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Eliminating PoE interference (lemmy.radio)

submitted 2 weeks ago by early_riser@lemmy.radio to c/amateur_radio@lemmy.radio

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I have an Ethernet cable running PoE+ to a wifi access point outside my shack that is very close to my radios. It exhibits the typical QRM pattern, with birdies at regular intervals making a warbling sound when the rig is on SSB.

I've eliminated this problem before using chokes, but this cable is thicker (meant for outdoor use) and much closer, it runs along the same cable runway as my antenna feedlines.

I'm pretty sure the cable isn't shielded. I just bought the cheapest thing I could find on Amazon. I wouldn't trust it if it did say it was shielded. Anyway, would getting a higher category of cable help the issue? Should I try choking the cable at a different point? I did it at the switch end, not the AP end.

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[–] I_am_10_squirrels@beehaw.org 1 points 1 week ago

The cable category only informs you about the maximum frequency the cable has been designed for. Cat5e can handle 100 MHz, cat 6 handles 250 MHz, cat 7 handles 600 MHz. Higher frequency allows higher speed because you can fit more information in the signal.

Shielding is what protects the cable from interference, and protects outside devices from the cable. As someone else mentioned, not all cable is shielded. Terminating shielded cable is more difficult than terminating unshielded cable, so I recommend buying factory terminated cables when possible.

Check out cables to go as a good alternative to Amazon. Look for shielded cables with metal plugs, this provides a continuous ground between the switch and the device which should help resolve interference.