[TenTec] Temporarily disabling Argonaut V transmitter

[Dmitriy Mayorov <dmitrym@dimview.org>]

Hello,

I'm trying to find a way to temporarily turn off Argonaut V  
transmitter while keeping the keyer on.  I'd like to practice sending  
CW using its built-in keyer and don't want to transmit garbage.
I can turn the power all the way down, connect a dummy load instead  
of an antenna, and hope that nobody hears me, or even open up the  
radio and add a switch somewhere, but hopefully there is a better  
way.  Couldn't find it in the manual, though, and Ten-Tec support did  
not answer either.
I saw the same question being asked before, e.g. http:// 
groups.yahoo.com/group/Ten-Tec516/message/2066, but not the answer.
Thanks!