No phone extensions for increased BB speed?

[#1]

I recently tried my PC (not laptop) downstairs in lounge using the line box master socket and got double my usual sync (2MB instead of 1MB) and 50% faster results from the PN speedtester (Max of 752Kb/381Kb instead of my usual 476-502 Kb range / 381 Kb).  I use a old Voyager 105 modem on Max for mainly just internet use and emails.
Since we have just signed up for PN Homephone+ without the BT 1571 Voicemail facility we got a new landline phone with answering machine and two cordless handsets.  This is plugged in to the master socket so I therefore realise that we can now do without any of our phone extension wiring to kitchen and main bedroom.
I currently run a phone extension cable from the bedroom extension socket to another bedroom with my PC in.  The microfilter is on the end of the extension lead and we have never used analogue phones on any of the extensions.
I am therfore thinking of fitting a filtered faceplate to the master socket and buying a wireless router which could sit in the lounge.  Not connect the extension wiring from the master socket to the new faceplate.  Continue to use the PC upstairs.
Advice please!
Will this work?
Just in case I do ever buy a laptop and want to network it, what would be a reliable router for just two computers?
Could I expect to see the speed improvement I saw on my test?
Do you leave routers switched on permanently?
The BT site says we are 3.25km from the exchange in a straight line and 4.83km by road and estimate our max d/l speed would therefore be 1Mb.
Expert opinions would be appreciated.

[#2]

Just do it. 
Can you obtain the downstream attenuation for your line from your current modem/router?

[#3]

A few weeks ago from the upstairs extension cable attenuation was "Loc 39.5  Rem 31.5" 
I will haul my big PC down to the test socket and try again tomorow if you need it from there.
Thanks.

[#4]

Not sure what those numbers mean.
IF 39.5 is your downstream attenuation it imples a line length of under 3km and potential speed of 7mbps!
At the distances and speeds you've quoted attenuation would be in the 60's, eg. 65dB.
Try it downstairs but it usually doesn't make a difference to attenuation as such. It's a measure of your total line length and indication of maximum speed in perfect conditions.

[#5]

Those figs from scribbled notes and no units.  At same time we tested a friend's laptop on our line and got 63.0 dB and 31.5db.  From what you say the PC/laptop used does not matter.  Are these figs more reasonable?

[#6]

Very reasonable and consistent. 63dB should give about 2mbps with everything fixed.

[#7]

OK HP will get back to you tomorrow with some new figures from the test socket.

[#8]

Those figures won't change much, if at all.
It's the sync rates that change and you've already done that I believe.
Attenuation tells you what the target is, sync speed how close. But it's never exact. 

[#9]

It is actually the SNR/Margin figure, not the line attenuation that determines the speed you will get on ADSL Max.
Line attenuation gives an idea of line distance and power of the signal (the further away you are the lower the power), SNR/Margin gives an idea of signal quality. You can have a short line but low SNR and get low sync speeds. You can also have a long line with high SNR and get faster speeds. In general the longer your line the lower your SNR will be.

[#10]

Whilst the SNR margin will have a considerable impact on synchronisation speeds, it is actually the synchronisation speeds that determine throughput, as that will determine the throughput speeds.
Although Peter, you can easily argue it from both sides of the coin

[#11]

@ HPsauce et al:
OK just tested from the test socket behind the master socket in lounge with a standard PN-supplied microfilter and the new cordless phone connected.
BT speedtester gave profile of 750K, connect rates of 1984/448 and actual throughput of 686.
Just prior to that the PN speedtester gave 744/381.
Modem (Voyager 105) data:
Data rate 1984/448
Line Rate 2208/544
Attenuation  Local 57.5 dB  Remote 31.5 dB
SNR margin  Local 6.5 dB  Remote 8.5 dB
As it happened the line then dropped and after reconnecting the figures changed slightly to
Data rate 1952/448
Line Rate 2176/544
Attenuation  Local 58 dB  Remote 31.5 dB
SNR margin  Local 7 dB  Remote 8 dB
Look forward to your comments.  But don't forget my questions from the original post please!

[#12]

Quote from: EmpireCad

Will this work? Just in case I do ever buy a laptop and want to network it, what would be a reliable router for just two computers? Could I expect to see the speed improvement I saw on my test? Do you leave routers switched on permanently?

Yes
Yes
Maybe
Yes
...in that order
Extensions can cause problems, so you will generally get the best speed by connecting straight to a filtered faceplate with a short cable from the router. You can either work wirelessly or run CAT5 network cable to the PC. If you are syncing at 2000-ish you should get a profile about 1500, but it might take a few days for BT to catch up.

[#13]

3 days at least to catch up, IF you consistently sync at higher speeds.
58dB attenuation could even get you 3mbps if you're lucky.
So you need to be consistently connected at the faster speeds and then wait at least 3 days before BT will believe it and let you use it. Meanwhile your IP profile stays low  :(.

[#14]

Thanks, Denzil and HPsauce for your replies.  The second question in the original post was really asking for a recommendation as to what make/model of router to go for.  Something good value, reliable and simple to use ideally.  Any suggestions?
When you talk about BT "catching up" and "BT will believe it and let you use it" I presume this all happens automatically as part of the line "training" process ie I just have to leave the router on permanently and hope it doesn't drop the connection?  Sorry if this is all basic stuff to you but I've never used a router before.

[#15]

Yes, automatic, just leave it on.