Astra 1N tests - latest chat

[BLUEPLATINUM]

It is 2D vericals we have trouble with in the Canary Islands. Horizontals are receivable on large dishes. The dish size required varies between the islands.

11127 V 22000 2/3 8PSK DVB-S2 - about 5db which is about what I would expect on this size dish for the current Ch 4HD and the ITV 2,3 & 4 HD transponders.

The channels mentioned in the quote are not on 2D

 

[Dan Dan]

Lanzarote, Canary Islands
Tecatel 1.2M dish, sharp cheap lnb (not the good one, the skinny thin one)

10964 H 22000 5/6 QPSK DVB-S - no lock

11127 V 22000 2/3 8PSK DVB-S2 - about 5db which is about what I would expect on this size dish for the current Ch 4HD and the ITV 2,3 & 4 HD transponders.

Cheers

is 28e signal generally better in Lanzarote then tenerife ??

10964 H 22000 5/6 QPSK DVB-S - Solid Signal Lock - Channel 5 etc. - UK Spot Beam
11127 V 22000 2/3 8PSK DVB-S2 - Solid Signal Lock - Channel 4 HD - UK Spot Beam

if BOTH of the above are on UK SPOT BEAM why can you get one not the other and why can you now get ASTRA 1N UK SPOT on a 1.2m when its 2.4m for ASTRA 2D UK SPOT ??

 

[trigger]

Yes Lanzarote is further east and north than Tenerife and I believe some beams are not as easy as they are in lanzarote

 

[Analoguesat]

if BOTH of the above are on UK SPOT BEAM why can you get one not the other and why can you now get ASTRA 1N UK SPOT on a 1.2m when its 2.4m for ASTRA 2D UK SPOT ??

Look at the maps on this link:

http://www.satellites.co.uk/forums/...y/191956-astra-1n-initially-28e-then-19e.html

The first map is the one that was rapidly withdrawn (but not before Id grabbed it ), and is vastly different from the later ones published.

 

[welshman234]

is 28e signal generally better in Lanzarote then tenerife ??

10964 H 22000 5/6 QPSK DVB-S - Solid Signal Lock - Channel 5 etc. - UK Spot Beam
11127 V 22000 2/3 8PSK DVB-S2 - Solid Signal Lock - Channel 4 HD - UK Spot Beam

if BOTH of the above are on UK SPOT BEAM why can you get one not the other and why can you now get ASTRA 1N UK SPOT on a 1.2m when its 2.4m for ASTRA 2D UK SPOT ??

Dont forget that 1n was not conceived with the Uk in mind , the beam has to have a footprint over Spain as it will be a coverage area. If you move the beam right ie to 19.2 all of Spain will be covered.

 

[M60]

35mm?

My typo, 35cm it should be... doh!!

Saying that I think a Zone 1 dish is a bit wider than 35cm, at least the newer ones seem it. I'd say it's closer to 45cm at it's widest point.

 

[Huevos]

Dont forget that 1n was not conceived with the Uk in mind , the beam has to have a footprint over Spain as it will be a coverage area. If you move the beam right ie to 19.2 all of Spain will be covered.

Everyone says that but it is not true. That applies to the pan-European beam, not the steerable spot beam, which moves completely independently of the spacecraft body, and would have a beam with a circular cross-section. Having a spot beam with a 'bulge' makes absolutely no sense, unless that antenna was built with one use in mind. The whole point of a steerable spot beam is that its purpose can be updated as the mission evolves. If 'bulges' were built in that would not be the case and the mission might as well have started with that antenna fixed in relation to the other two, thereby saving the weight of the steering gear.

 

[Analoguesat]

How do you explain this map then Huevos?? This a spot beam with a bulge........

This is SES's own map pulled from google earth a few months ago.

 

[park_gate]

Dont forget that 1n was not conceived with the Uk in mind , the beam has to have a footprint over Spain as it will be a coverage area. If you move the beam right ie to 19.2 all of Spain will be covered.

Spain has not used spot beams in the past so why start now?

Terry

 

[Analoguesat]

Spain has not used spot beams in the past so why start now?

Terry

Any beams that the Spanish channels use have to cover the Iberian peninsular. A straight spotbeam centred on north western Europe wouldnt cover Spain adequately.

 

[park_gate]

How do you explain this map then Huevos?? This a spot beam with a bulge........

This is SES's own map pulled from google earth a few months ago.

They might have pulled it becuse it was put up by mistake.

It looks remarkabe like the Astra 2D footprint so they might have put a 2D footprint up in error.

_http://www.digitalsat.co.uk/astra2dfootprint.html

Is there reason why it is difficult for satellite manufactures to stop these side lobes?

What we relly need is some good signal strength reports to tell us what the real 1N footprint is.

Terry

 

[Huevos]

How do you explain this map then Huevos?? This a spot beam with a bulge.

I'd say it is an error, which may be why it was quickly withdrawn.

Any beams that the Spanish channels use have to cover the Iberian peninsular. A straight spotbeam centred on north western Europe wouldnt cover Spain adequately.

Nor would that beam. EIRP for that zone is 46dB according to the map so wouldn't be of any use to any broadcaster here. Generic dish size here is 50cm so we're looking at 52dB EIRP being necessary.

 

[Hiach]

They might have pulled it becuse it was put up by mistake.

It looks remarkabe like the Astra 2D footprint so they might have put a 2D footprint up in error.

Astra 2D don't have EIRP of 54dBW.

I can't remember, but did the accidental footprint release occur before the 28.2E detour was announced?

 

[Analoguesat]

What we relly need is some good signal strength reports to tell us what the real 1N footprint is.

Terry

We will have plenty once a few more tp's are lit up. We do already know there is a very steep drop off eastwards on the uk (west European) beam

 

[Analoguesat]

Nor would that beam. EIRP for that zone is 46dB according to the map so wouldn't be of any use to any broadcaster here. Generic dish size here is 50cm so we're looking at 52dB EIRP being necessary.

So slew the spot south so the higher eirp stuff is centred over Spain and the bulge would cover the Canaries nicely

 

[Hiach]

Everyone says that but it is not true. That applies to the pan-European beam, not the steerable spot beam, which moves completely independently of the spacecraft body, and would have a beam with a circular cross-section.

Are you sure that the UK spot beam is on the "top-floor steerable 1.3m" antenna?

I don't get the difference in received signal power to add up with only a 1.3m Antenna on 1N.
Both birds have similar sized spot beam footprints.
1N Have at least two 2.6m fixed reflectors,
and one 3rd fixed that appears smaller than 2.6m, based on the picture of it.

2D has a 2.03m reflector, but less TWTA power.
I estimate antenna gain of 45.5dBi, and the TWTA power is 15.9dBW, the sum is 61.4.

The 1.3m of 1N should give 41dBi antenna gain + TWTA power of 21.1dBW, the sum is 62.1.
Yet the difference in EIRP from the footprints is 3dB, 54dBW vs 51dBW.
What's missing?

 

[Huevos]

So slew the spot south so the higher eirp stuff is centred over Spain and the bulge would cover the Canaries nicely

Someone else will have to comment on that because I don't know the generic dish size for Digital+ in the Canaries.

 

[Huevos]

Are you sure that the UK spot beam is on the "top-floor steerable 1.3m" antenna?

I'm not sure of anything and I am willing to admit it. On the other hand up until this satellite was switched on there were a lot of people that were sure about a lot of things which ultimately turned out not to be the case.

TBH, without reliable inside information the whole thing is one big guessing game based on a few photos and a couple of press releases and footprint maps that were subsequently altered. For all we know the 1.3m antenna could be for a Ka payload that hasn't yet been mentioned, like the one carried on Astra 3B.

 

[Dan Dan]

Any beams that the Spanish channels use have to cover the Iberian peninsular. A straight spotbeam centred on north western Europe wouldnt cover Spain adequately.

BY THE LAW OF SPAIN - any channels with a NATIONAL licence MUST cover ´´´the peninsular´´ NEVER CALLED THE MAINLAND IN SPAIN AND ´´the canary islands ´´ as there both areas are classed as INTERNAL parts of the same kingdom...there is a very important point,as no part of the kingdom can be treated as second tier
this is so the catalan republicians ,who are in power ,cannot say that the kingdom is not equal
people in england do not know that there are no spanish police in barcalona,and spanish is no longer the main lang. in schools

LICENCES ARE ISSUED AS national,Province,local...

 

[Analoguesat]

I'm not sure of anything and I am willing to admit it. On the other hand up until this satellite was switched on there were a lot of people that were sure about a lot of things which ultimately turned out not to be the case.

TBH, without reliable inside information the whole thing is one big guessing game based on a few photos and a couple of press releases and footprint maps that were subsequently altered. For all we know the 1.3m antenna could be for a Ka payload that hasn't yet been mentioned, like the one carried on Astra 3B.

Id say a lot of the early enthusiast predictions have come true, even if thy have been based "on a few photos and a couple of press releases and footprint maps that were subsequently altered" as you so eloquently put it.

If its in the press release then that info is as good as it gets without access to a source inside the operation as far as Im concerned.