On 2008-02-26, RST Engineering wrote:
Excuse me, sir, but most of us who design moderate power solid state
transmitters wouldn't THINK of a circuit that didn't have full VSWR
protection, either by overdesign of the output devices or a VSWR loop to
shut the finals down in the event of a situation that you describe.

You or I wouldn't do that. I've fried more than one solid state radio's
finals doing that, however, including one (a Kenwood TR-7800) that used a
module that supposedly had all that built in. (In 35 years as a ham, I've
made all of the classic mistakes, and a few not so classic.)

Bendix King and Garmin probably do the right thing. Would you bet
significant money that Narco or ARC did?

And, given a random length of coax between the transmitter and the open
circuit, all you can guarantee is that you will be on the outer ring of the
Smith chart somewhere between an open and a short ... a pure open is a very
low probability.

That one I'll give you, as long as the attenuator is placed down the
feedline instead of at the back of the radio.
--
Jay Maynard, K5ZC http://www.conmicro.com
http://jmaynard.livejournal.com http://www.tronguy.net
http://www.hercules-390.org (Yes, that's me!)
Buy Hercules stuff at http://www.cafepress.com/hercules-390