cancel
Showing results for 
Search instead for 
Did you mean: 

Balanced power levels any other ways hub5

smithy01793
On our wavelength

Hay guys and gals. 

So will try and keep this short as possible. 

I have hub5 1gig service. 

Is there any way of keeping power levels on up stream above 35 with out lowering power levels on down stream. 

I know on basic terms how levels work. 

So currently I have a 10 and 6 attenuator in line. This has made levels roughly

36 to 36.8 on upstream which is fine buy me it's above 35 that is roughly in line with what VM says is OK. 

How ever in that setup it has made my download levels roughly - 4.7 to - 2.0

Again I know this falls within levels that VM says is in range. But at them down stream level it is on boarder line with falling to low. I belive max - 7 is the guide line.

So I have removed the 6 attenuator and replaced with a 3 that I have laying around. This pulls down stream to where I would like around 0.5 to 3.5 but the upload stream then fall a little to low average 32.5 to 33.5. 

So is there a way of bringing the upload streams back to above 35 but not altering the download stream level. 

Hope that made sense. 

Thanks in advance 

10 REPLIES 10

legacy1
Alessandro Volta

your upstream is fine if your close to a cab setup a BQM to see how your connection is

---------------------------------------------------------------

Client62
Legend

That is quite a lot of attenuators even more that we have on RFoG.

Downstream of -7 to +10 dBmV usually works without any issues.  So your original figures are OK.
Did you see the extremes for DOCSIS are -15 to +15 dBmV of downstream signal arriving at the Hub.

Is there some special reason why working the VM Hub harder on the upstream transmission but dumping all extra power into an attenuator is going to offer the slightest improvement ?

Yea so what I am asking is. Do you know of a way of increasing upstream level with out it affecting down stream.

So if I am close to a cab my upstream of 33ish should be OK. 

Tudor
Very Insightful Person
Very Insightful Person

Any attenuator used by VM is a forward-path only attenuator. You should not use your own ones. A forward path attenuator only affects the downstream levels and does not change the upstream ones. Upstream levels are how much power the hub uses in communicating with the VM CMTS. For the upstream the power levels are low it usually indicates that the hub is near the street cabinet. If the power levels are high it can indicate one of two things, the hub is a long way from the street cabinet or there is a problem with the circuit. 


Tudor
There are 10 types of people: those who understand binary and those who don't and F people out of 10 who do not understand hexadecimal c1a2a285948293859940d9a49385a2

smithy01793
On our wavelength

Hi Tudor Thank you for your responce

However the Attenuators that vm installed did effect the upstream levels, TBC they have put in a 10 and a 6 attached to the hu inline with the coax cable going in to the hub, 

I only mentioned my attenuator what is a 3 because working out the effect between the 10 and then the 6 that was also added seemed like a 3 would be the sweet spot and removing the 6.

This is the case for the downstream levels but as i said the upstream seems to drop to around 33.5 ish. 

in doing testes the hub and speeds i am getting seem to be fine with that setup. 

So i would presume i am close to my street cabinet.

 

Client62
Legend

Have you grasped why changing a wide band attenuator has the opposite effect on the Downstream and Upstream signal levels shown by the VM Hub ?

Unless there is a fault, I'd put the connect back to the configuration installed by VM and leave it alone.

Tudor
Very Insightful Person
Very Insightful Person

"This is the case for the downstream levels but as i said the upstream seems to drop to around 33.5 ish"
That’s very unusual. If you put an attenuator into the upstream circuit the power levels should rise as they are negative values, never drop.


Tudor
There are 10 types of people: those who understand binary and those who don't and F people out of 10 who do not understand hexadecimal c1a2a285948293859940d9a49385a2

pete_at_home
Superfast

As said above, you need a "forward path attenuator", probably around 8-10db instead of the 10db + 3db..  It also depends on the slope, which will be shown in the modem downstream network status.    The modem will tolerate levels from -15 to +15, but ideally you want to be around zero averaged across all frequencies.

 

That will get your downstream into the optimum range

Sephiroth
Alessandro Volta

Your 32dBmv upstream level is fine, as would be a lower level.  The power level is demanded from the VM end according to what's necessary for the VM end to successfully receive data.

Seph - ( DEFROCKED - My advice is at your risk)