[App_rpt-users] Controlling radio with a knob

Steve kb9mwr at yahoo.com
Tue Feb 2 22:19:29 EST 2016

That depends on a number of things.  Unless you are planning on just emulating pulses for the microphone up down buttons.

If the radio supports some sort of remote tuning (CAT / CIV etc) then it can be addressed digitally though that port.

There is an excellent open source (Ham Radio Control Libraries) called hamlib that supports a number of radios that have native remote tuning support.

As for the remote knob, you'd likely want a digital(coded) rotary switch.  

Know that you know what the knob is called you can research how it translates its position to a digitally coded word that could easily be read in to GPIO/etc.  On the other end you'd need to take that word and convert it back to a properly formatted CIV/CAT command, or series of microphone up down puleses. etc.

Another possibility that is not as well documented for radio that don't support native CIV/CAT tuning is to look into how the Swedish Remote Rig intercepts and emulates TTL signaling on radios that have remote mounting.  I have always admired the somewhat pricey thing and have been meaning to try and serial sniff my own radio to possibly create my own.

The ARRL has an okay book sort of on this topic called "Remote Operating for Amateur Radio"  While its not real technical, you'd lkely pick up a few things from it.  I

Hopefully this  gives you a good starting place for things to further read up on.  Good luck.  I do believe this is an area of the hobby that needs more attention (with restrictive antenna ordinances for many), so please consider sharing anything you discover.

Steve, KB9MWR

> Is there any way to use GPIO to tell a radio with a turning knob which
> channel to switch to?
> Want to use a Kenwood TK-805D for a remote base (this is a 16 channel
> radio), but the problem is that I don't have a way to simulate a knob spin.
> Does anybody know how these knobs work, and without a mechanical servo how
> to tell the radio to switch channels?
> 73
> Skyler KD0WHB

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