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AHN-David
16-12-2009, 19:55
Hey guys I just looked at my signal levels and compared them to the levels suggested in the stickey. Do these look really high to anyone?

Cable Modem Downstream
Downstream Lock : Locked
Downstream Channel Id : 4
Downstream Frequency : 402750000 Hz
Downstream Modulation : QAM256
Downstream Symbol Rate : 5360.537 Ksym/sec
Downstream Interleave Depth : taps32Increment4
Downstream Receive Power Level : 0.6 dBmV
Downstream SNR : 37.7 dB

Cable Modem Upstream
Upstream Lock : Locked
Upstream Channel ID : 5
Upstream Frequency : 18384000 Hz
Upstream Modulation : QPSK
Upstream Symbol Rate : 2560 Ksym/sec
Upstream transmit Power Level : 59.0 dBmV
Upstream Mini-Slot Size : 2


Thanks

Peter_
16-12-2009, 19:56
Upstream to high, everything else fine, give support a call.

AHN-David
16-12-2009, 19:58
Does it make a difference that much? The engineer fixed them 2 days ago.

I was reading up and it says they can change randomly. Is that correct?

VMboy
16-12-2009, 20:00
@ AHN-David

Have you tried testing your upload speed just now? I would be interested to know what your current upload speed is, especially as I see you have QPSK.

Peter_
16-12-2009, 20:00
Does it make a difference that much? The engineer fixed them 2 days ago.

I was reading up and it says they can change randomly. Is that correct?
That is to high and should be ideally in the mid 40 range, keep an eye on it and if your connection degrades or the power level stays high give support a call.

AHN-David
16-12-2009, 20:03
https://www.cableforum.co.uk/images/local/2009/12/28.png (http://www.speedtest.net)

Is my latest speed test.

Normal service looks to be resumed in Glasgow for download speed anyway and my upload is always around 30/40's

VMboy
16-12-2009, 20:05
@ AHN-David

Seems your upload speed has been currently hit as mine is right now.

Peter_
16-12-2009, 20:06
If you are happy then ignore it for now.;)

Do not become a statistics monkey posting every slight variation, just enjoy your broadband and let it do what it does best, entertain you.:D

AHN-David
16-12-2009, 20:09
My upload has mostly been the same. Never peaks over 0.50kbps

Also what is QPSK?

---------- Post added at 19:09 ---------- Previous post was at 19:08 ----------

If you are happy then ignore it for now.;)

Do not become a statistics monkey posting every slight variation, just enjoy your broadband and let it do what it does best, entertain you.:D


I attend to do it now:D I am so happy I am back to my normal 10mb speed at peak times.:D

I have decided to stick with virgin even though I had already arranged a cancel date.

on in an hour!
16-12-2009, 20:11
Quodumn Spondoolint Parathingum Knowledgeability ;)

Welshchris
16-12-2009, 20:14
Upstream to high, everything else fine, give support a call.

we all know that 59dBmv is high on the upstream but network guys rate it upto 61dBmv as fine.

When i had 2 Senior network engineers here during the BSR calamity thats still ongoin in swansea they had my records that showed that my upstream was peaking around 59dBmv and told me it wouldnt cause modem reboots unless it was 61dBmv or over.

on in an hour!
16-12-2009, 20:19
we all know that 59dBmv is high on the upstream but network guys rate it upto 61dBmv as fine.

When i had 2 Senior network engineers here during the BSR calamity thats still ongoin in swansea they had my records that showed that my upstream was peaking around 59dBmv and told me it wouldnt cause modem reboots unless it was 61dBmv or over.

this may be so,but all you would need to disrupt your connectivity would be the signal levels off the amplifier in the cabinet fluctuating 2-3db and you would suffer.:(

Peter_
16-12-2009, 20:40
we all know that 59dBmv is high on the upstream but network guys rate it upto 61dBmv as fine.

When i had 2 Senior network engineers here during the BSR calamity thats still ongoin in swansea they had my records that showed that my upstream was peaking around 59dBmv and told me it wouldnt cause modem reboots unless it was 61dBmv or over.
Well seeming as no modem can actually show a reading above 61 the is no way of actually know how much higher it has gone, and we know that the modem is actually more stable in the mid 40's region.

What would you rather have a pair of bluffers trying to get away with doing nothing or someone actually checking out the issue, I think the answer is a no brainer here.;)

Welshchris
16-12-2009, 23:18
Since being put back on the UBR from the BSR my upstream went from being between 51 - 54dBmv to around 47dBmv.

Peter_
16-12-2009, 23:25
Since being put back on the UBR from the BSR my upstream went from being between 51 - 54dBmv to around 47dBmv.
As it should be.

Sephiroth
17-12-2009, 00:36
this may be so,but all you would need to disrupt your connectivity would be the signal levels off the amplifier in the cabinet fluctuating 2-3db and you would suffer.:

That's the point. When you're up towards the 61 dBmv threshold, your margin's gone = potential instability.

VMboy
17-12-2009, 01:00
As it should be.

My Upstream transmit Power Level is 52.5 dBmV, but then I have an attenuator fitted which was to lower the downstream level, and this I believe raises the upstream level, so I suppose my upstream level would be around 47dBmV too.

Does this upstream level look OK though? as I don't want it causing any future stability issues.

Sephiroth,

You went too far into your [/QUOTE] with your red colour causing the quote to show.

Sephiroth
17-12-2009, 01:12
My Upstream transmit Power Level is 52.5 dBmV, but then I have an attenuator fitted which was to lower the downstream level, and this I believe raises the upstream level, so I suppose my upstream level would be around 47dBmV too.

Does this upstream level look OK though? as I don't want it causing any future stability issues.

.....
The forward path attenuator doesn't increase the return path power in any way. The return path power is what's required to overcome impedances between your modem and the CMTS when uploading data. At the CMTS end it would read a receivbe power of around 2 dBmv.

52.5 dBmv is pushing hard but is well within margins.

BBings has provided the explanation for QPSK vs 16QAM switching in your case.

Welshchris
17-12-2009, 01:18
Why is there such a large difference between the UBR and BSR tho?

VMboy
17-12-2009, 01:35
52.5 dBmv is pushing hard but is well within margins.
Ok, but can this be lowered similar to what happened to my downstream power level when the engineer fitted an attenuator to the modem?


BBings has provided the explanation for QPSK vs 16QAM switching in your case.

Which post exactly?

By the way I was sure that the engineer said the upstream would rise due to the attenuator being fitted for downstream being too high.

---------- Post added at 00:35 ---------- Previous post was at 00:30 ----------

Just in case I got it wrong here are the modem details upstream first, and are these anything to be concerned about?

Cable Modem Upstream
Upstream Lock : Locked
Upstream Channel ID : 4
Upstream Frequency : 29200000 Hz
Upstream Modulation : QAM16
Upstream Symbol Rate : 2560 Ksym/sec
Upstream transmit Power Level : 52.5 dBmV
Upstream Mini-Slot Size : 2

Cable Modem Downstream
Downstream Lock : Locked
Downstream Channel Id : 5
Downstream Frequency : 339000000 Hz
Downstream Modulation : QAM256
Downstream Symbol Rate : 5360.537 Ksym/sec
Downstream Interleave Depth : taps32Increment4
Downstream Receive Power Level : 5.3 dBmV
Downstream SNR : 37.8 dB

Sephiroth
17-12-2009, 01:47
@VMBoy

Those levels are fine. I've seen better but for 10 Mbps they're fine.

I'll let you look up your own thread on QPSK vs 16QAM!

Anyway, have you got any problems or is this one of those going nowhere exchanges?

VMboy
17-12-2009, 02:01
I just want the best available, is that too much to ask?

You mentioned they could be better, so why did the engineer not leave them looking better?

Not that you can answer that being that you were not the tech that attended, but all I wanted to know was it possible for him to have lowered the Upstream transmit Power Level?

Like I say I could have sworn he said those forward path attenuators raise the upstream.

---------- Post added at 01:01 ---------- Previous post was at 00:54 ----------


52.5 dBmv is pushing hard but is well within margins.


I can see that too from this post, although it was for 50Mb power levels across all platforms, so does that mean it includes the 10 meg platform as well?

http://www.cableforum.co.uk/board/34896851-post3.html

Sephiroth
17-12-2009, 02:32
The engineer is looking at your kit and what comes into your house. He might be able to go to the cabimet if there is something way out. In your case there's nothing way out.

He would not have tampered with the upstream signal level because that's dynamic depending on what difficulty the modem is having getting throught to the CMTS. If he suspects a duff modem, he'll replace it.

The upstream power for 16QAM should not regularly exceed 55 dBmv. You're showing 52.5 dBmv. Pushing it but within margins. If SNR conditions on your upstream circuit vary and it pushes above 55 dBmv, it may be because you're on a poor SNR QPSK circuit. And that's where BBings' explanation comes in.

So you wanting the best available and going round in circles with the same questions when it appears you don't have a problem is a bit of a cheeky - don't you think?

You can Google and read the Brady Volpe stuff like BBings and I do and then you'll be able to understand for yourself what's what. And what's wrong with anything I've told you!!!

Peter_
17-12-2009, 07:17
Ideal is mid 40's but if it is working fine higher then the is no issue as we would not send an engineer out for your upstream as it would be a wasted visit.

Ignitionnet
17-12-2009, 10:30
I just want the best available, is that too much to ask?

For someone on upgraded M yes. You want the best available pay more! :p:

Seriously we all pay the same, none of us have an entitlement to 'the best available' so long as things work as they should. If they don't work as they should that should be fixed but complaining because a power level that isn't the cause of issues anyway isn't perfectly within the middle of the operating range is silly.

The power levels have a wide operating range due to the wide operating range on the network. Simply expecting all parameters to be absolutely perfect is entirely unrealistic. There are many reasons for a network to be configured as it is that would cause power levels to be higher or lower. Power levels in a lab and power levels in the real world are somewhat different things.

My modem should, according to VM guidance, be verging on melting:

Power Level (dBmV) 8.90 9.15 9.21 9.51

Works fine though.

You've no signal related problems now. 52dBmV is absolutely fine, your modem will go right up to 58dBmV on 16QAM and 61dBmV on QPSK.

---------- Post added at 09:30 ---------- Previous post was at 09:27 ----------

Ok, but can this be lowered similar to what happened to my downstream power level when the engineer fitted an attenuator to the modem?

Yes, moving you to a different tap in the cabinet if a higher level one is available which will increase your downstream power even higher, or a signal booster which will degrade your upstream SNR. Not a good idea.

By the way I was sure that the engineer said the upstream would rise due to the attenuator being fitted for downstream being too high.

Yes, about 0.5dBmv - 1dBmV of insertion loss.

VMboy
18-12-2009, 13:49
Can outside temperature cause levels like the downstream to rise?
I ask as my d/s level was around 5.3 after having the attenuator fitted, and last night it was as high as 6.6, although it's usually around 6.2 to 6.4, but wondered why the jump.

Sure I read somewhere that they can rise depending on temps .

Ignitionnet
18-12-2009, 14:08
Yes.

AHN-David
18-12-2009, 14:32
I have no idea why this thread is going oftopic away from My own issues,

This was why my last thread was closed:S

Sephiroth
18-12-2009, 14:45
I have no idea why this thread is going oftopic away from My own issues,

This was why my last thread was closed:S

Presumably you don't need this thread anymore as you're walking 10th Jan!

VMBoy obviously thinks he does need this thread! I don't think he does - but lah di da.

AHN-David
18-12-2009, 15:06
Nah I decided not to walk after all.

But if I get one more fud of a engineer or CS agent if I have a issue again I will be walking.

I should really be walking after not listening to me for 3 weeks.

Sephiroth
18-12-2009, 15:57
Nah I decided not to walk after all.

But if I get one more fud of a engineer or CS agent if I have a issue again I will be walking.

I should really be walking after not listening to me for 3 weeks.
LOL. We would have missed you! :rant: