How can I determine distance from exchange?

[stockhausen]

I am currently trying to get two users in the same street (about 100 yards apart) set up to work reliably with a particular ISP.

One house gets a download speed of about 10.5Mbps; the other gets about 5.5 Mbps according to www.speedtest.net.

The ISP (devils that they are) claims that the reason the speed is so slow is that I am using a Netgear DG834Gv5 ADSL Modem. This would be more credible if the modems were different - but they aren't and I have used them elsewhere in the past without problem. Added to all of this, the link seems to die periodically without any changes at my end. I am using a microfilter on the only socket available.

Sometime ago, I stumbled across a site (it may have been a BT site) that would provide such details as the distance from the exchange, SNR, Attenuation, etc. - does anyone have any idea what this link might be

From the "slower" site, according to the Modem status screen, I am seeing the following:

                              Downstream        Upstream
Connection Speed              6495 kbps         955 kbps
Line Attenuation               40.5 db 	         18.0 db
Noise Margin                   8.65 db           6.0 db

From the "faster" site, according to the Modem status screen, I am seeing the following:

                              Downstream        Upstream
Connection Speed             14979 kbps         947 kbps
Line Attenuation               31.0 db 	         12.5 db
Noise Margin                   8.35 db           6.0 db

 

[stockhausen]

Do you have any extensions from the master socket in the slower house?

No; there is only one 'phone socket there (a flat).

There may well be additional sockets in use, without microfilters, in the faster house

 

[stockhausen]

I have just checked my stats at home, they are:

                              Downstream        Upstream
Connection Speed             10697 kbps        1181 kbps
Line Attenuation               31.0 db 	         7.0 db
Noise Margin                   3.95 db           7.0 db

Download speed according to SpeedTest.net is 9,200kbps. I can't believe that the downstream SNR can be so low, that's insane; probably time to have a word with BT

 

[stockhausen]

You say modems, plural, but only list one, what's the other? ...

All modems are Netgear DG834G v5. I also have access to some Thomson (BeBox) job and will experiment with that.

... You can still do the quiet line test though.

What's the "quiet test"?

 

[stockhausen]

You shouldn't loose that much, I get 19.5mb down and 0.72 upload from my 20mb cable connection through the supplied D-Link router

From what I have read, cable appears to be MUCH more reliable and faster than anything supplied over BT lines and as such, comparisons are pretty meaningless.

 

[stockhausen]

Update and a further query

As an update to this story & a further query, in one of the houses, from irregular time to time, I find that the Netgear DG834Gv5 seems to lose the WAN connection and has significant problems reinstating it. This doesn't seem to happen while any data transfer is active, but only when the user is not accessing the Internet, e.g. when she is at work, out of the house for a while or asleep.

Cycling power on the modem doesn't appear to do the trick and it seems that the only way of re-establishing the link is to access the modem via a browser, go to the "Basic Settings" page, make no changes but just to apply the (unmade) changes. I suspect that this does some sort of "Reset"?

ISP is Demon who seem happy to charge you to say that they don't know what the problem is or what you might do to cure it other than buy a different ADSL Modem (they seem to favour Belkin and definitely don't appear to like Netgear).

The whole thing is very irritating; anyone got any suggestions as to what might be causing this behaviour and more importantly how I can stop it?

Speedtest.net:
	Download 5,809 kb/s
	Upload 484 kb/s
	Ping 19ms

Netgear:
	Downstream: 6,872 - kbps Line Att'n 39.5 db - Noise margin 8.7 db 
	Upstream: 947 kbps - kbps Line Att'n 17.5 db - Noise margin 6.0 db

I notice that the £50 Netgear DG834Gv5 whilst being described as a "Wireless-G ADSL2+ 4-port router" uses the Conexant chipset which is described as being ideal for normal ADSL up to 8Mb. On the other hand, the £57 Belkin F5D7633UK4A Wireless-G (125Mbps) ADSL2+ 4-port router uses the Broadcom Chipset which is described as being ideal for LLU ADSL2+ and 21CN ADSL2+ via BT.

So, perhaps Demon have a point

 

[stockhausen]

Well for adsl2+ you really want a broadcom chip, this plus that fact that the gt is more powerful than the standard dgs is why it's so popular. The fact it holds connection where other routers can't/won't makes it the preferred router. For adsl2+ isps will tell you to avoid the v5 and get a gt, that belkin 7633 however should be fine on adsl2+.

I'm on be with 39/21.1db with an snr of 3db and get 13.1 sync, on a 6db profile i get 11.5 (10.5 throughput) and 9 i get 10. That belkin should be achieving similar, the v5 simply wont It looks like you're on 9bd but without more detailed line stats i.e. error count (fec, crc etc.) which i don't know if you can get from the belkin, you can't rule out a poor line.

In any case, congested servers coupled with small files don't give speedtest.net the most accurate results, use the think broadband test files to get a better view of your throughput (larger the better)

Thanks for that advice; I'm not entirely sure that I understand it all but at the very least, it has encouraged me to look at ThinkBroadband.

I have now temporarily swapped one of the Netgear DG834v5s for a Thomson TG585v7 (BeBox) and the download speed has miraculously jumped by 50%! Q.E.D.

I don't know what chipset the TG585 uses but it certainly seems to work a whole lot better than the Netgear; oh, woe is me

 

[stockhausen]

Never been a fan of Netgear myself, i was playing hell with my ISP until i realised it was the router's fault
...

Same here so far as my ISP is concerned, nearly migrated away until I realised that it was the fault of my NETGEAR DG834Gv5 Modem/Router

Having read up on various other forums and a few ISP's sites, I can see that there is a real problem with the DG834Gv5 and ADSL2+.

 

[stockhausen]

I realise netgear brand the v5 as an adsl2+ modem but it can't deal with annex m (only a) because it uses a Conexant chip-set rather than Broadcom. The routers Be/O2 issue may be basic, but they're Broadcom based for a reason...

Thanks for that.

Can you elaborate please? Googling about, I get the impression that Annex M which is a superset of Annex A only affects upstream speeds and does nowt else?

I used to specify the Netgear DG834 because it was so easy for a user to setup/reset; I guess that I will now have to find some other reasonably priced family Modem / Router for use with ADSL2+

Any alternative suggestions?

 

[stockhausen]

Any alternative suggestions?

Annex M (I believe) does only affect upload speeds. It's common for routers not to support this.

Sometimes using different chipsets in your router from that in the DSLAMs can give you worse speeds (i.e. from moving from our BeBox's to our Draytek 2820vn's in each office, we expect to lose 2-3Mbs)

So, not Draytek 2820vn's then