Sean Breheny wrote:
> Hi Nate,
> 
> I think I get what you are saying, but reducing power will not change
> the SWR (since it is a ratio). I think in reality that there is some
> threshold for reflected power that the transmitter has and above that
> level it will cut down on the output power to get the reflected power
> below that level.
> 
> One thing which that article seems (in a quick skim) to fail to
> address is that reflected power can damage a transmitter. This
> aggressive power reduction MAY be necessary to protect the transmitter
> output stage. It isn't intended to protect the stuff outside of the
> transmitter (antenna, feedline, etc.) and so it would not be "better"
> if the transmitter did not cut back. That being said, it could be that
> some transmitters are too aggressive in doing so.
> 
> Sean

He does mention it as the reason the transmitters have that behavior, 
and that ALL modern transistor-final PA transmitters are very aggressive 
at protecting themselves.

Often an antenna system that worked "just fine" at a 3:1 SWR on an old 
tube rig will fold-back power on a modern rig to the point where the guy 
on the other end can no longer copy you.

The fold-back circuit can cause a much higher power "loss" overall in 
your transmitted signal than having a non-resonant antenna system.  Many 
newer hams do not understand this.

His point in the article, is that you can do the math (something 
Amateurs do less and less these days... "plug and play" radio operation, 
so to speak) and prove your overall system's performance.  And the 
numbers might surprise you if you take the rig's protection circuitry 
into account.  (Something that people also rarely do.)

And then if you're like me, you go MEASURE it to see if it matches 
theory, or find the reason why not.  And personally, I prefer resonant 
antennas, but if I have to work a band that just won't work with my 
antennas, I use a tuner and "make the radio happy".

Nate
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