Astra 1N chat - January 2012

[timo_w2s]

I think that the European beam is developed in a way that these birds can be used on the 19.2 position as well. There's a Canary Islands beam that doesn't fit the islands completely on 28.2 but most likely it fits when located at 19.2 degrees East. I guess the lobe over Poland shifts to the Ukraine and the Italy lobe over Greece.

Ah yes, of course. I always assumed this was one of the main reasons why the older Astra 2A/2B/2C had wide beams too - just in-case they where needed elsewhere.

 

[Satellite74]

been pondering this map today from the thread Astra 1N, Eastern Europe, reception survey, UK spot beam (11126V DVB-S2)



As reports by other users have shown, reception gets a little sketchy east of the red line on the map, unless you are prepared to invest in sizeable dish equipment.

I know it's all just guesses, educated ones at best, until 2F is in position and has started transmitting, but if this is as good as it currently gets with 1N, and if 2F unlike 1N will have a custom-designed UK spot beam, then shouldn't it follow that that red line will move west by as much as a few hundred miles?

And could somebody please explain again what relevance "off-axis" considerations might have here, given that my location in central Germany is only about one degree off the center of 2F's prospective spot beam?

 

[solly]

we can after launch iot testing signal after launch end of this year

 

[M60]

been pondering this map today from the thread Astra 1N, Eastern Europe, reception survey, UK spot beam (11126V DVB-S2)

View attachment 42086

As reports by other users have shown, reception gets a little sketchy east of the red line on the map, unless you are prepared to invest in sizeable dish equipment.

I know it's all just guesses, educated ones at best, until 2F is in position and has started transmitting, but if this is as good as it currently gets with 1N, and if 2F unlike 1N will have a custom-designed UK spot beam, then shouldn't it follow that that red line will move west by as much as a few hundred miles?

And could somebody please explain again what relevance "off-axis" considerations might have here, given that my location in central Germany is only about one degree off the center of 2F's prospective spot beam?

I reckon realistically we could see it move in more of an arc from Denmark down through southern Germany and sweep across the bottom of France. One thing we do know about 1N is that east of that line the field strength drops like a stone given the reception reports received. If this is a 'fudged' widebeam or steerable antenna which as we know has a lot of overspill then the custom UK 1N footprint will almost certainly be much tighter. 2D's footprint was never UK customised, just out of luck fitted the UK topography and SES found a use for it here although back in 2000 probably would have preferred another pan-European one. As things turned out that has been the saviour for FTA Satellite broadcasting and also Freesat's creation.

We'll have to see how things pan out, anything else is just guess-work at this stage.

 

[Satellite74]

I just wonder how far east will be too far... Hanover is 488 miles east of Birmingham, the center of the UK beam, according to Google Earth... and Birmingham-Norwich is only 150 miles...

I would have enough space on my balcony to accomodate a 120cm dish... anything larger than that, and I'll probably be looking at a rebroadcasting subscription.

If the UK beam on 2F turns out really tight, then I predict an explosion in Slingbox rebroadcasting services... who will then pretty soon become the object of class-action lawsuits by the content industry... they might even end up becoming the next stage in the industry's battle against copyright and licence infringement... it will be the same as with music and video filesharing... rather than providing a convenient feasible payment model for all those interested (like BT, Sky or Virgin Broadband subscriptions for UK TV that are valid abroad), they will flex their muscle and go after rebroadcasters - and their customers.

Evil, evil people... :mad:

 

[Analoguesat]

And could somebody please explain again what relevance "off-axis" considerations might have here, given that my location in central Germany is only about one degree off the center of 2F's prospective spot beam?

One of the lads did some calculations on one of the earlier threads. The centre point of the 1N beam was taken as being Birmingham, If I recall correctly the signals were ok up to 2.5 degrees off axis

If I understood it right you need to do the trig calculations to work out the angle between Birmingham and say Dresden up at the satellite.

 

[Lazarus]

"Subtended" is an apposite word.

 

[M60]

I just wonder how far east will be too far... Hanover is 488 miles east of Birmingham, the center of the UK beam, according to Google Earth... and Birmingham-Norwich is only 150 miles...

I would have enough space on my balcony to accomodate a 120cm dish... anything larger than that, and I'll probably be looking at a rebroadcasting subscription.

If the UK beam on 2F turns out really tight, then I predict an explosion in Slingbox rebroadcasting services... who will then pretty soon become the object of class-action lawsuits by the content industry... they might even end up becoming the next stage in the industry's battle against copyright and licence infringement... it will be the same as with music and video filesharing... rather than providing a convenient feasible payment model for all those interested (like BT, Sky or Virgin Broadband subscriptions for UK TV that are valid abroad), they will flex their muscle and go after rebroadcasters - and their customers.

Evil, evil people... :mad:

I reckon you'd be ok on a 1.2m in Hannover, even if the beam is ultra tight. Likewise the Benelux countries and Northern France would probably be fine on a 1.2m, purely guesswork as SES haven't given us any other field strength contours to work with. Given though the whopping 57dBW field strength across the UK one can assume the spotbeam is going to be 2dBW tighter than 1N's who's maximum is 55dBW if I remember correctly (without looking).

 

[Satellite74]

just made some more calculations...

According to the signal strength map for 2F, SES Astra expect the signal level to go down 2 dBW, from 57 to 55, between Cambridge and the southern North sea about north of Bruges. Which is a distance of about 90 miles. From what I just read somewhere on the web, a minimum of 40 dBW is needed for a 120 cm dish. And it's about another 290 miles from the southern North Sea, north of Bruges, to Hanover. If the signal drop-off would be perfectly linear (which as we know it won't be) and the signal dropped another 2 dBW every additional 90 miles, then that would leave around 48 dBW over central Germany. Again, in an unrealistic scenario, just for the sake of crunching numbers. So the question is again going to be, how "non-linear" will the drop-off turn out. Will it be reduced by more than 15 dBW over those 290 miles, which would be an average rate of 2 dBW every 36 miles instead of every 90...

I know... once again just guess-work...

 

[M60]

just made some more calculations...

According to the signal strength map for 2F, SES Astra expect the signal level to go down 2 dBW, from 57 to 55, between Cambridge and the southern North sea about north of Bruges. Which is a distance of about 90 miles. From what I just read somewhere on the web, a minimum of 40 dBW is needed for a 120 cm dish. And it's about another 290 miles from the southern North Sea, north of Bruges, to Hanover. If the signal drop-off would be perfectly linear (which as we know it won't be) and the signal dropped another 2 dBW every additional 90 miles, then that would leave around 48 dBW over central Germany. Again, in an unrealistic scenario, just for the sake of crunching numbers. So the question is again going to be, how "non-linear" will the drop-off turn out. Will it be reduced by more than 15 dBW over those 290 miles, which would be an average rate of 2 dBW every 36 miles instead of every 90...

I know... once again just guess-work...

It is an interesting one. If you look at the Pan European maps of 1N they hold out level and then drop off rapidly on their footprint edges, much quicker than 2A or 2B do. Astra 3B's footprint may also provide some clues as that's a fairly recent Astrium built craft too.

 

[L0nk]

Well, currently I have a 95cm (a Fuba one - so it seems to be very well manufactored) dish south of Frankfurt (Darmstadt) - I was able to get it by my landlady... she was ripped off by the installer who when she went digital for 19.2°E - he installed an additional 60cm dish (if I was already living here back then I would have killed that install guy) leaving the 95cm dish on the roof without function - in the end: an advantage for me, I have a single 95cm dish pointing to 28.2°E (in case of heave rain the signal of 19.2°E actually dies before 28.2°E), no multifeed solutions or anything.

But yeah, it's going to be interesting - how well, that 95cm dish will perform once 2F is here!

 

[Bjarne Nilsson]

The " UK / Ireland Pan Euro " Beam is basically also a UK spotbeam, just with a little bit less focusing. My guess is, the "real" spotbeam has the same shape, however some 1-3 dbW less in the outer skirts. Basically, it's back to 2D coverage, with the signal much stronger in the UK. You really wont need a dish there anymore, just point the LNB into the skies.

Well if you are right about the coverage (for the spot beam) I will be very happy as that will result in me having all fta channels 24/7. I did hav some signal fading before but a very nice person on this thread (IIRC) told me that this was caused by 2d wobbling (not keeping station perfectly) which will not be an issue with the new satellites. Well time will tell

 

[Lazarus]

All Satellites wobble and shift within their permitted area, which can affect fringe reception. Also, the degree of illumination of the solar panels varies, which can also have some effect.

 

[Bjarne Nilsson]

All Satellites wobble and shift within their permitted area, which can affect fringe reception. Also, the degree of illumination of the solar panels varies, which can also have some effect.

Well yes, what I was reffering to was tha fact that 2D wobbled quite a bit more than the new sats do (I dont remember the exact numbers but the difference between 2d and 1N is sustential), so I find it resenable that if I got signal fade (same rime each day) with 2D I will not get the same problem with 2E/2F spot beam, am I wrong or...?

 

[Analoguesat]

Well yes, what I was reffering to was tha fact that 2D wobbled quite a bit more than the new sats do (I dont remember the exact numbers but the difference between 2d and 1N is sustential), so I find it resenable that if I got signal fade (same rime each day) with 2D I will not get the same problem with 2E/2F spot beam, am I wrong or...?

That depends just how strong the signal strength is at your location on your dish - all satellites move around in a cube about 75 miles on a side due to gravitational effects.

At the very very edge of the signal the daily variation is enough to push the signal over the edge of the "digital cliff" from reception to no reception

And certainly at the end Astra 2D was not healthy with intermittent drop outs reported from all over Europe - one Sky+ episode of Top Of The Pops 1977 here is almost unwatchable due to stutter & signal dropouts. That was transmitted the night before 2D was switched off, and Ive seen numerous similar reports.

 

[Freckled]

New setup so nothing to compare with, pulling 1N in no problems at all. Have also been viewing 2B North (dave ja vu) all day, but have lost it now, it is chucking it down though. Weren't expecting to be able to get that anyway.

1n still strong though even in the rain. Happy days! (for now)

 

[Juan69]

New setup so nothing to compare with, pulling 1N in no problems at all. Have also been viewing 2B North (dave ja vu) all day, but have lost it now, it is chucking it down though. Weren't expecting to be able to get that anyway.

1n still strong though even in the rain. Happy days! (for now)

Further up just outside Murcia here, i.e. inland, did get good reception on most FTA; but now unusual heavy rain, so nothing till it clears. Great improvement on 2D.

 

[Satellite74]

At the very very edge of the signal the daily variation is enough to push the signal over the edge of the "digital cliff" from reception to no reception

And certainly at the end Astra 2D was not healthy with intermittent drop outs reported from all over Europe - one Sky+ episode of Top Of The Pops 1977 here is almost unwatchable due to stutter & signal dropouts. That was transmitted the night before 2D was switched off, and Ive seen numerous similar reports.

I experienced this too here in central Germany just before the channels got moved to 1N. Astra 2D really must have been on its last breath, and the move must have come in the nick of time right before it became unusable. All of my Freesat BBC channels got a bit wonky (interestingly, ITV and Channel4 were still fine), the artefacts and dropouts eventually became so strong that it sucked the fun out of trying to watch anything.

SES Astra, UK broadcasters, and rights holders really weren't doing this for nothing - putting Freesat on a satellite beam which wasn't designed for the British Isles and is essentially a flawed makeshift spotbeam, and thereby supplying nearly all of Western Europe with prime free-to-air unencrypted content, especially during an Olympic year... they really must have had no other choice. Charity is not to be expected from them anyway...

 

[Analoguesat]

BTW - Ive been told since I made that earlier post that the BBC signal dropouts on 2D were actually a transmission chain problem.

However one of our members did post that there was a distinct ripple visible (in Spain I think it was) on the 2D power output, almost as though one of the solar panels was down on power - remembering that 2D was a Being spin stabilised craft not a 3-axis stabilisation bird

 

[andrewcrawford]

i just wonder what would have happened if astra 1n failed in it launch or kept getting delayed??? clearly 2d was dying quicker than expected and they realy wanted it shut down before completely lost but would there been any other bird that been able to give a spot of some kinda big enough to cover the uk and not give to much overspill to keep everyone happy, could it have been possible that freesat was shutdown??? hypertorical quetion unlikely to happen now just wondering