A dumb ?...

[hillsmi]

Okay, don't laugh...

Is it at all possible for an FTA dish to lose it's reflective ability?

I've got a generation one (10+ years) GeoSatPro OLD gray dish, that for some reason, I just can't get any signal on. Alternatively, I have a brand new GeoSatPro, just shipped, that I was able to lock on in under 1 min. This isn't the first one of these that I have assembled or installed. I've put about 3 doz of these (newer generation GeoSatPro) together and never an issue. I have come across a couple of these older dishes over the past 8 years, but have just had to fine tune an already acquired signal. I can't for the life of me figure out why this old dish won't pick up a signal. It is not damaged or warped in any way. Any ideas from the experts? Yes, I have tried more than one LNB.

 

[primestar31]

Not likely.

What's far more likely, is a bad lnb or bad cable/cable connector, if there's a switch involved, one port can go bad. Followed by miss-aimed dish, bent lnb arms, etc.

 

[migold]

Okay, don't laugh at me.... But... I have heard that the military has developed coatings that absorb microwave radiation. You probably don't have that, but I believe the possibility that if there is some contamination on the dish surface that has absorbed water molecules, then the water molecules maybe absorbing the microwaves, thus attenuating your signal.
OK - I ASKED THAT YOU DON'T LAUGH !!
If this is the case, scrubbing off anything on the surface may help. Or - worst case - remove original paint and repaint - I assume this is a metal dish... I have a GeoSatPro 90cm that I have been using for over 6 years, consistently good results.
Of course, primestar31's suggestion is quite valid.

 

[Titanium]

Don't strip the coating off. It is an rf neutral poly coating and has no effect on the signal reflection. The only reasons the dish would not be working is if the parabola is warped or the LNBF is not in the correct position.

Maybe the rear bracket post clamp was installed using the "B" scale for elevation instead of the "A" scale?

 

[. Raine]

Strong magnetic fields can cause reception problems. But then, your other dish would be affected too, unless it was very localized, so not very likely that.

 

[Cham]

A tree or other object grew (moved) into the path?

 

[RT-Cat]

Not a giggle situation at all. When I just put back up my 10 foot orbitron mesh and could not get anything, I was thinking about the same thing. It was stored outside for about three years and did have some green(mold)look to the dish. After a scrubbing, still nothing. A new LNB made the difference. Very odd in your case where you tried more than one. Did you try the several string check to see they all touch in the center where they cross?

 

[cyberham]

Occam's razor:
Among competing hypotheses, the one with the fewest assumptions should be selected.

Check primestar31's ideas.