What are some causes of BEV signal strength variation?

[rossb]

I was off sick today, so I decided to catch up on stuff recorded on the PVR - and periodically dipped into the setup screens to monitor transponder signal levels. I'm in an extreme south location, but I do have an 8' solid aluminum dish - great gain. And today's weather was quite clear during the period of observations, when I observed transponders that are problematic vary from no lock/signal to 65% or more - implying 30% or more signal variation...

Maybe this has been answered in another thread (it should be a sticky one...) please point me in the right direction, but here's an appeal to some of the real gurus : in the forums - what causes BEV satellite signal levels to vary so much?

a) I realize moisture and/or precipitation can block signal.
b) I know that the satellites themselves slowly wander a bit in their assigned volume of space - so that a dish that is TOO finely focussed can be a problen.
c) I also realize BEV has some sick hardware with less output power in both Nimiqs than they would like.
d) I know that the LNBF can be affected by temperature - but a wacky observed effect is that peak reception can occur day or night...
e) I've got trial & error experience with signal variation depending on time of day (as above) and time of year.

It's the last point (and the rollercoater levels) that seemingly has no rhyme or reason.

Gurus (Mike, Iceberg and anyone else): any knowledge to impart?

Thanks....

 

[Mr Tony]

option C

Evu has 2 satellites at 91 and one has a different footprint than the other. N1 has a decent footprint (Can/US +). N3 or 4 I forget what crapelite is at 91 (the other crapelite is at 82) is an old Directv satellite so when they shifted it north that nuked the signal in Cali, Az, Nm, TX, etc

crapelite--a crappy satellite

 

[KE4EST]

Iceberg said it pretty much.

 

[rossb]

How about solar effects?

Thanks for the response... and a thought experiment:

Being an old fart and all, I used to experiment with radio reception before the airwaves got really cluttered and still periodically play with an old receiver where I can mess with center frequency and other manual tuning tricks (ah, yes... analog!!!).

I know that solar wind and flares could/can wreak havoc with the ionosphere. Also, as alluded to in point "e", we get broad variation in signal strength based on season - reception issues increase to June 21 and taper off slowly afterwards - best reception is usually at other end of year, around December 21...

So could we be looking at solar effects on transmission (top down) or atmospheric effects (humidity/ionosphere - bottom up)?

Or am I just rationalizing/babbling?

And do we have any satellite/RF engineers lurking? Your thoughts....

Thanks....