TIL running coax through a return air duct causes huge signal loss

I was doing a job in a house in Spokane and ran about 50 feet of coax through the HVAC return to hide it. Customer called me back saying the cable box kept losing channels. Checked the signal and it dropped 12 dB compared to my test in the basement. Learned the hard way that metal ducts kill signal strength. Anyone else run into this or other weird signal killers on jobs?

2 comments

2 Comments

the_diana2d ago

Funny how things like that sneak up on you... it's almost like the universe has this way of teaching you a lesson through the dumbest little details. I swear, half of life is just finding out that the thing you thought was fine actually messes everything up. Like when I painted a room once and didn't realize the new paint was semi-gloss, so now every speck of dust shows up like a tiny white flag waving at me.

terry_mitchell2d ago

Wait, wouldn't the duct basically act like a faraday cage and actually improve the signal by blocking interference?

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