Astra 1N tests - latest chat

[satelliteman]

_http://www.astrium.eads.net/media/document/launch_kit_203_1_2.pdf

Nice read ;)

 

[welshman234]

you say "certainly have much narrower reception parameters" but what do you base that on?

Can we have a link to the source?

The following shows Astra 1N use a 2.6M antenna:

_http://www.astrium.eads.net/media/document/launch_kit_203_1_2.pdf

As this is the maximim size antenna fitted to Eurostar E3000 how can 2E, 2F and 2G have tighter beams if they are the same design as 1N?

Terry

It also has a 1.3m according to the literature ..plus three 2.6m dishes. Therefore 4 antennas yet the info on the beams so far refers to 3 beams for Europe. The fourth antenna is KA band I assume???

 

[Analoguesat]

you say "certainly have much narrower reception parameters" but what do you base that on?

Can we have a link to the source?

The following shows Astra 1N use a 2.6M antenna:

_http://www.astrium.eads.net/media/document/launch_kit_203_1_2.pdf

As this is the maximim size antenna fitted to Eurostar E3000 how can 2E, 2F and 2G have tighter beams if they are the same design as 1N?

Terry

No you cant have a source - intuition bud. Look at how steep the 1N drop off is to the north east (the Nordic countries are having problems) then extrapolate that south westwards.

1N & the new 2's might be the same design but the beam coverage areas are likely to be engineered different. I fully predict the new 2's will be far more difficult to get in the Canaries than 1N is turning out to be.

 

[welshman234]

No you cant have a source - intuition bud. Look at how steep the 1N drop off is to the north east (the Nordic countries are having problems) then extrapolate that south westwards.

1N & the new 2's might be the same design but the beam coverage areas are likely to be engineered different. I fully predict the new 2's will be far more difficult to get in the Canaries than 1N is turning out to be.

Look at post 654 Terry for a theoretical possibility....

 

[Dan Dan]

No you cant have a source - intuition bud. Look at how steep the 1N drop off is to the north east (the Nordic countries are having problems) then extrapolate that south westwards.

1N & the new 2's might be the same design but the beam coverage areas are likely to be engineered different. I fully predict the new 2's will be far more difficult to get in the Canaries than 1N is turning out to be.

so in affect your saying it how its tuned,not the basic design...ie tuned for the uk unlike 1n which has a bump...

 

[Analoguesat]

Yup thats a good description - beam can be shaped to some degree by the transmission dish design - which has improved greatly over the last 10 years..

 

[Huevos]

Look at how steep the 1N drop off is to the north east (the Nordic countries are having problems) then extrapolate that south westwards.

I've got to agree about the south-west bias but maybe that is just orientation rather than beam shaping. The beam might be pointing at Lands End or south west Ireland (51N, 10W) rather than the central UK. That would put me just 1.2º off axis (instead of 1.5º), Helsinki 3.4º (instead of 2.7º) and the Canaries 3.5º (instead of 4.2º). That bias sounds about right too because so far (as far as I know) neither have reported reception on a 1.8m dish. The big difference though between the Canaries and the Nordic countries is 3+ metre dishes are the norm in the Canaries whereas a 1.8m in Finland is considered big. So the Canaries are always going to have a better chance of catching 1N transmissions based on access to big dishes alone.

 

[park_gate]

Look at post 654 Terry for a theoretical possibility....

Nice try but it doesn’t work like that.

Poland is 19E so it lines up with the Astra 1 satellites at 19E hence the tight beam.

If the satellite is move to point at the UK the beam will elongate. If the satellite is move further east to 28E the beam will elongate even more.

Try post 384 on page 16 for an explanation as to why things are probable not going to be that bad.

See Also the DS thread “Astra 1N - Any News” page 5 #117

Terry

 

[welshman234]

Nice try but it doesn’t work like that.

Poland is 19E so it lines up with the Astra 1 satellites at 19E hence the tight beam.

If the satellite is move to point at the UK the beam will elongate. If the satellite is move further east to 28E the beam will elongate even more.

Try post 384 on page 16 for an explanation as to why things are probable not going to be that bad.

See Also the DS thread “Astra 1N - Any News” page 5 #117

Terry

I dont post on DS satellite pages anymore as some of the posters seem to use it as a place purely to provoke or advance some rather odd points of view. Thats not personally directed at you by the way!!!!!! Terry the astra 1kr diagram above was adjusted to take into account a possible reshaping of the beam, were it to be repositioned at 28.2 degrees, after Huevos recommended that. The new generation of 2s will be made with a much different beam shape in mind. They will be principally deployed with the UK in mind. 1N is Spain and Canaries freindly because it has a lovely beer gut of a beam hanging over Spain and Portugal. This means significant reach into western Europe. 1N was conceived with Germany and Spain in mind. It is my personal view that the shape is designed for Spain and the canaries if you shift it South West ....Oh and before anyone accuses me of expat scemongering or whatever check my location. I too would like to keep my viewing of Brit tv going....But I am also realistic about the fact that this is a privilege which could disappear and am I always alert to having to plan for other possibilities may it happen.

 

[Hiach]

It also has a 1.3m according to the literature ..plus three 2.6m dishes. Therefore 4 antennas yet the info on the beams so far refers to 3 beams for Europe. The fourth antenna is KA band I assume???

The antenna details in the "launch_kit_203_1_2.pdf" document is different from the info on the astrium page:
_http://www.astrium.eads.net/en/programme/astra-1n-responding-to-demand-for-digital-and-hd-telecommunication-satellites.html

"The spacecraft will have three deployable antennas with diameter up to 2.6m and one top-floor steerable 1.3m antenna."
One of the three deployable antennas appears to be smaller than the other two (the one that is almost hidden in the picture)
There's also a better view of this in the video at 1:15.

 

[milestone 11]

The big difference though between the Canaries and the Nordic countries is 3+ metre dishes are the norm in the Canaries...

I would say that this is absolutely not the case. Whilst there are some 3.0m dishes around, the vast majority are 1.35m. Without being able to site a 3.0m dish in a non exposed area, I doubt a 3.0m would be still standing after a typical month here. I certainly wouldn't consider having such a beast, I'd spend my life chasing it around the island.

 

[Lazarus]

I would say that this is absolutely not the case. Whilst there are some 3.0m dishes around, the vast majority are 1.35m. Without being able to site a 3.0m dish in a non exposed area, I doubt a 3.0m would be still standing after a typical month here. I certainly wouldn't consider having such a beast, I'd spend my life chasing it around the island.

If I find a stray one during my visit to your Island next Friday, I shall be sure to acquire it for myself ............ Not sure how Mr. O'Leary will react on the Flight home, though!

 

[Huevos]

Whilst there are some 3.0m dishes around, the vast majority are 1.35m.

Those are for people that are happy to receive Astra 2A/B and EB1, but there are still hundreds of big dishes out there across the islands. I guess it all depends whether you live in a house or an apartment block. Same here too; most dishes are 80cm or less but there are still 10s of 1000s of 1.8-2.4m dishes around.

1N is Spain and Canaries freindly because it has a lovely beer gut of a beam hanging over Spain and Portugal. This means significant reach into western Europe. 1N was conceived with Germany and Spain in mind. It is my personal view that the shape is designed for Spain and the canaries if you shift it South West ....

I think Analoguesat was the first to put that theory out there, and it does look pretty plausable. It would mean the 3 deployable aerials would be fixed in relation to the space craft body. Aerial 1, Spain and Canaries; aerial 2 Germany and western Europe; aerial 3 eastern Europe. It doesn't necesarily mean frequency reuse, but it does mean the satellite can make more efficient use of the power it is sending down. So the Spain beam might be an easy catch in Germany with a 80cm dish and the Germany beam in Spain on an 80cm aerial but, unlike today, on a minidish you will only get your own beam.

 

[satelliteman]

Loading satellite plans into my meters.... and not wanting to rub it in , but thought I'd upload the current 1N signal measurements received here at base in the Midlands UK; at least for those of an interest anyway ;)

 

[Huevos]

Loading satellite plans into my meters.... and not wanting to rub it in , but thought I'd upload the current 1N signal measurements received here at base in the Midlands UK; at least for those of an interest anyway ;)

What is the dish size? How does that 15dB MER compare to 2D transponders?

 

[satelliteman]

0.43cm dish

2D's are typically around an MER of 11 -12dB.

Certainly a noticeable increase on the Horizontals.

 

[Analoguesat]

0.43cm dish

Ahem

I know 1N is a high power bird but.......

 

[satelliteman]

Ahem

I know 1N is a high power bird but.......

Yes, given those levels.... I may have to consider downgrading

 

[Huevos]

0.43cm dish

Those readings are more or less the same for me on a 1.8m aerial.

2D's are typically around an MER of 11 -12dB.

I guess the power increase (2D:38W -> 1N:130W) is responsible for that.

Certainly a noticeable increase on the Horizontals.

That's just because the vertical transponder is 8PSK, otherwise the MER would be the same on that as the horizontal ones. If you look at the SNR compared to the MER in the images I've posted you'll see what I mean. Anyway I guess the 2/3 FEC should more than compensate for that.

 

[M60]

0.43cm dish

2D's are typically around an MER of 11 -12dB.

Certainly a noticeable increase on the Horizontals.

That's pretty much also what I get with my Horizon HDSM with a 43cm minidish, 1N here blows the windows out although C/N-wise maxed out at about 15.3dB using 10964H as a benchmark for testing. I've not had the opportunity to test the verticals yet as mine won't support DVB-S2 and as such the only DVB-S modulated uplinks are all horizontally polarised.