900 MHz interference with television.

I have a customer who has called in stating his Internet service is causing interference on his television. Specifically his local, off air channels. Has anyone experienced this? His connection is via 900 MHz connectorized SM. It is mounted on an antenna mast in his back yard, which his tv antenna is also located on. He specifically mentioned a channel with its digital transmission on VHF 13 which should be 210 - 216 MHz.

I have not yet gone out to his site to investigate this but wanted to see if there is any merit to this or not.

We saw a similar issue with a 5.7GHz install. Turned out that the outdoor-rated ethernet cable (unshielded) we tie-wrapped to the TV antenna cable (also unshielded) caused the issue. Once we separated the cables by 1-2 feet, the TV reception issues (snow and lines) went away. We were trying to minimize the number of cables running down the side of the house. In the future, we’d probably used shielded outdoor cable for these situations.

we saw this once also…we mounted the sm on the opposite side of the house. problem went away.

Thanks guys! I’m headed out there with my shielded cable and I’ll try dropping the antenna a little bit down the mast for some seperation as well. It is outdoor rated, unshielded. I’ll move it off the mast if that doesn’t take care of the problem.

Ran into this more than a few times before the digital switch. Easiest solution was always just to drop the link speed on the SM from 100Mbps to 10Mbps. The cause is RF bleed between the cables.

I Installed a 900sm by adish network dish (behind it) for some reason it would only run at 10mb even the the cables dont even run near one another, I assumed a flaky surge protector or a bad crimp (I am using shieled outdoor, unshielded indoor) is it possible this is related?

Could be but I have my doubts. We’ve run next to (even cable tied to) existing DirecTV/Dish cabling and never had any issues.

I do know that the 300SS surge suppressors sometimes have issues with 100Mbps ethernet, so it could be something to do with that. Other than that, I’ve seen it with cable runs that are near or just beyond the “maximum” distance limit of 100m.

IMO, there’s no reason to run your 900MHz SMs at 100Mbps. The radio will never be capable of handling more than, we’ll say 5Mbps (being very generous) anyway. We run all of our SMs at this ethernet speed because the way we have our DL% set on our APs none of them would ever exceed 10Mbps in one direction.

Problem resolved. It was neither the wire shielding, wire location, or the link speed in this situtation. I tried these first. Next, I dropped the antenna 10 feet below the customers TV antenna. It still digitized their local digital channels beyond recognition. I then moved the SM to the house about 20 feet away from the mast but, now only about 5 feet lower than the elevation of the TV antenna and the problem was resovled. Seems that vertical spacing didn’t help. The TV antenna was a Terk TV55, which is powered, has 10dB of gain and operates from 54 to 806 MHz.