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Standard User WilliamGrimsley
(experienced) Tue 05-Sep-17 12:22:05
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Trying To Track Down The Cause Of High FEC's


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Hi all,

I've been away for a long time, but thought I'd come back to ask about this "issue", I say issue, it isn't really, but I'm trying to investigate what's causing high amounts of retranmissions on my line.

I've done some investigating. Yesterday, I switched everything off except the router and the heat pump (this cannot be replaced) and found that the DS SNRM increased slightly, but the FEC's still continued to build at a rate of sometimes thousands/min. So, surely this must mean that what's causing the issue is not in the property, but either in the phyiscal line, in another property close to the cable and/or crosstalk. I want to try and find the cause of this as it could be capping what my line speed could acheive.

I've also noticed that the retransmissions increase whenever the phone line is in use. Could this be a sign of a high resistant joint developing?

I am uploading to MDWS under the ID "Grimmerbob".

Thank you!

William

William Grimsley.

Edited by WilliamGrimsley (Tue 05-Sep-17 16:43:20)

Standard User WilliamGrimsley
(experienced) Tue 05-Sep-17 16:27:12
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Re: Trying To Track Down The Cause Of High FEC's *DELETED*


[re: WilliamGrimsley] [link to this post]
 
Post deleted by WilliamGrimsley

Edited by WilliamGrimsley (Tue 05-Sep-17 16:28:07)

Standard User WilliamGrimsley
(experienced) Thu 07-Sep-17 10:04:22
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Re: Trying To Track Down The Cause Of High FEC's *DELETED*


[re: WilliamGrimsley] [link to this post]
 
I have now found what was causing the drop in and oscillating DS SNRM when the phone line is in use. It was the MK4 SSFP that the engineer installed earlier in the year. So, yesterday, I removed it. Now, the modem and phone are both plugged into the test socket via a microfilter. The FEC's have dropped slightly and the DS SNRM is more stable. Just shows...

William Grimsley.

Edited by WilliamGrimsley (Thu 07-Sep-17 14:38:21)


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Standard User WWWombat
(knowledge is power) Tue 12-Sep-17 15:15:07
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Re: Trying To Track Down The Cause Of High FEC's *DELETED*


[re: WilliamGrimsley] [link to this post]
 
You asked whether the FECs could be caused by crosstalk.

In this case, I don't think that would be the primary cause. Crosstalk would have an impact 24x7. Unless the modem gets turned off - in which case you'd see a rapid transition from lots of FECs to no FECs.

In your case, the FECs fade in in mid-evening, and fade out in the morning.

Perhaps your line picks up RFI from the air, rather than anything else, and is just susceptible to changes in the ionosphere at night.
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