Abc Broadcast Problems

[Matt Doran]

Hi,

Long story, but it seems that the DVB ABC broadcast in Melbourne might be setup incorrectly ... which may cause reception problems.

In my MythTV media pc, I use the DVB tuner (Hauppauge Nova-T 500). It has had problems with picking up ABC (and also SBS). Even with strong, good quality signal strength, the channel locks on ... but suffers from glitches and quality problems. This is described in a vvery long thread.

This problem was very particular to Melbourne. After much debugging effort from Hauppauge and the australian distributor, they found the cause of the problem and issued a driver fix.

I use this card on Linux ... and discussed the problem with the Linux driver developer. It turned out that the problem was with the broadcast ... not the card. Here's the quote from the developer:

I have discussed with the people involved with Hauppauge at DiBcom and

wanted to know the problem.

They explained me, that the actual problem/mistake is the broadcaster:

They are using SFNs (single-frequency network, a DVB-T mux is transmitted

by several, geographically different, transmitters) and each transmitter

has its own cell-id in the TPS. As the channels are the same, the cell-id

should be the same as well.

Does anyone know what this means? DVB experts? How can we confirm this? Is this something that the ABC should change?

Obviously, some tuners are better at overcoming this than others. But maybe this causes reception problems receiving ABC for others in Melbourne???

Cheers,

Matt

[mtv]

Matt,

You haven't mentioned which suburb of Melbourne you are in.

What specific Melbourne suburb/s was the 'quote' referring to?

ABC TV's Melbourne main transmitter is NOT on a SFN (single frequency network) it is on VHF channel 12.

There are a few low-powered translators that are on an SFN, however they are geographically well-separated and I have not seen any SFN problems with the ABC, or any of the other networks in Melbourne, unlike several issues with SFN's around the NSW central coast.

The post on the link you gave states "For people recieving on the VHF band with the Hauppauge dual tuner (Mainly Melbourne Metro people), you will more than likely have issues with SBS and ABC stuttering."

Firstly, ss I mentioned the ABC VHF transmitter is stand-alone... NO SFN... secondly, SBS Melbourne is on channel 29 UHF.. nothing whatsoever to do with VHF.

I would agree with your post "This problem was very particular to Melbourne. After much debugging effort from Hauppauge and the australian distributor, they found the cause of the problem and issued a driver fix."

Why would the card manufacturer say they found a problem and issued a fix for it, if a fault in their equipment didn't exist?

If your received digital signals are within channel-power and BER requirements for reliable digital reception, you should have no problems.

I suggest your problems are more to do with the tuner-card, than any SFN issue.

Try a set top box in the same outlet you have your tuner-card connected to and see if that also has the same problem

[beeblebrox]

Does anyone know what this means? DVB experts? How can we confirm this? Is this something that the ABC should change?

Obviously, some tuners are better at overcoming this than others. But maybe this causes reception problems receiving ABC for others in Melbourne???

Cheers,

Matt

It means they're spinning BS!!!!

There are no VHF SFN networks running in Melbourne. There is ,as MTV states, a UHF (Band 5) SFN operating but unless you are in a bayside suburb using one of these SFN tranmitters... with an incorrectly setup antenna system you shouldn't be seeing SFN issues. but this is very rare and is only on UHF anyway...

Other than normally coming of the same broadcast tower at Mt Dandenon, ABC/SBS use totally different frequencies and have different modulation parameters they use different guard intervals and FEc ratios.

The issue is much more likely to be your card /software or recieving equipment (antenna etc)...

[Matt Doran]

Fair enough. All that talk was way over my head!

I'm in Blackburn, and I have a friend in Glen Iris with exactly the same card, and the same problem on ABC. I have another brand of tuner card, an cheap STB and a tuner in my Panasonic plasma ... and they all work fine.

The fix issued for the Windows driver definitely fixed the problem for Windows users. I'll be interested to see if Patrick (the linux driver developer) can fix the problem. And unlike the Windows driver we can actually see what changed with the driver.

So you don't think the cell-id thing could be the cause?

[spider1503559973]

Fair enough. All that talk was way over my head!

I'm in Blackburn, and I have a friend in Glen Iris with exactly the same card, and the same problem on ABC. I have another brand of tuner card, an cheap STB and a tuner in my Panasonic plasma ... and they all work fine.

The fix issued for the Windows driver definitely fixed the problem for Windows users. I'll be interested to see if Patrick (the linux driver developer) can fix the problem. And unlike the Windows driver we can actually see what changed with the driver.

So you don't think the cell-id thing could be the cause?

[spider1503559973]

Fair enough. All that talk was way over my head!

I'm in Blackburn, and I have a friend in Glen Iris with exactly the same card, and the same problem on ABC. I have another brand of tuner card, an cheap STB and a tuner in my Panasonic plasma ... and they all work fine.

The fix issued for the Windows driver definitely fixed the problem for Windows users. I'll be interested to see if Patrick (the linux driver developer) can fix the problem. And unlike the Windows driver we can actually see what changed with the driver.

So you don't think the cell-id thing could be the cause?

Matt,

You did not mention what type of Antenna DO you have <If you have older Model SOME OF THEM WILL NOT PICK ch.12 WHAT IS YOUR ABC ,i HAVE Had similiar case where KEON STB was working Perfect and PC Tuner did have only 25% from 100% QUALITY.

It my be same problem in Your Friend Place !

Some Pc Cards are very sensinitive ...and require Top Installations

[mtv]

I have another brand of tuner card, an cheap STB and a tuner in my Panasonic plasma ... and they all work fine.

Matt, looks like you've answered your own question.