Really flakey Connection

I've got an 8meg Max ADSL line which is really starting to get on my nerves. I've used a BT voyager 205 with a couple of different Wireless routers, this proves slow and annoying due to the voyager trying to be a router too.
I've also got a Linsys Wireless Modem/Router which doesn't seem to hold a connection for more than about 2 hours at the absolute maximum(normally more like 30 mins), once it drops it needs rebooting to get the connection back again.
It reports some stupidly high number in the downstream margin eg. 21423423423db
I have the same problem with a normal Linksys Modem too.
I've emailed the ISP (Freedom 2 Surf) they couldn't find a problem and 'escalated' it to BT, from who I haven't heard a dickie bird!

Anyone else hear anything familiar there?

Thanks.

How long have you had your ADSL service?

Almost 3 months. Moved from Cable and REALLY regretting it. Cable on the old isle of wight is just too slow compared to the speeds available on ADSL.

There is too much noise (permanent or otherwise) on your line, for the router to hold sync for long.
The stupid noise margin figure is usually an indication the noise margin is approaching, or below zero.
Can you post the rest of your stats (sync speed, line attenuation, noise margin)?

Also try the modem/router plugged into the 'test' socket inside your BT master (if you have the newish type of master socket with the removable lower front panel), this will remove, from the equation, any internal wiring problems and some/most of the interference - post your stats for this as well.

This is my current stats: Whilst its working
DSL Status: Up
DSL Modulation Mode: GDMT
DSL Path Mode: INTERLEAVED
Downstream Rate: 4224 Kbps
Upstream Rate: 448 Kbps
Downstream Margin: 11 db
Upstream Margin: 26 db
Downstream Line Attenuation: 26
Upstream Line Attenuation: 12
Downstream Transmit Power: 0
Upstream Transmit Power: 0

PVC Connection

Encapsulation: RFC 2364 PPPoA
Multiplexing: VC
QoS: UBR
Pcr Rate: 0
Scr Rate: 0
Autodetect: Disable
VPI: 0
VCI: 38
Enable: Yes
PVC Status: Applied

Are you plugged, or can you plug, into the master socket?
Try the internal test socket (if you have the newer master where the lower half of the front plate can be removed), with only your router and a micro-filter plugged in.

Your ds line attenuation is very low (at 26db), this indicates a nice short line, and one that should really be able to sync at the full 8128kbps, but your noise margin (at 11db) is not very high for such a short line, and a low sync (4224kbps).
All this indicates noise on the line, which is preventing your router from syncing at a higher speed.
If you can do the tests, connecting inside the master socket, it'll prove whether the interference is coming from inside or outside your home (if inside, there are measures that can be taken to improve things). It's also possible dodgy internal 'phone wiring could be causing this (the same test will show up this too).

I've detached the lower section of the master socket and plugged in as you suggested, this is results. Even lower margin, does this suggest a problem with the external phone line? BT job I take it?

DSL Status: Up
DSL Modulation Mode: GDMT
DSL Path Mode: INTERLEAVED
Downstream Rate: 6112 Kbps
Upstream Rate: 448 Kbps
Downstream Margin: 5 db
Upstream Margin: 26 db
Downstream Line Attenuation: 26
Upstream Line Attenuation: 12
Downstream Transmit Power: 0
Upstream Transmit Power: 0

PVC Connection

Encapsulation: RFC 2364 PPPoA
Multiplexing: VC
QoS: UBR
Pcr Rate: 0
Scr Rate: 0
Autodetect: Disable
VPI: 0
VCI: 38
Enable: Yes
PVC Status: Applied

Well the margin is lower, but 5db is not unusual (the default starting point is 6db).
But you've noticed you're now connected 1.5Mbps faster than you were before. This implies there is some element of wiring problem or something dragging in interference internally.
You need to leave it in the master 'test' socket during the evening, or overnight, to see the effects of interference from distant AM radio stations.
I would suggest getting an ADSL face-plate/splitter from ADSLnation or Solwise (they're only about