[linux-dvb] Re: Developments with DVB-T in the UK

[Dave Chapman <dave@dchapman.com>]

On Thursday 04 July 2002 19:17, steved-linux-dvb@daviesfam.org wrote:
> On the technical side there seems to be lots of support to move from 64QAM
> to 16QAM modulation to improve signal reach and stability.  Looks like its
> going that way.

For those living in London (i.e. using the Crystal Palace transmitter), there 
are currently tests on the old multiplex B, C and D frequencies (529833KHz, 
578166KHz and 537833KHz) using a variety of parameters:

B - 2K, 16_QAM, FEC_3_4
C - 8K, 64_QAM, FEC_2_3
D - 8K, 16_QAM, FEC_3_4

Each multiplex is broadcasting a copy of BBC1, (labelled TEST1, TEST2 and 
TEST3) and two other "DTG" test channels.  

My Nokia DVB-T receiver only finds TEST1 when doing a channel scan, it can't 
tune in to the 8K multiplexes.  The Nova-t card has no problems with any 
multiplex.

A full (technical) report on DTG's tests can be downloaded from:

http://www.dtg.org.uk/dtgactivities/published/dtt_modes_trial_report.pdf

According to this report, a switch from 64_QAM to 16_QAM is the same as 
quadrupling the transmitter power (but with a 2/3rds reduction in capacity).

Dave.



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