[TenTec] AUX Keying OminiVI Plus

[Paul Christensen]

> Or if you don't want even the tiny click of a reed relay (someone has
> claimed it is not true QSK if you can hear a relay click) you could use
> an optocoupler.

If the relay is fast enough, it is capable of real QSK.  The reed switching 
response time of all Ten Tec's I've ever used can safely be put into the 
"real QSK" classification.

>LED in optocoupler only needs a few mA, not enough to
> bother that transistor, and no inductive kickback. Maybe even faster
> than a tiny reed relay.

The opto-coupler must still interface into another RF switching device.  I 
don't know of any opto-couplers capable of cleanly switching RF, let alone 
switching at the100 watt level.

> Typically a lot faster than a reed relay, microseconds instead of
> milliseconds.

Both reed and vacuum relay types can be shock-mounted to provide nearly 
silent operation.  PIN diodes can switch +2KW and these devices are about as 
fast as QSK gets.  However, without an external tuning network, PIN diode 
switching designs for high-power amplifiers are safety limited to about a 
2:1 VSWR.

Given the repeated failures in that particular Omni VI, there's something 
going on that's external to the radio.

Paul, W9AC