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Sun, 11 Aug 2013 12:32:11 -0700 |
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If my TW-1's were accurate to within 5%, I wouldn't mind, but the one that
is in my HF circuit now is off by about 60%. Once I realized how inaccurate
they are, I stopped relying on it for anything other than the tone function.
I agree that it is good for tuning an amp, because you are just tuning for
max pitch. Max pitch = max smoke.
I am troubled by comments I have read on this reflector about 6 to 1 or 4 to
1 SWR being totally acceptable. They are not. Solid state equipment with
fold way back on a SWR of 2 to 1. It must be understood that a high SWR
generates heat, and heat destroys coax. If a station running a kilowatt had
an SWR of 2 to 1, you risk burning up the coax. Also, just because you use
a tuner to reduce the SWR as far as the rig is concerned, the transmission
line is still with the original high SWR. That is, a tuner does nothing to
lighten the load of the coax. Transmitting into an SWR of 4 to 1 means that
very little of the power is ever finding its way to the antenna.
Personally, I have my PM2 configured to open the amp key line if it sees an
SWR of 1.5 to 1. Fortunately I use a SteppIr antenna which automatically
maintains an SWR of approximately 1.1 to 1. I just performed a quick test
on 20 meters. I measured 1486 watts forward, with 1 watt reflected power.
Since the SteppIr controller follows the frequency of the rig, the antenna
is always in resonance.
73
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