Replies to This Discussion

Permalink Reply by hello on October 11, 2013 at 20:55

Tv is soniq

Permalink Reply by Biggles on October 12, 2013 at 8:59

Sounds like your antenna system has suddenly developed a fault e.g. bad connection due to weather damage or strong winds, or your TV has developed a fault. Your symptoms are indicative of a bad joint somewhere though. Check your antenna, co-ax and all connections are OK. If that fails try another Freeview TV or STB on the same antenna outlet.

Permalink Reply by John Richardson on November 5, 2013 at 16:01

My Sony TV has worked fine on terrestial tv digital transmissions for years but during the past two weeks I have had problems with reception of the following channels; Maori, Prime, Trackside, Choice, Sommet Sports, TVSN Shopping, Yes shop, First Light and a Chinese channel. All others are normal including the new Al Jazeera channel. When checking the signal level for Prime using the System Information facility in Technical Set-up menu of the TV, it fluctuates wildly between 'no signal' and 'good' but only later in the day. In the morning the signal level indicates 'good' and reception is OK on all the above-mentioned channels. I have trimmed down a tree that had grown in front of the aerial and checked all the connections at the aerial, the distribution hub and between the wall socket, the digital recorder and the tv but cannot provoke a change in signal level when reception is OK on the above-mentioned channels.

I live in New Plymouth and receive signals from the transmitter on Mt Taranaki. We are in line-of-sight of the transmitter and well within its service area.

Any suggestions as to what has gone wrong will be gratefully received.

 

John.

 

 

 

Permalink Reply by Biggles on November 5, 2013 at 16:19

As you've checked all the likely causes it sounds like you may be getting external interference from somewhere. Basically see if anything nearby turns on at the same time as the signal starts fluctuating. Could be anything like a PC, Modem, Heat pump etc. Presumably something new about 2 weeks ago? Check with neighbours to see if they suffer the same fault. Is the digital recorder showing the same problem? Could also be a transmission problem or a TV fault. Hard to diagnose. You could also try plugging the TV into a diffent antenna socket.

Permalink Reply by Jo Assink on November 14, 2013 at 16:50

Hi John,

Have exactly the same problem here, living in Masterton. Started around early November, after advise     from Prime to retune. We use HD Aerial, not satellite.  After that had only 11 channels left, from 19. Have used Freeview helpline  0800 873384, and the best they could do was refer me to a television service company. A bit of old-fashioned 'Switch everything in the house off, including the DishTV recorder, lights behind the Bravia, computer and modem, plug the set directly into the aerial connection on the wall. Then retune the Bravia digital on automatic. Have now 20 channels, clear as a bell. Plug everything in back to normal and Bob is your Uncle. Hope this helps.  

Jo

Permalink Reply by John Richardson on November 16, 2013 at 20:37

Jo Assink said:

Hi John,

Have exactly the same problem here, living in Masterton. Started around early November, after advise     from Prime to retune. We use HD Aerial, not satellite.  After that had only 11 channels left, from 19. Have used Freeview helpline  0800 873384, and the best they could do was refer me to a television service company. A bit of old-fashioned 'Switch everything in the house off, including the DishTV recorder, lights behind the Bravia, computer and modem, plug the set directly into the aerial connection on the wall. Then retune the Bravia digital on automatic. Have now 20 channels, clear as a bell. Plug everything in back to normal and Bob is your Uncle. Hope this helps.  

Jo

Permalink Reply by John Richardson on November 16, 2013 at 21:06

Problem: the same channels disappear each evening at various times between 5.40pm and 6pm and do not reappear until much later in the evening.

During the day (normal operation) figures displayed fluctuated but a sample is as follows.

Pre Viterbi: 3e-3 COFDM AGC: -132

Post Viterbi: 0 UEC: 0

Signal level: High.

Under fault conditions (evening) the channels showing a stable picture displayed typically:

Pre Viterbi: 9e-3 COFDM AGC: -57

Post Viterbi: 3e-6 UEC: 0

Signal level: Good.

Under fault conditions (evening) a channel suffering some disturbance of picture displayed typically:

Pre Viterbi: 3.4e-2 COFDM AGC: -105

Post Viterbi: 3.2e-3 UEC: 42

Signal Level: Low.

Under fault conditions the Viterbi error levels are much higher but there seems to be little correlation with the signal level displayed or with the AGC figure shown.

The receiver aerial signal is fed through a DVD recorder.

In the evening it is often possible to watch a channel using the tuner of the DVD recorder while the tuner in the receiver is unusable for that channel.

Feeding the TV directly from the aerial outlet instead of through the DVD recorder seems to have little effect on the fault symptoms.

I have asked neighbours whether they have switched something on when our problem occurs and whether they have interference with their TV reception but with negative result as most are using satellite receivers.

For two years the aerial has been fed through a ‘hub’ or 3-way splitter box in the garage so that the aerial feeds three rooms, bedroom, lounge and living room. A second analogue receiver has been operating from the lounge outlet for over two years.

Digital reception has been trouble-free for that period but problems started at the beginning of November 2013 around the date the analogue signal was turned off at the transmitter and the Al Jezeera channel appeared.

Last  evening during the usual fault conditions I bypassed the ‘hub’ and connected the signal from the aerial direct to the outlet feeding the DVD recorder the television receiver. Reception is now perfect and the displayed COFDM AGC figure fluctuates around -400 instead of around -100 as it was before the alteration of the aerial connection.

On performing digital automatic re-tuning I now have an extra channel: ‘Parliament’.

The pre-Viterbi error level now fluctuates around 4e-4 then as 6pm approaches and the interference starts it increases to around 3e-3, well within the capability of the error-correcting circuit, so post-Viterbi is zero and the picture is stable.

Conclusion.

It seems to me that the signal from the transmitter has been weakened at the beginning of November so that our reception has become marginal and easily upset by locally produced interference which starts between 5.40pm and 5.55pm every evening.

For more than two years the aerial signal has been fed through the ‘hub’ with its inherent attenuation without any problems with reception. Something has definitely changed very recently and neighbours do not report any new equipment in use at the relevant times.

Does anyone know of any relevant power reductions made recently at NZ TV transmitters, in particular that on Mount Taranaki?

Permalink Reply by Mike G on November 16, 2013 at 21:32

Hi John,

I don't think the transmitter power would have been reduced as there would have been a lot more complaints from your area. 

It sounds to me like your aerial or cabling has slightly reduced performance over time to the point where the signal can't overcome the losses in the splitter. I would start by checking the balun on the antenna and connections to make sure there is no water in there. It might have crept down inside of the feeder cable too and reduced its performance.

Is the splitter a good quality one with F-connectors or an older style with Belling-Lee TV plugs? Older splitters aren't great at UHF frequencies and this might not be helping. Sometimes this affects only a group of channels.

I had a similar problem that turned out to be agravated by the aerial feeding via the DVD recorder. It lost a lot of UHF signal through it. It might be better to split the feed into both devices rather than loop the signal on.

Permalink Reply by Jo Assink on November 17, 2013 at 14:38

Hi Everyone with Freeview problems, especially Prime etc.

Mine was OK as described two days ago, but same problem back again. Either Prime related stations want to force us into subscribing to Sky, or they are trying to save money on transmission power. So I just give up on Prime etc., or watch them via the DishTV recorder. Not that I am happy about it.

No, I have not checked signal strength, but since I am watching TV less and less I am only annoyed. But we have a good library here in Masterton, and a stack of CDs in the cupboard. Nice and peaceful.
 
John Richardson said:

My Sony TV has worked fine on terrestial tv digital transmissions for years but during the past two weeks I have had problems with reception of the following channels; Maori, Prime, Trackside, Choice, Sommet Sports, TVSN Shopping, Yes shop, First Light and a Chinese channel. All others are normal including the new Al Jazeera channel. When checking the signal level for Prime using the System Information facility in Technical Set-up menu of the TV, it fluctuates wildly between 'no signal' and 'good' but only later in the day. In the morning the signal level indicates 'good' and reception is OK on all the above-mentioned channels. I have trimmed down a tree that had grown in front of the aerial and checked all the connections at the aerial, the distribution hub and between the wall socket, the digital recorder and the tv but cannot provoke a change in signal level when reception is OK on the above-mentioned channels.

I live in New Plymouth and receive signals from the transmitter on Mt Taranaki. We are in line-of-sight of the transmitter and well within its service area.

Any suggestions as to what has gone wrong will be gratefully received.

 

John.

 

 

 

Permalink Reply by John Richardson on November 17, 2013 at 15:37

Hi Mike,

A I mentioned in my original submission to the forum (November 5th) the first thing I did was check the aerial and its connections and all appeared OK.

The splitter is about 2 years old, having been installed when the house was built. It uses F type connectors and I have connected the aerial lead to that feeding the TV using an F81 female to female adaptor. 

I did try feeding the TV directly from the aerial, not through the DVD recorder, but with little effect so it seemed pointless to split the signal to feed the recorder and the TV separately.

My aerial was installed about 2 years ago when the house was built, just before the local transmitter began regular digital broadcasting and was producing test transmissions in preparation. Interestingly, I have noticed that during recent months, when everyone has been preparing for the close-down of the analogue transmitter, the aerials being installed around the town are a much higher gain type with about 40 elements.  Perhaps they are playing safe, wishing to avoid the sort of problem I have experienced. Perhaps I will have install such an aerial as well if I ever want to use the splitter again to feed other rooms.

Mike G said:

Hi John,

I don't think the transmitter power would have been reduced as there would have been a lot more complaints from your area. 

It sounds to me like your aerial or cabling has slightly reduced performance over time to the point where the signal can't overcome the losses in the splitter. I would start by checking the balun on the antenna and connections to make sure there is no water in there. It might have crept down inside of the feeder cable too and reduced its performance.

Is the splitter a good quality one with F-connectors or an older style with Belling-Lee TV plugs? Older splitters aren't great at UHF frequencies and this might not be helping. Sometimes this affects only a group of channels.

I had a similar problem that turned out to be agravated by the aerial feeding via the DVD recorder. It lost a lot of UHF signal through it. It might be better to split the feed into both devices rather than loop the signal on.

Permalink Reply by Mike G on November 17, 2013 at 17:26

Hi John and Jo, I think the best thing that you could both do is to get an installer with a meter around to test out the reception from your aerials. I'm sure that the Kordia mux, (with Prime etc), hasn't been reduced in transmission power at either transmitter site.