I have a great news for the RC community that you can DIY the most powerful RC + Telemetry system on the market "ULRS 2000mW" using OrangeRX 433MHz 1W module and my 2W power mode. You need to have a magnifying lens and a small tip knife to do this mod. My greatest gratitude to FlipFlap (Ben) for his excellent firmware of ULRS.


Gain of the power MOSFET may differ slightly from module to module so one can get variation of 100 to 150mW higher or lower. Did the 2W mod in OrangeRX 433MHz 1W module and got 2030mW at 9V Drain supply.

I have cut a track on the RFM23BP which connects the RF MOSFET to the 3.3V main power line and power the RF MOSFET with external variable power supply and set it at 9V, achieved 2030mW RF output power. 

After running throught the night, measured the temperature of the RF power MOSFET, is was 148 deg F, on touching it was just warm, not hot. Its because of the fact that the PCB design of the RFM23BP and its integration in the OrangeRX host board all together makes a large heat sink for the RF power MOSFET.


Tested with inbuilt spectrum analyzer of ULSRcc, did not observe any unexpected surprise. Perhaps you can analyze that better with your real spectrum analyzer.

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  • Narpat, You are an RF engineering genius. no one can beat you in this part of the world in this field. I remember how you were able to obtain ppm sum out from an ordinary futaba receiver.

  • Excellent mod. Too bad that this frequency is not legal in USA. :-(

  • Then how will you receive with same antenna ? As all telemetry radios does the switching from Trans to Receive mode automatically inside only.

  • My idea was one on the plane, other on the ground

  • Thanks Tobias, yes multi user can operate, at the moment there is configurable 5 channel hopping provision in the firmware and more in his list to-do.

    @Dusan, The one you are referring to is a uni-directional amplifier can only be used with transmitter, for radio telemetry you require bi-directional amplifier.

  • Did anyone try to use RA07M4047M  power amplifier ? It is only 20$ and it can provide up to 7W@9V.

    Im using 7W booster from flytron on my long range missions. I haven't yet used it at full power (only 1/2 3.5W) my video always fade first.

    It would be really nice to see someone integrating power amplifier directly on RC module. Only problem I can see is that some RC transmitters start bugging in close proximity of strong RF transmitter. That is why I have my booster connected as far as 3ft away from my radio

  • very cool! Is this now frequency hopping, i.e. multi user capable?

  • You are more than a welcome Ben. Thanks for posting too.
  • Hey, here's some background info about the project for people who are interested in using it, especially to replace their 3DR radio or other telemetry systems. All information is centralized on my site www.itluxembourg.lu/site and the main discussion forum about the project is on rcgroups in this thread

    The Ultimate LRS provides drone and FPV flyers with a long range 1 watt 2 watts bidirectionnal link for RC and telemetry. Use it to replace your other telemetry or LRS systems by a single system having many advantages :


    With 1W 2W of power, the Ultimate LRS provides full telemetry and RC control up to 40 km. Check the user provided content page to see many flight videos.

    Notice that 40 km is not the limit of the system, but the further a user has flown with it, limited by his plane’s battery range. The system is capable to go to 100 km with good antennas and a sufficient altitude to keep a direct line of sight (earth’s curvature). (Well this should be recalculated for the 2W of power)


    The speed of Ultimate LRS allows to make all mavlink operations in the air. For example connecting, modifying parameters in flight, uploading new waypoints, or any other mavlink command.

    It not only support the default Mission Planner telemetry speed, but can handle much more such as 10 refresh per second for the attitude and position, giving completely smooth artificial horizon movements.



    A more detailed features comparison with 3DR radios is provided here.

    Fast RC link & Mavlink telemetry : 72 packets per second

    Fast RC link & Mavlink telemetry : 72 packets per second


    Unbeatable price

    The Ultimate LRS is based on two Hobbyking OrangeRX 1W TX modules (or a 1W module + a 100mW module).

    These 1W modules are available for $28.95 each, a total of $57.90 for a complete system, notice that the firmware is completely free.

    Complete documentation

    The project provides a complete documentation on this site, including clear installation instructions, links to user videos and content, complete spectrum analysis, proposed mods etc.

    Active community

    A very active user community has grown in this rcgroups forum. Feel free to join the community and propose your ideas and suggestions, or get answers to your questions.

    Users have made new 3D printed cases, new antennas designs and videos,click here to see user provided videos and other ULRS related creations.


    The Ultimate LRS is complex inside and simple outside : no technical settings to guess, it’s just plug and play.



    Besides the stable version presented on this page, a beta version is currently under testing by a team of 100 beta testers. Some of its features are presented here. It will become an official release around mid-January.

    Notice that the Ultimate LRS is only a part of a more complete, that will include a complete  ground station with a 3D virtual cockpit. This is not the latest status, but gives an idea of the features :


  • MR60

    Yeah that's a great alternative, not only to 3DR radios but also a substitute (or backup) for your 2.4Ghz radio tx control link.

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