Channel 7 Wide Bay Pixleing

**MrRadio** · 06-08-12, 12:43 PM

For a month or so the 7 group has suffered minor annoying pixleing at my place. Today I got up to the antenna and found/rectified a loose cable connector (I was surprised to find it was a screw on not crimped) on the amp and at first glance the problem is fixed but the wind is calm at the moment and I am yet to see if it plays up in a blow.
To my knowledge 7 is still VHF (vertical) where as all the others, I believe, are UHF(horizontal). Does this make 7 more susceptible to low signal than the others and can it be affected by the neighbours trees that have grown into the signal path over the years. I don't know the brand of the antenna but it is a dual band multiplexed in the antenna with single co-ax to the amp which I bought about two years ago from the local elect supplier to replace the original one that had elements falling off.

Edit: Buggar

**beerman** · 06-08-12, 02:07 PM

Originally Posted by MrRadio

To my knowledge 7 is still VHF (vertical) where as all the others, I believe, are UHF(horizontal). Does this make 7 more susceptible to low signal than the others and can it be affected by the neighbours trees that have grown into the signal path over the years.

The Cooloola translator site is vertically polarised transmission. All digital services are UHF. The Gympie Black Mountain site is horiziontally polarised transmission and again all services are UHF.

While ABC is frequently VHF and other services UHF to be getting two different polarity signals you would have to have two different antennas facing in two different directions. As you say you have a combination antenna (VHF/UHF) then you will be receiving just one polarity - either vertical or horizontal.

Sorry I can't be more accurate without knowing which translator/transmitter site you are pointing your antenna at.

**nbound** · 06-08-12, 02:20 PM

Originally Posted by beerman

As you say you have a combination antenna (VHF/UHF) then you will be receiving just one polarity - either vertical or horizontal.

You can get cross polarised combo antennas. They are used in places like canberra and a few others.

I havent looked into the OPs problem but ill probably post on that later. As beerman states knowing which site you are pointed at, or location and approx bearing, would help alot. A pic of the antenna system would help also.

**nbound** · 06-08-12, 02:34 PM

Originally Posted by beerman

As you say you have a combination antenna (VHF/UHF) then you will be receiving just one polarity - either vertical or horizontal.

You can get cross polarised combo antennas. They are used in places like canberra and a few others.

I havent looked into the OPs problem but ill probably post on that later. As beerman states knowing which site you are pointed at, or location and approx bearing, would help alot. A pic of the antenna system would help also.

**mtv** · 06-08-12, 03:41 PM

It may not be your reception (although it sounds like it is).

I've noticed some brief pixelation on both 7 in Melbourne and Prime in a few Vic areas, which suggests it's either from the playout centre, or somewhere in the distribution chain.

Received signals are fine with no dropped packets, so the issue does not appear to be a local transmission issue.

This may or may not be relevant to your area, but considering it's happening over a huge area in Vic with otherwise excellent signals, I thought I'd mention it.

**MrRadio** · 06-08-12, 05:41 PM

We are pointed at Mt Goonaneman

This is not as I understood it .... now makes me wonder why only getting problems on 7 alone

**mtv** · 06-08-12, 07:06 PM

Mt Goonaneman:

STQ7 184.625 MHz 60 kW Vertical

TNQ9 198.625 MHz 60 kW Vertical

ABC9A 205.625 MHz 60 kW Vertical

RTQ10 212.500 MHz 60 kW Vertical

SBS28 529.500 MHz 250 kW Horizontal

**nbound** · 06-08-12, 08:28 PM

So its either the issues MTV has described about Vic Prime (which ive heard also - maybe similar going on up there). Or its because all your VHF stations are weak, but Prime moreso (probably only by a small amount) than the rest and therefore is affected first. This latter could be due to your location or the gain curve of your aerial, but would be rectified with a higher gain antenna and/or amplification (and/or rectifying a problem that has caused the signals to drop to this level).

Easiest way to find out is to ask your neighbours/friends if they all have the same issues. Its fairly unlikely that everyone will have similar antenna faults, so if they all get the same breakup id suggest its just the issue MTV described (a problem further up the signal distribution chain).

Checking MER/BER/DCP on a meter will rule out things more definitively but will obviously not be free.

I'll add Wide Bay to my mental banks as a cross polarised area

**MrRadio** · 06-08-12, 08:36 PM

This gets more confusing for me, this afternoon just before I posted I watched 7 for half an hour with no problems, just after I posted there was again some pixleation. I watched 7 news for an hour tonight and not a glitch in sight.
I am beginning to wonder if it is coming from the electrical installation of the house with which we have had a similar problem on analogue TV since it was built but that was only when a light or something was switched on or off.
The difference between this afternoon after posting and tonight was that the washing machine was running this afternoon.

**nbound** · 06-08-12, 08:43 PM

Have fun chasing the interference source. You will need to find something that turns on or off at the same interval as the breakup. It may not even be in your house.

What is the model of your antenna? Aerials designed to receive VHF-Low (CH0-5A), can occasionally pick up interference that would be better ignored by aerials that receive only VHF-High (6-12). Digital Tv in Oz does not use 0-5A.

It'd probably be better to get an installer out to rule out some of the more likely and easier to diagnose problems already mentioned.

**MrRadio** · 06-08-12, 09:05 PM

Originally Posted by nbound

Have fun chasing the interference source. You will need to find something that turns on or off at the same interval as the breakup. It may not even be in your house.

What is the model of your antenna? Aerials designed to receive VHF-Low (CH0-5A), can occasionally pick up interference that would be better ignored by aerials that receive only VHF-High (6-12). Digital Tv in Oz does not use 0-5A.

It'd probably be better to get an installer out to rule out some of the more likely and easier to diagnose problems already mentioned.

I don't remember the model of the antenna, except to say that it's one commonly used throughout this area and recommended as the correct one by the mob I bought it from ... I'll search for some pics and see if I can recognise it ... post if I find it.

**cmatten** · 06-08-12, 09:35 PM

Originally Posted by MrRadio

This gets more confusing for me, this afternoon just before I posted I watched 7 for half an hour with no problems, just after I posted there was again some pixleation. I watched 7 news for an hour tonight and not a glitch in sight.
I am beginning to wonder if it is coming from the electrical installation of the house with which we have had a similar problem on analogue TV since it was built but that was only when a light or something was switched on or off.
The difference between this afternoon after posting and tonight was that the washing machine was running this afternoon.

A month or so ago I sold a Spectrum Analyser to a Ham Radio guy in the Wide Bay area (Torquay 4655 QLD is where I posted it to).

This is what he said to me

"we are all UHF Digital in the Wide Bay Region now, and there have been numerous complaints about the quality of the service. I live about 500m from the local Translator, and have the correct antenna, and I still get pixelation, so something is not right."

**MrRadio** · 06-08-12, 10:16 PM

Not a good pic but best I can get tonight

**nbound** · 06-08-12, 11:17 PM

That antenna is VHF-High (and UHF) only, so rules out that one.

**nbound** · 06-08-12, 11:27 PM

Originally Posted by cmatten

A month or so ago I sold a Spectrum Analyser to a Ham Radio guy in the Wide Bay area (Torquay 4655 QLD is where I posted it to).

This is what he said to me

"we are all UHF Digital in the Wide Bay Region now, and there have been numerous complaints about the quality of the service. I live about 500m from the local Translator, and have the correct antenna, and I still get pixelation, so something is not right."

Torquay is covered by the Hervey Bay Transmitter which is UHF only. Living 500m from a transmitter can produce pixellation from the signal being too strong. (I get 80dB+ readings from a local 10W (extremely weak) transmitter at that distance with standard aerials). For comparison, Hervey bay is 500W.

The main Wide Bay region transmitter is definately VHF (with SBS on UHF), as backed by ACMA data and digitalready.gov.au

**beerman** · 07-08-12, 04:29 PM

Originally Posted by nbound

I'll add Wide Bay to my mental banks as a cross polarised area

Yep, me too. However it may change after the restack.

**stump1100** · 07-08-12, 06:48 PM

Originally Posted by cmatten

A month or so ago I sold a Spectrum Analyser to a Ham Radio guy in the Wide Bay area (Torquay 4655 QLD is where I posted it to).

This is what he said to me

"we are all UHF Digital in the Wide Bay Region now, and there have been numerous complaints about the quality of the service. I live about 500m from the local Translator, and have the correct antenna, and I still get pixelation, so something is not right."

We have seen a number of complaints like this and it usually turns out that the viewer has too much signal as they used to have an amp on an antenna pointing at Goonaneman and don't need it anymore.

**nbound** · 07-08-12, 09:48 PM

Originally Posted by beerman

Yep, me too. However it may change after the restack.

For everyone's reference, at this stage Wide Bay is slated to be VHF-only, Vertical polarisation post-restack. (ie. SBS will move into the VHF band)

**nbound** · 10-08-12, 09:51 PM

Any progress MrRadio?

**MrRadio** · 13-08-12, 11:17 PM

Originally Posted by nbound

Any progress MrRadio?

NO, but I have to say I haven't spent much time looking into it, I am leaning toward the problem being created by electrical appliances in the house, we have always had dodgy electrical installation, TVs pixle (even the old analogue flashed) when a light or power point is switched on or off etc.
MrsRadio watches 7 between 5 and 6 each day and hasn't complained about it recently.