Costa Blanca, 2E/2F, seasonal signal fluctuation.

Huevos

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Why between about 0200 and 0800 do the sats seem to do the opposite to each other - its almost a mirror image?
 

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No idea. What do you think?
 

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Interesting. Is this dish pointed at 28.2 or 28.35?
 

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What is the elevation on the dish/LNB for this satellite??

It could be a signal bounce that is caused be certain weather conditions, water or ground temperatures and atmospheric temperature variations from season to season.

This bounced signal would be 180 degrees out of phase from the main signal, when the bounced signal gets close to the right amplitude it will cause a drop in the main signal, this is called phase cancellation, and is a common in microwave signals, the bounce is determined by the elevation of the dish/LNB and what ever is causing the signal to bounce.

RF signals can bounce off things, just like Sun light bouncing off the heat of the road, thus causing a mirage in the road that looks like water, and it disappears when you get closer to it.
 

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What is the elevation on the dish/LNB for this satellite??
Don't really see where you are going with this. Everyone's performance here has changed by the same amount, so nothing to do with the install.

Overall signal is now down by 1dB SNR on all transponders compared 4 months ago. If it drops much more everyone in Torrevieja with a 1.4m offset dish is going to lose BBC/ITV.
 

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What is the elevation on the dish/LNB for this satellite??

It could be a signal bounce that is caused be certain weather conditions, water or ground temperatures and atmospheric temperature variations from season to season.

This bounced signal would be 180 degrees out of phase from the main signal, when the bounced signal gets close to the right amplitude it will cause a drop in the main signal, this is called phase cancellation, and is a common in microwave signals, the bounce is determined by the elevation of the dish/LNB and what ever is causing the signal to bounce.

RF signals can bounce off things, just like Sun light bouncing off the heat of the road, thus causing a mirage in the road that looks like water, and it disappears when you get closer to it.

Seems strange that two sats so close together exhibit opposite effects from each other when viewed from the same point on earth, over such a specific period of time. For the rest of the day they appear more or less to follow each other albeit one at a higher level than the other - which seems more logical. I can see the argument could explain why a signal is diminished for a period of time but if that is so, then why deo it not affect both signals ithe same way?
 

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My dish was aligned in february on 10818V as 2E was weaker than 2F for me, now the channels on 2F seem about the same as in february but all the 2E channels are gone or much weaker. Has 2E moved that much between february and now or has the UK spot beam been tweeked as no other channels seem affected on 2A or E28A?
 

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My dish was aligned in february on 10818V as 2E was weaker than 2F for me, now the channels on 2F seem about the same as in february but all the 2E channels are gone or much weaker. Has 2E moved that much between february and now or has the UK spot beam been tweeked as no other channels seem affected on 2A or E28A?

I was also thinking that maybe the power has been tweeked down on 2E or the angle of the spot beem adjusted a little (don't know how much scope ther is for that if any!) - but then again almost anything else could have a weakening effect on the signal. - I also wondered if the 2e position was slightly less stable than 2f i.e. the fig of 8 it makes is slightly bigger than 2F's!
 

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2E hasn't moved and power is down on both satellites as the graphs above show.
 

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Don't really see where you are going with this. Everyone's performance here has changed by the same amount, so nothing to do with the install.

Overall signal is now down by 1dB SNR on all transponders compared 4 months ago. If it drops much more everyone in Torrevieja with a 1.4m offset dish is going to lose BBC/ITV.


The install is not the problem, and Joddle if the two satellites where right next to each other (so you could reach out and touch each other) then they would preform the same way, but they don't, there are 7 satellites (active) at the 28.2 degree orbital location an they have a maximum/minimum separation distance of 250 to several thousand miles, they may look to be at the same co-ordinates but they are not.

This maybe one reason you would/could see a difference in performance between the 2E and 2F satellites. (but my bet is on a ground or ocean bounce off a temperature inversion layer, if the elevation of the dish is just right you pick this up and it causes a drop in signal)

These satellites are 22,500 miles out traveling at 17,500 miles per hour, this puts them in a fixed location over one spot of the Earth, and due to the receive beamwidth or your satellite dish you can pick them all up at once when pointing to the 22.2 degree orbital location.

And they do not play around with the transponders power level, nor can they adjust the spotbeams, these are fixed shotgun antennas on the satellite pointing at a fixed location, they do not move, adjusting one would affect all.

Most of the satellites up there do wobble a bit, and this could be the problem, this wobble is due to solar wind and other things affecting the Earths magnetic field and gravitational field, this can cause a wobble in the satellite, then the satellites gyro stabilizers have to correct it, in extreme cases they may have to use the satellites stabilizing jets, but they do not want to do this as it uses fuel, and they only have so much fuel on board.

And one other thing that could affect them is the Moon, if it can cause the lunar tides, it can affect the geosynchronous satellites, and this effect can be at a certain time of day, month or year.

So there are lots of forces out there affecting these satellites.

All these effects can be compensated for by going to a larger dish, we in the broadcast industry know about all these effects and use very large dishes to compensate for them, for "C" band we use 6 to 10 meter dishes (this depends on the satellite and location) for "kU" band (if needed) we use 3 to 6 meter dishes, (again depending on the location and satellite)
 

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Terryl, how do you explain the Main/Sidelobe pendulum as shown here: http://www.satellites.co.uk/forums/...ern-europe-reports.159945/page-16#post-888728

Is this "wobble" for you or is there anything else on top contributing to this effect ? Is the wobble you talk about the (usually) 0.05 degrees pointing error ?
We see here at the eastern border variations between the seasons as well. I tend to think those occure to the different angle between the sun and the satellite.
 

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As the Earth turns, the satellites follow, as they go between the Earth and the Sun they get a bit of a tug out towards the Sun, as they get back to 90 degrees to the Earth Sun alignment they get a bit of a tug back towards the Earth, when the Earth is between them and the Sun the get another tug, but this time a bit more towards the Earth, the gyroscope stabilizers on board the satellites put them back at the proper distance.

When they get the tug away from the Earth the signals will drop, and then go back up, look at your graph, watch the timing on these highs and lows in the signals, for the Asta 2E I see a dip at 07:00, and one at 19:00, this could be due to the Sun Earth Moon effect, all this is part of the wobble you see in the signals, also the satellite is solar powered, when in the dark side of their orbit they are on battery power, when the come around to the sunny side the solar panels will have been tracked to maximize the charge to the on-board battery's.

This movement of the solar panels also causes a wobble, now on some of the older satellites the battery packs may be getting a bit weak, so during the night time the power levels on some of the transponders may drop a bit, this is all determined by how old the bird is and if any of the cells in the solar panels may have sustained any debris (there is a ton of junk up there) or micro meteor damage, or if any of the battery's cells have gone south for the winter.

The "Lobes" you may be talking about maybe imperfections in the antennas, these things are not perfect, all transmit antennas have side lobes, and some develop over time, again this due to any debris or micro meteors..

It also could be my fault, this due to cleaning the windshields and checking the air in the tires.
 

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Huevos, what are you using to track these signals?

And what signal is it, is it the actual 10 to 11 GHz transponder signal coming down from the satellite, or the IF "L" band signal from the LNB?
 

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And here is another possibility as to the signal wobble, watch this video.

Code:
http://en.wikipedia.org/wiki/Van_Allen_radiation_belt
 

Huevos

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several thousand miles, they may look to be at the same co-ordinates but they are not.
2.5 miles difference in altitude between 2E and 2F. And 0.15º along the geostationary arc from each other is 69 miles.
 

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Woops, sorry my post #12 as an error, "an they have a maximum/minimum separation distance of 250 to several thousand miles," I missed a decimal point, it should be 25 miles, I've got to quit playing with big numbers, a 6 pack is all I should stick too now days.
 

Terryl

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Check these out.

Code:
http://www.satellite-calculations.com/Satellite/satellitemotion.php?26/171/0/38778
Code:
http://www.satellite-calculations.com/Satellite/satellitemotion.php?26/171/0/39285
 

joddle

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Wow - so much infromation Terryl - and to me very interesting and informative. I think Huevos maybe has every right to poo poo my comments as it seems he knows far more than me - but I am trying to learn! And as he says the signal on both sats is down. although here I am not noticing that as much as I would have expected but then of course I don't have the more sophisticated kit and am relying only on the sat box reradings - so perhaps not the best way to make a scientific judgement! nevertheless its all very interesting.
 
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