external antenna

[ssvenn]

What a huge difference an external antenna made!

Finally my razberry has a direct signal to all nodes, the only ones missing from my setup now are the ones that need to be reincluded because the original interviews failed. I think the next version of the razberry should have a version with some official big external antenna. I think a lot of the difference might just be getting some more distance from the noisy main raspberry pi board.

Screenshot 2021-04-13 at 21.36.47.png (391.73 KiB) Viewed 7382 times

Screenshot 2021-04-13 at 21.37.17.png (42.46 KiB) Viewed 7382 times

[PoltoS]

New one will!

[enbemokel]

Hmm, I´m wondering, normaly a smaller RSSI like -60 should be better?!
Is there something wrong with the page in Z-Way?

[ssvenn]

If I understand it correctly these graphs measure the random background noise and you want it to be as low as possible since the actual z-wave transmissions have to be stronger than the noise to pick them up reliably.

To get an idea about the RSSI of each node you have to look at the zniffer history, I have a lot of nodes that have weak signals and with the integrated razberry antenna I had trouble communicating with them. Some of them even got wrongly included as battery devices even though they are mains powered. I have reincluded those devices after switching antennas and now they all got included correctly and seem to respond much faster since the network doesn't have to figure out alternative routes and retransmit all the time.

Node 24 with -89dbm was one of the unreliable ones, but it works now that the background noise is below -90dbm

[piet66]

In next version V1.14 of MxInfo/Communication you can display the rssi values of your devices as charts.

[PoltoS]

@piet66 Thanks for your tool. We are also adding few more diagnostics including the avg RSSI per device based on last packets

[vinisz]

What a huge difference an external antenna made!

Finally my razberry has a direct signal to all nodes, the only ones missing from my setup now are the ones that need to be reincluded because the original interviews failed. I think the next version of the razberry should have a version with some official big external antenna. I think a lot of the difference might just be getting some more distance from the noisy main raspberry pi board.

Screenshot 2021-04-13 at 21.36.47.png
Screenshot 2021-04-13 at 21.37.17.png

How far away is the antenna now ? (From the rpi I mean)

[cesarvog]

Many thanks for this very informing thread.
I was able to directly solder an 868-915Mhz 6dB external antenna to my 908.40Mhz blue Raszberry 2 card and it apparently has lowered the noise to around -100 dBm in both channel 1 and 2.

I don't quite understand how to correctly read the dBm noise and signal numbers, so I really don't know if I've done it right or not.

Any help here would be much appreciated. The screen grab below show the **original** reading before I cut off the onboard antenna and soldering the external one.

Screen Shot 2022-01-26 at 09.55.12.png (106.53 KiB) Viewed 4369 times

After the installation of the external antenna, the blue (greenish?) lines for channels 1 and 2 in the chart above (not shown) are all around 100dBm.

Instead of removing the 0 Ohm (resistor?) and moving it to the upper solder point position, I simply joined the two upper solder points, leaving the 0 Ohm thing in place. My hands were not steady and I was afraid to damage the other components / PCB around it... Since it now connects to nothing as I cut off the onboard antenna segment, I thought that would not matter. Please someone correct me if I'm wrong and I will take my razberry 2 to some specialized shop for them to remove it in case it's really necessary.

Even though I tried, I quickly discovered I would not be able to solder a u.Fl connector to the board, because everything is quite small and like I said, my hands are not steady enough.

So I cut off my new 6dB antenna SMA connector and soldered is core to the green connector and the shield to the red, as shown on the first picture of this thread.

SInce I still can control all my z-wave devices, I believe it may have worked. I will ran some tests and try to optimize the paths between nodes and post back here in case I find anything amiss.