[HowTo] improve Razberry signal strength (antenna upgrade)

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cyberhofi
Posts: 26
Joined: 31 Oct 2015 13:48

[HowTo] improve Razberry signal strength (antenna upgrade)

Post by cyberhofi » 16 Apr 2016 13:09

In the last months i had some connection issues due to the poor singnal strength of the pcb antenna.
So i decided to upgrade the antenna. I read a bit about adding a lenghth of wire to improve the antenna but that was not what i was looking for. Also i tried this method but ist was not much better.

Because Z-Wave and ZigBee use the same frequency range i decided to add a ZigBee antenna.

Here is what you have to think about:
This work can damage your RaZberry. You will loose your warranty. Im not responsible for any damage - you do it on your own risk!

Here is what you need:
- ZigBee Antenna e.g. Delock No 88688 (Wireless-LAN Antenna will not work)
- IPEX to RP-SMA cable e.g. Delock No 88340
- Ultra-Mini Coax Connector e.g Hirose U.FL-R-SMT ( 01 )

Here is what you have to do:

1) Locate the coupling capacitor C7 of the antenna and the empty footprint for the Inductor L1
razberry_1.jpg
razberry_1.jpg (155.7 KiB) Viewed 9527 times
2) Remove the capacitor C7 (I just turned int around, si i dont loose it). After that solder the connector on the Footprint of L1 (and C7 because it is larger) the inner contact has to be connected to the z-wave chip (the right pad of C7 and/or the left pad of L1 on the photo), the outer ring has to be connected to ground (the right pad of L1 on the photo) Make sure you do not short out the contacts of L1
razberry_2.jpg
razberry_2.jpg (97.08 KiB) Viewed 9527 times
3) Drill a hole (around 6.5mm) in the case of your Raspberry (if you have one) and fasten the Antenna. Also connect the cable to the RaZberry. Make sure to be careful, because the connector is not very strong.
razberry_3.jpg
razberry_3.jpg (230.12 KiB) Viewed 9527 times
4) Screw on the Antenna and be happy about your better signal.
Last edited by cyberhofi on 16 Apr 2016 15:06, edited 1 time in total.

cyberhofi
Posts: 26
Joined: 31 Oct 2015 13:48

Re: [HowTo] improve Razberry signal strength (antenna upgrad

Post by cyberhofi » 16 Apr 2016 13:13

Because its only allowed to upload 3 pictures here is the finished RaZberry "Walkie Talkie" :D
razberry_4.jpg
razberry_4.jpg (106.6 KiB) Viewed 9525 times

pz1
Posts: 2053
Joined: 08 Apr 2012 13:44

Re: [HowTo] improve Razberry signal strength (antenna upgrad

Post by pz1 » 16 Apr 2016 13:47

Interesting! Do you happen to have an images of the routing table from before and after this operation?

cyberhofi
Posts: 26
Joined: 31 Oct 2015 13:48

Re: [HowTo] improve Razberry signal strength (antenna upgrad

Post by cyberhofi » 16 Apr 2016 15:04

Unfortunately no. But now i have more devices with direct association to the RaZberry and less packet losses.

pz1
Posts: 2053
Joined: 08 Apr 2012 13:44

Re: [HowTo] improve Razberry signal strength (antenna upgrad

Post by pz1 » 16 Apr 2016 17:02

Well, I hope the next person that tries does make the screen shots ;)
Is it OK with you if I move this topic to the Recipe section?

cyberhofi
Posts: 26
Joined: 31 Oct 2015 13:48

Re: [HowTo] improve Razberry signal strength (antenna upgrad

Post by cyberhofi » 16 Apr 2016 18:02

If you think it fits better in this section feel free to move it.
[moderator action] move done, left shadow copy under RaZberry

tellblom
Posts: 2
Joined: 30 Jul 2016 12:00

Re: [HowTo] improve Razberry signal strength (antenna upgrad

Post by tellblom » 30 Jul 2016 20:33

Just wan't to thank cyberhofi for the excellent guide. I ordered exactly the same components and did all the soldering and the range drasticly incresed.

I have a garage door sensor and the Razberry was in the main house (15m apart, and two thick walls) and they could not communicate , I had to place the razberry in the garage. Now with the rewireing of the antenna I can place the razberry on the other side of the main house (35m apart and a lot of more things in between)

So once again, thank you for the guide.

vlad
Posts: 30
Joined: 19 Oct 2016 04:58

Re: [HowTo] improve Razberry signal strength (antenna upgrad

Post by vlad » 12 Nov 2016 04:04

cyberhofi wrote:
In the last months i had some connection issues due to the poor singnal strength of the pcb antenna.
So i decided to upgrade the antenna. I read a bit about adding a lenghth of wire to improve the antenna but that was not what i was looking for. Also i tried this method but ist was not much better.
1/4 wave vertical wire has gain about 1 dBi vs. that vertical dipole gain of 2 dBi minus loss in 2 connectors and length of coax. So, I don't think you will see significant difference in between two. Obviously vertical wire mode is free... but Delock 868 MHz Antenna looks cool and your design looks much cleaner.

With 1mW Z-Wave transmitter power it's less critical to match impedance, so plus/minus couple mm from that vertical wire will do just fine.

The problem with current PCB antenna is that it's not even a 1/4 wave length and too close to Raspberry PI board (PI will induce some RF noise and screen it, reducing efficiency even more).

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