There is a web site "RFDUDE.com". There is a free, easy to use Smith Chart
Program there.
Changing the length of the transmission line merely moves the complex impedance
around the VSWR circle. Start with a complex impedance of say, 30 -j20. Then
insert a piece of transmission line. You can change the length of the
transmission line by using the up and down arrows on your keyboard. The
impedance does change but it is still on the VSWR circle and is not normalized
to 50 ohms.
I think someone mentioned this when this question first surfaced.
Handy little program.
Mike NY9Y
> From: w7ry@centurytel.net
> To: kb8nty@wowway.com; amps@contesting.com
> Date: Sat, 10 Jan 2015 17:06:26 -0800
> Subject: Re: [Amps] Alpha Input SWR
>
> I have found that I use a 6' cable between SB220s and rigs for best SWR.
>
> I also tune the input coils using this length and advise my customers to do
> the same when they use their amps.
>
> 73
> Jim W7RY
>
>
> -----Original Message-----
> From: KB8NTY
> Sent: Saturday, January 10, 2015 1:01 PM
> To: amps@contesting.com
> Subject: Re: [Amps] Alpha Input SWR
>
> My Amp Supply LK-500ZB GG. amp manual also states to use a 6' length coax
> between your exciter's RF output and the LK-500ZB RF input connector.
> Possibly the feeder length does factor in!
>
> -73-
> Ross KB8NTY
> http://www.rossradio.net/
> https://groups.yahoo.com/neo/groups/groundradial/conversations/messages
>
>
> ***************************************************************
>
> "Collins Radio recommends a 20.5 ft. coax between exciter and linear amp.
> .Perhaps this would work with the Alpha.
> 73, Jim - w5ifp@gvtc.com"
>
>
>
> -----
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