[UK-CONTEST] BT Infinity

[Dave Sergeant]

On 16 Aug 2011 at 11:22, David G3YYD wrote:

> Does anyone have experience of the EMC compatibility of this product
> with high power contesting? Both good and bad.
> 
> With the normal BT Broadband I had to design, make and install a 1MHz
> cut off LPF on the line going to the router. Without it on the low bands
> the modem retrained to a very low download speed.
> 
> BT Infinity still uses tones on the normal phone pair coming into the
> house but from a roadside cabinet which is fibre fed. To get its higher
> (40MB/S) speed I presume the bandwidth on the line must go higher than
> 1MHz. Hence the question asked.

BT Infinity (and similar fibre products marketted by a FEW other ISPs) 
uses fibre to your nearest cabinet, then over normal twisted pair to 
your house as VDSL - this uses up to 12MHz. I have no information as to 
its EMC characteristics, but imagine radiated noise will be more 
noticeable than ADSL/ADSL2+ (up to 2MHz). Most problems with broadband 
disconnecting from amateur transmissions are due to it getting into the 
router, these will be no different with Infinity, but since your 
broadband signal is likely to be stronger depending on the distance of 
your cabinet then I would think it would be more immune.

Have you checked that you can actually get Infinity? Our exchange in 
Bracknell has slipped a year and won't be upgraded till the end of this 
year. And having your exchange upgraded does not mean you can get it, 
as BT have been very slow in installing the actual fibre and putting in 
cabinets.

> Also anyone had problems with Vigin Media "fibre" broadband?

Virgin cable puts the broadband on UHF channels along with the TV 
service, so is totally immune to the sort of problems ADSL suffers. 
Note that the 'fibre' part goes to a major distribution hub in the 
vicinity, it is then distributed to other cabinets and eventually your 
house over normal coax. The fibre bit may some distance away. Obviously 
an option if your street is cabled, but of course you are then 
restricting yourself just to Virgin broadband.

73 Dave G3YMC
 


http://www.davesergeant.com