Could i split my cable modem with a TV

[aagiants]

If i get a TV and a spliter will my Cable modem still work at peak?/

Frequency 687000000 Hz Locked
Signal to Noise Ratio 37 dB
QAM 64
Network Access Control Object ON
Power Level 3 dBmV

Upstream Value
Channel ID 3
Frequency 26000000 Hz Ranged
Ranging Service ID 506
Symbol Rate 1.280 Msym/s
Power Level 29 dBmV

[crazyman]

Originally posted by aagiants
If i get a TV and a spliter will my Cable modem still work at peak?/

Frequency 687000000 Hz Locked
Signal to Noise Ratio 37 dB
QAM 64
Network Access Control Object ON
Power Level 3 dBmV

Upstream Value
Channel ID 3
Frequency 26000000 Hz Ranged
Ranging Service ID 506
Symbol Rate 1.280 Msym/s
Power Level 29 dBmV

yes it will if the signal is not border line in strength,if you have enough signal strenght and use a one gighz splitter it should work fine.you will know right away because your modem won't lock.if it locks then no prob,I use a splitter with my internal tv tuner card and it works fine.

[andrewe77]

Yes. You have great signal strength. Mine is around -13 dbmv on downstream and 48 up. I have 2 splitters in front of my modem.

[arkie]

Originally posted by aagiants
If i get a TV and a spliter will my Cable modem still work at peak?

I first had a two way splitter, feeding my modem and feeding a three way splitter for my TV's. This was hurting my big screen TV. I installed one Regal four way... feeding my modem and the other feeds to the TV's. This reduced the signal to the modem but not enough to hurt it and it increased the signal to my big screen TV. In fact I use two other splitters down stream going to other smaller TV's. I have cable going to the modem and 5 TV's... now all work great!

[legalmind]

Are you paying for it?

[glen4cindy]

The primary concern is if you are paying for it or not.

I work for AT&T @Home, which recently became Charter@Home.

In the AT&T world, if you only subscribed to internet service, then we put a special device called a trap into the drop line. It may be at the tap port, connected to a jumper that is connected to the tap port, or in a house box mounted to your house.

The trap in that we use for that purpose is a 2-78 trap, which "notches out" the entire frequency range covered by channels 2 to 78.

If one of these traps is installed in your drop connection, you will be unable to receive any signals on those channels even if you do split it off and run one leg to the television.

[arkie]

Originally posted by glen4cindy
The primary concern is if you are paying for it or not.

Where I live you don't get cable internet unless you pay for at least basic cable TV.
That takes care of cable theft.

[LanEvo IV]

how do i look for the cable strength?

[glen4cindy]

From the above posts, I am going to assume that you are asking about signal level.

It takes a special meter to determine signal level. I have one because I work for Charter@Home, but I don't think I live near enough to you that I could check it for you.

You have any friends that work in CATV or at a televison repair shop? If so, they may have the meter.

A television picture is somewhat of an indicator, but you can have a pretty negative signal level and still have a good picture. FCC requires 0 dBmv to +5 dBmv (dBmv = decibel millivolts). I've seen good pictures at -10 dBmv, and the cable modems in our system operate at up to -15 dBmv.

So, as long as the cable company is supplying you with good signal, you should be ok. What I would suggest is trying a two-way splitter with one line to your cable modem, and the other line to your tv. IF you want to hook up more than 1 tv, then a better route to go would be to use a Directional Coupler which looks similar to a splitter. You would feed the input with the cable from outside, the output to your two-way or three-way splitter that feeds your tv's, (however many you want to try to feed is the splitter value you would need). Then feed the tap feed on the DC to your cable modem. This DC will probably be a 6 value, which means that it loses nearly zero through the output to the tv's (which are more susceptible to low signals) and -6 dB to your cable modem (which probably can operate at a negative signal level).

Hope this helps!

[tweakmeister]

I was looking into putting a tv card in my computer and splitting the output from my cable modem jack. I do get basic cable service but don't have a separate tv jack in the computer room. The tech from ATT said that I wouldn't be able use the modem jack as this line had a filter on it. So is it really only a matter of signal strength. Was the tech misinformed?

[Syclone_A]

Yes it should work, cable tv and cable internet operate at different frequencies and have nothing to do with the other much like dsl and voice over phone lines. Like all the other replies just beware of signal strength and your good to go. You wil still have tv and the internet bandwidth will be unaffected.

[HalfLifer]

Frequency 687000000 Hz Locked
Signal to Noise Ratio 37 dB
QAM 64
Network Access Control Object ON
Power Level 3 dBmV <-- Keep between -15 and 15

Upstream Value
Channel ID 3
Frequency 26000000 Hz Ranged
Ranging Service ID 506
Symbol Rate 1.280 Msym/s
Power Level 29 dBmV <--Keep under 60


And you will have no problems.

[pureghetto]

I have one cable line going into my home, and it splits into 4 different routes.

Also, it should be noted that the person who installed my cable internet used a splitter. So I guess it doesn't matter at all.

[NYR 56]

Originally posted by HalfLifer
Power Level 29 dBmV <--Keep under 60

Actually, it shoudl really be:
Transmit: 35dbmV to 55dbmV
Carrier/Noise Ratio: 30dB to 36dB

Yours is on the low side...

[HalfLifer]

Im running at 58 with no problems, NYR56.

If he experiences lose of block sync, then he should worry.

[Indy]

Originally posted by HalfLifer
Im running at 58 with no problems, NYR56.

If he experiences lose of block sync, then he should worry.

58 is max for most modems with the exception of the surfboard series of modems from Motorola, which can go up to 60 dB.

However, optimally, it would be good to see the modem betwen 40 and 50 dB, just so you have a buffer zone on either end. Your power level is inversely proportional to the amount of signal coming in, so, the higher your power level, the less signal you have coming in, and vice versa.

The whole point being is that if you are above 55, you're lacking in signal strength. If you are below 30, you're signal strength is booming coming in, which isn't necessarily a good thing (overdriven levels tend to distort the signal quality)...


The biggest issue, tho, is if you have a signal to noise ratio below 30. This ratio is the separation of your carrier signal from the noise floor. The greater the separation, the "cleaner" your signal. With yours sitting at 37 dB, there's no worry needed over noise...

[NetworkTech13]

Halflifer, if your transmitting at 58dbmv then you are on the edge to going offline. I know the Toshiba modem will only transmit up to 58dbmv. Not sure bout some of the others.

[Indy]

These are the max limits on the modems that I've encountered:

58 dB max:
Toshiba
RCA
Com21
Best Data
3Com

60 dB max:
Motorola (General Instruments)

I've seen modems that operate fine at 58 dB, but only under optimal conditions (ie, no noise on the line, no in house amps, etc)...anytime that I run into a high power modem, I take whatever action is appropriate to get that modem transmit power down between 30 and 50 dB...

[LoWang]

Hello everyone. I had a question relating to signal-to-noise ratio. The lower the number, the better, correct?

I recently checked my grey cable junction boxes on the outside of my house, only to find that my cable modem had been put behind the "Multimedia Drop Amplifier" that my friend installed for me. I used a splitter to split the wire from the pole so that my cable modem had an unabstructed path to the cable headend. Then, the other cable went through the amp and to the TV's i have. Well, it turns out that there was an extra cable in there, that I have no idea what it goes to. (Unplugging it doesn't disrupt my 4 tv's or my cable modem.) I was able to remove an extra splitter this way. However, it seems like sometimes my cable internet runns crappier than before. I have all the splitters properly grounded, and all the coxial cable throught my house is brand new, and is the same exact huge thick stuff that they used to run the cable from the pole to my house. Was it a mistake to make the changes that I did in the boxes outside ?

Here's my info from my modem BEFORE the change:

Downstream Value
Frequency 579000000 Hz Locked
Signal to Noise Ratio 33 dB
QAM 64
Network Access Control Object ON
Power Level 0 dBmV The Downstream Power Level reading is a snapshot taken at the time this page was requested. Please Reload/Refresh this Page for a new reading

Upstream Value
Channel ID 1
Frequency 21488000 Hz Ranged
Ranging Service ID 1032
Symbol Rate 1.280 Msym/s
Power Level 52 dBmV


Here's my info from my modem AFTER the change:

Downstream Value
Frequency 579000000 Hz Locked
Signal to Noise Ratio 29 dB
QAM 64
Network Access Control Object ON
Power Level 0 dBmV The Downstream Power Level reading is a snapshot taken at the time this page was requested. Please Reload/Refresh this Page for a new reading

Upstream Value
Channel ID 1
Frequency 21488000 Hz Ranged
Ranging Service ID 1032
Symbol Rate 1.280 Msym/s
Power Level 51 dBmV

[MtCableman]

Originally posted by Indy



If you are below 30, you're signal strength is booming coming in, which isn't necessarily a good thing (overdriven levels tend to distort the signal quality)...

The levels are never overdriven. That is why the modem "ranges" with the CMTS. The CMTS will tell the modem to range unitl it receives around 0dB from the modem. The problem that you can get from the modem if the level isn't high enough is that it could be into the noise floor of the transmit section of the modem. It could also be into the noise floor of the system as well. That is why the operating spec is from around +34dB to +54dB.