Paul,
That is a good suggestion. I was just using the internal cable lengths
supplied with the upgrade. I suspect that the length supplied was more for
physical needs inside the radio, rather than any particular frequency
matching.
One more test, I plan on making, now that the PT-11 has been removed is
place a known SWR on the output of the PT-11 and measure (with the MFJ 259B)
the SWR on the input side of the PT-11. According to LDG, the PT-11 bypasses
itself when no power is applied, so all this test requires is for me to
solder some SO239's on the input and ouput leads. It will be a relatively
simple matter to use different length coax jumpers in this test.
73 and thanks for the suggestion,
Mark, N8ME
----- Original Message -----
From: "Paul Christensen" <paulc@mediaone.net>
To: "Mark Erbaugh" <mark@microenh.com>
Sent: Tuesday, January 08, 2002 17:15 PM
Subject: Re: [TenTec] Pegasus Internal Tuner
> Does the indicated SWR on the Pegasus change if the coax line length is
varied between the transceiver and PT-11?
>
> -Paul, W9AC
>
> ----- Original Message -----
> From: "Mark Erbaugh" <mark@microenh.com>
> To: "Dwayne Kincaid (LDG)" <ldg@ldgelectronics.com>;
<ditsnbits@tentec.com>; "Ken Brookner" <kenb@brookner.com>;
> <tentec@contesting.com>
> Sent: Tuesday, January 08, 2002 4:33 PM
> Subject: [TenTec] Pegasus Internal Tuner
>
>
> > I'm continuing my investigation into the problem of the Pegasus
displaying
> > high (2.0:1 or greater) SWR readings when the PT-11 tuner believes that
the
> > antenna is tuned.
> >
> > Further to my earlier posting and encouraged by some comments received
in
> > reply, I have removed the PT-11 tuner from my Pegasus and rerun my
tests.
> > The results clearly show that on 18 MHz and above, the tuner has an
adverse
> > affect on the Pegasus SWR reading. The results also tend to disprove one
of
> > the explanations about the problem - that is, that the Pegasus SWR
system is
> > not reporting proper values. From the data, the Pegasus SWR readings
track
> > very well with the SWR.
> >
> > Test description: I a manual antenna tuner to create a load of known
SWRs
> > (1.0, 1.2, 1.5, 2.0 and 3.0) at frequencies at the middle of each ham
band
> > 160m - 10m. The SWR was measured and the tuner was set using an MFJ 259B
> > antenna analyzer. I than ran the max power from the Pegasus into this
load
> > and recorded the forward and reflected power as indicated, and
calculated
> > the SWR. The Pegasus and MFJ 259B were connected on the two sides of a 2
> > position coax switch to facility switching back and forth. The tuner was
> > connected to the common position of the switch (just like using the
switch
> > to drive two different rigs, with the Pegasus being one rig and the MFJ
259B
> > the other).
> >
> > The bottom line for me is that I believe that the PT-11 introduces some
sort
> > of SWR problem into the Pegasus on 18 MHz and above. I'm not planning on
> > reinstalling the PT-11.
> >
> > comments?
> >
> > 73,
> > Mark, N8ME
> >
> >
> > (The following data will probabl look better using a fixed pitch font)
> > The columns are: frequency (MHz), SWR Reading on MFJ Analyzer, Pegasus
SWR
> > w/PT-11, Pegasus SWR w/o PT-11
> >
> > Tuner No Tuner
> > FREQ MFJ SWR Rig SWR Rig SWR
> > MHz
> > 1.900 1.0 1.0 1.2
> > 1.2 1.3 1.0
> > 1.5 1.7 1.5
> > 2.0 2.1 2.0
> > 3.0 2.8 2.6
> >
> > 3.750 1.0 1.0 1.0
> > 1.2 1.2 1.3
> > 1.5 1.6 1.7
> > 2.0 2.1 2.2
> > 3.0 2.8 2.9
> >
> > 7.150 1.0 1.2 1.2
> > 1.2 1.2 1.3
> > 1.5 1.6 1.7
> > 2.0 1.9 2.2
> > 3.0 2.7 3.1
> >
> > 10.125 1.0 1.3 1.0 Analyzer Measured SWR was 1.1 for no tuner
> > 1.2 1.6 1.0
> > 1.5 1.9 1.6
> > 2.0 2.4 2.1
> > 3.0 3.0 2.8
> >
> > 14.175 1.0 1.0 1.0
> > 1.2 1.0 1.0
> > 1.5 1.2 1.4
> > 2.0 1.7 1.9
> > 3.0 2.4 2.6
> >
> > 18.118 1.0 1.6 1.0
> > 1.2 1.0 1.0
> > 1.5 1.0 1.5
> > 2.0 1.3 1.9
> > 3.0 1.9 2.6
> >
> > 21.225 1.0 1.8 1.0
> > 1.2 1.9 1.0
> > 1.5 2.0 1.4
> > 2.0 2.4 1.9
> > 3.0 2.7 2.5
> >
> > 24.940 1.0 2.0 1.2
> > 1.2 2.2 1.2
> > 1.5 2.5 1.6
> > 2.0 2.9 2.0
> > 3.0 3.5 2.9
> >
> > 28.850 1.1 2.0 1.3
> > 1.2 2.0 1.3
> > 1.5 2.4 1.6
> > 2.0 2.8 2.2
> > 3.0 3.5 3.0
> >
> >
> > _______________________________________________
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> > TenTec@contesting.com
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>
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