I have two Z-Wave devices both about the same distance, about 12 or 15 feet from the Hubitat. The LWR RSSI readings are as follows:
Dome Siren & Chime: 25 dB
Yale YRD-216 Deadbolt: -7 dB
The only obstructions from the hub to the devices are some wood framing and drywall clad walls. The hub is about 2' vertical from my WiFi router/access point although clearly the Zwave is a long ways way frmo the 2.5 Ghz WiFi band. I had a repeater installed but removed it after a short while to see how things would work without it.
Theses RSSI values seem rather wonky to me. But in reading the wiki article at Received signal strength indication - Wikipedia RSSI can be either positive or negative and entirely dpeends on the other device vendors method of calculating the values.
Furthermore these values can be based on any scale the device vendor wants. That is the first couild be on a scale of 0 to 100 where 100 is best strength available or 0 to -255 where 0 is the best strength available. So chances are the -7 is quite good and the 25 is decent. Or do I need to contact the device manufacturer to see what scale they used.
Not that I'm very concerned as all is working quite well and I've never had any issues with these devices. I'm more curious is all.
Believe the RSSI reported is purely from the hub’s point of view so -7 would mean that it is being overwhelmed by other devices in the area and could use some assistance, i.e. a repeater…
On this representation negative is always undesirable and more positive is always better. It isn't a "normal" RSSI number (which I find annoying, but it is what it is). I think what is being shown is really a Signal to Noise Ratio (SNR), not RSSI.
On this number one would like it to always be positive, but that said I have devices in the negatives that work perfectly fine - but it all depends on how chatty they are and what the reason is for the low RSSI - interference, antenna alignment, etc.
I'll just throw out that I have nothing higher than 26 dB - I forget what the max is on zwave (and I think it is different between 500 and 700 anyway), but it is likely somewhere in the 30 dB range I would guess based on the protocol, radio, and antenna type.
Typically below ~ -5 is where I start to get a bit concerned. But even then, one of my Ring Extenders insists on routing directly to the hub, and has a -9 RSSI and is working fine, so .
I'm a bit late weighing in on this, but I'm not sure the value is necessarily related to the hub's received signal. I have a variety of RSSI results posted, the highest being 40dB, which is from an outside-the-house power meter that is relayed inside the house by a repeater. The same repeater also relays another outside device with RSSI of 5dB. If the indication is just the hub's point of view, I should expect both to be the same strength, coming from the same repeater device. Else, the repeater is not really a "repeater" in the digital sense, i.e., the signal is not regenerated but just relayed directly on alternate channel, which doesn't really seem to make sense. The repeaters, BTW, don't show any RSSI, themselves, presumably because they don't really interact directly with the hub.
Oddly, my worst RSSI is 1dB, from a wall switch that is directly in front on the hub, about 2.5 feet lower, and just to the side, about 11 feet away, with no obstructions at all. Similar types of wall switch are seen to repeat signals from devices at the opposite end of the house, and further from the hub, with much higher RSSI. There hardly seems any correlation in RSSI numbers.
Details on LWR_RSSI measurements can be found in the Z-Wave Network Installation and maintenance Procedures User Guide (Document No.: INS12712) by Silicon Labs (appendix .
Appendix A.4 Last Working Route RSSI measurement
LWR_RSSI = The difference between LWR RSSI and background RSSI
The LWR_RSSI is an estimation of the signal-to-noise ratio for each LWR in the network.
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The LWR_RSSI for the entire route is the minimum of the LWR_RSSI values for each hop in the route. In particular:
LWR_RSSI(route) = min ( LWR_RSSI(0), LWR_RSSI(1), ... LWR_RSSI(N) )
where N is the number of hops in the route. N=0 for direct range, N=1 for one repeater etc.
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