[TenTec] Orion and TL922 linear switching using the Orion

[Paul Gallier]

Dave:
I think you need to look at the published work by Rich Measures, AG6K.  See his web page at
http://www.somis.org/QSK922.html

I implemented his QSK circuit and other mods in my SB-220 and it works fine.  He sells a kit for fast QSK switching.  It uses a vacuum relay for RF output and a reed relay for input RF switching, including an electronic switch for bias control. He states that switching time is about 2 ms.  He discusses the TL922 as well. I did have to add another transistor stage to take the "AMP out" signal from the Orion to trigger the switching circuit.  It works beautifully.

Paul,
WQ1C