Charly,
Changing the length of coax to the input will not change the SWR. Look at a
Smith Chart. Only dealing with the tube's capacitance along with the 50 ohm
resistor to ground with a suitable matching network will lower the input
SWR. I wish Alpha and whoever is the designer of amps now would match the
input to every band but they don't. It's not that much more money to do it
right.
I am going to sell this 8410 because of that reason. What a piece of junk.
73 HNY to all.... Hardy N7RT
----- Original Message -----
From: "Charles Henry" <k4vud@hotmail.com>
To: <ed@w0yk.com>; <amps@contesting.com>
Sent: Friday, January 09, 2015 3:15 PM
Subject: Re: [Amps] Alpha Input SWR
All I have been able to do is to cut and try the length of the drive coax
from the radio RF output to the amplifier input.
Sri forgot the lengths and never got 1:1 anyway. Charly
From: ed@w0yk.com
To: amps@contesting.com
Date: Fri, 9 Jan 2015 08:44:18 -0800
Subject: [Amps] Alpha Input SWR
What experience can anyone share for reducing the input SWR on Alpha
amps?
On some bands the input SWR is 1.6:1 or higher on our 86A, 87A and 91B
amps.
Thanks,
Ed W0YK
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