Rpi 4 - how many radios?

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1 
Hardware: Raspberry Pi 4 Model B Rev 1.2
OS: Raspbian GNU/Linux 10 (buster) 
JRE: OpenJDK Runtime Environment Zulu11.45+27-CA (build 11.0.10+9-LTS)
OH: 3.1.0 (Build)

Hi all,

It’s been a while since I tinkered with my OH setup - a busy summer! Since I migrated over to a Rpi 4 & OH3 at the end of last year, there are a few things I never got around to setting up.

At the moment I have the following radio devices connected to my Rpi 4 OH instance via USB:

  • RFLink Transceiver
  • RFXcom Transceiver

I’m about to add:

  • RFM69Pi radio (for EmonHub)
  • Zigbee USD stick

Before I do so, does anyone have any experience of putting this many radio’s on a single Pi - the option I’m thinking is to put the RFM69Pi & RFLink onto a separate Pi (I use MQTT for RFLink rather than the binding).

Cheers
James

2

I don’t see any reason why this won’t work, but maybe you should use some USB cables to place the modules with some distance between them.

3

It really depends on the devices - each will (likely) emit some RFI and they could well interfere with each other. It’s not uncommon for two nearby devices (by nearby, I mean within an inch or two) to cause interference - or in fact for the RPi itself to emit quite a lot of interference such that it raises the noise floor at some frequencies, making them unusable or at least reducing the performance.

The issue is that when you have these sort of problems, they can be difficult to identify - everything looks fine, but it just doesn’t work (or doesn’t work well). I recently spent quite a few hours (over about a week) helping someone with with this sort of issue with a Zigbee stick.

Bottom line - it might work fine - but keep an open mind if you start seeing problems and don’t jump too quickly to blame the software :slight_smile:

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4

Thanks both,

I’ll give it a go - with the necessary USB extensions to ensure some separation between the aerials.

Cheers
James

5

I just want to mention the builtin Bluetooth and WiFi radios.
Turn them off if not used to further lower the noise floor.
rfkill is the command for checking and disable/enable

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