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One to Watch
warezWally
Posts: 10
Registered: ‎17-08-2010

Forward Path Attenuator

Hello, Had 50Mb BB for a few weeks now...

 

When the engineer came round to install they found my line was running at 33dBmV. They didnt have a 30 dBmV attenuator on them, so they put on a 20 instead.

I suppose this has been ok, the connection is stable enough however I can just sense that we're not getting a nice smooth signal into the house that the modem can take advantage of. We live in a fast area, a friend of ours who lives round the corner gets a nice smooth download on speedtest.net that rockets up to 49.9x Mb/s right at the start, however ours often has a jumpy time on speedtest. With speed increases in busts like: 5 > 20 >35 > 40 and eventually peaking out in the mid 40's during the process. Occasionally we get speeds as low as 20 or 30.

Here is the SuperHub connection page:

 

 

Connection


Startup Procedure
ProcedureStatusComment
Acquire Downstream Channel314750000 HzLocked
Connectivity StateOKOperational
Boot StateOKOperational
Configuration FileOK 
SecurityEnabledBPI+

Downstream Channels
Lock StatusModulationChannel IDMax Raw Bit RateFrequencyPowerSNRDocsis/EuroDocsis locked
LockedQAM2567755616000 Kbits/sec314750000 Hz14.2 dBmV44.3 dBHybrid
LockedQAM2567555616000 Kbits/sec298750000 Hz14.1 dBmV45.4 dBHybrid
LockedQAM2567655616000 Kbits/sec306750000 Hz14.1 dBmV44.9 dBHybrid
LockedQAM2567855616000 Kbits/sec322750000 Hz13.8 dBmV44.8 dBHybrid
        
Upstream Channels
Lock StatusModulationChannel IDMax Raw Bit RateFrequencyPower
LockedATDMA520480 Kbits/sec45800000 Hz35.9 dBmV
UnlockedUnknown00 Ksym/sec0 Hz0.0 dBmV
UnlockedUnknown00 Ksym/sec0 Hz0.0 dBmV
UnlockedUnknown00 Ksym/sec0 Hz0.0 dBmV

Primary Downstream Service Flow
Downstream(0)
SFID21912
Max Traffic Rate53000000 bps
Max Traffic Burst10000 bytes
Mix Traffic Rate0 bps

Primary Upstream Service Flow
Upstream(0)
SFID20279
Max Traffic Rate5140000 bps
Max Traffic Burst8160 bytes
Mix Traffic Rate0 bps
Max Concatenated Burst8160 bytes
Scheduling TypeBest Effort

 

Been doing some reading about power levels and stuff and 14 dBmv seems too high for me and I imagine we're probably getting a bit of line distortion. Do 30/35 dBmv forward path attentuators exist, if so... where can I get one as I feel this is the root of the problem.


Also... on a side note, any idea why speedtest seems to think I live in Manchester, when im actually in Portsmouth? 

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Captain Clued-Up
jimGY89
Posts: 869
Registered: ‎26-07-2011

Re: Forward Path Attenuator

Hi warezWally yer you can get 30db Forward Path Attenuators ive just bought a 2db one the other day i got mine from maplins electronics and i can remember seeing a 30db one in there do you have maplins where you live ? otherwise you can get them online with next day delivery for about £6. regarding www.speedtest.net its on manchester because thats the closest server to you it dus it to me aswell but take no notice go on setting on speedtest.net and choose the london server cos thats the best one all the others give ya inacurate results so just use that one cos it can handle speeds of 100mb and it will always give you the true speed. If someone's helped you out say thanks by clicking on the Kudos Star. If someone's solved your problem, why not mark their message as an Accepted Solution? You can also help other users find useful posts by Taggingthem with keywords.

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XL TV 1x 500Gb TiVo 1x V+HD 1x VHD 152Mb BB XL Phone
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One to Watch
warezWally
Posts: 10
Registered: ‎17-08-2010

Re: Forward Path Attenuator

Thanks for the reply jim.

Cool. Looked on Maplin and there only seems to be 12dBmv attenuators and they aren't the same as the one in my house (square). I might try a store in that case, unless anyone else has any ideas as to where I can get hold of one?
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Superuser
Sephiroth
Posts: 13,510
Registered: ‎01-09-2009

Re: Forward Path Attenuator

You must get a Forward Path Adaptor and Maplin don't do them. You can get them on ebay. The 10 dB ones can be screwed onto the 20 dB you've got. And you're right, pulling the forward path (downstream) power down closer to zero will most likely stabilise your connection.

You must be right close to the street cabinet.
Seph - (My advice is at your risk)

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One to Watch
warezWally
Posts: 10
Registered: ‎17-08-2010

Re: Forward Path Attenuator

I can see it from my window.
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One to Watch
warezWally
Posts: 10
Registered: ‎17-08-2010

Re: Forward Path Attenuator

Hmm... looking on eBay I cant really find much:

http://www.ebay.co.uk/sch/i.html?_nkw=forward+path

Whats the difference between adaptor/equaliser/attenuator?
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Superuser
Sephiroth
Posts: 13,510
Registered: ‎01-09-2009

Re: Forward Path Attenuator

It'a all there on ebay.  You can buy 2 x 6 dB FPA and screw one into the other and add it to what you've got.  That'll do a perfect job.

 

As to your other question:

http://www.cableforum.co.uk/board/432440-post11.html

Seph - (My advice is at your risk)

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