[Amps] Sequencing an Alpha 87a

[Paul Christensen]

> So the question that pops into my head after that experience is...
> Has anyone put the 7800 on a scope and looked at the timing?

I believe QST's expanded product reviews cover the transmit delay time and 
transmit receive turnaround time, but an actual scope representation of the 
full sequence would be a welcome addition.  I use a modified microHam CW 
keyer and have the ability to trigger the scope from the keyer using a 
buffered output which lets me observe the transmit delay time, but I haven't 
measured the complete sequence back to receive.

The worst sequencing radio I owned was a Collins HF-380.  RF appeared before 
the complete external T/R closure and a leading edge power spike was very 
apparent even after a Collins' service bulletin was implemented.  It used 
the most thermally unstable ALC I've encountered.  You could start at say 
40W and in ten minutes, power would gradually creep up to 80W owing to 
thermal changes.  I got rid of it before it damaged my amps.

Paul, W9AC