HERB KEATON N2GEW
Thanks very much for the thought and confirming you had some experience on a hum issue.
I just replaced a 14’ Ethernet cable with a 10’ Cat 6a 550 MHz Shielded (SSTP/SFTP) Gigabit Patch Cable. Confirmed by audio and the radio spectrum display, the feedback hum level is reduced by 70% I estimate. It is not gone and now remains to be seen whether it is below detectable level over the air.
I will consider trying the WiFi as you have suggested.
73 / N2GEW / Herb