Pixelation - DVB T - Waiatarua

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steve2222

498 posts

Ultimate Geek

#90924 3-Oct-2011 16:03

Did anyone else experience the above last night (Sunday 2 October).

Admittedly it was raining - but not that bad I would have thought.

Some Kordia transmitted channels were completely unobtainable, others were pixelated.

All TVNZ and Mediaworks channels were fine.

If it was rain/weak signal, why would it not affect all 3 MUX?

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1961 posts

Uber Geek

#528688 3-Oct-2011 19:39

steve2222: Did anyone else experience the above last night (Sunday 2 October).

Admittedly it was raining - but not that bad I would have thought.

Some Kordia transmitted channels were completely unobtainable, others were pixelated.

All TVNZ and Mediaworks channels were fine.

If it was rain/weak signal, why would it not affect all 3 MUX?

More oftern than not one mux will drop out before the rest depending on many factors.
The drop out while raining probably indicates your signals are marginal and the rain is enough to reduce signal level below droput level on one or more mux.
You may be getting water in the co-ax.
Check signal levels on each mux via your TV setup menu and also check quality of antenna and co-ax. If the antenna and co-ax is old one or both may need replacing.

steve2222

498 posts

Ultimate Geek

#528722 3-Oct-2011 21:04

B1GGLZ:

More oftern than not one mux will drop out before the rest depending on many factors.
The drop out while raining probably indicates your signals are marginal and the rain is enough to reduce signal level below droput level on one or more mux.
You may be getting water in the co-ax.
Check signal levels on each mux via your TV setup menu and also check quality of antenna and co-ax. If the antenna and co-ax is old one or both may need replacing.

Yes, I am going to need to check the aerial and connections.

Interestingly the 2 good MUXs are getting full signal strength according to the meter on the TV. The Kordia MUX is getting nil signal and I have now lost all the Kordia channels (weather is pretty bad outside right now).

I am still surprised 2 of the MUXs can be so strong and one completely bad. Cannot even re-tune the channels (it just does not find them now).

B1GGLZ

1961 posts

Uber Geek

#528848 4-Oct-2011 09:27

steve2222:

Interestingly the 2 good MUXs are getting full signal strength according to the meter on the TV. The Kordia MUX is getting nil signal and I have now lost all the Kordia channels (weather is pretty bad outside right now).

Not strange really. The 3 mux are on channels 29, 33 and 45. That's a large frequency gap (200mhz ?) between the two low freq mux and the higher freq mux. Your antenna system is obviously not working very well at the high end of the UHF band where external factors such as rain etc can have great influence.

steve2222

498 posts

Ultimate Geek

#529002 4-Oct-2011 12:57

B1GGLZ: Not strange really. The 3 mux are on channels 29, 33 and 45. That's a large frequency gap (200mhz ?) between the two low freq mux and the higher freq mux. Your antenna system is obviously not working very well at the high end of the UHF band where external factors such as rain etc can have great influence.

Assuming the worst - what is a good aerial (make and manufacturer) for me to buy.

I live in Devonport Auckland with line of site to Waiatarua (but it is a reasonable distance).

Currently I have a combined UHF/VHR aerial with in built diplexer, but given the pending closure of analogue it seems to me it would make semse to go for a dedicated UHF aerial only.

Thanks

minigopher17

281 posts

Ultimate Geek

#529006 4-Oct-2011 13:02

I might be completely wrong here, but if you're in Devonport, shouldn't you be pointing at the Sky Tower? It's a lot closer.

nzkc

1571 posts

Uber Geek

#529045 4-Oct-2011 14:12

steve2222:
I live in Devonport Auckland with line of site to Waiatarua (but it is a reasonable distance).

I live on the Whangaparao Peninsula and get Freeview HD from Waiatarua...now thats a reasonable distance

I would expect you'd be able to get reliable reception in Devonport. Might just need to adjust your aerial a bit - Ive had an occasion where wind blew my aerial off a little and caused lots of reception drop outs. Trip to the roof fixed that.

B1GGLZ

1961 posts

Uber Geek

#529076 4-Oct-2011 14:47

steve2222:

Currently I have a combined UHF/VHR aerial with in built diplexer, but given the pending closure of analogue it seems to me it would make semse to go for a dedicated UHF aerial only.

Thanks

And that could be your problem. Get rid of the VHF antenna and diplexer if separate (or the whole lot if truly combined).
That quite often upsets the whole applecart for Freeview reception. The VHF antenna is probably causing problems with the high UHF mux.
You should be able to get a signal in Devonport using a pice of wet string!
Try the Freeview Shop online
http://www.freeviewshop.co.nz/terrestrial-aerials-c-11.html
The 21 el should be fine either Horizontal at Waiatarua or vertical at Sky Tower. I use the 47 el in Kauri Park but it's somewhat overkill as I can get an OK signal on al mux on a short piece of wire on the end of a short co-ax lead indoors at the PC.
Make sure you have good rg6 co-ax.

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steve2222

498 posts

Ultimate Geek

#529082 4-Oct-2011 14:56

Thanks all for the replies.

I agree that I should get good reception.

I used to on all Freeview channels, even when they had the HD demo channel (which was on the Kordia MUX).

In fact it was only this Sunday (with the bad weather) that I noticed the issue.

I suspect equipment deteriation (cable and aerial only 3-4 years old), but we are very close to salt spray.

Trip to the roof, inspect and maybe replace the aerial with UHF dedicated one seems in order.

lorenzo

91 posts

Master Geek

#529192 4-Oct-2011 21:43

Just to add - I live in Greenhithe and was blaming the neighbours huge Poplar Trees - but perhaps I was maligning them.

The signal up til Sunday has been pretty good for a year with only minor pixellation.

As the good wife said - "well this is sh!t - in a year we won't have analogue to fall back on then what ?"

injuised

256 posts

Ultimate Geek

#529200 4-Oct-2011 21:54

lorenzo: Just to add - I live in Greenhithe and was blaming the neighbours huge Poplar Trees - but perhaps I was maligning them.

The signal up til Sunday has been pretty good for a year with only minor pixellation.

As the good wife said - "well this is sh!t - in a year we won't have analogue to fall back on then what ?"

Then youll have satellite to fall back on

lorenzo

91 posts

Master Geek

#530149 6-Oct-2011 15:08

injuised:
lorenzo: Just to add - I live in Greenhithe and was blaming the neighbours huge Poplar Trees - but perhaps I was maligning them.

The signal up til Sunday has been pretty good for a year with only minor pixellation.

As the good wife said - "well this is sh!t - in a year we won't have analogue to fall back on then what ?"

Then youll have satellite to fall back on

Wouldn't that require a Dish and DVB-S box? The point is at least analogue doesn't require additional equipment(read expense) on the consumer.

hdinsider

552 posts

Ultimate Geek

#530165 6-Oct-2011 15:32

It's not fair to compare dtt to analog. Those consumers with a well set up antenna system now have twice the number of channels, HD pictures, widescreen, Dolby 5.1 and all for (relative to 60's,70's,80's and 90's) a much cheaper capital outlay. And let's not forget it has no ongoing cost to receive. Even if you need to get a dish and decoder for satellite, it's still a great deal of entertainment for the one off cost.
Analog was rugged, but ghosty, soft and noisy.
I'd choose the new system anyday.

don't mess with me.... i'm the hd insider....

injuised

256 posts

Ultimate Geek

#530324 6-Oct-2011 19:16

hdinsider: It's not fair to compare dtt to analog. Those consumers with a well set up antenna system now have twice the number of channels, HD pictures, widescreen, Dolby 5.1 and all for (relative to 60's,70's,80's and 90's) a much cheaper capital outlay. And let's not forget it has no ongoing cost to receive. Even if you need to get a dish and decoder for satellite, it's still a great deal of entertainment for the one off cost.

Analog was rugged, but ghosty, soft and noisy.

I'd choose the new system anyday.

lorenzo

91 posts

Master Geek

#530400 6-Oct-2011 22:47

injuised:
hdinsider: It's not fair to compare dtt to analog. Those consumers with a well set up antenna system now have twice the number of channels, HD pictures, widescreen, Dolby 5.1 and all for (relative to 60's,70's,80's and 90's) a much cheaper capital outlay. And let's not forget it has no ongoing cost to receive. Even if you need to get a dish and decoder for satellite, it's still a great deal of entertainment for the one off cost.

Analog was rugged, but ghosty, soft and noisy.

I'd choose the new system anyday.

+1

hmm OK I suppose I could always watch a DVD or read a book when it rains or the leaves on the neighbours tree or the farting cat or whatever it is that causes random pixelation and freezing take hold.

Not wanting to compare analogue and dtt (apples and oranges) - but in a year there won't be a fall back and I hope the reliability of the dtt service improves before that date. The Sunday in this discussion an example of the widespread issues that although seeming less and less common still occur too often.

jimbo99

1 post

Wannabe Geek

#530704 7-Oct-2011 19:46

Not sure if this will put your mind at rest Steve but I work for a local TV company in the South Island and use Kordia as our uplink to the freeview service. Last week they were experiencing some issues with their link to freeview which resulted in the same problems that you were experiencing. Because it was an issue with their link it was only affecting channels supplied by them.

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