RFD900 Telemetry: http://store.jdrones.com/jD_RD900_Telemetry_Bindle_p/rf900set01.htm
During the USA trip I'll need extra telemetry range for emergency landing situations, aircraft recovery, poor transmitting environments, etc. While the 3DR radio has performed very well, the airplane's cruise speed would allow it to be out of range in less than a minute if it were to fly away from the ground station. To remedy this, JDrones sent me their RFD900 transceiver set which not only operates at 10x the transmitting power, but features the identical software and set up as the 3DR modules, meaning they are plug and play.
The 3DR modules lost more than 60% of their signal at about 2.5km from the ground station, and received sporadic transmissions up to 4.5km away.
The RFD900 modules dramatically outperformed it by transmitting 99%+ signal strength at almost 5km, while banking at 40 degrees. Amazing.
See you next week!
-Trent
Safety Statement: This flight was very unusual as I didn't maintain line of sight during the whole flight. I DO NOT RECOMMEND DOING THIS. I RARELY do this, and only after the absolute strictest of preparation and research. To prepare for remaining safe, I:
-obtained personal permission from a vast majority of property owners (I couldn't reach all of them)
-maintained a continues watch for full scale aircraft, and;
-maintained direct control of the aircraft for the majority of the flight
-this airplane and system has OVER 1,000 MILES of perfect performance, with 90% of it autonomous with this exact set up. It has been tried and proven many, many times, including over 200km of cross country flights
-the autopilot was programmed to continue to fly after a signal loss, which has been tested and proven to perform many, many times
-the flight was over a very open and low populated area, with 99%+ of the area being open fields or trees
-the altitude read over 120m, but elevation increased during flight as I took off out of a low valley. True AGL for the flight is 100-120m.
-avoided all airports and populated areas.
-I've flown at this location 3-5 times a week for the last year. I know it very, very well.
-I conducted test flights with the new set up that I did not show during the video to confirm stable performance
-and many other things to remain as safe and ethical as possible.
Raptor 140b+ Stats:
Weight: 2280g
Max Flight Time: 70min
Max Range: 97km
Stall Speed: 35kph
Cruise Speed: 90kph
Max Speed: 135kph
Radio Range: 1.5km
Energy Carried: 167wh (15,000mAh at 11.1v)
Drive Power: 850w
Total Flight Time on Craft: 7.0 hours
Total Flight Distance on Craft: 498km
The equipment used---
Raptor 140 airplane: http://store.mygeekshow.com/product-p/raptor-140-kit.htm
Radio Tx: ParkeFlyer Turnigy 9x Tx: http://parkeflyer.com/
Telemtry: 915mhz 100mW 3DR http://store.3drobotics.com/products/3dr-radio-telemetry-kit-915-mhz
Laptop: Compaq Presario CG57
GPS Dongle: http://www.amazon.com/gp/aw/d/B000PKX2KA/ref=redir_mdp_mobile?redirect=true&ref_=oh_details_o02_s00_i00
Flight Controller: APM2.6 https://store.3drobotics.com/products/apm-2-6-kit-1
Reciever: 6ch FlySky http://www.hobbypartz.com/79p-r6b-receiver.html
Telemtry: 915mhz 100mW 3DR http://store.3drobotics.com/products/3dr-radio-telemetry-kit-915-mhz
Battery: (3) 5.0Ah 20C Lipo: http://store.mygeekshow.com/product-p/5ah-3s-battery.htm
ESC: 60A Brushless http://store.mygeekshow.com/product-p/60a-esc.htm
Motor: 3542 1450kv brushless http://store.mygeekshow.com/product-p/1450kv-3542-motor.htm
Prop: 10x7 Carbon Fiber Folding http://www.hobby-lobby.com/10x7_carbon_fiber_cam_blade_798_prd1.htm
Servos: 11g digital http://hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=42620
Onboard camera: http://www.ebay.com/itm/16-V2-Lens-D-808-Key-Chain-Video-Camera-/380627482427?#ht_5755wt_1149
Learn More:
Raptor Details: http://www.mygeekshow.com/theairplanes/Raptor140.html
USA Trip Details: http://www.mygeekshow.com/usatrip/
Follow the Show:
Website: http://www.mygeekshow.com
Facebook: http://www.facebook.com/MyGeekShow
Twitter: http://twitter.com/mygeekshow
Google+:http://plus.google.com/116950154481685699344
Skype: MyGeekShow
UStream: http://www.ustream.tv/channel/mygeekshow
Filmed, Edited, Produced and Published by Trent in Arkansas, USA
Comments
good job.
In that case, as long as the modulation and data schemes are published, some provision for station ID has been made (ideally CW or FM/FSK ID every 10 minutes or so (minor firmware change, or possible serial command sequence to the RFD900), it can be 25wpm) you can probably declare it a digipeater and you are (probably) legal under part 95.
There are VHF and UHF data modems that can operate on a 25khz channel (I think Mouser and Digikey even stock a few) that would provide better range than the 900mhz system. The data rates will be lower but if you using the link as a failsafe to determine the location and attitude of the airframe and issue short messages for RTL or safe landing you shouldn't need much bandwidth.
It would be interesting to make a 70cm packet terminal and integrated transceiver that has a GPS based directory of packet repeaters (if I was condoning beyond LOS flight, which I am not).
Dean: Again, thank you for the response! Really, really interesting insight and experience. I received my Technician Class in 2012, which has been a valuable resource and network.
Also having gone through the FCC certification process for a high powered 900mhz zigbee based radio system, I can pretty much assure you that if they are running at 1 watt and have not had the unit tested by a certification lab it is almost surely not compliant. On the surface it looks like you can just add a power amp and keep the output power under 1 watt and you are ok, but all amplifiers add distortion and amplify LO noise and other unwanted signals in the transmitter and measures are almost always required to address these issues. I don't know anything about the RFD900 other than what is in their online documentation and I don't know the engineers or company so it is entirely possible that it is compliant, but I have tested a few similar devices and so far 0 out of 8 were compliant and we had to design and build our own.
BTW, go get a Technician Amateur Radio license, it is pretty easy, cheap and will let you operate on a wide variety of frequencies and allows transmit power levels well above your needs. I think everyone who is serious about UAV operation should. Be aware that operating under amateur radio rules for commercial gain is also forbidden.
Dean: Thank you for the info! That is super helpful. I love this community.
I see that you are in the US, so ignore everything about customs. Here is the deal on FCC approval.
If someone complains about you operating a non-certified transmitter, you will receive a letter from the FCC which typically just asks you to contact them or cease such operation. If you fail to comply, fail to respond, or commit another breach of FCC regulations that results in the complaint then you will be fined up to $10,000 for each occurrence and all equipment will be confiscated. This is an administrative law process, not your typical civil or criminal process so the rules, appeal process, etc are quite different. You can view the enforcement letters on the ARRL website (arrl.org) if you are curious about how the process works and is applied.
Gary: In fact, on both my Cross Country flights, I flew across the Arkansas and Missouri state line. There is a sign telling you that you are in a different state, and that's it.
Sorry, I got the impression he was heading here from another country. On the second paragraph, there are probably better authorities here but that is my understanding of the rules for RC aircraft operation (and the rules our group operates under).
The whole commercial operation thing is a separate issue. My understanding is the the appeals court ruled that the FAA had only established a recommendation for operation and not a rule. This probably does not prevent the FAA from hauling you into court anyway, but means they will probably ultimately loose. The prudent approach would be to keep a very low profile if you are doing anything commercial with a UAV.
Gary: Nope! "United" Sates of America : )
-
1
-
2
-
3
-
4
of 4 Next