Marcel,
You need to take the Titan 425 out of the line and just use the FT-1000MP
connected to the Ten Meter antenna and with the AutoTuner turned off.
Then, what is the SWR on 10 meters with only the FT-1000MP without using the
internal autotuner??
If it is less than 3 : 1 you can turn on the internal autotuner and see if
it takes care of the mismatch.
If the SWR is greater than 2:1 without the autotuner, then you are going to
need an external tuner after the Titan
amplifier.
When you use the Autotuner going into the Titan 425 amplifier, all you are
doing is attempting to match to the input circuit of the Titan, however, the
high SWR that existed previously is still going to be between the amplifier
and the antenna. The autotuner does not take care of this problem.
Therefore, you have only two options:
1. Fix the antenna and feedline so that the SWR is less than 2:1 without any
internal or external tuners.
2. Use an external Antenna Tuner such as the Ten Tec 238 after the Titan
425. This will definitely take care of your SWR problem between the amp and
the antenna, however, as I said, if the SWR is already greater than 2:1
on the 10 meter antenna everywhere, then something else has happened on your
antenna or feedine or balun.
So, even is you can use an external tuner for matching normal SWR values of
3:1 or less, you should further investigate your antenna and feedline and
determine is it is resonant any where in the 10 meter band, or do you have
an intermittent condition that causes the SWR to be high once in a while,
such as under a higher power load.
I have seen certain antenna / feedline installations, that under higher
power, something breaks down and the SWR
will jump up when high power is applied, which is a further indication of a
balun problem or a connector or feedline problem.
So, there is a lot of checking out to do, and you need to know that an
external antenna tuner is being used to match
a normal antenna VSWR range of 3:1 or less and not be used to match to a
VSWR that is being caused by an antenna, balun, feedline, or connector
problem.
I have an FT-1000D that I use the internal autotuner when not using the
amplifier. When I use the amplifier, I kick in my NYE Viking MB-VA Tuner and
I use it for my Force 12 C31XR on 10, 15, and 20, and I also use the tuner
for both my 40 meter and 80 meter full size delta loops. So, it makes a very
nice addition to the station, so that the amplifier is always seeing a 1:1
VSWR match.
So again, without the amplifier, I use the internal autotuner on the
FT-1000D, and with the amplifier, I turn of the autotuner and use the
external tuner between the amplifier and the antenna. This is the best
option.
And fininally, on areas of the band where the VSWR is less than 1.5 to 1, I
don't have to use either tuner, however, you will see a little bit of
reflected power on the amplifier.
Hope this helps.
Thanks,
Jim Dunbar
K4PV
----- Original Message -----
From: "Marcel Jorba" <ea3in@yahoo.com>
To: <tentec@contesting.com>
Sent: Sunday, October 12, 2003 2:58 AM
Subject: [TenTec] High SWR on 28 Mhz in Titan 425
> Hi!
>
> I ask for your help again!
>
> My Titan is showing very high SWR to my FT-1000mp so
> it doesn't drives it most of the time. Time to time
> the internal tuner tunes it and I put abt 1KW out, but
> nothing most of the time.
>
> I tried with an FT-990 and the SWR is there also on
> 10.
>
> Any help?
>
> Regards
>
> Marcel
>
>
>
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