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Standard User MHC
(sensei) Sun 22-Oct-17 09:58:47
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Re: Slightly slow ADSL2+ speeds – possible PSTN issue?


[re: Zarjaz] [link to this post]
 
May do ... or may not.

Do you no the frequency characteristics for an RF3? If they work to stop AM transmissions then they will also kill and ADSL signals - the problem the OP is seeing is 1584kHz being picked up, and that is right in the ADSL2+ spectrum.

Screened and earthed cables might help but how far back would they need to go?


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M H C


taurus excreta cerebrum vincit
Standard User Zarjaz
(eat-sleep-adslguide) Sun 22-Oct-17 10:35:50
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Re: Slightly slow ADSL2+ speeds – possible PSTN issue?


[re: RobertoS] [link to this post]
 
SFI visits are paid for by the CP, whether they then pass them on to their punter is up to them.

RF3 filters do improve this kind of issue with broadband, technically how they do this I don’t know ...

{You’ve seen me Bob, clearly employed for my looks innit grin}

Standard User Zarjaz
(eat-sleep-adslguide) Sun 22-Oct-17 10:38:11
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Re: Slightly slow ADSL2+ speeds – possible PSTN issue?


[re: MHC] [link to this post]
 
As I just mentioned to Bob, not sure of the technicalities of it ... I’ll see if I can discover details.


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Standard User MHC
(sensei) Sun 22-Oct-17 11:03:42
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Re: Slightly slow ADSL2+ speeds – possible PSTN issue?


[re: Zarjaz] [link to this post]
 
Problem here is that the OP is extremely close to the transmitter so the field strength will be very high and probably swamping the ADSL signals.


Have a look at your VDSL plots in DSL Stats and you will see notches with zero bit loading where the major AM transmitters broadcast ... so even miles away, it can have an effect. Close up, it can cause wideband issues.


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M H C


taurus excreta cerebrum vincit
Standard User Zarjaz
(eat-sleep-adslguide) Sun 22-Oct-17 11:34:49
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Re: Slightly slow ADSL2+ speeds – possible PSTN issue?


[re: MHC] [link to this post]
 
So your suggestion would be to move to Virgin then smile

Standard User Be3G
(newbie) Mon 23-Oct-17 18:07:53
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Re: Slightly slow ADSL2+ speeds – possible PSTN issue?


[re: MHC] [link to this post]
 
In reply to a post by MHC:
Have a look at your VDSL plots in DSL Stats and you will see notches with zero bit loading where the major AM transmitters broadcast ... so even miles away, it can have an effect. Close up, it can cause wideband issues.


Whilst not directed at me, that suggestion has spurred me in to seeing if I can get some more detailed line stats from my modem – I don't generally have access to that kind of thing 'cause it's a router being used as a PPPoE bridge. Anyway, I found it has a CLI so reset the modem/router to gain access to it via telnet, and have been able to obtain bit loadings and per-tone SNR info. It doesn't look like I can upload attachments here but suffice it to say there're quite a lot of blips and troughs in the data, more than I'd expect for a line that's mostly underground and no more than 1km from the exchange. The largest of the troughs lines up perfectly with the 1584kHz radio station: it completely knocks out three frequency bins and reduces the throughput of about 30 more. There're a couple of other noticeable troughs (affecting approximately half as many bins as the one I can hear) and they both tally with MW radio stations, with several other narrow blips too.

I've also been able to obtain a downstream attenuation figure, which is reportedly about 20dB, which does seem a bit high for the expected line length. Do people think that's going to be caused by the radio interference issues or will be that be down to something else entirely (like the old GPO box)?

Anyway, thanks everyone for your input. I feel like I might actually have a fault diagnosis now, which will hopefully make it slightly easier to get fixed!
Standard User Zarjaz
(eat-sleep-adslguide) Mon 23-Oct-17 18:17:10
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Re: Slightly slow ADSL2+ speeds – possible PSTN issue?


[re: Be3G] [link to this post]
 
Interference won't be altering attenuation. Conductor type, gauge and length do that.

For me the next steps would be pushing your ISP for an SFI visit from Openreach ..... but then you are going to have to give them good cause to send one out, and I'm sorry to say, there's a few noobies out there who wouldn't have a clue if you started to explain your issues.

Good luck.

Keep us posted.

Standard User Icaras
(experienced) Mon 23-Oct-17 19:34:46
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Re: Slightly slow ADSL2+ speeds – possible PSTN issue?


[re: Zarjaz] [link to this post]
 
In reply to a post by Zarjaz:
SFI visits are paid for by the CP, whether they then pass them on to their punter is up to them.

RF3 filters do improve this kind of issue with broadband, technically how they do this I don’t know ...

{You’ve seen me Bob, clearly employed for my looks innit grin}


I asked the REIN helpdesk recently about this, apparently the innards of the RF3 filters are included in SSFPs now so rheees no need to fit RF3 filters if a mk4 SSFP exists.

I’d like to get this clarified by high up though as no one seems to know for sure.

Icaras
Standard User Zarjaz
(eat-sleep-adslguide) Mon 23-Oct-17 20:10:31
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Re: Slightly slow ADSL2+ speeds – possible PSTN issue?


[re: Icaras] [link to this post]
 
Well I am by no means claiming to be ‘high up’ but yes, there has been RFI filters built into SSFP’s since the mk3 version.

For me though, I’d still rather see it fitted where the line enters the property, seemed to reduce the errors more that way.

A colleague removed the active components from an RF3 connected wires to crimp on to then encased it all in a blob of Dexbond ..... these he called ‘REIN-drops’ too convenient a name to pass up I suspect. If having no joy in gaining access to a property thought to be the source he could put them across the pair on an OH DP or at the 66, or in the UG radial ..... it helped.

Standard User MHC
(sensei) Mon 23-Oct-17 22:58:30
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Re: Slightly slow ADSL2+ speeds – possible PSTN issue?


[re: Be3G] [link to this post]
 
How close are you to the Panjab transmitter? If you are very close even underground cables will be susceptible and the overheads if any will be wonderful receive antennas.

If the transmitter is the cause - you will have a problem getting it resolved. Filters may not work due to power levels and the radio station are fully licensed.


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

M H C


taurus excreta cerebrum vincit
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