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Subject: C-31XR 15-Meter SWR Measurements
Author: Jan Fisher <jan.fisher@virgin.net>
Date: 15-May-2000 12:07:52
I have had the same problem. In windy conditions my Alpha 87A trips out due
to high SWR on 15m. Not a problem when using amps without high SWR sensing.

Used to get the same thing with the C3S but cured it with extra spacers.

Think I will add another couple of spacers near the ends of the elements on
the C31XR

73 Jan
G0IVZ
-----Original Message-----
From: Hank Phillips <aa4hp@titustek.com>
To: Force12Talk@qth.com <Force12Talk@qth.com>
Date: 15 May 2000 17:38
Subject: [Force 12 Talk] C-31XR 15-Meter SWR Measurements


>I guess from the questions coming back, this isn't a very common
>problem. But I'll try to answer given the instrumentation limits (i.e. no
>anemometer).
>
>When the wind is perfectly calm, I measure 1.4:1 on the Nye Viking meter in
>the shack on 21.300. At wind speeds under 20 MPH (my best guess), the SWR
>varies from 1.2:1 to 2.2:1 with a period of 2 to 3 seconds which
>corresponds directly with the observed element motion and spacing variation
>of the driven elements (15/20 meter elements). On really windy days, it's
>worse in direct proportion to the wind speed.
>
>Because of the horrendous lightning in Florida, I don't play with antennas
>much in the rain.
>
>The antenna is essentially flat at 21.150 , rising to about 3:1 at 21.450
>and 1.3:1 at 21.000. We made no attempt to trim elements at install time,
>just played with the parallel wire feed lines and hairpin coil to minimize
>SWR on 15 and 20. Other bands are not affected by wind.
>
>Tnx es 73,
>
>Hank
>AA4HP
>
>
>
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This Thread
  Date   Author  
15-May-2000 JBaumgarte@aol.com
15-May-2000 Phil Howlett
15-May-2000 Hank Phillips
* 15-May-2000 Jan Fisher
15-May-2000 Hank Phillips
This Author (May-2000)
  Subject   Date  
* C-31XR 15-Meter SWR Measurements 15-May-2000