Too Much Signal??????

xbit · Post by **xbit** » Mon Jul 23, 2001 2:12 pm

An att tech came today to exchange my nic. while he was there he tested the lines and said that there is too much signal coming to my line. Would this slow me down if its too high or low?

HalfLifer · Post by **HalfLifer** » Mon Jul 23, 2001 2:13 pm

Wont hurt a thing, but it could cause your modem to de-sync, if the signal becomes out of range.

Let me add that signal and speed are two different things, they dont affect each other, unlike DSL.

Indy · Post by **Indy** » Mon Jul 23, 2001 2:15 pm

Yeah, it's possible...modems typically operate in the -15dB to +15dB range...outside of that and you start looking at retransmissions because of signal degredation....too much signal can be just as bad as not enough...
I've seen places where the signal coming into the back of a TV set was sitting at +30dB and it looked almost as bad as no signal at all...

xbit · Post by **xbit** » Mon Jul 23, 2001 2:17 pm

So i'm guessing the best place to be is around zero, right?

Indy · Post by **Indy** » Mon Jul 23, 2001 2:18 pm

Just to re-iterate what Halflifer said, signal doesnt really affect speed so much as it does keeping sync with the head end. However, if the signal becomes distorted or has noise, then you start wandering into the realm of retransmissions, which has the perceived effect of slowing down your throughput (the speed stays the same, but since you're losing packets and having to retransmit, then it appears that your speed slows)

Indy · Post by **Indy** » Mon Jul 23, 2001 2:19 pm

Originally posted by xbit
So i'm guessing the best place to be is around zero, right?

Yeah, 0 to -5dB is the sweet spot for most modems...

xbit · Post by **xbit** » Mon Jul 23, 2001 2:21 pm

ok thanks just wanted to know what he ment by high signal. Will the picture on my cable tv look better?

HalfLifer · Post by **HalfLifer** » Mon Jul 23, 2001 2:23 pm

A line tech was at my neighbors and changed something at our tap, and my power level went from -5dB to -11dB, what the hell did this guy change?

Indy · Post by **Indy** » Mon Jul 23, 2001 2:24 pm

If the signal is too high and they adjust it to bring it down to the appropriate level, then yeah, it should look better...typically with an overdriven signal, you'll get kind of a sparkle pattern on the cable channels...looks a little bit like snow, but not quite...

Indy · Post by **Indy** » Mon Jul 23, 2001 2:25 pm

Originally posted by HalfLifer
A line tech was at my neighbors and changed something at our tap, and my power level went from -5dB to -11dB, what the hell did this guy change?

Maybe he changed the face plate on the tap? Or maybe a filter was changed...we've had some issues with some of our filters causing more problems than they're worth...

xbit · Post by **xbit** » Mon Jul 23, 2001 2:32 pm

How does this look?

Signal Acquired at 699 MHz
SNR: 36.5 dB
Received Signal Strength: -4.1 dBmV
Micro-Reflections: 26 dBc
Modulation: 64 QAM
Return Path:
Connection: Acquired
Frequency: 19 MHz
Power Level: 50.0 dBmV
Channel ID: 4
Modulation: QPSK

HalfLifer · Post by **HalfLifer** » Mon Jul 23, 2001 2:34 pm

power level is awful high! mines like -9dB!

xbit · Post by **xbit** » Mon Jul 23, 2001 2:36 pm

Is that the power for the line or the cable modem. Does that affect anything?

Indy · Post by **Indy** » Mon Jul 23, 2001 2:37 pm

Originally posted by xbit
How does this look?

Signal Acquired at 699 MHz
SNR: 36.5 dB
Received Signal Strength: -4.1 dBmV
Micro-Reflections: 26 dBc
Modulation: 64 QAM
Return Path:
Connection: Acquired
Frequency: 19 MHz
Power Level: 50.0 dBmV
Channel ID: 4
Modulation: QPSK

Not too bad...in our system a modem doesn't get red flagged until the Return Path Power level hits 55 dB...your signal to noise (SNR) level is good (the higher the number, the better)...that doesn't get red flagged until it drops below 30 dB...and your received signal strength, that's the actual signal level behind your modem transmitting in at 699 MHz...

HalfLifer · Post by **HalfLifer** » Mon Jul 23, 2001 2:38 pm

Frequency 591000000 Hz Locked
Signal to Noise Ratio 33 dB
QAM 64
Network Access Control Object ON
Power Level -10 dBmV

Upstream Value
Channel ID 5
Frequency 19984000 Hz Ranged
Ranging Service ID 784
Symbol Rate 1.280 Msym/s
Power Level 57 dBmV

Indy?

Indy · Post by **Indy** » Mon Jul 23, 2001 2:46 pm

Here's a pic for Xbit:

Halflifer...you might want to have wee come out and take a look at your line...you're just about at max power on your modem...max power is 58, and you're sitting at 57 (not good)...probably wouldn't be a bad time to replace that rg59 line you've got

Indy · Post by **Indy** » Mon Jul 23, 2001 2:50 pm

Halflifer:

Frequency 591000000 Hz Locked
Signal to Noise Ratio 33 dB <==not great, but not bad
QAM 64
Network Access Control Object ON
Power Level -10 dBmV <==replacing the 59 line will fix this...

Upstream Value
Channel ID 5
Frequency 19984000 Hz Ranged
Ranging Service ID 784
Symbol Rate 1.280 Msym/s
Power Level 57 dBmV <==not good

HalfLifer · Post by **HalfLifer** » Mon Jul 23, 2001 2:59 pm

Thanks Indy,

Ill be sure to ask him

PhyberOptix · Post by **PhyberOptix** » Mon Jul 23, 2001 6:23 pm

Let me preface this by saying I'm a bit out of my element. I'm an IP dude who works w/ routers and switches, so RF isn't really my field - but I though I'd chime in anyways.

When I worked at Nortel (prior to the layoffs) I handled the IP side of their wireless/cable equipment. I would run stress tests and report on packet loss, latency etc......There were numerous occasions that I would set up a test and would see substantial packet loss. After verifying my routers etc., I would bring in one of the RF gurus to look at the RF side of things. They would look at signal strength and add or subtract signal if it was too hot or cold. Every time they did this my packet loss cleared right up and throughput was back to normal.
It could very well be that I just didn't understand everything they were doing, but, I watched and listened as they said they needed to increase/decrease the signal strength. Once they added 10 dB pads (as an example) the problems cleared right up. So in my experience, signal strength had an enormous impact on throughput.

My 2 cents

HalfLifer · Post by **HalfLifer** » Mon Jul 23, 2001 6:30 pm

If you are getting re-transmissions from very bad signal, it will degrade performance....in that manner

brembo · Post by **brembo** » Mon Jul 23, 2001 6:37 pm

Frequency 117000000 Hz Locked
Signal to Noise Ratio 35 dB
Max bitrate 10000000 bps
QAM 64
Network Access Control Object ON

Upstream Value
Channel ID 2
Frequency 32752000 Hz Ranged
Ranging Service ID 1384
Symbol Rate 1.280 Msym/s
Power Level 37 dBmV
Min-Max Bitrate 0-128000 bps

Indy? Look good? We need to play some UT soon.

Indy · Post by **Indy** » Mon Jul 23, 2001 6:48 pm

Originally posted by brembo
Frequency 117000000 Hz Locked
Signal to Noise Ratio 35 dB
Max bitrate 10000000 bps
QAM 64
Network Access Control Object ON

Upstream Value
Channel ID 2
Frequency 32752000 Hz Ranged
Ranging Service ID 1384
Symbol Rate 1.280 Msym/s
Power Level 37 dBmV
Min-Max Bitrate 0-128000 bps

Indy? Look good? We need to play some UT soon.

Yep, looks good

The snr is decent, and the upstream power looks good (if I were to put a signal meter on, I'd probably see about a +5 or so on the signal coming in...

Yeah, we need to get a game of UT going again

wee96 · Post by **wee96** » Mon Jul 23, 2001 7:17 pm

He adjusted downstream levels from the nearest LE or from the BTD feeding your neighboorhood, halflifer. Was probably done to even out the flow of high and low end, I wouldnt worry about it at all. What I'd worry about is that fairy 59 cable you have runnin to your bedroom *giggle*

HalfLifer · Post by **HalfLifer** » Mon Jul 23, 2001 8:46 pm

Originally posted by wee96
He adjusted downstream levels from the nearest LE or from the BTD feeding your neighboorhood, halflifer. Was probably done to even out the flow of high and low end, I wouldnt worry about it at all. What I'd worry about is that fairy 59 cable you have runnin to your bedroom *giggle*

hehehheheheh, It'll be replaced

My dad and I are re-doin the house come August 1st, and Im doin my room by myself, so Ill get some RG6 from *someone* and run it

wee96 · Post by **wee96** » Tue Jul 24, 2001 7:35 am

Like my truck avatar? Heh I got the idea from Indy.

Indy · Post by **Indy** » Tue Jul 24, 2001 8:32 am

Originally posted by wee96
Like my truck avatar? Heh I got the idea from Indy.

HalfLifer · Post by **HalfLifer** » Tue Jul 24, 2001 9:12 am

Indy's got a Ford, you got a shovie

Indy · Post by **Indy** » Tue Jul 24, 2001 10:59 pm

Originally posted by HalfLifer
Indy's got a Ford, you got a shovie

Found
On
Road
Dead

HalfLifer · Post by **HalfLifer** » Tue Jul 24, 2001 11:06 pm

First
On
Race
Day

Damnit! Ford rocks!

hehe

DaveM · Post by **DaveM** » Tue Jul 24, 2001 11:41 pm

I have RG-11 buried from the pole to the house. Then we have a 1 in 2 out splitter, where a straight feed of RG-6 90% Braid with foil shield hits the office, and the computers, the second off that split hits out satellite system and it's all RG-6 90% Braid with foil shield with Diplexors and **** for local channels and satellite. Every room in our house has a home run to the Garage. What a nice feeling it is to know you have good signal in the whole house.

To top it off, I also wired up 12 ea 10/100 cat5e throughout the house, all interconnected with a Lynksys unmanaged 10/100 switch.

Before the caps were put on our neighborhood. I was taking in 6.5 mbits/second and 1.5 megabits outboud, depending upon the server I was sending to.

I now have to settle for the 1.28 mbit/sec download and 128 kbit/sec upload speeds. Oh well, I had incredible fun with the fast speed, but I can't complain for nearly having T1 download speeds for $35.00 a month with AT&T @Home.

Here's my specs for all you speed junkies:
Win 2k PIII with 512MB ram, No speed tweaks as they can't get me past the speed caps... LOL
Netgear RT311 Router Firmware 3.25 with Port 'Range' forwarding. 12 outlets throughout my home.

Before the speed caps were in place, I had 5 computers in the house all watching 300 kbit Video Streams at the same time viewing different Videos from Launch.com. We still could play Ultima Online and browse the web with no noticable jerkyness in the games, Video streams or Web browsing.

RCA 226 Cable Modem with 10/100 WAN outlet and an unused USB outlet.

Forward Path:
Signal Acquired at 633 MHz
SNR: 36.7 dB
Received Signal Strength: -3.7 dBmV
Micro-Reflections: 22 dBc

Return Path:
Connection: Acquired
Frequency: 30 MHz
Power Level: 32.0 dBmV
Channel ID: 1
:2cool:

Vermy · Post by **Vermy** » Wed Jul 25, 2001 3:04 pm

Downstream Value
Frequency 609000000 Hz Locked
Signal to Noise Ratio 31 dB
QAM 64
Network Access Control Object ON
Power Level 0 dBmV

Upstream Value
Channel ID 3
Frequency 37008000 Hz Ranged
Ranging Service ID 397
Symbol Rate 2.560 Msym/s
Power Level 31 dBmV

this is with a SURFboard SB3100 btw.......

Watch5869 · Post by **Watch5869** » Wed Jul 25, 2001 8:27 pm

How did you guys get those s/n ratio and power level values?

HalfLifer · Post by **HalfLifer** » Wed Jul 25, 2001 9:54 pm

Downstream powerlevel is PERFECT!

Watch5869 · Post by **Watch5869** » Wed Jul 25, 2001 10:04 pm

No, not how was it possible to get such good values. Where did you obtain or how did you know what your s/n and sig levels were?? In other word, how can I find out what my ratings are for the above?

HalfLifer · Post by **HalfLifer** » Wed Jul 25, 2001 10:08 pm

What modem do you have?

Watch5869 · Post by **Watch5869** » Wed Jul 25, 2001 10:36 pm

Toshiba pcx1000 cable modem

Watch5869 · Post by **Watch5869** » Fri Jul 27, 2001 6:59 pm

Halflifer, you never gave the response to my question after asking what modem I had.

Toshiba pcx1000

Thanks

4way · Post by **4way** » Fri Jul 27, 2001 7:29 pm

Too high of forward levels will cause slow downs on certain modems. zenith for instance likes to see between 0 and 5db on the forward path.

Watch5869 · Post by **Watch5869** » Fri Jul 27, 2001 7:42 pm

The question was, by what means do you determine what your signal to noise rations and power levels are???? how can I find this out?

Thanks

4way · Post by **4way** » Fri Jul 27, 2001 7:44 pm

the power levels are actually rf levels (not power) and the only way is to have the cable co. come out and check levels at computer to make sure they are within normal operating parameters.
hope this helps

SG Broadband Community

Too Much Signal??????

Too Much Signal??????

hows mine look?