Sarma,
Thank you for the suggestions. My problem has been solved with the exchange of the nano (now on headers as I have room).
I have also used screened cable to the encoder and had to decouple the push button at the nano due to rfi on Tx sometimes triggering the menu.
I might also decouple the encoder.
What maximum values capacitors can you use for decoupling?
Regards,
John (VK2ETA)