[CQ-Contest] MFJ-434 Voice Keyer

K0HB k-zero-hb at earthlink.net
Sun Dec 25 11:54:13 EST 2005

Santa left me a new MFJ-434 voice keyer to help with contesting vocals.  

Has anyone here used that with CT or other software, and built the interface shown in the MFJ literature?

MFJ shows two resistors on each 'input' wire --- a 470-ohm at the computer end of the wire and a 1K in series with that on the circuit board at the gate of the switch transistor.  What's the point of separating these series transistors?  It requires hiding a glob of 470-ohm resistors inside the Dsub at the computer end of the cable.  Why not just put single 1.5K resistor on the circuit board?

73, de Hans, K0HB
><{{{{*> http://www.home.earthlink.net/~k0hb 

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