[mythtv-users] UK DVB-T problems

[Nick Craig-Wood]

On Thu, Jan 06, 2005 at 11:45:24PM +0000, James Fidell wrote:
> Having managed to find a few channels from the Mendip transmitter (which
> carries just about everything), I'm getting:
> 
> $ tzap "BBC ONE"
> using '/dev/dvb/adapter0/frontend0' and '/dev/dvb/adapter0/demux0'
> tuning to 778000000 Hz
> video pid 0x0258, audio pid 0x0259
> status 01 | signal 1717 | snr 0000 | ber 0000ffff | unc 0000000b | 
> status 1f | signal 1616 | snr 9292 | ber 00008581 | unc 00000007 | FE_HAS_LOCK
> status 1f | signal 1717 | snr 9090 | ber 000073c9 | unc 00000009 | FE_HAS_LOCK
> status 1f | signal 1717 | snr 9696 | ber 0000680f | unc 0000000e | FE_HAS_LOCK
> status 1f | signal 1717 | snr 9999 | ber 00005e70 | unc 00000009 | FE_HAS_LOCK
> status 1f | signal 1717 | snr 8f8f | ber 00006a03 | unc 00000004 | FE_HAS_LOCK
> status 1f | signal 1717 | snr 9292 | ber 0000639f | unc 00000007 | FE_HAS_LOCK
> 
> 
> I'm guessing those figures really aren't good news and might explain why
> I can't see any channels from other muxes on that transmitter?

Yes you are correct!

The mux with BBC ONE (Myx 1) in is broadcast in QAM 16 which is better
than the QAM 64 of the other multiplexes, and is probably at higher
power.  You have a very low signal on that so its unlikely you'll get
the other muxes.  You are getting uncorrectable errors in the above
which will render the video very annoying!

My worst multiplex (Mux A) has around 0x1000 correctable errors per
second and no uncorrectable errors.  You've got about 10 times that
many errors.  On Mux 1 I get no ber/unc at all!

Use this (sort by mux) if you want to see what channel is where

  http://homepages.enterprise.net/cavan/scripts/dtt/dtt.cgi

So, better upgrade your aerial!

-- 
Nick Craig-Wood <nick at craig-wood.com> -- http://www.craig-wood.com/nick