I was goin nuts trying to figure out what the heck was going on with my network. Almost gave up and had a HAM buddy come over to scan for interference. Sure as snot, massive interference in the same range as z-wave. Took me a while to pinpoint them all but got 5 of these silly units out of the apartment building. Most of them were in the attic. They were used for nurse call necklaces years ago and still powered up!
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That is soooo cool.
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It's way cooler in the dumpster! 
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Was your building formerly a nursing home or hospital?
How does the zwave interference snooping work? Do you own the entire building or did you have to get permission from the LL to go snooping around everywhere to find the source of the problem?
Those look like they are connected via phone wire that goes to a transformer - can you also power that off? Amazing they were still powered up and nobody noticed...how long do you think they have been unused?
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Hook line voltage to it and get revenge for all the electronics that were fried in 2022
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It was a requirement years ago for a HUD elderly living facility. I own the entire building and gave 48 hour notice that I would be there looking at the mechanical areas of the building and may have to enter the tennan's apartment.
As far as hunting for the signals, my friend came over with a really neat spectrum analyzer that was wired to what looked like a pistol. The pistol antenna had a triangular blade on it and we could narrow down frequencies specified in the device. It only took us about half of an hour to find them all. He said I could buy a cheap version of his for less than a hundred bucks and be able to identify many frequencies.
The protected DC voltage lines were 18ga and ran back to individual transformers that were running off of a dead backup but operational UPC. It was all gladly powered down and "recycled".
If I had the time, I would use them as target practice. Live and learn!
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Thanks! Appreciate the info. Googling "Spectrum analyzer" now...
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lots of stuff to learn! https://www.hamfesters.org/main/wp-content/uploads/2020/02/Hamfesters-EMI-RFI-Feb-2020_V2.pdf
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Do. you know what make and model he had? I used to have a service monitor we used to use for tuning duplexers on ham radio repeaters and it would work but it rolls around on an equipment cart!
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RSA-306-B Tektronix
I certainly don't need anything like his rig. His job is RF doing towers and stuff, hobby is HAM. He suggested I could make a unit work for what I needed and it would cost under a hundred bucks. I know very little about RFI hunting but it seems like a fun thing to do. Here is the device I'm learning about. tinySA | Main / HomePage
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Yeah that's professional grade stuff... I just ordered a $250 cheapo one.
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Z-Wave frequency range from my cheapo $250 SA. Not bad! Notice that marker 1 and 2 reflect Z-Wave frequencies in the US.
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Very cool! I found that the two water meters (R900) Schlumberger are on the same frequency as Z-wave today. Hope they don't interfere with the network. They are everywhere around the town too!
I should have clarified the above is from the TinySA Ultra... it isn't $10k Tektronix lab gear on a rolling cart but it's pretty slick for the price.
Here's Zigbee and wifi... marker 2 is Zigbee channel 20, which is where my hub is.
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Nice! I didn't even look at the Ultra. I didn't think it was accurate at 900mhz. Nice to see it works!
Yeah the ultra gives you the extra range... 800mhz-5ghz
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Have you hunted for any smart meters owned by the City yet?
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