vhf/uhf radio changes channels...by itself

[VE3QJ]

I have an Icon IC-208H radio connected to an Alinco DM-330MV power supply and a homebrew j-pole.
While monitoring memory channels, the rig will change channels although nobody is touching the mic.
The radio is not on scan mode and there is no priority channel set.
Replies are anticipated 

Thank you

[G8HQP]

Unlikely to be an antenna problem, even with a J-pole!

Maybe try posting in a more appropriate forum? (VHF/UHF perhaps?)

[WB6BYU]

Might be an intermittent connection in the microphone plug.
I have both the IC207 and the IC207, and occasionally have
to push the plug in all the way to make sure it is properly
seated.  An intermittent in one of the control wires could be
interpreted as a button press.