Hi! I recently wrote this on the Fibaro forum. It is about the range of a UZB1 <-> Wall Plug and especially the difference in range I get depending on how I power that UZB1. It might give you an idea of where to look. I think it has to do with noise on the power supply. But I am not sure...
I am trying to help a guy with 10 - 20 nodes, mostly Qubino and Fibaro stuff. His controller is a UZB1. He gets poor performance, not many of the nodes seem to have the controller as neighbor and log files indicate RTT is sometimes as expected but often shoots up in the seconds range.
I wanted to check the range of some of my devices anyway.
Having a portable controller station (My MAC or a Lenovo laptop + UZB1) running my Python NOP test enabled me to map range and indicate weak spots. I might post some data later. (EDIT: I did, you can see the maps here: https://forum.fibaro.com/topic/42703-ge ... ent=179282
But then I forgot... RF is almost like voodoo... I am an engineer and I toyed with FM radio transmitters when I was young.
I might be able to explain why this users' range is not good and might be able to fix it.
I have tested the range of the UZB1 on my Macbook Pro and it is OK. It depends on the other device as well and a Wall Plug Gen1 is not as good as a Roller Shtter 3 = Z-Wave Plus.
Then I used my Lenovo Laptop, to see if the results were consistent.
Range on my Lenovo was reduced by 50 % compared with my Mac and an extension cord improved things a bit but it was still bad
My suspicion is, not only the fact that the Mac is a large slab of aluminium gives it a good range... But it might have less noisy USB ports (supply).
Then I put a small, unpowered USB hub (4-port) between UZB1 and Lenovo laptop and the result was that the range got almost as good as on my Macbook
This got me thinking... Why?
I added a function to my test-python-script to get the "Background Noise" between NOP test.
Dongle plugged directly into the laptop:
Noise: Ch0: -80 Ch1: -85
Noise: Ch0: -68 Ch1: -77
Noise: Ch0: -80 Ch1: -74
Noise: Ch0: -74 Ch1: -79
Dongle plugged into the USB hub:
Noise: Ch0: -89 Ch1: -91
Noise: Ch0: -82 Ch1: -89
Noise: Ch0: -85 Ch1: -94
Noise: Ch0: -79 Ch1: -88
Without the hub the noise is 5 to 10 dB higher, and this is what kills the range.
My theory is that the extra capacitors in the hub filter the supply voltage to the UZB1. But that is hard to prove right now.
For sake of completeness... The docs say:
The rssi level is defined as the RSSI measured at the antenna when no Z-Wave traffic is present.
The dynamic range of rssi measurements on a 500-series Z-Wave chip is from -94 dBm to -32 dBm. The
precision of the measurement is +/- 2 dBm. The returned values assume a path loss of ~7 dBm from chip
input to antenna.
To put that in perspective, where I am sitting now here is a representative NOP stat:
Status TX ms #rep RSSI ACKCha LTXCha Routing Scheme Repeaters Speed Tries Fail_from_to
OK 30 0 -88 1 1 DIRECT 0 0 0 0 40k 1 0 0
So RSSI of -88 for this node is clearly close to the background noise level of the UZB1 plugged into the hub. I am sitting at the edge of the range of my Wall Plug. If I were to plug in the UZB1 directly, the noise would overwhelm the signal and I get 0% ACK... It is still OK for my MAC (but not great and it will switch to routing mode if it gets a bit noisier).
Figures on my Mac, UZB1 plugged in directly:
Noise: Ch0: -94 Ch1: -94
Noise: Ch0: -92 Ch1: <MIN
Noise: Ch0: -94 Ch1: -94
Noise: Ch0: <MIN Ch1: <MIN
That <MIN means "lower than measurement floor" so less noise than -95 dB. A few dB better than my Lenovo I think...
Note: users of eg Z-Way can find background noise in "Expert User Interface".
forgot to test MAC + USB hub + dongle. Surprise... It makes things worse... Apparently the same hub now increase the noise floor...
Noise: Ch0: -75 Ch1: -79