LightwaveRF - possible conflicts and compatibility

Submitted by tomkerswill on Fri, 03/01/2014 - 12:36

I'm having a look at which wireless band to use for my OpenEnergyMonitor setup --- 433 or 868 Mhz.

I also have two other 868 products:

- The house alarm system
- A LightwaveRF system to control light switches and heating thermostats (TRVs on radiators)

I was wondering if it's a problem to have different systems all using the same band? If so, I'll probably opt for the 433 band to avoid conflicts.

On the other hand, perhaps in future it might be possible to expand the OpenEnergyMonitor system to control LightwaveRF devices --- in which case, I guess having the same radio band might actually be an advantage.

So I guess my question is, does anyone have any experience of using multiple different 868Mhz systems in the same building? And could there be conflicts etc?

Thanks in advance!

Tom

Re: LightwaveRF - possible conflicts and compatibility

Submitted by cybergibbons on Fri, 03/01/2014 - 16:05.

I mess around with wireless systems a lot from a reverse engineering perspective. You need to think about what is around you as well as what you run, especially if you are in a built up area.

A 433/868MHz system not using spread spectrum and complying with EU specs (which even most European systems do) can only use the channel for a limited portion of the time - it's 10% for 433MHz and 1% for 868MHz. This means there should be a lot of room for plenty of devices to be using the same frequency.

433MHz is incredibly busy in London.

868MHz is much less busy, and devices using 868MHz seem to be more advanced and use things like listen before talk.

I have LightwaveRF, a wireless alarm and a JeeNode network and don't have issues.

I've been messing around with RF for years and the only problem I have had is when an ATmega328 sketch got stuck in a pre-amble state, and trasmitted 0101010 all night. My wireless heating was disabled by this, and it was a -5 night...

Re: LightwaveRF - possible conflicts and compatibility

Submitted by tomkerswill on Sat, 04/01/2014 - 10:11.

Hi @cybergibbons --- ah, brilliant --- sounds like my setup will have a similar collection of devices to yours (LightwaveRF / JeeNode / Alarm). That's good to know. I think I'll gof for 868MHz. I'm in Manchester, and so I guess there will be a lot of other devices around. Hahah - that's a good story re: the wireless heating... If mine starts playing up, I'll definitely check the arduino first then :-)

Thanks for the help!

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