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sprog1033
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Forward Path Attenuator

I have had a look at my downstream power levels on my Hub 3.0. I believe that the addition of a 3dB forward path attenuator (or maybe more?) might be needed. I realise my levels are still within the -6 & +10 dBmV band, but surely getting them closer to what I believe the optimal level of 0 dBmV would be beneficial? 

Please can I get some guidance on where best to source one from. Are they something that can be posted to me by Virgin, or can I purchase one directly from somewhere? I have found some by searching the internet but they often refer to satellite and not cable. Is there a difference?

Please see screenshots below of my stats for reference:

Downstream Power 20210522.png

 

Downstream Errors 20210522.png

 

Upstream 20210522.png

 

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DJ_Shadow1966
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Re: Forward Path Attenuator

Hello

Are you experiencing any problem like slow speed as looking at your stats as you have already stated they are within range, changing closer to 0 will not make any difference ?

 

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VM-Jon
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Re: Forward Path Attenuator

Hi ,

Thank you for your post. For clarity the optimum levels for your broadband are -6 to +10. Forward path attenuator will make no difference to the performance of your modem.


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sprog1033
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Re: Forward Path Attenuator

Hi DJ_Shadow1966,

Generally no, the connection is mostly fine, but there are certainly times when especially the upload speed drops significantly. My guess is that the slow-downs have been more related to potential over-utilisation in our area than our local connection to the network. I was just wondering if getting the downstream levels closer to 0 would give it more headroom to drift before causing an issue.

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DJ_Shadow1966
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Re: Forward Path Attenuator

Hello

One thing you can do to check if there is a utilization issue is to setup a BQM - https://www.thinkbroadband.com/broadband/monitoring/quality.

You should get a graph similar to what I have.

https://www.thinkbroadband.com/broadband/monitoring/quality/share/a65083dae8b127d335117017b79717b4ae64b94e

Regards Mike

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sprog1033
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Re: Forward Path Attenuator

Hi Mike,

Many thanks for your continued interest in helping me. I have had a BQM setup for a few years now. I tried following up utilisation issues that were evident in the BQM in the past, via this forum, without success at the time. Since the reduction in lockdown requirements the BQM has been looking reasonably good (for a DOCSIS connection).

My original post was not intended to be for the purpose of looking into over-utilisation though.

Below is my current BQM and below that an example of previous over-utilisation issues:

 20201112.png

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Adduxi
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Re: Forward Path Attenuator

As stated the levels are within spec, so VM will take no action.  You can get an FPA if you wish, but IMHO it will not make any difference.

However, you have a small amount of PostRS errors, but not sure if they are historical?  Can you reboot the Hub and keep an eye on those, as ideally PostRS errors should be zero.

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sprog1033
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Re: Forward Path Attenuator

Hi Adduxi,

Many thanks for your response. I take on board the general consensus of all responses so far that if the power levels are within -6 to +10 dBmV then there if little point in trying to get the downstream level to 0 dBmV. That said, I may still experiment to see if I get a stop to the few Post RS Errors. 

Please can I get some guidance on where best to source one from. I have found some by searching the internet but they often refer to satellite and not cable. Is there a difference?

Below shows how long it has been since my last re-boot.

sprog1033_0-1621690864935.png

 

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Adduxi
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Re: Forward Path Attenuator

From memory I sourced mine from Amazon, but a quick Google brought this up Technetix Forward Path TV Signal Attenuator 3dB UHF / virgin / "F" connector m-f | eBay

As for PostRS errors, they are "usually" caused by noise on the circuit, and not by the power levels being not zero.

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sprog1033
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Re: Forward Path Attenuator

Hi Adduxi,

Many thanks for the suggestion.

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