Illegal cable connections and air traffic control

The local Crimestoppers organization recently ran an announcement about illegal cable hookups. In it, they said the illegal hookups can interfere with signals to/from airplanes from/to ground control. How, exactly, does this happen? Is it a function of improperly shielded cable, or something else?


And the problem with small furry animals
in corners is that, just occasionally,
one of them’s a mongoose.
Terry Pratchett, Witches Abroad

Sounds like propaganda to me. Aircraft VHF radios transmit on the order of several watts which would be magnitudes more than what would escape from poor cable shielding. In addition, if true, you could have the same problems with a sloppy yet legal hookup.

WAG Alert

Perhaps some of the illegal descramblers are dirty enough to jam aircraft communications but I would think that they would trash your TV reception as well making them useless and unused.

Oblio

I think those planes must be flying too low!


We live in an age that reads to much to be wise, and thinks too much to be beautiful–Oscar Wilde

We have some people who know cable who read this board; maybe one of them can weigh in with an informed opinion.

The only reasonably possible way I can think of for cable TV to interfere with flight communications would be if the aircraft were parked in your living room with the windows open and you had the TV on REALLY LOUD.

Turns out that it’s not completely without foundation.

Over at the FCC Website, I found that they pay a lot of attention to this issue.

Their Fact Sheet on Cable Signal Leakage talks about it generally, and the Cable Service Bureau Aeronautical Frequency Notifications talks about it in depth.

The discussions I found were about the cable company’s duty to prevent interference, but I can certainly see that pirating equipment (especially that with a signal booster) would cause a similar problem.

All that said, it still sounds like bunk to me. Seems like the same kind of thinking that bans cellphone use on aircraft during takeoff and landing. I say that if 6/10 Watt can kill the airplane, they should ground it. Perhaps an engineer can take a look at the power limits in the last link and opine.

Livin’ on Tums, Vitamin E and Rogaine

Good links manhattan,

I’m wondering if when the cable company inspects the distribution routes for leaks they only sniff where there are subscribers. It sounds like the real problem would be large amounts of illegal and hence unmonitored users (possibly) leaking. Each individual user probably would not cause a problem, but if the ‘plant’ contains many thousands of users and a certain percentage leak without detection I could see where interference may develop.

Oblio

I’ve occasionally got aircraft flight talk on one local TV station. That however was broadcast television and the wrong direction, flight interfering with broadcast. But if the flight channel is interfering with my broadcast reception it seems that at some point the opposite may be true.

I put away my linesman tools long ago, but here’s what I remember:

CLI (Cummulative Leakage Index) is a huge concern for Cable companies. The FCC and the FAA can and do punish systems with too much leakage. Not just fines, but also by taking away the cable industry’s bread and butter; Band width.

Several times a year the FCC (or maybe the FAA. I don’t remember) flys over each cable system and measures the CLI. If it’s over a certain level the Cable Company is in deep s**t. We would hear about companies losing the use of 25% or 50% of their channels because of a flunked survey.

The company I worked for always had at least one person driving out the system each day with a “sniffer”. We would broadcast an obnoxious tone on a certain frequency over the lines. The sniffers would pick up the tone if there was significant leakage.

I pulled this duty several times and about 75% of leaks were caused by half assed attempts to steal cable service. The other 25% was caused by our own installers who at $7.00 an hour could hardly be expected to actually tighten all their connections. (Note: installers are at the very bottom of the Cable TV heirarchy, although they do most of the work.)

As a maintainace technician I was encouraged to freighten the new installers with stories of planes falling from the skys because some lazy installer forgot to tighten a fitting!