[Elecraft] K3 and AL-811 amplifier interfacing...

[Mark Kempisty]

The AL-811 manual states that "Relay:  keys amplifier when grounded.  Sources
+12 VDC open 
circuit and supplies 100mA when grounded.  A built-in pulse canceling diode
protects the exciter. "

<SNIP>


Several years ago the question of how much voltage and current does an Ameritron put in its key line.  I measured mine which was configured for 220V (I no longer have that amp).  I came out with around 14 or more volts and at least 100 mA, maybe higher.  Looking at the schematic there was no regulation on that circuit, it came straight from the transformer.  Since mine had more juice going in, it surmised that more was coming out.

So be careful if you connect a rig with a keying line that is not as robust as a K3's.

 
Take care,
Mark
AA3K