Astra 1N - made it to geostationary orbit, now the fun starts

[Huevos]

for uplink providers logistics-wise they won't be able to uplink to, say 2A, B or D and 1N using the same uplink dish

Why not? ...

 

[Pietclock]

1N has 52 (!) active transponders ! It can service more than half of all channels available (120 TP from 10.7-12.75GHz). It could take over large numbers of transponder of the existing three satellites of SES at 28E.
My guess is, that 1N will take load from all three plus provide additional capacity using the empty Band C. 2A,2B and 2D are quite old, and certainly need a reduction of active transponders to prolong their life. That's the usual procedure.
The only interesting thing will be, if BSkyB like the FTA channels will be using the 1N spot beam or make use of the pan-European beams.

Also after some calculations, I think the steerable dish will be for Ku Band too. It can produce a spot with a diameter of about 900km and might be intended for Afrika using frequency re-use. That would explain the high number of 52 TPs.

 

[M60]

Why not? ...

I'm under the impression that one antenna can only uplink to one specific satellite, i.e. you couldn't use one to uplink concurrently to 2D and 1N as the two craft drift slightly and thus the Earth Station antenna needs constantly to track the specific satellite. I might be wrong here and so happy to be corrected.

1N has 52 (!) active transponders ! It can service more than half of all channels available (120 TP from 10.7-12.75GHz). It could take over large numbers of transponder of the existing three satellites of SES at 28E.
My guess is, that 1N will take load from all three plus provide additional capacity using the empty Band C. 2A,2B and 2D are quite old, and certainly need a reduction of active transponders to prolong their life. That's the usual procedure.
The only interesting thing will be, if BSkyB like the FTA channels will be using the 1N spot beam or make use of the pan-European beams.

Also after some calculations, I think the steerable dish will be for Ku Band too. It can produce a spot with a diameter of about 900km and might be intended for Afrika using frequency re-use. That would explain the high number of 52 TPs.

You might be right and we'll just have to see what transpires. I suppose it depends on whether the existing widebeam transponders for the likes of C5, ITV are swapped over to 1N using the same frequencies or if these are then discontinued and moved to the unused 'C' spectrum when migrating to 1N. Either way, once 1N's in service I suspect we'll see some major reshuffling after what has been a pretty quiet few Months at 28.2E.

 

[dvdfilm]

1N has 52 (!) active transponders ! It can service more than half of all channels available (120 TP from 10.7-12.75GHz). It could take over large numbers of transponder of the existing three satellites of SES at 28E.
My guess is, that 1N will take load from all three plus provide additional capacity using the empty Band C. 2A,2B and 2D are quite old, and certainly need a reduction of active transponders to prolong their life. That's the usual procedure.
The only interesting thing will be, if BSkyB like the FTA channels will be using the 1N spot beam or make use of the pan-European beams.

Yes i agree.I think Sky will use the pan-european beams in the same way as the current Astra 2A-2B

 

[Analoguesat]

I'm under the impression that one antenna can only uplink to one specific satellite, i.e. you couldn't use one to uplink concurrently to 2D and 1N as the two craft drift slightly and thus the Earth Station antenna needs constantly to track the specific satellite. I might be wrong here and so happy to be corrected.

I think you are right - they use BIG uplink antennas so the beamwidth will be very small. I also know that SES will be upgrading the facilities at Betzdorf in the not too distant future to add more uplink dishes. (Its on their FB page somewhere about a month back - I asked a question about the number of dishes at Betzdorf)

 

[M60]

I think you are right - they use BIG uplink antennas so the beamwidth will be very small. I also know that SES will be upgrading the facilities at Betzdorf in the not too distant future to add more uplink dishes. (Its on their FB page somewhere about a month back - I asked a question about the number of dishes at Betzdorf)

That's my thinking, the one at BBC TVC is massive as I've been there and seen it. They must have the reserve at a DR location somewhere else? I'd say the beamwidth on a dish it's size must be less than 0.5 degrees, funny to spot people in houses just behind the complex with Minidishes on their walls. What they watch on BBC services has travelled literally 22500miles in to space and then back down again when in reality it's origin is only 150mtrs away!

 

[Pietclock]

Uplink antennas have a diameter from 4.8 to 9m. Since the RX reflectors on the satellites are usually much smaller than the TX ones, the signal sent up must be stronger than the one broadcast down by satellites.

 

[Huevos]

I'd say the beamwidth on a dish it's size must be less than 0.5 degrees,

How big is the dish? The 3dB point on a 5m dish is 0.15º off centre at 14GHz, which must be somewhere near the uplink frequency for 10.7GHz downlink.

Uplink antennas have a diameter from 4.8 to 9m. Since the RX reflectors on the satellites are usually much smaller than the TX ones, the signal sent up must be stronger than the one broadcast down by satellites.

That's not the reason they are so big. News feed trucks have much smaller aerials than that, sometimes as small as 1 meter. The reason for the big uplink aerials is so as not to interfere with adjacent satellites.

To me it doesn't make any sense to make the beamwidth so narrow that you would need multiple uplink dishes for satellites that are located in the same slot. Maybe it is true but if it were it is just a complete waste of resources (and licence payers money).

 

[dvdfilm]

Which TPs are being tested today?

 

[Analoguesat]

To me it doesn't make any sense to make the beamwidth so narrow that you would need multiple uplink dishes for satellites that are located in the same slot. Maybe it is true but if it were it is just a complete waste of resources (and licence payers money).

Thats what they do though - remember the birds are actually dozens if not hundreds of miles apart in space. Also remember the birds are moving around slightly so the dishes have to track them

And has the bonus that if a transmission uplink system goes down you only take a third of the channels off air

 

[Llew]

Which TPs are being tested today?

Yes, some activity on or about 11710H.

 

[strs65]

Yep, nice signal today...

 

[M60]

How big is the dish? The 3dB point on a 5m dish is 0.15º off centre at 14GHz, which must be somewhere near the uplink frequency for 10.7GHz downlink.

That's not the reason they are so big. News feed trucks have much smaller aerials than that, sometimes as small as 1 meter. The reason for the big uplink aerials is so as not to interfere with adjacent satellites.

To me it doesn't make any sense to make the beamwidth so narrow that you would need multiple uplink dishes for satellites that are located in the same slot. Maybe it is true but if it were it is just a complete waste of resources (and licence payers money).

I'd say the dish at TVC is about 8mtrs across, certainly a big beast! 0.15º is certainly very tight indeed, I had an idea it would be something like that. Also, they have tremendous gain at those sorts of sizes, gain in order of 70-80dBi I've been quoted.


Looks like they are testing on one of the pan-European beams again today, wonder how more testing they'll be doing before she heads off East?

 

[Huevos]

Thats what they do though [...] the birds are moving around slightly so the dishes have to track them

Still doesn't make sense. Apart from reduce interference to adjacent slots why use a huge expensive dish and track a satellite when you could use a smaller and cheaper one that doesn't need to track. The smaller cheaper dish could still be on a one dish per satellite basis for redundancy purposes.

 

[Analoguesat]

Makes perfect sense to me

If you want to know more why dont you email the technical guys at SES

 

[Vipersan]

Found my first confirmed service Conto TV ...on Astra 1N

see TBS card thread for details


rgds
VS

...channel found in error ...see below..
(insert red face here)

 

[Analoguesat]

Ah just what the UK needs - an Italian mature content channel

 

[Vipersan]

Appologies to anyone reading the thread ..
A suspect switch or possibly lost control of the switch caused bleed through from a second dish ..allowing phantom channels to appear ..
The Hunt continues however..
rgds
VS

 

[Analoguesat]

Look out for the Luxembourg mux. (Chamber TV / RTL Lux). Thas what they normally use.

 

[dvdfilm]

Yep, nice signal today...

View attachment 37182

As expected the pan-European beam goes well over the official footprint map,it seems you're getting a strong signal in Greece