Shielded or unshielded cable for close proximity to radio tower

[Nidstang]

Hi all

I live next to a 5kW AM radio antenna, which in the past used to cause interference on analogue TVs in the area. Also sometimes when an audio jack has been half plugged into speakers, it can start playing the radio - the cable is acting as an antenna.

I'm planning to install some cameras. The longest run will be 50m of cable around the steel perimeter fencing running in plastic conduit. My question is should I consider shielded cable?

If the radio tower did interfere with the cable in someway, would it just limit bandwidth or cause noise in the video feed or connection issues or something else? I currently have some 10m and 15m ethernet cables running through the roof for general internet use and haven't noticed any issues watching 1440p videos and streams. I'm assuming the cameras will use more bandwidth though.

I've learned from the forums that if I bought shielded cable, then one end must be grounded, which doesn't seem too tricky, but it will add to the cost.

Thanks

 

[looney2ns]

I would use shielded.
Take a look at these lessons: Cable Academy

 

[SpacemanSpiff]

I would think EMT conduit would be a great additional layer to an already shielded cable. I see discussions in other forums suggesting adding ferrite chokes to either end of the cat 5e/6 cable. Looks like there are some other RF filtering options (in lieu of ferrite choke) as well... #WAL3K - RF Eliminator™ - 4 Pair Ethernet - AM

That same website has an interesting knowledgebase page for RFI troubleshooting

 

[garycrist]

RFI and data cables. 468/fMHz/2 = 1/2 dipole antenna or 1/2 of an antenna in feet. In non-radio speak one never wants an antenna with multiple odd 1/2 wave lengths of cabling.
Shielded cabling might help if the bonded at one end. The problem with high powered A.M. stations is the Diode effect if a solid connection is not achieved.
Usually one would notice dropped packets at certain frequencies, depending on bandwidth usage. In other words everything would work at the sacrifice
of total data transferred depending on total bandwidth usage at that time.

 

[Nidstang]

Thanks for the replies and links. I'm in Australia and metal conduit is only used in commercial/industrial applications, so it is rather expensive here

@garycrist Sounds like you know a bit about radio transmissions. Not sure if it helps, but this tower is 180m (590 ft) tall and broadcasts at 720kHz, 882kHz and 1080kHz (and possibly in-between). It's actually 50kW, not 5kW as I previously said. I'll have ethernet cable runs anywhere from 10m to 60m.

I'm a complete noob when it comes to this stuff. Could there be any risk of damage to the cameras or PoE switch, or will the only effect be reduced data transfer rate as you mentioned?

So currently my plan is to use the cable below, which is foil shielded with a drain wire - which I will connect into my house earthing. I'll run the cables in PVC conduit and see how it works. If I run into issues I'll look into adding ferrite chokes or RF filter devices. Does that sound reasonable? Please offer suggestions, appreciate it!

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[DsineR]

Also don't forget to use shielded RJ45 connectors.
Using fiber is another option, immune to RF.

 

[garycrist]

You will not get enough induced voltage (signal) to damage the equipment from the nearby TXR.
Buy a length of ethernet cable (cheaper kind) and test it 1st. before determining a future problem.