Comment by James Turner on June 15, 2010 at 12:31am

Nice work.

Comment by Tim - Arduino for Visual Studio on June 15, 2010 at 7:49am

Very useful thanks.

I'm considering a mod to my ArduFab GCS and to the ArduPIlot code that would use Xbee in API mode.

This would allow the radios to start off in low power mode and to up the power if the signal breaks. The API mode also allows the signal strenght of the xbee to be known which would allow an auto pilot to automatically "return to base" if the signal breaks at highest power.

Comment by Adam Conway on June 15, 2010 at 12:37pm

One thing to know, as you get lower than a SNR of 5 on an XBee you don't lose connectivity, but the Bit Error Rate (BER) spikes. Fortunately the protocol is resilient enough to retransmit if there is a CRC error or an ACK is missed. So if you look at the BER you would know when to turn around before losing connectivity. Just so you know, I have not looked deeply enough at the XBee to know if you can get the BER out of it :). By the way, when the BER drops to 10^-4 (1 retry for 2 packets roughly assuming a 64k frame) you should probably turn around.
Best,
AC

Comment by Tim - Arduino for Visual Studio on June 15, 2010 at 3:00pm

Excellent, appreciated thanks

Comment by Adam Conway on June 15, 2010 at 10:47pm

By the way, I was off by an order of magnitude, I meant to write a BER of 10^-3 is 1 in 2 frames.

Comment by Tim - Arduino for Visual Studio on June 16, 2010 at 3:48am

ok

Comment by Peruzatto on June 16, 2010 at 5:11am

Thanks!

Comment