Guys,   I want to use an FT-847 with a mast mounted SSB preamp and a single feedline antenna (Cushcraft A270-10S) that I already have mounted on my tower.   Can I send the DC for the preamp up through the coax and still use a duplexer?   I have checked the continuity of a Comet CF-4160 duplexer and the 1.3-170MHz side appears to be isolated from the 440 side.  Since there is direct continuity on the 1.3-170MHz side of the duplexer I would run the DC for the preamp up that "side."   I really don't want to blow up my 847 by doing something foolish so any thoughts, cautions etc. welcomed.   73 de harry, W6DXO