[NLRS] Kenwood TR-751A external keying

[Bruce Richardson]

I used my 751 for years pulling out the ptt line from that little accessory jack.  I had
one little plug and I wired shielded phono patch cord into it.  Then I ran that to the ptt
jack on my 160w bricks.  And similarly, when I use a transverter, it works too.  But that
little plug is fragile and no longer available from Kenwood.  Just sticking wire in there
doesn't cut it for rough roving.  Oh, if you use multiple transverters, you end up having
to build a little switch box to switch the ptt line from xverter to xverter.  But the
ultimate mod of the 751 (and I had help with this) is to inject 8v DC on to the coax as it
leaves the 751 and have each of your xverters have a FET that grounds or changes state (I
forget) when the rig is keyed.  With help, I've had all three of my 751's and all of my
xverters modified.  Oh, not my 10g xverter.....yet.  What's cool about DC on the coax to
do the keying is that when you use a coax switch to switch the IF rig to various xverters,
the keyline goes with it.  Saves one or more cables.

Bruce Richardson - W9FZ

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