[Elecraft] Requirements for keying a KXPA100

[Lyle Johnson]

John,

The diode drop is likely the primary culprit.  If you must use a series 
diode, use a Shottky diode (like a 1N5711) and not a silicon diode (like 
a 1N4148).

The key input goes to a microprocessor digital I/O pin inside the 
KXPA100, and a diode drop - especially with a significant series 
resistance -- puts the detected voltage in the indeterminate region.

73,

Lyle KK7P

> So, I got my KXPA100 kit and have assembled it. But I'm having trouble 
> keying it with my transceiver ...There is a 560 ohm resistor in series 
> internally, along with  diodes...