On 28/05/13 6:22 PM, Allan Duncan wrote:
The best indication of what you will get is the Loss
and SNR margin that
you can find on the modem's web interface.
Distance is only a partial indicator, weight of copper is the other.
For lines put in over the last 40 years that figure is "cheap". Quality
of junctions also matters - I just had Telstra around to deal with one
of them - even voice calls failed with water-caused crackle.
I'm about a Km closer than you and I get 6.4Mb at a SNR of 7 dB, loop
atten 37 dB (the Draytek Vigor120 I'm using gives slightly different
info to the Netgear DG834N I was using).
The Vigor 120 has an Infineon chip apparently.
Well, the line is 4.6km according to
Internode, and various modems have
got speeds ranging from 1 to 4.2 Mbps. The Fritzbox was managing 1Mbps
with some tweaking. However, I have managed to make a considerable
improvement by puting an old D-Link DSL-502T into bridge mode and
setting it for ADSL 1 (G.dmt). This has increased my speed to 3.6 Mbps,
which is in the range I would regard as acceptable. Interestingly, this
modem wouldn't sync at all in ADSL 2+ mode. Other modems tried include
a Netcomm modem (loan unit) at 2.8-3.0 Mbps, and a Bigpond modem at 4.2
Unfortunately, I am unable to check the SNR margin on the D-Link easily,
because I can't access its web interface due to routing issues, unless I
take the router out of circuit, and connect a PC directly to the modem,
or add a switch, so I can connect a PC at any time (the web interface
and DHCP server do remain active for the LAN port in bridge mode). From
memory, I think it was around 6 or 7 dB at 3.6Mbps sync speed.
That data rate is for Internode's "ADSL2+ High Speed" profile. Now the
dud junction is gone it has been rock stable. In fact this has prompted
me to put in a profile change to Very High Speed. Fingers crossed.
I'm on a
Telstra exchange here, so can't access line profiles. No
choice. Optus is in town, but effectively can't get Optus powered
services due to RIMs and/or pair gain on the Optus network (the coverage
checker says you can go through Optus, but the change request will fail
- I've tried at two different addresses). Internode will probably never
install a DSLAM out here. As for NBN, it's still more than 3 years away
(i.e. not on any of the rollout schedules yet :( ).
73 de Tony VK3JED