Astra 28, 2D fade out

[guest poster]

........I've been watching "A Time to kill" for about an hour but now (00:25) it's starting to get unwatchable. Very frustrating.

sorry to hear that, wish we had all the answers ...

did you put an incline actuator on that ?

 

[Huevos]

did you put an incline actuator on that ?

No. Pipino has one so maybe he could check north and south a bit.

 

[pipino]

well i did try to fine tune up/down and left/right ..doesnt make a change at all,,, today i´v lost the signal about the same time as huevos ..in a way it does explain that we have a big issue with astra 2d in our doomed area..regards

 

[guest poster]

well i did try to fine tune up/down and left/right ..doesnt make a change at all,,, today i´v lost the signal about the same time as huevos ..in a way it does explain that we have a big issue with astra 2d in our doomed area..regards

hi pipino..

What resolution to you get from the incline/elevation actuator ... how many degrees x how long an actuator?

cheers..

 

[Huevos]

we have a big issue with astra 2d in our doomed area..regards

It's getting worse too. In 2003 when BBC moved to Astra 2D a 1.8 metre dish was fine even with rain. These days that dish is right on the limit. Now even people with a 2.4 are complaining about ITV pixelating late at night. I think 2D has only got a couple of years left. It was launched in 2000 and HS-376's only have a 12 year lifespan.

 

[Zorba]

I don't think it's worse over here. Since BBC went to 2D,I think this year is better than previous years(although winter is better than summer) but we also get ITV on 12.402V now,since they left 10.714H and was replaced by CH4(which also was an improvement as we get interference from Arabsat)

 

[dxsat]

The drop in signal of 2D is noticed all over Spain and other parts of Europe. I saw a report from someone in Norway complaining of the same thing. The theories floated above don't correspond with reality however. It's not local interference. It's not the sun hitting the satellite's antenna (if this was the case it would improve late evening after sunset. The opposite is the case) The ionosphere reflects short wave, but not microwave, I believe.
Dust & moisture do affect satellite signals but this doesn't explain the effect of 2D signals weakening every evening, every day of the year, at the same time.

The post above about stronger signal currently late at night is a result of 2D's batteries being switched on during eclipse. The satellite is moving through the earth's shadow at night for the next 2-3 weeks. This happens agaain in the autumn. Batteries are swiched on for eclipse protection and received signal on the ground goes up to daytime levels for about 40 minutes during eclipse. Many have observed this effect on the fringes. During the day at this time of year, signal is lost briefly in the morning due to sun outage.

The various theories in this and other forums on footprints moving are shot through of holes, as if the footprint really was moving daily then Norway would have better signal in the evening at Spain's expense. This doesn't happen. One engineer I spoke to ventured the explanation that the two polarities of the beam vary in relative intensity during the day, in a complex and unpredictable way, more noticeable the further out of footprint they are being received. At night in Spain, at least in Madrid where I used to live, horizontals are very weak at night, verticals much stronger. During the mornings it is the opposite.

I suspect there may be other factors, but the daily variation is most surely not dust, interference, moisture, sunlight, lower uplink power (how could this affect downlink?), or the ionosphere.

It is related the orbit not being perfect, the earth not being a perfect sphere, and variations in the amount of sunlight falling on the spacecraft's solar panels.

 

[Analoguesat]

I suspect there may be other factors, but the daily variation is most surely not dust, interference, moisture, sunlight, lower uplink power (how could this affect downlink?), or the ionosphere.

Lower uplink power - lower downlink power. Ive seen it reported a two or three times when theres been a big rainstorm over the uplink station. All of a sudden the forums are full of folks reporting poor signals for a couple of hours as the uplinked signal is absorbed by the moisture.

Eutelsat once described the the on board twta's as bent pipes in space - they just amplify & return whats thrown at them (with some frequency shifts as well)

 

[Huevos]

lower uplink power (how could this affect downlink?)

It does because a transponder is linear, i.e. it retransmits (on a different frequency) as near as possible to an exact copy of what it is receiving. The opposite effect is also true, if one uplink puts up too powerful a signal power is drained from other transponders.

 

[satesco]

the two polarities of the beam vary in relative intensity during the day, in a complex and unpredictable way, more noticeable the further out of footprint they are being received.

In N-W of Romania,vertical polaritie is quite strong.Astra 2D is received with 1.5m and 1.8m,but signal has a big variation between night and day.Better signal is at noon and in the evening when all vertical transponders are pickup!The best signal are on trp.10878 V and 10847 V.
No way to receive horizontal polaritie in this part of Europe.
Outage phenomenal,in this days{March} and in our zone{Cluj_N},started at 12.20 EET and lasted only 10 min.After that signal as it seems become stronger.

 

[Analoguesat]

Ok this has gone far enough - various posts have been removed. Please everyone remember we pride ourselves on being a FRIENDLY forum

Debate closed for the time being.