Invacom qph-031 Lnb (Problem)

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bic

Well-Known SatelliteGuys Member
Original poster
Sep 2, 2006
25
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British Columbia, Canada
I'm hoping someone can help me solve a mystery. How did the amber lens on my lnb disintergrate?
I've been happily watching AMC 4 and Galaxy 19 for over a year on my Geosatpro. A few days ago my signal was gone and I discovered the lens broken out, leaving small bits around the edge. There had been no strong winds, we don't have squirrels and the 30 inch dish, mounted on a motor is intact. That probably rules out angry neighbours or malevolent teens. My neighbour suggested the CIA got me by satellite for watching Aljazeera.??
Please, someone tell me what happened!
 
is the remaining parts of the cover brittle? Could be accelerated degradation by chemicals. (hopefully not floating about in the atmosphere)(cleaning products?) Or normal degradation. If your signal died from anything other than water infiltrating the feed - you should be able to carefully clean out the throat. If water entered the throat, it may have gotten into the electronics. Probably done for if that's the case. I've fashioned covers out of 2 liter soda bottles and a heat gun. They seem to last a year or two before they need replacing. FWIW - My Chaparral polarotor feed covers usually got brittle and cracked in a couple of years. My BUD's LNBF cover is on the watch list as it's a couple of years old now.
 
Invacom has a 5 year warranty on their products. Sounds like your LNBF is within the warranty period and if the lens appears to have failed due to UV exposure as suggested by Fat Air, contact the distributor and RMA the product.
 
Definitely UV exposure. Same thing happened to my first Invacom QPH-031. I suggest replacing and resealing the feedhorn throat with UV-resistant material, that's what I'm going to do as soon as I find a source to cut a suitable replacement from.
 
My QPH-031 is going on 3 years and the lens is fogged but otherwise not degraded. Hoping yours is an anomoly. Invacom should honour the warranty though. Please let us know if they honour it.

Sent from my Timex Sinclair using SatelliteGuys
 
My QPH-031 is going on 3 years and the lens is fogged but otherwise not degraded. Hoping yours is an anomoly.

this is actually a very common problem with the invacom QPH-031....i think the problem is less or worse depending on where you live/weather conditions....i have heard the problem is worse for people living in very hot climates and relatively close to an ocean....

Anybody who buys this lnb I would recommend wrapping a small plastic bag around it as soon as you install it, this way if the lens does break water still won't get into it
 
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Not sure if the addition of a plastic bag is a good idea as it is likely to not last more than a season in the UV exposure and plastic material would break down long before the Invacom lens.

The lens material was originally spec'd and tested for uv exposure. I am still using the first prototype ever produced and while the lens is fogged, it has not disintegrated in the Northern California exposures. Later production models have not fared as well and if not for applying a UV protection they will break down.

For years I have used products like 303 Aerospace Protectant on all plastics that are used or stored outdoors. I first learned of these products to protect marine plastics. Without these products the plastic windows in the canvas become brittle, crack and opaque. These products keep all plastics in like new condition if applied annually.

I recommend applying UV protection sprays to the LNBF lens, body and clamps to extend their life expectancy. This is especially true for us hobbyists who do not just install once and walk away!
 
I want to get something straight in my mind - the cause of failure is water intrusion to the electronics and not the lens breaking, right? I have always thought the lens was like a weather cover and not something required for operation of the LNBF. EDIT: and Brian, does 303 Aerospace Protectant offer UV resistance or does it just seal up small cracks preventing water intrusion? I may try that product if it offers UV protection help.
 
Not sure if the addition of a plastic bag is a good idea as it is likely to not last more than a season in the UV exposure and plastic material would break down long before the Invacom lens.

I guess when I wrote that I just assumed people would use some common sense and figure out that the bag would need to be replaced every so often, I guess I should have been more specific :rolleyes:
 
I want to get something straight in my mind - the cause of failure is water intrusion to the electronics and not the lens breaking, right? I have always thought the lens was like a weather cover and not something required for operation of the LNBF. EDIT: and Brian, does 303 Aerospace Protectant offer UV resistance or does it just seal up small cracks preventing water intrusion? I may try that product if it offers UV protection help.

Yes you are correct, the lens is only a water/weather cover, and yes the cause of failure is water getting into the electronics
 
does 303 Aerospace Protectant offer UV resistance or does it just seal up small cracks preventing water intrusion?

It has a UV "sunscreen" and if used regularly, will prevent the drying and oxidization of plastic based products. The best part is that it does not leave a residue and will not be a magnet to dust like other plastic / vinyl "restoration" products. I preferred it over McGuiars on my boat canvas. A very superior product.

BTW, tried Armor All once on an LNBF lens... never again! It made a mess with dust and grime coating the lens. Didn't check if it affected the reception, but I would put money on the line that it did with the build-up that was caked on several months later.
 
just a quick note i seem to remember a similar thread a while back. if memory serves a quick solution (assuming no water damage) was to remove the plastic cover from a junk LNBF (like a Bell or Starchoice unit if the size is correct) and glue it in place of the Invacom one.
 
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