Saorview with Amplified Indoor Antenna

AprilPhilips

A friend had a ONE FOR ALL SV9365 Freeview DAB Amplified Indoor Antenna which would pick up saorview at start but no longer works see pixmania dot ie sv9365

Would a 4life Amplified Indoor Aerial DVB-T50 be better?

See did dot ie 4life amplified indoor aerial dvbt50-prd

they only want saorview and do not want an external aerial as they don't watch tv much

And can someone explain about RTE1 being on one channel and the rest on another?

Sam Russell

You can only get away with an indoor aerial if you have a strong signal. Many of these indoor aerials are crap, and the amplifier just amplifies the crap signal. It is signal quality you are after, not signal strength.

If you want to watch Saorview and you need an external aerial, you will still need an external aerial no matter how little you watch it.

Digifriendly

AprilPhilips wrote: »

And can someone explain about RTE1 being on one channel and the rest on another?

RTE 1, RTE1+1, RTE Junior and UTV Ireland are on a different multiplex than the other channels so their signal quality/strength may be slightly different than the other channels.

AprilPhilips

Sam Russell wrote: »

You can only get away with an indoor aerial if you have a strong signal. Many of these indoor aerials are crap, and the amplifier just amplifies the crap signal. It is signal quality you are after, not signal strength.

If you want to watch Saorview and you need an external aerial, you will still need an external aerial no matter how little you watch it.

There is signal and signal level
level = strength?

Sam Russell

Most digital receivers show two figures - signal strength and signal quality. More signal strength does not add much but more signal quality does. Amplifying only effects signal strength - so no benefit.

TAFKAlawhec

AprilPhilips wrote: »

And can someone explain about RTE1 being on one channel and the rest on another?

In the days of analogue TV, a channel/station/programme was/is sent within an 8MHz wide 'channel' on a specific frequency range that had a recognised number or letter associated with it.

In Ireland this used Channels A-J for VHF TV transmission, and 21-68 for UHF. Within this 8MHz wide channel would be a mix of different signals - at the very basic level this would include a luma signal for black & white picture information and an FM mono audio signal for sound. As time went on a chrominance signal was added to provide colour information, a NICAM signal was also added to provide digital stereo sound, while the luma signal also had enhancements added within its own transmission, the most well known being teletext (Aertel). Of course the limitation here was that only one tv programme or station could be carried in this frequency block. This is why video recorders had their own tuners so that you could record one station (say RTÉ 2) on to tape while watching something on RTÉ 1 on the TV. In some parts of Ireland cable networks still distribute a limited amount of stations this way, but it is really only a matter of time before this ends.

For digital TV, or at least that used in Ireland, the rest of Europe and in many other parts of the world outside of the Americas and parts of eastern Asia, the 8MHz wide channel allocations that were used to carry one analogue tv station is instead used to transmit digital data in a standard known as DVB-T and an updated version, DVB-T2. Instead of the channel carrying one luma signal, one chrominance signal etc. it creates a data channel for the sending of video, audio and associated information (e.g. programme info, aspect ratio) in digital form with a capacity known as a "bitrate" that can be adjusted either for greater data capacity or signal robustness depending on the transmitter set up. This is called a multiplex.

Computer based compression is used to reduce the bitrate of video and audio information not only to allow it to fit into a multiplex, but also to allow several video and audio streams. So when four different frequency blocks were previously used to deliver four analogue TV channels for RTÉ 1, RTÉ 2, TV3 and TG4, these same four channels could be easily compressed for digital TV at SD resolutions into being sent to receivers in one multiplex taking up just one frequency block instead.

There comes a point however when if you compress video and audio too much, the resulting viewing and listening quality is reduced. This results in pictures that either become 'blocky' or soft (especially for fast panning scenes like live sports) and audio starts having artefacts the same way a poorly ripped MP3 with a low bit rate sounds awful. Trying to cram in too much video and audio into a multiplex might end up with the picture and sound quality not being much better than a Real Video stream in 1998 at 56k dial-up speeds! :eek:

The way a Saorview multiplex in Ireland is configured gives a bitrate of roughly 24Mbps, very similar to that in other countries like the UK. Using MPEG4 for video compression and MP2 for audio compression, an acceptable picture for SD viewing can be delivered with an average video bitrate of 2Mbps per station and 6Mbps for HD per station, while audio is delivered at 192kbps (or 0.192Mbps). Audio compression is fixed, but video compression is done using a technique called statistical multiplexing or stat-mux that varies the amount of compression applied to make a best effort for quality across all video streams on a multiplex.

When Saorview was officially 'launched' there was only one HD channel (RTÉ2) with all others being in SD - RTÉ1, TV3, TG4, 3e, RTÉ News Now and RTÉ Junior & RTÉ 1+1 on a time-share basis. This could be adequately accommodated on just one multiplex. However when RTÉ1 was about to start broadcasting in HD, the extra bitrate requirements for HD video meant that it could not do so without significantly affecting picture quality on all channels, so a second multiplex started transmitting with the same config as the first multiplex which allowed RTÉ One to broadcast in HD on the second multiplex. As a station keeping and best use of bitrate exercise, RTÉ Jr & RTÉ 1+1 were also transferred over to the second multiplex.

The big problem was that when Saorview had just one multiplex, it was possible to record one station on the platform while watching another channel because all channels were on the same frequency block, so set-top-boxes and televisions that had recording capabilities were often done so as a crude PVR using a USB memory stick or portable hard drive. On the likes of these forums there was plenty of warning given that this wouldn't last when a second multiplex was eventually launched to allow for extra channels (like UTV Ireland) or HD content. When that happened, then this single-tuner PVR system broke. A true PVR like that supplied by Sky or UPC has at least two separate tuners - otherwise it is impossible to watch another station unless it is on the same multiplex as the one being recorded.

This isn't a "typically Irish" situation regarding Saorview, in most countries multiple multiplexes are transmitted. The the UK there is universal coverage with 3 multiplexes of TV and radio channels, large (92%) coverage of another three multiplexes with commercial broadcasters and additional multiplexes in places that carry extra HD content, local TV etc. For example in much of Greater Belfast ten different multiplexes are available to receive from two transmitter sites just outside the city before any cross-border reception of the Saorview multiplexes are added on!

Sorry if all of that is a bit long-winded or tl;dr but basically if what you want to watch is on one frequency and what you want to record at the same time is on a different frequency, then you need a tuner that fills each need.

Sam Russell

Excellent explanation.

The only thing I would add is that digital signals are very robust up to a given point giving a perfect picture and then they deteriorate so rapidly it is like they go off a cliff. Analogue signals on the other hand deteriorate slowly from the very start and slowly get worse and worse - so analogue signals slowly go into a snow storm until nothing can be made out.

With digital signals, the engineers decide the quality of the picture by how much bit rate they give it and the system corrects the signal as it goes if the signal is strong enough. But in analogue they are always fighting to give the picture the best quality they can with better equipment and better transmission power, etc.

AprilPhilips

Thanks everyone. i was visiting with my friend just after starting this and the indoor antenna works very good again on all of the saorview channels. It just has to be positioned in a certain place.

The last time i was there - and previous times gong back months- there was hardly any signal and you might spend ten minutes looking for a spot for RTE 1 but that spot would not work for the others . Sometimes it would not work at all. At no position would it pick up any channell

It is now as good as when saorview started. i believe there is some changes being made to the transmitter. Why would they do that if they do? If they don't what could explain it? Same antenna/tv/box etc

The Cush

AprilPhilips wrote: »

It is now as good as when saorview started. i believe there is some changes being made to the transmitter. Why would they do that if they do? If they don't what could explain it? Same antenna/tv/box etc

This is what 2RN, the network operator, says about the use of indoor aerials

Can I Use An Indoor Portable Aerial, Rabbits Ears?

RTÉNL does not recommend the use of indoor portable aerials. They are too susceptible to localised physical and electrical interference. Terrestrial transmission of television, analogue and digital, is designed and built around rooftop reception.

It will be possible for over 50% of the population to receive SAORVIEW with an indoor portable aerial. However on a house to house basis there are many factors than impact on the effectiveness of a portable aerial. For example the orientation of your house, the location of the television in the house, the construction materials, the insulation materials, the proximity to neighbouring houses, walls and obstructions will all impact reception.

An outdoor aerial, positioned as high as possible, pointing towards the appropriate transmission site, with no local obstructions is recommended and will give the best results.

Thurston?

AprilPhilips wrote: »

... i believe there is some changes being made to the transmitter. Why would they do that if they do? If they don't what could explain it? Same antenna/tv/box etc

A nearby hedge or trees being cut, a large vehicle moved from a driveway ... I could probably come up with more suggestions but the point I'm making is that an indoor aerial, particularly at ground floor level, can be affected by the kind of environmental changes that would have no effect at all on an aerial mounted at roof height.

Even putting an aerial in the attic (if you have an attic) would generally put it in a stronger signal area, & get it away from clutter. The attic might be a DIY possibility, there might already be cable installed between TV point & attic, & in this case it would only need someone reasonably competent to connect a suitable aerial to the cable, & set it up for the best available signal.

AprilPhilips

Thurston? wrote: »

A nearby hedge or trees being cut, a large vehicle moved from a driveway ... I could probably come up with more suggestions but the point I'm making is that an indoor aerial, particularly at ground floor level, can be affected by the kind of environmental changes that would have no effect at all on an aerial mounted at roof height.

nothing like that same house, garden etc. No walls built of vehicles moved