[Heathkit] Amp Keying Interface?

[kb0nly]

Anyone know of a good design to interface the SB-200 to a modern radio, such as my FT-847?  I have been looking online and can't find much other than a few commercial products that seem to be far overpriced for what they are and I would like to build something myself.

This isn't my first tube type amp, but its the first time I'm going to interface it to a modern radio, and I know the 847's circuitry can't handle the SB-200.  

Thanks and 73,

Scott