[TenTec] Pegasus Erratic SWR readings

[Carl Moreschi]

The Pegasus does not have over current protection and as such has a small
exposure to an overcurrent situation blowing the finals.  And this
overcurrent situation would most likely occur with a high SWR.   I added a
feature that allows you to set a maximum SWR (say 3 to 1) that once reached,
will drop the drive to the level you define (usually 50 watts).  Because of
your excellent analysis on the pegasus SWR computation, I have now modified
my algorithm slightly.  This change will be sent to everyone as Version 2.14
on March 1.  What I am now doing is reducing drive power when the reflected
power reaches the value that would have caused the threshold SWR to be
reached if you were running 100 watts.  In other words, I am just looking at
reflected power to make this decision rather than SWR.  This completely
solves the problem you described with SWR computation.

73,

Carl Moreschi N4PY
Franklinton, NC
----- Original Message -----
From: "Mark Erbaugh" <mark at microenh.com>
To: <tentec at contesting.com>
Sent: Saturday, February 14, 2004 5:19 PM
Subject: Re: [TenTec] Pegasus Erratic SWR readings


> Carl,
>
>
> > The idea of the power reduction feature is to reduce power BEFORE the
> finals
> > blow.  Adding a delay here defeats the purpose of the feature.  I don't
> see
> > the erratic SWR with my pegasus.
>
> Most non-TT rigs are designed with hardware that will drop (fold back) the
> power output when a high SWR is sensed. However, TT has always claimed
that
> their finals can handle high SWR conditions and no fold back is required.
>
> Is your control program's fold back a indication that the Pegasus has a
> problem in this area?
>
> I realize that there is no internal overcurrent protection in the Pegasus
> (except the main fuse, and I'm betting the finals will blow to protect
that
> fuse <g>). TT recommends the use of their power supplies which do have the
> overcurrent protection. I hope those who, like me, are using larger
supplies
> (I have an Astron 35 A) are using the AirPax magnetic breakers in line.
>
> 73,
> Mark
>
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