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Re: Preamp / SWR issue



----- Original Message -----
From: "Tony" <dxdx@optonline.net>
To: <amsat-bb@amsat.org>
Sent: Wednesday, June 14, 2006 6:45 AM
Subject: [amsat-bb] Preamp / SWR issue

> All:
>
> Just installed a new Mirage preamp and noticed a jump in SWR from 1:1 to
> almost 3:1
>
> I tried different lengths for the coax jumper, but the result is the same.
>
> Any ideas?
>
> 73, Tony KT2Q

Hi Tony, KT2Q

Just disconnect on top the coax cable from the antenna connector and
replace the antenna with a 50 ohm dummy load suitable for the frequency
and for the power in use than again measure the SWR

If the SWR is low than your preamplifier do not introduce mismatch
between the 50 ohm coax cable and the 50 ohm dummy load.

If your SWR meter is using a directional coupler with poor directivity
than cannot efficiently separate the forward power from the reflected
power and the SWR can be wrong even if  measured to be 1:1

73" de

i8CVS Domenico
----
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