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ojava

join:2002-07-11
Boston, MA

Signal Leak Notification

I searched in this forum for something on this and couldnt find it, if I missed it and its already here, I apologize. That being said, I got a notice on my door from Comcast telling me they will be shutting off my HSI/Cable in 5 days unless they can get in to my house to fix my "signal leakage" Allegedly my signal leakage can cause "interference with aircraft guidance systems and other government communications" Has anyone one else gotten one of these on their door and know what the deal is? Or is some guy just trying to get in to my house to steal my TV?



Neophyte101
All Your E-Mail Are Belong To Us

join:2002-01-02
Deep River, CT

Interference with aircraft guidance systems??? Whoever stuck that on your door is pulling your leg. A signal leak would only affect CABLE... it wouldn't defy the laws of physics and travel through the air to a plane 30,000 feet up and cause it to crash. If you're still worried about your HSI/Cable getting shut off, I'd call Comcast and ask them if they've ever heard of such a thing (but they'll probably give you the same response I just did).
[text was edited by author 2003-08-13 06:17:36]



Epikos
Surpass the Usual or Ordinary
Premium
join:2003-07-27
Hillsboro, OR
reply to ojava

Is the notice on any kind of letter head?
I would call comcast customer support with the date that you got the notice and have them look up your account. see if this is for real.

I've never heard of such a thing and my first thought is that big_d needs to do some serious flag raising.
Any signal inside your house isn't nearly strong enough to
a: transmit 40,000 feet above your house
b: cause problems with radar tracking or anything.
The frequency that you're modem uses is something like 650mhz. cordless phones transmit higher frequencys then that.

And the FCC and FAA assign different things different frequencies JUST FOR THIS REASON so someone using their microwave oven cant crash a 747 flying over their house.

I highly doubt the FAA would use equipment that was that easly messed up.

And again, the signal coming out of that coax isn't powerful enough to transmit 40,000 feet above your house.

But joe cat burglar wouldn't know a HSI drop if the cable wraped its self around the guys package. So all of my thoughts could be wrong... It could be legit.
All I'm sayin is it sounds really fishy.
--
I refuse to have a battle of wits with an unarmed person!



callihn4

join:2002-01-10
Space
reply to ojava

Do you live around a base?

If so it is probably legit.



ojava

join:2002-07-11
Boston, MA
reply to ojava

They left one of those things that hang on your door knob. It looks legit, has the comcast logo, number, etc. I just called Comcast and they said I do in fact have signal leakage, but the brilliant CS person could not explain what or how my leakage is doing anything to government or aircraft airwaves. I have a feeling the "leakage" has to do with the fact that I hitched cable up to all TV's in my house. Whatever, they're coming Saturday. If any other Massachusetts people, or anyone else knows the deal, or got this dorr knob hanging thing, please post


Kip patterson
Premium
join:2000-10-23
Columbus, OH

1 recommendation

reply to ojava

Cable TV uses frequencies that are also used over the air for various purposes, including aircraft communications and navigation. The FCC has mandatory standards for the amount of leakage, or radiation, permitted from a cable system, and the cable operators are required to scan their plant periodically looking for excessive radiation.

They really will shut you down. They are interested in your wiring because of radiation. They could care less about the additional outlets you have installed, as it is your right to do so. You just can't do sloppy work.

Yes, a cable system can interfere with aircraft navigation.

If you want to know details, search the FCC site.


RFtoLitetoRF

join:2002-08-11
Mechanicsville, VA

1 recommendation

reply to ojava

»www.fcc.gov/mb/engineering/part76.pdf

Rule 76.611, on page 627, and 76.617, page 631 tells all... It's a serious issue
--
A job worth doing is worth doing right!



fruhead

join:2002-01-29
Mosquito,NJ
reply to ojava

Kip speaks truth.

Many of the frequencies are 'shared', since they're supposed to be isolated from each other (via shielded cable wiring). The frequency of Ch. 14 (old ch. A, in an HRC system) is right in line with airline navigation frequencies. Ordinarily this wouldn't create a problem coming from a single household. Multiply this by dozens, hundreds, thousands of homes in a large city which 'leak' these frequencies (either with bad fittings, open ports, unshielded wiring, multiple amps, etc) and you get a dangerous, potentially disastrous situation. I'm sure you wouldn't want your wiring to contribute to a passenger airline accident...

The FCC puts these leakage guidelines in place for a very good reason. Here in NJ we have lots of small local airports, and the triple-threat of Newark, Kennedy and LaGuardia, so our skies are crowded all the time. We take signal leakage VERY seriously here, and will shut down a customer's feed after a number of attempts to gain access. We won't shut someone down arbitrarily or without notice, but we also need to be within FCC regs.

And, let's face it...we live here, too. We want it safe for our families, friends and neighbors.

Give them a chance to fix your problem - you may also find that it speeds up your connection and/or cleans up your TV reception.

Peace,
Tim from Jersey



Big_D
Premium
join:2003-06-02
Augusta, GA
reply to Epikos

said by Epikos:
I've never heard of such a thing and my first thought is that big_d needs to do some serious flag raising.
LOL, sorry no flag on this one. As others have said, its legitimate.
--
You want the truth? You can't handle the truth!


coffaro
Moonie
Premium
join:2003-07-05
Arlington, TX
kudos:3

Its real. If they say you have a signal leak then they do need to fix it. If you are leaking out that means other signals are getting in. The signals that get in raise the noise floor. When that happens you start having slower speeds and bad ping times. If its bad enought it will lock up the router card and take everyone down.......


Shopper1492

join:2003-04-06
USA
reply to ojava

OJAVA,

The others that have posted here are correct that this is legit. The Comcast pearson will come to your house and will check for leakage inside your home. If you did a poor wiring job they will disconnect your cables that are causing it or charge you to fix it. Don't think that after they leave they will not check back. So don't just reattach the faulty wiring after they leave.



Neophyte101
All Your E-Mail Are Belong To Us

join:2002-01-02
Deep River, CT
reply to Kip patterson

quote:
They really will shut you down. They are interested in your wiring because of radiation.
Radiation? It's not a nuclear reactor pal, it's a cable line. I guess this whole thing is true but I still don't see how it can be... let's say that, theoretically, he is "leaking signals" into the thin air from his cable line. Like somebody else mentioned before me, cable signals are typically only 650 MHz - 1 GHz. If you have a portable phone in your home, it leaks a higher frequency than your cable line (e.g., 900 MHz, 2.4 GHz, 5 GHz)! The FCC is also supposed to define the different spectrums of the market so something like this couldn't happen. Oh well... looks like the original poster will get a free truck roll to improve his picture quality and possibly HSI connection!


Jeff_B
Premium
join:2000-09-24
Brick, NJ

He means RF radiation of course. Cable tv uses a very wide spectrum of frequencies that go well below 650mhz. It is supposed to be a "closed system" and that is why they are allowed to use such a wide range.


Kip patterson
Premium
join:2000-10-23
Columbus, OH
reply to Neophyte101

Radiation is the correct term. Electromagnetic radiation if you prefer.

I am not your "pal".

Cable signals run the gamet from 5 Mhz to 860 Mhz, which includes the band used for VHF and UHF aircraft communications, VHF aircraft navigation, several amateur radio bands, all VHF and UHF mobile radio for public safety and private use, broadcast television, etc.

The FCC prevents problems from happening by regulating the amount of spurious emissions permitted for each of these services, not by separating the bands. There is not enough bandwidth available for that.


Daemon
Premium
join:2003-06-29
Berkeley, CA
Reviews:
·Comcast
·webpass.net
reply to ojava

aircraft use ground based radio installations to guide them to runways and airports.

It's not as though the leaking radiation is going to go up into the sky and overwhelm the radar on the plane, rather it will muddle the clarity of the ground based beacons.

Not that one single household could put enough radiation out to guide a jet into the house (unless the wiring was mistakenly wired to create a signal amp), but imagine that there were no FCC guidelines and all houses were leaking signals. Imagine what a headache it would be.
--
-Ryan
the louder you yell, the less they hear


DBLClick

join:2002-06-07
Manassas, VA
reply to ojava

Gee,

Cable used to use the term "Signal Leak Notification" for stolen cable signal.


ClearToLand

join:2002-12-20
South Plainfield, NJ
Reviews:
·Comcast
·Verizon FiOS
reply to Kip patterson

  • How do they measure the leakage?
  • How close to your house do they need to be?
  • Would "cheap" coax (with a loosely woven braid) cause this?
  • If I stuck a bare 3' long piece of solid copper wire into a cable outlet and extended horizontally, are you saying that it would radiate upwards to 40,000' and affect the aircraft passing over my house?
  • How many watts/milliwatts/microwatts of power could we be talking about here?
TIA...
--
The reasonable man adapts himself to the world; the unreasonable one persists in trying to adapt the world to himself. Therefore all progress depends on the unreasonable man. --George Bernard Shaw (1856 - 1950)


mbernste
Boosted
Premium,MVM
join:2001-06-30
Piscataway, NJ
reply to fruhead

said by fruhead:

Many of the frequencies are 'shared', since they're supposed to be isolated from each other (via shielded cable wiring). The frequency of Ch. 14 (old ch. A, in an HRC system) is right in line with airline navigation frequencies.
Hmm...I wonder if that's the reason why HBO comes in so clear as I make final approach into Newark.
--
Tell Comcast to keep or get TechTV: »home.comcast.net/~mbernste/ttv.html

UPDATED: Watch Comcast Executives Get Grilled: »home.comcast.net/~mbernste/catv_hearing.html


Big_D
Premium
join:2003-06-02
Augusta, GA
reply to ClearToLand

said by ClearToLand:
  • How do they measure the leakage?
Usually with a device called a "field strength meter".
quote:
  • Would "cheap" coax (with a loosely woven braid) cause this?
  • It could, especially if it has bad/loose/worn connectors. Remember the only thing keeping your coax from being a gigantic antenna is the shielding around the copper.
    quote:
  • If I stuck a bare 3' long piece of solid copper wire into a cable outlet and extended horizontally, are you saying that it would radiate upwards to 40,000' and affect the aircraft passing over my house?
  • No, comcast never said anything about affecting aircraft 40,000 feet in the air. It affects the ground systems. Also if you have an airport close enough, then you know that the aircraft on takeoff/landing will be only a few hundred feet overhead
    --
    You want the truth? You can't handle the truth!


    oliphant5
    Got Identity?
    Premium
    join:2003-05-24
    Corona, CA

    Also the FCC doesn't care about having to be near an airport. They will fine the cable company no matter where they are.

    There can be significant leakage in the 110-140MHz range that aircraft use regularly.


    Shopper1492

    join:2003-04-06
    USA
    reply to ojava

    Cable companies have to run a leakage test yearly for the FCC. They hire a company and they actually fly over the system. The have an antenna attached to their plane and a signal generator broadcasting a signal out of the headend.

    The plane will make passes over the whole system and track where the leaks are coming from. They then coralate the leaks to the city map. The cable company will then go through these areas and try to find where the leak is being generated from.

    Again the reason for this is because the cable system gets to use the entire frequency spectrum. But because they run a "closed system" in other words no signals are suppose to leak out and cause interferance the FCC allows them to use all frequencies. But for the right to use all frequencies they have to test for signal leakage and file a report yearly on their findings.

    One leak will not cause a problem but if you have hundreds of them they all add up. Think about how many connections you have in your house alone now times that by a million.

    So that is why they are doing this.



    imrf
    Premium
    join:2002-06-06
    Utica, MI
    reply to Big_D

    said by Big_D:
    said by ClearToLand:
    • How do they measure the leakage?
    Usually with a device called a "field strength meter".
    Actually they use leakage meters, like this one . »data.normann.buy-now.at/Acterna/···1750.pdf


    Big_D
    Premium
    join:2003-06-02
    Augusta, GA

    ah, I shoulda known. I used to use a field strength meter to check for leaks on the coax feeding my ham antenna.
    --
    You want the truth? You can't handle the truth!



    fruhead

    join:2002-01-29
    Mosquito,NJ
    reply to ClearToLand

    said by ClearToLand:
    • If I stuck a bare 3' long piece of solid copper wire into a cable outlet and extended horizontally, are you saying that it would radiate upwards to 40,000' and affect the aircraft passing over my house?

    No, your line probably would not affect navigation. It's you along with the other couple of thousand homes with small amount of leakage that add up.

    The FCC refers to 'Cumulative Leakage Index' (CLI) to pinpoint hotspots of signal leakage, with the key word 'Cumulative'. There's a certain level of leakage which can't be removed, and the FCC isn't looking for zero leakage (can't happen). The amount of leakage just needs to be below a preordained level.

    Peace,
    Tim from Jersey


    Neophyte101
    All Your E-Mail Are Belong To Us

    join:2002-01-02
    Deep River, CT

    reply to Kip patterson

    Useless flame deleted....
    [text was edited by moderator]



    DrVidiBoomBa
    No Respect
    Premium
    join:2000-02-17
    Bellevue, WA
    reply to ojava

    Just let them in your house. If your stealing then your caught, if your not then it's a good thing that they fix it because that means your probably not getting the best signal anyways... geez people it's not rocket science.

    Stop beating it into the ground.



    Nerdtalker
    Working Hard, Or Hardly Working?
    Premium,MVM
    join:2003-02-18
    Tucson, AZ
    reply to ojava

    I have to disagree with all of this, cellphones are known to cause detectable ammounts of interferance with planes and yet nobody has problems with the towers surrounding the airport and on final approach? Much less the towers in and around the pattern. Anyways if (and it is if) this is a problem I think it's comcast's responsibility as the cable company to fix the problem.


    Kip patterson
    Premium
    join:2000-10-23
    Columbus, OH

    All towers are restricted in height around airports. For a major airport, the tower has to be no taller than one foot for each 100 feet of separation from any point on any runway. To go higher, you need FAA (and FCC) approval.

    Cell phones fortunately do not transmit on bands near any aircraft frequencies. I saw last week where one airline has relaxed some of the restrictions on cell phone use.

    Your point is important - every source of interference can make problems. Wait until the real battle starts over power line networking.



    Nerdtalker
    Working Hard, Or Hardly Working?
    Premium,MVM
    join:2003-02-18
    Tucson, AZ

    Now that I can se as a problem with big power lines and such, but generally those are placed away from the airport for obvious reasons.



    odog
    Cable Centric Vendor Biased
    Premium,VIP
    join:2001-08-05
    Atlanta, GA
    kudos:14
    Reviews:
    ·Comcast

    reply to Neophyte101

    don't speak of what you don't know

    said by Neophyte101:
    Interference with aircraft guidance systems??? Whoever stuck that on your door is pulling your leg. A signal leak would only affect CABLE... it wouldn't defy the laws of physics and travel through the air to a plane 30,000 feet up and cause it to crash. If you're still worried about your HSI/Cable getting shut off, I'd call Comcast and ask them if they've ever heard of such a thing (but they'll probably give you the same response I just did).
    [text was edited by author 2003-08-13 06:17:36]

    may day may day.... "today on days of our lives" que cheesey music

    a big cable leak can wreak havok on the aerial frequencies. the bigger problem and probably why they actually tagged you house is ingress. as simply as your signal gets out unwanted signal gets in. this causes large problems for cable modems, and most likely what provoked their visit.
    --
    disclaimer: my opinions are my own, my employer is not responsible.

    [text was edited by author 2003-08-14 19:36:34]