My rooftop antenna (owned by me at the cost of $300 five years ago) seems to have speedtest.net ~2500ms latencies (instead of ~22ms latency) when it rains hard.
I called the ISP who tested THEIR antenna and said it's fine so it must be my rooftop antenna. They'll gladly replace mine for $300 insalled.
Question: If I just put a plastic bag around the rooftop antenna box to keep out the rain, will that plastic hurt antenna reception?
I once used a big plastic bag over my antennas, t'was to hide my second(hacker) antenna, though. No perceptible decrease in reception. Saved it from rust, too (I left the bottom slightly open, so any humidity would fall out. But this is besides the point. Rain (water) is the worst natural enemy of wireless waves. Even clouds and mist can cut the signal. 300 dollars ? I paid about 40 dollars for my 25dBi parabolic and 30 dollars for my 12dBi hacker antenna. []'s
I should think IF the bag carried an amount of water it would interfere but a good coating of water resistant paint should provide protection and interfere minimally
Just read this again and should mention painting the dish not the bag , try placing a wet bag over the lnb and the reception goes all to hell
The reason for the dramatic increase in latency is called "retransmissions". Packets are being lost for some reason, and the wireless system is resending each packet several times until something useful arrives at the other end. That's a common problem for water in the coaxial cable or antenna.
There's no easy way for the ISP to test their antenna without using a known working antenna. If you contact some of the other users on the same system (same tower, same radio, and same antenna), and they're having similar problems, then it's possible that the ISP's antenna is the culprit.
Probably will work just fine. The official name is a "radome". A plastic bag will work but there are some potential problems. Don't seal it at the bottom. Give it some air circulation with which to breathe or you'll have condensation on everything.
It's not just the antenna that needs to be waterproofed. If the radio is in a box on the roof, it needs to be protected.
If there are any exposed coaxial cable connectors, they are a major source of signal loss if water enters. For those, I suggest 1" wide teflon plumbing tape. Embalm the connectors with the teflon tape with a 50% overlap. Cover the teflon tape with ordinary electrical tape, to keep it in place. For UV protection, spray the tape with acrylic (Krylon) clear spray.
Be wary of standing water on any RF connectors or case joints. When the sun comes out, the air pressure inside the connectors or case will increase. When it then gets cold, the partial vacuum inside the connector or case will suck the standing water into the connector or case.
Don't use a black plastic bag. Some of these bags are impregnated with carbon filler which will act as an attenuator. If you're not sure if the bag, radome, cover, trash can, or whatever, suitable for
2.4GHz RF, just place it in a microwave oven for a few minutes. If it gets warm, hot, or melts, it's not going to work. My rooftop panel antenna currently has a 20 gallon green trash can covering the antenna, antenna box, connectors, and pipe. The green trash can worked fine. The black trash can did NOT work.$300 is about right for a spun stainless steel solid dish, with hardware suitable for surviving a hurricane and purchased from the most expensive vendor (Tesco). Seems a bit high methinks. A 24dBi cast aluminum barbeque grill dish is about $70. Add another $30 for pipes, brackets, and hardware.
Harold:
As long as the cover is not conductive it should have a minimal impact (1 dB or so). I once built a 12GHz microwave link and encased it in a green house so it would not disturb the adjacent property owners. Worked fine. You see ray-domes all the time as well.
I even saw a radome once.
They put a cell phone tower on a church and erected an extended fake bell tower around it. Today I was testing the effect of efficient windows on wifi. I don't know if anything gets through. Dramatic effects.
Greg
My neighbors used to share my network thru a wifi card in a laptop thru their office window. Had 4 bars signal from my access point. One day it just 'went away', no bars at all. Slide the window open - 4 bars. Close it - 0 bars. They'd had low E windows retrofitted. Installed an outside antenna, problem solved.
My neighbors used to share my network thru a wifi card in a laptop thru their office window. Had 4 bars signal from my access point. One day it just 'went away', no bars at all. Slide the window open - 4 bars. Close it - 0 bars. They'd had low E windows retrofitted. Installed an outside antenna, problem solved.
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Years ago we had a cell system client that was complaining a new hand set did not work in the CEO's car. Everyone tried to tech to problem over the phone.
Turned out the windows were metalize and every time the window was rolled up or the door closed the call would drop.
Nothing like on site observations to show the real problem.
The local university built several new buildings and extended their micro-cellular system to the roof tops. However, since the windows were all coated with Low-E material, cell phones inside the building would not work reliably.
Some detail on Low-E coatings:
There's not much on RF characteristics in the report except for the graph at Fig 4, which shows how titanium nitride passes visible wavelengths (370-750nm), and blocks lower frequencies. 2.4GHz (125mm) is far off the graph towards the right. With 35 ohms/square it's as good as a dead short to RF.
I often wonder about using gps in cars.
I bought some cheap coax 8 foot long. Probably has at least 8 dB loss! Too lossy but it fits in the gap between double hung windows. I want to get some better wire no more than 4 foot. I found a company that has good prices. I have to see what size the coax is.
Greg
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