RaZberry2 antenna extension


When playing with Smart Home I play with different chips but currently heart of my application is RazBerry2 with Z-Wave. This chip was improvement comparing to version 1 including PCB antenna. Team from z-wave.me gave however possibility to attach external antenna using connector or simply wire antenna.

As I wasn’t fully satisfied with coverage finally I have decided to solder piece of wire. Why wire not connector? I am more software engineer than hardware and I decided to give first try to just cutting piece of wire and soldering it in one place. Original PCB antenna must be disconnected. Permanently.


Piece of copper wire. Just it. As z-wave in Europe operates in 868MHz range you need 86mm long wire, soldering unit and something to break antenna.

86mm of wire
Size of wire antenna for 868MHz is 86mm


It is quite easy. Definitely easier then soldering connector in the middle of the board. Locate the place for the wire as on picture below

RaZberry with place for wire antenna
Hole to solder wire antenna

Put the wire and solder.

Soldered antenna
Soldered antenna on RaZberry2

And break PCB


Enter ExpertUI on Smart Home and run reorganise command. Range is definitely better although it wasn’t completely mandatory as Z-Wave usually handles this correctly. However one of my switches is in poor place and packets were lost more often then I wanted. Changes in range for base station are below

Devices in range of central station with new antenna

Was in worth? Yes, I like it. Maybe with better antenna and connector results will be better – maybe another time. Anyway for attic and basement I will use range extender – but this is separate story


One thought on “RaZberry2 antenna extension

  1. i’ve been having big issues with my razberry zwave device and want to try your method. Can you tell me what “better” is made of or how to do it ? because i want to give it the best shot. Also does it habe to have exactly that length ?

    Thank you

    1. Frankly speaking first check what software you are using. My personal experience shows that

      • SmartHome coming from z-wave.me has poor responsibility. For very long time I was blaming my walls, bricks etc. Finally I have changed antenna as in this article
      • 2 months ago I switched to OpenHAB with z-wave binding and responsivity of the system changed dramatically. I was really surprised in positive way and I do not plan to come switch back (maybe later for some testing)

      Regarding antenna length – it is strictly related to frequency and part of wave lenght. Without coming into details we need 0.25 wave lenght antenna – which means for 300 000 000 m/s : 868 000 000 : 4 we get around 8.6 cm length of the wire.

      What software are you using?

      1. Hi,

        I am having issues with Z-way too, and thought that I could solve it in part by increasing the antenna range. I have a large-ish network so I absolutely love the facilities that Z-way provides for managing it.

        However, responsiveness is an issue. I am unsure whether the issue lies in the z-wave engine or the rules engine of the system. Switching to openhab and the Z-way binding seems like a good fix if the rules engine is the problem, but if the underlying z-wave system is a problem then I guess I need to look elsewhere. Unless the guys at z-wave.me solves the problem in the upcoming release.

        Would you like to share your experiences of the OpenHAB Z-wave binding some months later? What is the size of your network?

        1. Hi,

          First of all when switching to openHAB – give up Z-Way. At first I thought it is great idea however after some time system was slowing down incredibly. And you were still dependent on old stack.

          If you move to openHAB use z-wave binding not z-way. It is talking natively to RazBerry and for me it was burst of performance.

          I have 31 z-wave devices + controller stored on 4 tiers – garage, ground floor, 1st floor, attic, controller is on 1st floor.

          Thanks to openHAB you can merge more technologies – simple presence like working on pinging mobile phones visible on your router and other stuff.

          When I was quite busy my Raspberry was running 50 days without touching any service πŸ™‚

          Piotr “Rook”

          1. Thanks! I did that and also saw a fantastic performance increase. in openHAB using the w-wave binding compared to z-way (even when just running that system, and no OH at all).
            I should however keep in mind that when I went over to OpenHAB from Z-way I also went from securely included devices to insecure device inclusions due to me not wanting to run the not yet stable version of the binding. Secure communication is also more network intensive, so some of the increased network performance is likely not related only to the switch of platform, but also related to less traffic on the network.

            However, even in a secure network the system running it should nog be kept so busy that the user cannot access the GUI.

    2. Hi

      I am sorry for late answer. Reasons for such antenna length comes from law of physics πŸ™‚ Different lenght will work worse for this frequency to make it simple.

      Have you tried it already?


  2. Thanks for the info – I just did this and it noticeably improved my range / reliability.

    A couple of notes.

    1. I cut the wire to 90mm – since the 86mm counts from the part above the board (the “ground plane”).

    2. I used 1.5sqmm mains wire, which stands up quite nicely through a hole I cut in the Pi box.

    1. @Richard – I did many tests with Razberry 2 board in order to optimise coverage and I can tell you that 1.5sqmm wire for antenna is too much. I used initially 1.1sqmm copper conductor taken from RG6 coax cable but system performance was very poor. When I changed it to 0.5sqmm wire it helped a lot. Possibly thick wire has too much capacitance and is not working properly.

      Also I installed antena horizontally, but I have Raspberry on the first floor close to the router and most of z-wave devices are on the ground floor. With antena installed vertically coverage was not so good.

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