Pete,
In general, today's transceivers will reduce the output power function of
the detected level of the SWR. Thus, the more SWR you have, the less drive
from the transceiver is available.
As all other form of energy, SWR must go somewhere ... As it is not allowed
to reach the transmitter output it will dissipate in the antenna tuner
components as heat. If there is enough heat it might melt some components
like my roller inductor in the MFJ -989C :)
Manufacturers of Antenna Tuners are specifying them for certain power levels
... 100W to more than 4KW. However, this is valid in a perfect resistive
load, where there is no reactance. Once some reactance is added, like a real
life antenna will do, the tuner specifications must be derated.
Interestingly enough, I still have to find an antenna tuner manufacturer
that will specify the power input derating curves in function of SWR.
I believe that the MP 1000 series transceivers have an tuning output setting
that you can
program to 10W or less. At these levels I believe that you are safe with
your investment :)
The internal tuner has a very limited range in the 80 -160m band. I will
suggest to
use an external tuner and disable the internal one.
Hope this helped
Happy Holydays from
Alex, N2NNU
----- Original Message -----
From: "Pete Smith" <n4zr@contesting.com>
To: <towertalk@contesting.com>
Sent: Sunday, December 09, 2001 3:58 PM
Subject: [TowerTalk] High SWR and Modern Transceivers
>
> Does it do any harm to run a modern transceiver (such as an FT-1000 Mk 5)
> into a high-enough SWR that the protective circuitry is folding back the
> output power? I was unable to get the internal tuner to reduce the SWR
> during the 160 contest (it worked fine just now) and accordingly ran as
> little as 60 watts high in the band.
>
> 73, Pete N4ZR
> www.qsl.net/n4zr
>
>
>
>
>
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List Sponsored by AN Wireless: AN Wireless handles Rohn tower systems,
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supporting towers up to 100 feet for under $1500!! http://www.anwireless.com
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