Time will tell if the engineer accepts.

Edited by Chrysalis (Fri 05-Apr-13 13:37:14)

Right,

My IP profile is 77.44, which would seem to indicate that I have a sync of 80mbps.

If that's the case though, why don't I see download speeds closer to 77mbps?

how much interference does a simple bridge rectifier produce ? Is switching the right choice of technology for a simple power supply if the result is excessive RFI ?

Firstly it's a contended service, you're only guaranteed a maximum of 30M from the cabinet to the exchange although if lightly loaded this isn't an issue. For BTW based services "For End-User Accesses selecting the "Standard" traffic option, BT Wholesale will provide a throughput level of at least 12 Mbit/s for 90% of the busy 3 hour period"

Secondly you have the overheads and layers to consider - "For example, if the reported downstream VDSL2 data rate is 40,000kbit/s and the IP packet size is 1500 bytes(i.e. Ethernet frame size at End User LAN is 1514 bytes) the maximum throughput achievable is actually 39,178kbit/s (when measured at the EU LAN i.e. no VLAN header, but including Ethernet header)." (Openreach FTTC SIN)

If that 1500 IP packet carries a useful payload of 1460 bytes of application data (wrapped up in various headers) then 39178 becomes 39178*1460/1500 = 38133 or with PPPoE possibly 1452/1500 giving 37924 or in your case 75848 of useful data throughput.

A long time since I did any EMC formal testing...

prefer ye olde 50 Hz comforting hum of a transformer

engineer I guess normally would have just left, as he been telling me 80mbit sync not possible on FTTC at all (justify current situation), but he got a call whilst here from high level of BT telling him to persist, so he is off to cabinet now and ringing me back in a bit.

He doesnt seem keen to do a pair swap.

Edited by Chrysalis (Fri 05-Apr-13 14:30:38)

In reply to a post by mikehiow:

If that's the case though, why don't I see download speeds closer to 77mbps?

There are other overheads that mean you won't see more than 75-76 at best.

Edited by kasg (Fri 05-Apr-13 14:48:34)

In reply to a post by yarwell:

how much interference does a simple bridge rectifier produce ? Is switching the right choice of technology for a simple power supply if the result is excessive RFI ?

I used to have LED lights in my kitchen but they obliterated DAB reception so they went in the bin and were replaced with a flourescent strip light.

Nearly all the lights in our house are now LED, with no issues whatsoever that I'm aware of.

Edited by RobertoS (Fri 05-Apr-13 15:35:10)