MX-P50 & ELECRAFT KX3

Having got my IC-705 working with the MX-P50 amplifier, I thought it was time to do the same with my Elecraft KX3. In theory, there should be no problems interfacing the two, but I did of course have to sort out a connecting lead.

The MX-P50 has a rather odd connector for the PTT signal and because I intend using a few different radios with the amp, I decided to cut it off and replace it with Anderson PowerPoles for the sake of uniformity (plus I've got loads spare). With that job done, it was easy to start making up interface cables.

I already had a KX3 amp lead which was terminated with a male phono connector. At first I was going to snip off the phono and fit powerpoles, but I thought the phono connector might come in handy at some point in the future with another amp, so instead I kept it and made up a short patch lead to convert it from phono to powerpoles (as seen in the photo above).

At the other end, the KX3 lead has a 2.5mm TRS jack-plug which connects to the phono-plug thus...

TIP : not used

RING : Centre-Pin (PTT)

SLEEVE: Shield

Once the lead was made up, it was time to connect the amp and radio together and test it. I set the KX3 to a power output less than 2W and switched to DATA mode for a constant carrier.

I attached a power-meter fitted with a dummy load, set the band selector to match the radio and transmitted. With 1.5W in, the amp put out around 25W. Perfect for Foundation License holders!

The next job will be to make up similar leads for my ELAD FDM DUO, (tr)uSDX, QMX+ and others. This secondhand cheap little amp is proving to be a great investment.

Brief video showing it in action

 

73, Tom, M7MCQ.