Spikes

Another question about signal/noise margin!

My router (ST585 v6) syncs happily for days on end to maintain an IP Profile
of 5.5 Mbps. The diurnal variation of the noise margin is ~ 5.5 to 13
dB. My router is located at and directly connected to the master socket
filter faceplate but occasionally there is a brief noise spike that according to
RouterStats plunges negative off the scale. This spike is quite random and
occurs at no particular time of day or night and upon daytime resync the margin is ~12dB.

Is there any way of suppressing this brief spike to smooth out the noise margin and maintain sync, in a similar way to a power surge limiter?

Line Stats for reference:

Bandwidth (Up/Down) [kbps/kbps]:448 / 6,432
Output Power (Up/Down) [dBm]:11.5 / 19.5
Line Attenuation (Up/Down) [dB]:25.0 / 41.0
SN Margin (Up/Down) [dB]:22.0 / 11.5

Yes, slow the broaband down to the point where you have enough spare margin that it does not disconnect.

A spike once or twice a day is one of those you have to live with issues on ADSL.

Thanks Andrew, not the answer I was hoping for

A spike a day keeps the margin at bay

This is what I'm up against!

Now, if someone could just invent something.........

Do these "spikes" occur during daylight hours, or just between dusk & dawn?

An all too familiar picture and one I used to regularly see until I switched from a BT wholesale ADSL1 (ADSLmax) product to BE's ADSL2+ LLU product.

The culprit may be traceable (if you have a suitable router).
The 2-wire 2700HG or 2700HGV (often branded as a BT business hub) has an "impulse noise" figure on its web interface.
Normally this figure sits at zero, but occasionally starts to rise and suddenly goes through the roof (at which point a resync occurs).

Using a 2-wire router, I traced one of my noise sources to a cheap ebuyer DVD player, which would give off massive amounts of noise every time it accessed a disc.

In answer to your question "can it be filtered".....
No, unfortunately not.
If the noise is at ADSL frequencies of anything up to 1.1MHz (or 1100kHz in AM radio speak) for ADSL1 or 2.2MHz for ADSL2+; if you filter out the noise, you filter out the ADSL signal too.
Unfortunatly ADSL works up into the same frequencies as AM (MW) radio, so anything which makes a "pop" on AM radio, can affect ADSL broadband (lightning strikes, tube lighting, TVs, microwaves, street lights, and several thousand other things - sometimes it appears just looking at an ADSL router will force it to drop sync).

That is not a spike! I would call that a "burst" and for RSL to pick it up it must have a duration of several seconds. You need to look close to home and see if there is anything causing it. Possibly a freezer which may only come on twice a day

In reply to a post by MHC:

That is not a spike! I would call that a "burst" and for RSL to pick it up it must have a duration of several seconds. You need to look close to home and see if there is anything causing it. Possibly a freezer which may only come on twice a day

I had similar in the summer, and my ISP called out BTOR who found three dodgy connections *outside* my flat, but *inside* the block of flats, not touched since built in 1971....

In reply to a post by MHC:

That is not a spike! I would call that a "burst" and for RSL to pick it up it must have a duration of several seconds.

Something arching then? It can happen at any time of the day so perhaps so as you say, maybe my freezer thermostat.

My phone line also passes under but at right angles to a 11kV power line but it's only me on the end of the power line!

In answer to your question "can it be filtered".....
No, unfortunately not.

OK, thanks

Where's the transformer?