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Plusnet's Sagemcom router affected by domestic interference

Posts: 33
Thanks: 1
Registered: ‎12-03-2013

Plusnet's Sagemcom router affected by domestic interference

Hi,   My ADSL comes from the exchange via a long (~4kms) and old rural cable route so the best speed I can get is ~1.5Mbps.  Plusnet  have tweaked my line for the best speed/error rate compromise,  but there are times,  particularly in weekend evenings when the error rate on the line is too high and it intermittently completely drops out.   


I've discovered that when it drops out, I can usually bring it back by unplugging my laptop's power unit from the mains and running my laptop on battery.


Now my laptop power unit converts 240v AC mains to 19v DC by means of a mini built-in high frequency inverter.  This is the normal way these power units work,  and in doing so they generate some RF interference.  I can detect this easily on my FM radio since it immediately goes "fizzy" as soon as I plug my laptop PSU in to the mains.   Previous laptop PSUs have always done the same, so this is not a fault as such;  they all do it.


But this implies that my Plusnet's Sagem router is picking up interference from my laptop's PSU and the router's performance is being compromised by it.  


This only seems to be a problem around internet overload times at weekends and occasionally in weekday evenings when the router is working near the threshold of its ability to manage errors.   Most weekday days I can happily plug my laptop's PSU in and the router copes fine.


But what I'm observing is that Plusnet's Sagem router is susceptible to a kind of RF interference that must be entirely commonplace around internet setups.  There's nothing out of the ordinary in having a working laptop and its PSU located close to a working router,  is there!.  


A couple of months ago I complained to Plusnet about the intermittent dropouts I was experiencing.  After tweaking the server as best they could for my poor ADSL line,  and when the dropouts still persisted,  they remotely tested my router and concluded its performance was substandard.   So they posted me a new Sagem router similar to my old one.   After I changed to the new router,  there was some marginal improvement for a while,  but now the same problem is back again.


The fact that two routers exhibit the same symptoms makes me suspect there must be a design flaw that's making them oversensitive to this common type of RF interference.    I'd like to know whether other different design routers suffer from this same defect or if it only affects Plusnet's Sagems.  I didn't have this problem with my original old Technicolor (now sadly deceased).


Any thoughts?


     +   John




Posts: 3,855
Thanks: 1,462
Fixes: 18
Registered: ‎06-04-2007

Re: Plusnet's Sagemcom router affected by domestic interference

Hi John


That's quite possible, but also as likely (or not more so) to be the cabling before the router.  The unshielded phone cable is quite susceptible to interference.



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