2D power reduction?

[izefisherman]

I did a check here and noticed it is much stronger than the other V-transponders. This one locks the tuner and produces an often pixelated picture here. Other V-transponders on Astra 2D won't even lock.

I live on the Finnish west-coast and the extended line drawn from Astra 2D boresight trough the Stockholm area. The H-transponders clear most of the day on a 1.8m prime focus but the V-transponders have been completely unavailable since early spring. At that time I noticed a 2% reduction in H-pol signals and V-pol went from occasional lock/picture to NIL. I have tried to realign my system but found no improvement. Hoping dry and clear winter conditions will bring the signal levels back.

Ize

And suddenly, as we have passed the autumn equinox those lost 2% are back... Cold dry weather is not the factor. Do they (SES-Astra) fiddle with the attitude of the satellite at equinoxes? The sun changes side of the equator (and the clarke belt) at the equinoxes. Optimizing solar panel power output?

Astra 2D is a spin-stabilized can-shaped bird with the solar panel wrapped around it's hull so the solar panels can not be tilted around like on a three-axis gyro stabilized satellite with "wings".

Ize

 

[dxsat]

Ize,
I think the answer lies in astronomy rather than weather or what SES Astra is up to. As you are on the opposite side of europe to me, and have noticed the same recovery in signal after the summer, it is certain that it is not the beam moving or weather conditions. I noticed that things got better the very day the sun went behind the satellite, 10th. October. It's probably receiving a bit more sun on its panels now.

 

[izefisherman]

You are correct there. If south europe is experiencing the same recovery as northern europe at the same time, the improvement cannot be due to a shift in satellite attitude since a gain up here would be a loss down there.

The change for worse/better is just so sudden. I find no easy "natural" explanation for it.

 

[Likvid]

My receiver starts to block in the image at 62% quality.

Right now i have about 64/65% on the vertical transponders during the whole day from about 11AM to 5PM, then it drops quickly below 62%

The Horizontal transponders are strong here, during the same time span from about 11AM to 5PM i get about 72% quality and at the worst time of the day they are at 67%, so it drops about 5%

I would guess a good 120cm dish like Andrew would pull in the vertical 24/7 at my place as there is maybe only 1dB C/N margin between the strongest signal and the weakest during the day.

My Fibo got 40.2dBi at 11.7GHz and the Andrew 120cm got 41.8dBi at 11.7GHz

 

[iceman]

Right now i have about 64/65% on the vertical transponders during the whole day from about 11AM to 5PM, then it drops quickly below 62%

Sounds about the same problem all round europe...Would like to know why the signal drops around 5pm CET (for a couple of hours) then increases again after 7pm..