RTE Announce FTA Saorsat service

Apogee

I see what you're getting at - 9E Irish DVB-T on B-band and 28E UK DVB-S/S2 on L-band both diplexed onto the same cable - but I reckon it's unlikely.

My guess is that Kasat will use the B segment of Ka-band (i.e. Hi) and the transmission standard will be DVB-S2, not DVB-T. And to receive the UK sat channels will be done with aid of a Diseqc switch.

Sponge Bob

Hmm, Saorview ( or Nordig Unified) does support Diseq so you could be on the right track there Apogee. The Saorview DTT unit can diseq switch...handy if the other unit is a Sky Box ....as is likely

Another point is that Circular polarisation supports right hand and left hand allowing RTE to add a second mux on the second polarisation later...if this is feasible on a Ka spot that is.

watty

Sponge Bob wrote: »

Right , so power injection is required. Following Zaphods comment you linked

18.3 - 18.8 GHz is downconverted to 250-750mhz.

RTE need to transmit a DVB-T mux , in full, at around 18.6-18.8Mhz , map it precisely to a DVB-T Europe base mux frequency and a Saorview tuner will work properly.

A gizmo will sent the DC Voltage it needs to the LNB, I thought 18v or 13v were the LNB switching voltages. I do not know the amplification voltage and assume it is a tad less, maybe 9v.

no.
Only the Transport Stream is the same.

You can't convert direct from DVB-s2 to DTT.

Instead of a Dish, LNB and sat-receiver that selects one channel you have a special sat receiver that only has a Tuner and MPEG2-TS decoder. It does the error correction (according to FEC, Viterbi and Reed Solomon etc), but doesn't de-multiplex or do MPEG4 video or AAC audio etc. Instead ALL the channels (as a single MPEG2-TS) are output on a BNC cable on the "ASI" bus at a fixed 270Mbps no matter what the actual lower bit rate is.

This then is used as primary signal for small infill site, or backup for microwave or Fibre.

The DVB-t modulator usually has ASI input and either direct UHF output (any channel 470MHz to 860MHz) or a 45MHz approx IF out.

No analogue signals nor separate channels involved.

All the encoding is done in Donnybrook or wherever not at TX sites. That would be too costly.

You must have a DVB-s2 tuner and then all the error correction and creation of "clean" transport stream (MPEG-TS) this Transport Stream then has FEC (Forward Error Correction) added to suit DVB-t. Then the 2K or 8K "OFDM" (2K mode: 1,705 carriers and 8K mode: 6,817 carriers) DVB-t signal is generated. The transmitter sites should not have the expensive Encoders and Statistical Multiplexors that create a Transport Stream.

The Satellite signal for a Transport stream is a single QPSK or 8PSK carrier. (what is normally called a Transponder). The Terrestrial signal can use the same Transport Stream (multiplexed data) but different FEC and symbol rate and 6,817 QAM16 carriers per Transport stream.

Don't think about how Analogue does stuff

watty

Sponge Bob wrote: »

Hmm, Saorview ( or Nordig Unified) does support Diseq so you could be on the right track there Apogee. The Saorview DTT unit can diseq switch...handy if the other unit is a Sky Box ....as is likely

Another point is that Circular polarisation supports right hand and left hand allowing RTE to add a second mux on the second polarisation later...if this is feasible on a Ka spot that is.

There is NO circular polarisation! That's DirecTV only.

Each spot beam is either ALL horizontal or all vertical.

There is about 70Gbps. So per beam that is 875Mbps. Assume 1/2 is upload and 1/2 download (not actually true)... so over 430Mbps downlink. RTE need 2 x 25Mbps MPEG-TS to feed two mux (two 8MHz DTT transmitters). That's all easily done on one physical transponder. The the "Surfbeam" limit per modem is 72Mbps! So for convenience it may appear to a satellite receiver that there are 2 TV transponders (two DVB-s2 carriers). The rest of the "transponders" will be data (internet downlinks). Any number of modem users can share a downlink. So if there is 875Mbps there can be no less than "12" apparent transponders (separate carriers really) and could be as many as 32 perhaps. Per spot.

There is no technical reason why all the "carriers" in a Spot are not the same band and polarisation, in fact I believe that it's inherent that they have to be the same.

Sponge Bob

Thanks Watty, so you simply cannot broadcast a DVB-T 'mux' as a package on a sat, end of, too many differences.

watty

In summary...

you have a small dish and a different LNB.

TX sites have a special DVB-s2 sat receiver (QPSK or 8PSK) per multiplex that "tunes" a carrier (transponder, but probably only a carrier on a shared transponder). That tuner only decodes as far as a "Transport Stream". That can optionally feed a DVB-t OFDM modulator. Tanberg and others make these 19" rack mount "head end" receivers.

Home users have a regular DVB-S2 HD setbox. Nothing to do with a DTT setbox. Only the dish and LNB is different from Freesat HD.

The actual digital data used for Satellite can be an exact copy of the DTT data. There is no way to carry the actual DTT RF (an analogue signal using 6,817 QAM carriers) on satelllite RF (an analogue signal using a single QPSK or 8PSK carrier). It's not a matter of frequency conversion.

DTT is specially designed analogue signal to carry encoded digital on the strong but multiple paths of terrestrial (ghosting). DVB-s2 is specially designed for the 22,500 mile journey to space and back (45,000 miles!) and is very very weak but has no multipath (ghosting).

[Edit Cable Digital uses a 3rd system. It's got no ghosting like Terrestrial and can have a stronger signal so uses simple single carrier like Satellite, but 256QAM, thus much higher bitrate in the 8MHz or 6MHz channel.]

All digital systems use the same serial digital data at "baseband" but differing FEC and analogue modulation schemes. The actual RF signals are essentially "Analogue". Only morse code and 433MHz remotes uses digital signal on RF (on off keying OOK/ASK)

watty

Sponge Bob wrote: »

Thanks Watty, so you simply cannot broadcast a DVB-T 'mux' as a package on a sat, end of, too many differences.

yes you can.

Not the final Analogue Modulated signal, no. But the actual digital stream before it's modulated. The whole transport Stream... The actual "modulator" is cheap (one per Mux). It's the encoders (one per channel) and multiplexor to make a Transport stream that's expensive.

Loads of broadcasters do this. I have a paper on it somewhere.

Tony

Indeed, I had forgotten about the different ways terrestrial and sat signals behave. So definitely has to be a satellite receiver.

STB

Interestingly the new DIRECT TV KU/KA Multi satellite 3/5 LNB Dish has 20 degrees seperation between Ku and Ka and dont look that bad.



http://www.solidsignal.com/pview.asp?mc=02&p=AU9-S&d=DIRECTV-Five-LNB-KaKu-Slim-Line-Dish-Antenna-for-MPEG4-C-HD-Programming-%28AU9S%29&c=DIRECTV%20Dishes&sku=

GeneHunt

cgarvey wrote: »

Well the RTE CFO believes that a SD DTT picture (RTE on test DTT) is better than a HD satellite picture (BBC HD)...

Should've gone the Specsavers!:D


I have to say this is a great thread, I just found it on Thursday last (I must check into the Satelite forum more often!) spent most of my free time over the weekend catching up!

This is a little off topic, but bear with me on this!

As this Kasat satellite is really intended for internet use and someone mentioned here (I can’t find it now) a speed of 3Mbps for broadband from this satellite. If 3Mbps is possible from this satellite, I think a good few people in rural Ireland would be very interested in that service, as there are lots of homes in Ireland which still couldn’t get a broadband conection – now add Saorsat to the mix and I think a lot more that 2% to 10% would be interested. Could RTE be planning to be an internet provider with this Kasat satelite? RTE player via your dish!

Tony

GeneHunt wrote: »

Could RTE be planning to be an internet provider with this Kasat satelite? RTE player via your dish!

They could possibly partner with another provider and get another revenue stream, interesting idea.

STB

Well Gene I wouldnt like to second guess them, but it would certainly make it more attractive.

If they havent thought of it already (which I am sure they have!) they know about it now.

Apogee

Mentioned in presentation:

Conor Hayes wrote:

Our satellite option would operate on the Ka band as opposed to the Ku band. The Ka band is typically used for telecommunications purposes or contributions between broadcasters. The Ka band is used by the single largest pay television operator in the US, DirecTV, which uses it to deliver high definition television. It works on a consumer basis and is a proven product in weather conditions.

People are offering satellite services over broadband. If one has a broadband service over satellite, one is capable of offering telephony or voice over IP, VoIP. If we are up there in the clear, some bright spark might offer people broadband, telephony and Irish channels - RTE, TG4, TV3 and so on - without their needing to spend much money.

Sponge Bob

Ultimately the thru put is around 800mbits per spot beam as Watty said. Even small telephone exchanges have more backhaul than 800mbits nowadays.

A spot could supply an average country parish in Ireland before contention kicks in of an evening

dunleas

GeneHunt wrote: »

Should've gone the Specsavers!:D


I have to say this is a great thread, I just found it on Thursday last (I must check into the Satelite forum more often!) spent most of my free time over the weekend catching up!

This is a little off topic, but bear with me on this!

As this Kasat satellite is really intended for internet use and someone mentioned here (I can’t find it now) a speed of 3Mbps for broadband from this satellite. If 3Mbps is possible from this satellite, I think a good few people in rural Ireland would be very interested in that service, as there are lots of homes in Ireland which still couldn’t get a broadband conection – now add Saorsat to the mix and I think a lot more that 2% to 10% would be interested. Could RTE be planning to be an internet provider with this Kasat satelite? RTE player via your dish!

Interested how you mentioned broadband, there is a "fresh" announcement from breaking news today

http://www.breakingnews.ie/ireland/rte-to-begin-70m-digital-tv-switchover-467819.html

Now bare with me I have already linked this in the "terrestrial speculation" but following your thread above I had another quick look and at the end of this item there is a mentioned of broadband by E.Ryan.

"This is good news for television viewers, for the broadcasting industry and for those looking for faster and better broadband. This will bring a huge boost to Ireland’s economic and social development by providing jobs, new services and revenue to the country"

Sponge Bob

dunleas wrote: »

Interested how you mentioned broadband, there is a "fresh" announcement from breaking news today

Looks like last weeks news, here is todays grim news

mikom

A new global survey has ranked Ireland 50th out of 160 Countries for broadband speeds.

Minister Ryan
"Ireland is moving firmly into the digital age and we will all reap the benefits."

Tell that to a dead ass and he'd kick ya.

watty

Lets say 50:1 Contention (Comreg limit for FWA is 48:1 and traditional Satellite is 500:1 to 3000:1 contention, really!).

Lets say average 3Mbps package (maybe some 1Mbps and some 12Mbps.)
so ... if we say only 360Mbps for downlink and the rest is TV and uplink
360/ 3 = 120 full speed downloads.
multiply by number of customer contention ratio
50 x 120 = 6000 users.

Contention will be limited also by traffic cap. So say 20Gbyte.
but 3Mbps (download only) is 972G byte a month.
so user can't transfer data more than 2% of time...
That's about 1/50th. So that ensures that users at 50:1 contention see close to package speed on Average, Maybe 30% less at peak times. (2.2Mbps instead of 3Mbps)

If we make cap 10Gbyte, then we can have 100:1 contention (sales = 12,000 users) and on average you will see package speed, but peak times might be only 50% of package speed.

As you get more penetration you get more "ordinary" people and light users. The early adopters are really wanting Internet and tend to max out to gap. People just doing card transactions, email, paying road tax etc may only use 1/10th of cap.

So my conclusion is that the speed will be poorer than Mobile peak speed on an economic 3Mbps package, but until there are about 15,000 to 20,000 users the average speed at peak usage times will be x3 to x6 better than Mobile. Latency is 790ms minimum. Page load time just under 1s which is up to twice as good as Mobile when its latency has reached 250ms. (due to clever stuff that satellite does that mobile doesn't).

For the first 5,000 users it will be pretty good. By the time there are 20,000 to 40,000 users it may go at 1/2 speed during busy periods. Tooway has quite complex cap enforcement (hourly, daily, weekly) giving at the minute about 6Gbyte max on a cheapish package. They may offer about twice the cap and lower pricing on the new Kasat as the existing Tooway from 13E has only 4 spot beams and the Irish customers share with most of Western Europe! The current Tooway 6 Gbyte cap implies a 170:1 contention approximately. So if they do the same on Kasat that puts a limit of 120 x170, approximately 21,000 customers, or maybe up to 30,000+ assuming less than half of people use more than half their cap

So. Not a real solution to Rural Broadband, but possibly better and cheaper than Mobile, especially if Mobile Data was charged according to real costs.

Now you see why Mobile (esp LTE), Fixed Wireless and Satellite are never going have much bigger caps and why DSL, FTTH, FTTC and HFC/Cable can in theory have x10 caps or more.

Conclusion:
Up to 5000 customers the Kasat in Ireland would be fairly good. At 21,000 customers it might be similar to existing 13E Tooway in performance. If you don't need real time gaming and can live with 6Gbyte cap, then it's likely a better solution than Mobile for Fixed usage as you get an ethernet port, really always on (It's similar system to UPC cable) and should not get dropped connection except in most severe weather. The signal from Kasat will be hugely stronger than 13E Tooway, esp. in West and South West of Ireland.


Satellite Broadband Ireland and Digiweb will be the main sellers/installers of Tooway Kasat as they are already that! Digiweb has the most or 2nd most number of Satellite customers in Europe.

RTE is extremely unlikely to be involved.

Apogee

Sponge Bob wrote: »

Better be Ka Lo between 18.6 and 18.8mhz if we are to benefit in any way from commodity LNB gear. It will also mean that a typical combination of Astra Ku and Ka St Ka Lo will not collide.

Just to note that the DirecTV LNBFs are highly proprietary and downconverting from Ka to B-band is unusual. Typically, both the Lo Ka and Hi Ka bands are downconverted to the L-band with commercially available LNBs.

One fly in the ointment is the paucity of LNBFs available. Norsat (always horrendously expensive) and Fujitsu both sell Ka-band LNBs, but I haven't been able to find anyone who sells integrated Ka-band LNBFs - anyone else located a supplier?

Although if all the channels are transmitted on the same TP/polarisation, then LNB + feedhorn is sufficient.

http://www.norsat.com/lnb/blog
http://www.fujitsu-general.com/global/products/lnb/lineup/ka_dro.html

watty

Apogee wrote: »

Just to note that the DirecTV LNBFs are highly proprietary and downconverting from Ka to B-band is unusual. Typically, both the Lo Ka and Hi Ka bands are downconverted to the L-band with commercially available LNBs.

The DirecTV stuff doesn't apply at all, we need not even consider it.

Apogee wrote: »

One fly in the ointment is the paucity of LNBFs available. Norsat (always horrendously expensive) and Fujitsu both sell Ka-band LNBs, but I haven't been able to find anyone who sells integrated Ka-band LNBFs - anyone else located a supplier?

Although if all the channels are transmitted on the same TP/polarisation, then LNB + feedhorn is sufficient.

The LNB used on Tooway ODU (Out door unit = Dish, arm, LNB, BUC, PA, horn, secondary reflector, OMT) is cheap. It of course isn't an LNBF, it's connected to a Orthomode transducer (OMT) that has a filter to block higher uplink band and separates H &V polarisation. (TX and RX use opposite polarisation). The Tooway LNB converts down to 950MHz to 1700MHz band (older sat IF rather than newer 2100MHz upper limit!), perfectly compatible.

I'd only worry if you don't see cheap LNBFs for Ka by May 2011.

I'd be 99.99% certain that any particular spot is only one polarisation and only one part of band. Much easier and cheaper to design the satellite that way!

Also

"This is good news for television viewers, for the broadcasting industry and for those looking for faster and better broadband. This will bring a huge boost to Ireland’s economic and social development by providing jobs, new services and revenue to the country.

Read more: http://www.breakingnews.ie/ireland/rte-to-begin-70m-digital-tv-switchover-467819.html#ixzz0vXcyooAp

I'm nearly sure this relates to Digital Dividend Sell off of TV spectrum for 800Mhz LTE Mobile or similar. Not kasat.

Apogee

watty wrote: »

The LNB used on Tooway ODU (Out door unit = Dish, arm, LNB, BUC, PA, horn, secondary reflector, OMT) is cheap.

Do you know how much the receive LNB costs and who manufactures them, or the model number?

Tony

If I read it right though he is reffering to re using the existing UHF spectrum for broadband when it becomes available.

dunleas wrote: »

"This is good news for television viewers, for the broadcasting industry and for those looking for faster and better broadband. This will bring a huge boost to Ireland’s economic and social development by providing jobs, new services and revenue to the country"

watty

Apogee wrote: »

Do you know how much the receive LNB costs and who manufactures them, or the model number?

I can't remember all the details. But it's cheap. With Tooway on Wildblue and then 13E "test" and now 80 spot Kasat and 110 spot Viasat1 (end 2011) they want to compete with "Mobile" and DSL! The whole system has to be sky-box cheap. They have done over 300,000 so far... I think.

Check your PM. Think we make it someone else's work to find the cheap LNBF for Kasat TVRO.


These people have a 22 degree arc mount and dish big enough for offset Sky + Kasat in wilds of South West Cork/Kerry or North West Donegal
http://www.ozdemirler.com/8_lnb.asp


Football enthusiasts can add 16E or 19E etc.. A regular Diseqc or Multiswitch will let you have four LNBs. The Kasat LNBF can likely just feed one port of a multiswitch (quattro or splitter not needed) rather than normal four.

In fact I put a Ku Quattro LNB on two ports (as only one polarisation needed) and a C band Twin (for both polarisations) on the other two ports of one set of sat ports of a Multiswitch once.

Noreen1

watty wrote: »

I can't remember all the details. But it's cheap. With Tooway on Wildblue and then 13E "test" and now 80 spot Kasat and 110 spot Viasat1 (end 2011) they want to compete with "Mobile" and DSL! The whole system has to be sky-box cheap. They have done over 300,000 so far... I think.

Check your PM. Think we make it someone else's work to find the cheap LNBF for Kasat TVRO.


These people have a 22 degree arc mount and dish big enough for offset Sky + Kasat in wilds of South West Cork/Kerry or North West Donegal
http://www.ozdemirler.com/8_lnb.asp


Football enthusiasts can add 16E or 19E etc.. A regular Diseqc or Multiswitch will let you have four LNBs. The Kasat LNBF can likely just feed one port of a multiswitch (quattro or splitter not needed) rather than normal four.

In fact I put a Ku Quattro LNB on two ports (as only one polarisation needed) and a C band Twin (for both polarisations) on the other two ports of one set of sat ports of a Multiswitch once.

Nice system!

I've been wondering whether a KA LNB will work as a second lnb on a 1M Hirschmann dish, using 2 receivers - one with a regular KU band lnb connected for freesat on 28E, the other for Saorsat?

Noreen

watty

It could work...

I think the 1m dish might be a bit large though, more awkward to align (the Kasat part would be like aligning a 1.8m dish. You might even overload the LNBF as the system may assume a 30cm to 44cm dish for TV only!)

I don't think you want bigger than 80cm. The 90cm pictured might be too big
Right Focus 39.3 db Ku (about 45dB on Ka)
Left Focus 39.5 db Ku
Antenna Diameter 89-90 cm

What ever gain the dish is add about 6dB more on Ka Band.

Noreen1

Thanks, Watty.

I hadn't thought about overloading the LNBF!:eek:
It looks like I'll be doing some dish-swopping when the time comes, then.

I have 2 digiboxes,(non-HD) and a Darkbox HD, at the moment. I'm just wondering whether the Darkbox HD will prove adequate for saorsat, or which HD receiver would the experts recommend?

Noreen

Tony

Noreen1 wrote: »

I'm just wondering whether the Darkbox HD will prove adequate for saorsat, or which HD receiver would the experts recommend?

Noreen

Theres no way of knowing this until the satellite is launched and test transmissions begin, it really depends on what lnb's will be used and what band they downconvert to as well as other factors.

Apogee

Noreen1 wrote: »

I hadn't thought about overloading the LNBF!:eek:

Frankly, there's more chance of my cat spontaneously combusting than the LNBF being overloaded.

Apogee

watty wrote: »

The LNB used on Tooway ODU (Out door unit = Dish, arm, LNB, BUC, PA, horn, secondary reflector, OMT) is cheap. It of course isn't an LNBF, it's connected to a Orthomode transducer (OMT) that has a filter to block higher uplink band and separates H &V polarisation.

Are you sure the Ka-band version of Tooway uses an OMT setup with Ka-LNB?

I had a look at this page, and the Ku-Tooway does show an OMT setup, but the Ka-Tooway appears to use an integrated receive/transmit unit.

watty

It might be all in one box (Like the Astra2connect) but there *has* to be an H & V separator (I have two Orthomode transducers and they are just bits of clever shaped empty "pipe". The TX blocking RX filter is just metal ridges/plates). Ultimately there is a 2W or 4W power amp with up converter (higher IF band than RX to reduce crosstalk), the BUC and an LNB on separate polarisations and with a mechanical waveguide filter between the OMT "proper" and the LNB.

ka dish


ku dish Tooway VSAT


The exact same modem is used on Ka and Ku. It's not much bigger than an older DSL router.

combo Ku TV + Ka VSAT Tooway


see http://www.eutelsat.com/news/media_library/brochures/tooway.pdf

Ka Tooway VSAT only


The ka stuff does look like an "all in one" package, but it has all the "normal" VSAT stuff as described above in it.

You have a microWatt receiver running same time as a several watt transmitter. They have to be opposite polarisation, H &V. That's one reason why Kasat is orthogonal polarisations and DirecTV (only TVRO) can be circular.

All the VSAT use higher IF for TX coax and 900MHz to 1700MHz lower IF for RX coax.

All the Ka Band waveguide, Orthomode transducer and mechanical waveguide RX filter parts will be nearly 1/2 width, height and length as the Ku versions. So easy to put them in a small box. The PA takes about as much space due to upconverter, power regulators, Ka uplink band power transistors and cooling.