played with
> the key swr was nearing 2:1 on 40 Meter CW. After he left, I played
> around and could not get swr below 2:1 on any band.
> Two days ago I was on 40 Meters and the internal tuner tuned from
> 1.0:1 to 1.6:1 on all bands just fine. Now I am confused! This is not
> the first time this has happened either.
> For those who may think it's in my antenna; when my internal auto
> antenna tuner would not tune below an swr of 2:1 and higher, my manual
> antenna tuner tuned to 1.2:1 as soon as I put it in line.
>
> I want to talk to the folks at TT and see if they will take out my
> internal
> antenna tuner and replace it with the external LDG AT-11MP Tuner
> thinking it may work better.
>
> Has anyone else experienced similar problems with the Jupiter/AT ?
> After reading what Bill has to say, I am at a loss of what to do.
>
> 73,
> Lee N4AAD
>
>
> > I bought the subject tuner Saturday for use with my Jupiter.
> >
> > It has been acting a bit "squirrely" I guess. It tunes for a good SWR
> on
> > low power but that SWR seems to increase as output is increased. In
> most
> > cases I can touch up the SWR (under higher power) using one or both
> of
> the
> > Cap and Ind. Up/ Down switches. These increase or decrease those two
> > elements in incremental amounts (fine tuning I guess you would call
> it.)
> >
> > I called LDG today and was left with two thoughts:
> >
> > 1. I should not try to reduce the SWR at power levels any greater
> then 25
> > watts or so.
> >
> > 2. He mentioned that there has been some reported "problems"
> > (un-specified) with the tuner working properly with Ten-Tec rigs.
> Part
> of
> > it apparently related to the fact that the TT rigs do not "fold
> -back"
> at
> > higher SWRs.
> >
> > I am sort of inclined to return this tuner, but thought I would ask
> here
> > and see if there is any "real world" knowledge on the compatibility
> (or
> > lack thereof) between these two pieces of equipment. I know Ten-Tec
> was
> > marketed a internal version of the AT-11 in kit form for use in the
> > Jupiter. I guess that made me assume that the external version would
> also
> > insure a large degree of compatibility.
> >
> > Any comments would be appreciated.. I subscribe to the digest so, if
> you
> > have timely comments that you think are significant in helping me
> decide
> > what to do.. please email me direct.
> >
> > Thanks..
> >
> > Bill, W6WLB
> >
> >
> > _______________________________________________
> > TenTec mailing list
> > TenTec@contesting.com
> > http://lists.contesting.com/mailman/listinfo/tentec
> >
>
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