How do I add a buddy box connector to old JR tx?

[jaeder]

Hello all-
First post here so I hope this is not an old topic..

Is it possible to add a buddy box jack to an old AM jr transmitter, namely one of the old circus 4 types, sorta similar to the max AM..?

My old tx is too cheap to be worthwhile to narrowband, so life as a sim controller would be a nice retirement for it.

thanks,
clint

[jeffs555]

It is usually possible to find the PPM signal that feeds the modulator, but you may have to add a buffer to it in order to drive anything external. If you don't have schematics for it, you would probably need a scope to identify the proper signal.

[jaeder]

thanks for the reply, I was mainly worried that since the signal I need on the tip of the jr style buddy cord is called 'PPM', which I understand to mean Pulse Position Modulation, which is a FM type of thing, would not exist on an am tx..
But now I think the rf modulator section is actually doing the frequency shifting based on the so called PPM signal which is probably the same thing on an fm and am transmitter.. now to get a mic input adaptor for my ibook...