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Just learned a hard lesson about cellular backup placement
Just learned a hard lesson about cellular backup placement. Last month I installed a Vista 20p with a cellular communicator in a warehouse outside of Phoenix. Put the module near the main board like I always do, inside a metal electrical room. System passed the test call fine. Then three weeks later the customer calls saying the alarm won't report. I drive back out and find the signal strength at like 2 bars. Moved the cellular unit to a window about 40 feet away with an external antenna and now it's solid at 5 bars. Guess I never really thought about how much metal shelving and concrete blocks can kill a signal. Anyone else run into this where the test call goes through but real world conditions mess it up later?
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shane_park921mo ago
Yeah I had this exact same thing happen to me last summer. Did the install on a metal building for a small auto shop, put the cellular module right next to the panel inside a storage closet full of junk. Test call passed no problem. Two weeks later the customer says the alarm keeps showing "comm loss" on the keypad. I drove back and checked signal strength and it was bouncing between 1 and 3 bars. What worked was running a long cable to mount the cellular unit up in the ceiling near a skylight. Ended up using a yagi antenna pointed at the nearest tower. Its been solid for 8 months now. @alicecraig is right about testing at different times too. I went back at midnight one night just to check and the bars were down from what they were at noon. The concrete and metal really mess with things in ways you don't notice on a quick test.
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alicecraig1mo ago
Oh jeez yeah that's a classic gotcha. The test call thing is tricky because it only checks if the module can talk to the tower right then, not if it can hold a steady connection over time with all the metal and concrete around. Signal can fluctuate like crazy once the building's fully loaded with equipment and people moving around. I've seen installs where a test call passes fine at 10am on a Tuesday but fails at 3am when the cell towers are congested or the weather's bad. Moving it to a window with an external antenna is usually the fix, but you gotta check signal strength at different times of day too, not just right after you install it.
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