[TRLog] Logikey K-3 & TR-Log

Dave Hachadorian k6ll@juno.com
Wed, 20 Feb 2002 11:03:57 +0000

On Tue, 19 Feb 2002 12:12:09 -0600 "Mike D." <hrg@cifnet.com> writes:
> Is anyone familiar with a way to key my tube rig (grid-block keyed) 
> with TR?
> I'm currently using a K-3 for fills, etc.

You can build 1/2 of a K3KU interface, leave it permanently
attached to your grid block keyed rig, and then plug the
standard TR positive keying interface to it.

You need a source of 5 or 12 vdc for the interface. The current
is low, so you can usually pick it off one of the rig
connectors. I remember I used the VFO connector of my old

It requires a high voltage (greater than the rig keying voltage)
pnp transistor, and a resistor, 2.2k for 5vdc, or 5.7k for 12vdc.
Other voltages can be used. In that case R = 500 x voltage.

Emitter goes to the tube rig key line.
Base goes to the standard TR interface.
Collector goes to the resistor.
The other end of the resistor goes to the voltage source.

I remember I just built it into a male 1/4" mono plug,
and left it permanently plugged into the 830. A little
single conductor pigtail came out of the plug and was
inserted into the 12vdc from the 830's VFO connector.
A 4" piece of shielded cable also came out of the plug,
and was connected to a female 1/4" mono in-line jack,
all of which dangled permanently from the 830. Basically,
it converted the 830 to low voltage positive keying.

Dave Hachadorian, K6LL
Yuma, AZ

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