[TenTec] Amp Hot Switching Prevention

[Gary Hoffman]

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