We only used one 4G modem at the time and went out and tested both the Optus and Telstra networks by swapping static IP SIM cards at the nearest main road near the remote landing site. The Optus network was best there, but didn’t really want to work under 50cm above the ground. Our aircraft was only 2kg and therefore only 25cm high. Didn’t look good.
Our last minute idea was to mount it on one of the main wing tips, and then only have one leg on one side of the aircraft, so when it landed it tipped to one side and so that on the other wing tip with the 4G antenna would be higher off the ground.
Thanks Pavel!
That is actually really useful to see. So about 4-5minutes of no reception being the longest, but a period of about 30minutes of fairly patchy reception. Not Ideal, but probably useable still. How long does it actually take to send a message if it does have reception? 10-20 seconds? And from what signal quality upwards will it still send roughly?
The software does not try send/receive sessions if the signal quality is <2. The sessions usually succeed with signal quality >=2 and take about 10-20 seconds.
I’m curious how antenna affects the signal quality. What makes a good antenna for 1600MHz?
Hmm ok. That makes it a fair bit worse. About 40-45% offline. About 6-7minutes at a time offline. Probably no certainty with the satellite coverage, so it could be up to 30-40min worse case. In air would be probably better, but for the challenge we don’t need it in the air at all with the RFD900 available.
Antenna would be critical, as would RF noise floor and a good ground plane. Not sure what sensitivities they operate at, but it’s probably similar to GPS. Stephen would know more.
Iridium signal power would be higher than GPS (at the Earth’s surface). Any Iridium modems would have had great care taken not to interfere with the GPS.
In summary:
-Iridium won’t interference with GPS, assuming you’re using off-the-shelf equipment
-Noise floor would be similar to GPS
I could not make my RockBLOCK work with GA™ 38 GPS/GLONASS antenna. As soon as the external antenna is attached and the patch antenna is shielded, the signal quality becomes flat zero. It work pretty well though with pretty much any other piece of metal used as antenna.
Thanks for that Pavel. It does give a good indication of the Irdium performance. There’s not to many position points missing from what I can tell on the map. Looks good, I think it should work.
Very cool project. Is there any sort of guide for a total n00b to set this up if you have the hardware (autpilot, RPi, and RockBlock 9603) but no idea where to start?
Hello, I have been following the forum for a long time but it is the first time I have written, since I saw the seacharger project, I wanted to build my own boat controlled by satellite, I have enough knowledge of electronics but not much programming.
more than 5 months ago I build in a boat of 2 meters in length, 4 solar panels of 100w each, with a T200 thruster, 2 batteries lifepo4 12v 50AH, all controlled by pixhawk with the software ardupilot.
all this has worked well, although there are still things to improve, but the most important thing is the satellite communication, I used the envirover software http://envirover.com/
but In my first test had problems with communication, sometimes I lose connection with the boat for periods of more than 2 hours, and this does not feel good.
the envirover team has been very kind, and they have oriented me, I am waiting for a new version to try it, I hope I do not have the problems I said before.
