Long Range Telemetry Testing

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/


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Twitter: http://twitter.com/mygeekshow
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Skype: MyGeekShow
UStream: http://www.ustream.tv/channel/mygeekshow


Filmed, Edited, Produced and Published by Trent in Arkansas, USA

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Comments

  • Great test Trent.  Your excitement is infectious.  Seppo would be pleased to see this.

    If "running a smaller, lighter, leaner system would be more ideal" is desirable and you have found the RFD900 to perform well beyond your needs, then perhaps the RFD900s smaller, lighter leaner cousin is a better fit for your needs.

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    Making your own antennas or converting antenna connector to SMA is no more problematic, with RG178 coax terminated with u.FL connectors cheap as chips and easy to source.

    Regarding Compliance in the US -  back on the 12th of December 2013 Seppo said that he was "planning on getting the RFD900u FCC/IC certified in January, this will make it easier to use the RFD900u in all kinds of applications." and also that "The RFD900's are also planned to follow with approval later in the year."

  • What the APM needs is an output that orientates a 1 or 2 axis pan/tilt servo system back towards home. That way you could use directional antennas with high gain instead of nasty omnis. I guess this would work best with copters which are relatively level and only really need to pan the antenna back towards home .

  • Developer

    Note that it is a RFD900, not a RDF900 (it was designed by RFDesign in Australia).

    Also note that if you use a RFD900 you need to be VERY CAREFUL with how you power it. For in the aircraft you should not just run it at 30dBm (1W) off the telemetry port as the current draw when transmitting (around 900mA) can cause significant voltage fluctuations in the autopilot which can be dangerous.

    Either power it externally (eg. from the servo rail) or run at it 24dBm or less. You will still get plenty of range.

    Also note that regional power limits are often in EIRP, which means it includes the antenna gain. For example, in Australia if you have a 3dBi antenna you should not run the RFD900 at above 27dBm or you will be in breach of ACMA rules.

    Finally, antenna orientation does matter!

    Cheers, Tridge

    Home
    Designers and manufacturers of RF Electronics, Telemetry modems and RFID equipment. Specialists in UAV telemetry with the RFD900 radio modem.
  • I've just ordered a 3DR radio to do some testing and comparison with my XBees.

    I can get 16km out of a standard XBee in the plane (with those pathetic little antennas) and using a high gain panel antenna on the base station so I'm hoping to get similar performance out of a 3DR as from what I understand they are a better unit.


    I'll let you know how I get on.
    As with anything in the land of RF, the antenna is far more important than the radio you use.

  • Except for the interlaced video ;) Great job Trent and congrats on your success.

  • Artem: Awesome link and tips! Thank you for sharing! I'm going to have to mess with antennas as time permits. However, with such incredible performance as is, its hard to argue with. Then again, running a smaller, lighter, leaner system would be more ideal. Thanks!

    Rostislav: I TOTALLY believe it! It was 100% perfect at 5k, even with all that banking... Very impressive stuff!! You'd get a 100km badge just to fly to it's max and back! : )

  • Trent,

    I had stable connection 30k away at 150m heght with this baby,

    was able to read and wright. I bellieve you can get telemetry ~50k using directional antena on one of them!!

  • Trent, try using good dipoles on the 3dr radio (both modules) and you will get about 7-8km  56kbps with about 80% RSSI,  make sure those are good proper dipoles and the land module is at least 5-6 feet off the ground.  take a look (if you haven't already) at this thread: http://diydrones.com/profiles/blogs/antenna-feedpoint-matching-balu... 

    I think you could put a RHCP on the air module with an insignificant signal loss, but in the event the aircraft pitches/rolls you will have better reception as RHCP antenna receives vertically polarized signal from a dipole on the ground even if not pointed directly up.  (it only rejects left hand polarized signals)

  • Freddy: Thank you!

    Mike: RFD900 on both air and ground module! 

    Brent: Ha ha! I love it... I really asked the owners as I fly there quite a bit (3-5 times a week)

  • Only if it is an RC aircraft, licensed pilots in civil, commercial or military aircraft do not require permission, and UAVs with FAA wavers also do not require permission (they are not operating under the RC rules).

This reply was deleted.