[TenTec] Amp Hot Switching Prevention

[Walt Amos]

Foot switch for the amp!

Walt K8CV Royal Oak, MI.


----- Original Message ----- 
From: "Gary Hoffman" <ghoffman at spacetech.com>
To: "Discussion of Ten-Tec Equipment" <tentec at contesting.com>
Sent: Monday, March 22, 2010 8:36 PM
Subject: [TenTec] Amp Hot Switching Prevention


> Hi All,
>
> I'm having a new (to me) problem with one of my rig/amp combinations.
>
> I've begun using my Corsair II with my SB-200 amp in some digital modes -
> mostly RTTY of course.
>
> These rigs were not meant for digital service nor computer control of
> course.
>
> What I have is a rigblaster, and I use a serial port from the computer to
> both send the digitaal data and the PTT signal to
> the Corsair through the Mic Jack - in the well known manner.
>
> The Corsair switches the amp into transmit through its key line.
>
> Unfortunately the rigblaster sends data and PTT to the corsair together, 
> at
> the same instant.
>
> Thus when the amp relay is being switched - the corsair is already
> outputting RF.  Hot switching the amp in that fashion
> allows 1 kw of power to see momentarily an open circuit, as the amp relay
> has not yet reliably closed the contacts to the antenna.
> This does a LOT of damage !!!
>
> I'm sure others have run into this.
>
> What are people doing ?  Some other external control box I don't know 
> about
> ?  Somehow delaying the production of tones in the
> rig control software ( I'm using N1MM) ?
>
> I'd appreciate any useful ideas.
>
> 73 de Gary, AA2IZ
>
>
>
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