[Elecraft] Key Line protection for MFJ-1026 Noise Cancelling Unit

[pentrose]

I am trying to use an MFJ-1026 "Noise Canceling Signal Enhancer" with my KX3
serial #08668.
The MFJ unit has a T/R phone jack for protecting its circuits from RF
currents when transmitting.

Q: The voltage seems to be too high according to the Cady book.  I need to
use the Key Line to signal the MFJ unit to bypass sensitive circuits during
transmission.

Pg 150 of the Elecraft KX-Line Fred Cady book says the ring has +30 volts on
the circuit when open.  The MFJ-1026 Manual says to never put over 15v
positive to the T/R phone jack?

>From the MFJ-1026 Manual
“T/R Control: We Strongly recommend using this phono connector to switch the
MFJ-1026 to the transmit (or bypass) mode.  The MFJ-1026 switches
out-of-circuit whenever this line is pulled low (below one volt).  
Never apply negative voltages, or over 15 volts positive, to this jack.”

I have the E980232 Cable adaptor with Key Line information on the Ring.  I
think I could use the phone jack to send the low signal through the Ring. 
But when it opens up the voltage is too high?

Also, am I on the right track here?  Other ways to do this?  I am not
qualified to create my own circuits.
can I just run a phone jack from the adaptor plugged into the ACC2 port? 
Provided I can deal with the +30 volts?  I have the KXPA 100 Amplifier and
no other amplifiers.  This is all I want or need. So the antenna 1 line
would run from the KX3 into the MFJ-1026 and then to the 100 watt amplifier. 
Is this right?

Peder Kittelson W7RPK





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