Alternative 868mHz transceiver for Europe

Hey Folks.

While looking around on the interwebs today for alternatives to the Digi Xbee 868 modules for use in Europe, I found this from http://www.rfsolutions.co.uk. It's specifically the Tiny Pro with external antenna that caught my eye. (The photo above is from the smd on-chip antenna version)

TINY PRO
High Power - Up to 500mW
Serial Baud Rate 1.2 to 115.2Kbps
RF Baud Rate up to 38.4Kbps
Range up to 4KM using external antenna

From the manual for the TinyPro:

"This band is free to use but the module and the user must respect some limitations. Most of these restrictions are integrated in the conception of the module, except the duty cycle. The 869.400 to 869.650 MHz band is limited to a 10% duty cycle. This means that each module is limited to a total transmit time of 6 minutes per hour. It is the responsibility of the user to respect the duty cycle"

It looks fairly expensive, and I don't think the baud rate is as high as the Digi modules, but asking the user to enforce the duty cycle would allow us much more control. Assuming we wouldn't just ignore the DC entirely, we could allow the APM to control it rather than having to hack it as the current thinking on the digi 868's suggests.

Has anyone tried this, or have any comments on suitability? Perhaps there are other 868mhz modules out there who also have less draconian enforcement of the DutyCycle?

Jim

The EU telemetry issue has been rolling on for some time now, I know of ways to work around the duty cycle on the 868s, it's not pretty, and may cause issues with the units freezing. The other downside to the "hack" is the length of time the units will put up with being used in that manner.
To that end I've placed an order for some 2.4 xbees to see if these will work and if they do should offer s range of about 1 mile. Both Johann and myself have been looking for a solution to this issue for a while now, I hope that there is some light starting to show at the tunnels end. I spoke to Chris a week or so back about using the 2.4 xbees, there is a modification which needs to be done to make them work, I have an understanding of what needs to be carried out, and I hope that we can all enjoy a little of the telemetry goodness this side of the pond some day soon!

Regards

Martin

www.buildyourowndrone.co.uk

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Comments

Jim May 7, 2011 at 1:24am

@johann - wow, I didn't know 868 was banned in SA, I guess 2.4 is the only way to go if we are aiming for a common DIYd supported telemetryplatform outside of the US.
Amilcar Lucas May 6, 2011 at 3:48pm

It looks like the only European options are: RFM22, RFM 23 or twig.

I have a couple of RFM23 modules, but had no time to test them yet.
Jim May 6, 2011 at 1:33pm

Martin, i'm just getting a bit fed up with digi, perhaps its time to look at their competition. 2.4ghz is never going to be the best solution for any of us, 868mHz is what we should be using to retain parity with our american cousins and free ourselves from the fear of interfernce with our control systems (imaginary or not).

Good luck with the trials, I guess running at 2.4 is better than no telemetry at all!
Jim
I.S. May 6, 2011 at 1:05pm

BTW how bad is transmitter and telemetry working at 2.4GHz at the same time.

In the past, it was a bad idea for sure, but nowadays how well 2.4G XBees and FHSS&DSSS transmitters interact?
Distributor

Martint BuildYourOwnDrone.co.uk May 6, 2011 at 11:56am

The EU telemetry issue has been rolling on for some time now, I know of ways to work around the duty cycle on the 868s, it's not pretty, and may cause issues with the units freezing. The other downside to the "hack" is the length of time the units will put up with being used in that manner.
To that end I've placed an order for some 2.4 xbees to see if these will work and if they do should offer s range of about 1 mile. Both Johann and myself have been looking for a solution to this issue for a while now, I hope that there is some light starting to show at the tunnels end. I spoke to Chris a week or so back about using the 2.4 xbees, there is a modification which needs to be done to make them work, I have an understanding of what needs to be carried out, and I hope that we can all enjoy a little of the telemetry goodness this side of the pond some day soon!

Regards

Martin

www.buildyourowndrone.co.uk
mquintilian May 6, 2011 at 10:32am

anybody tried this http://www.seeedstudio.com/depot/twig-serial-rf-pro-p-794.html?cPat... Its a drop in replacement for the xbee and has 1KM range, only $24
Wouter van Verre May 6, 2011 at 9:34am

Perhaps this device could be an option as well? It's based on the RFM12B chipset and works in the 868Mhz band.

It was recommended to me a little while ago, but haven't had a chance to check it out yet.
Grizouille May 6, 2011 at 8:20am

I think that it has to free by the parameter setting................If somebody made it ?????
Jim May 6, 2011 at 7:55am

I would assume that being a Digi 868 product, that still suffers from the firmware enforced 10% duty cycle.
Jim
Grizouille May 6, 2011 at 7:51am

Why not , but you have this http://www.digi.com/pdf/ds_xbeepro868.pdf

The Xbee pro in 868 Mhz

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