Is this normal to keep getting lost packets? It seems to affect how quickly the APM planner shows up the satellite status and position. I tried HK GCS out of interest and that shows a very poor link quality (around 10%), but shows the position on google earth almost instantly and the data received when looked at through the serial tab is fine and clear. I have to wait ages for the position to be shown on the APM planner, despite the fact that the APM 2 has a 3D Fix fairly quickly.

This is on an arducopter 2.4.1 firmware with xbee pro s2's running 2.5gHz. I also use the same netbook to monitor another APM2 fitted to a Maja running arduplane v2.28, that is better marginally using a different xbee pro s2 2.4gHz pair. Is this something we are doing, have not set right or what?

Both our radio systems also use 2.4gHz.

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The 2.5gHz is a typo, should be 2.4gHz as well.

It's my understanding that you don't want your radio, video or X-Bee's to be on the same frequency. So if you've got 2.4 on your X-Bee's, you should be using 72Mhz on your radio and 900 or 1.3 on your video.... I know there's a serious problem trying to fly FPV on 2.4 with people using 2.4 radios. I assume the same holds true for X-Bee's.


What happens if you turn off your radio?

Our problem being in the UK is only 2.4gHz, 5.8gHz and 35mHz are available. 35mHz is a waste of time with electric as it is too easily interfered with by the electrical noise.

I disconnected everything just leaving the xbee and we still get the lost packets on both systems.

Are you saying if you run your system and then look at the apm planner serial screen that you don't lose any packets?

Apparently there is also 459MHz - but no one really uses it. I have read about some success with people using the Flytron Open LRS system at this frequency.

You can also get the XRF modules at 868Mhz or something like that. The legality of this band is less clear. 

But yeah I would have thought that within short range, you would get no packet loss. I certainly don't on the bench using bluetooth or the XRF. 

How about the baud rate on your X-Bee's. What are they set to?

Intriguing, I will give the XRF's a go...thanks :)

Currently 57600, I have however tried everything from 9600 upward, same results if they connected.

i am facing the same problem. experimenting about 4 day with no success. I did some measurements on the 2.4Ghz spectrum with my Spectrum Analyser. I the attached picture I try to explain what’s going on between 2.4Ghz and 2.490 Ghz. The Blue line show the Turnegy 9X RC Transmitter this Transmitter sends all the blue carriers at the same time. This 16 Carriers blocking the whole 2.4 Ghz spectrum at least with noise. The red carriers are the possible XBEE frequencies. But xbee is just using one out of the 15. this will be decided by the xbee during start-up.  The last channel as you can see is the only one which is not interfered by the Turnegy. I forced the xbee to use only this channel 26. it works not so bad but the problem with this channel is that the power is reduced to meet the german law. Instead of 10dbm output power you will get only 0 dbm which is to less power for me. I ordered yesterday the XRF ……..


Interesting Michael, I also ordered the XRF's yesterday!

Ok, now have the XRF's up and running and still lose packets as before, how can that be when the link is now on a totally different frequency?

I have tried a whole array of different baud rates and am now back to 57k where I started.

Where is the crc checking done, in the APM and APM planner?

I know this may sound bizarre but are the Xbee's too close together and swamping  or too far apart and not running enough power?

On the point about running Xbee's on 2.4Ghz and R/C on 2.4GHz on an Arducopter, I am successfully running the two together although mine are series 1 Xbee Pro's. There has been considerable discussion about how to set up Xbee's on this board so it maybe a setup issue. 


the XRF receive saturation is about -14dBm.  when your xrf is less then 1m separated  then the RX is saturated. try 5m in between the two XRF.



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