[Raleigh]

Well, folks, I finally got a chance to take the customer's radio and newly restored turntable to his house. The radio still had the same hum, so I took one of my radios, a Philco 40-150, into the same room, and it hummed, too.

Previously, we had turned off the fluorescent light, his laptop, and two printers. He didn't want to close down his wireless router and cable modem, but once we knew the Philco had the same interference, I persuaded him to try it. That did it. His radio sounded great.

When he hooked everything back again, as soon as he connected the short Ethernet cable between the modem and router, the hum started. Unplug that cable, even with everything else plugged in and running, and the hum goes away. So I guess it's up to him whether he wants to pursue some shielding solution, move the network equipment or the radio to another room, or just live with it.

Thanks again for all your help. I'm glad this project is off my workbench!

[Ron Ramirez]

Have him try some shielded CAT 5 or CAT 6 Ethernet cable between modem and router. No guarantees...just a thought.

[morzh]

Or/And put a lossy ferrite bead right where the cable plugs into the either router or the modem (see which location has the effect). The cable can be wrapped around the ferrite several time to maximize the effect.

https://www.ebay.com/itm/20pcs-Ferrite-C...Sw-0xYcBtm

Like above.
The large ones could allow a full turn around the ferrite.

[Paul Philco322]

Glad you figured it out. There are 2 kinds of shielded ethernet wire I understand one is a braid type of insulation, the other is a foil wound type, Mouser has them, I may be wrong but it may be Alpha Brand?

Good luck.

Paul