Reach Out And Touch Your Next Project With Long Range RC Controller


Long range wireless control of a project is always a challenge. [Mike] and his team were looking to extend the range of their current RC setup for a UAV project, and decided on a pair of Arduino mini’s and somewhat expensive Digi Xtend 900Mhz modems to do the trick. With a range of 40 miles, the 1 watt transceivers provide fantastic range. And paired with the all too familiar Arduino, you’ve got yourself an easy long range link.

[Mike] set the transmitter up so it can plug directly into any RC controller training port, decoding the incoming signal and converting it into a serial data package for transmitting. While they don’t provide the range of other RF transmitters we’ve seen, the 40 mile range of the modem’s are more than enough for most projects, including High Altitude Balloon missions.

The code for the Arduino transmitter and receiver sides is available at their github. Though there is no built-in error correction in the code, they have not had any issues.  Unfortunately, a schematic was not provided, but you should be able to get enough information from the images and datasheets to construct a working link.


27 thoughts on “Reach Out And Touch Your Next Project With Long Range RC Controller

  1. Geez if these were legal for average-person use in the US, they would make the Parrot AR Drone worth getting. Seriously battery and range are the only major issues with it, and there’s battery packs and mods galore for powerful but I haven’t seen any good ones for range…

    1. This is completely false!! ISM band limits are much below 1W for 915 MHz. You technically need to get certified for FCC 15.247, however it is possible to get modular certification, and I think the manufacturer has done that (you can certainly check)

      I should also mention that the 915 MHz band is a mosh-pit. There are A LOT of 1W DSSS and FHSS users on this band, and the regulations do not require particularly advanced hopping or DSSS, so in urban or suburban environments you are going to get a ton of interference. Out in the open, though, it should be pretty nice.

        Summary of Power Output Rules for ISM bands
        The limits are three:

        Maximum transmitter output is 1W (30 dBm) (47CFR15.247.b.1)
        Maximum EIRP is 4W (36 dBm) (47CFR15.247.b.3) i.e. for every dB of antenna gain above 6dBi, transmitter output must be reduced by 1dBm; per this rule, a 24dBi antenna limits the output power to 12 dBm which is 16mW
        For fixed point to point operation in ISM2.4, peak output need only be reduced by 1 dBm for every 3 dBi of antenna gain above 6 (47CFR15.247.b.3.i) i.e. per this rule, a 24 dBi antenna may be fed by 24 dBm or 250 mW
        In ISM5.8, you can apply all the antenna gain you want (47CFR15.247.b.3.ii) with no reduction in output power.

        The responsibility for staying within these power limits falls on the operator (or, if professionally installed, on the installer).

    1. In short-no. The AMA (Academy of Model Aeronautics) requires LOS if you fly from their fields, and that’s about it. Currently, the only official operating limitations placed on private UAVs (or FPV as most of us call it) is that we cannot use them for commercial purposes, as it then becomes a UAS, which is illegal. It should also be noted that this is not a law, but a recommendation by the FAA which was recently shown to not hold up well in court.

  2. I’ve been using the XStream / XBEE XSC for my drones since 2007. The interface is a simple serial port with a 128 byte buffer, it has about this much range, and it’s gotten a lot cheaper lately ($60 per unit). Try it!

  3. No way a 1W 900MHz transmitter will have a significant data rate over 70km. Maybe if the drone is flying high and the reciever uses a directional (array of yagi) antenna(s), but I doubt that a normal wire antenna will go this far

    1. …and certainly nowhere near that length if either end is within 4m of ground in any populated area. the 900MHz band has a metric hashton of noise anywhere you’ve got population (ok, maybe not the indigenous parts of Brazil, but you know what I mean). Great for remote operations, remote to drone operations, or maybe highrise to highrise operations with clear LOS and no other TX within the Fresnel zones… Impressive output for such a small footprint!

  4. It’s a pretty simple matter to get a Technician’s ham license which opens up all kinds of possibilities for longer range communications. Technicians are even allocated the high power use of some of the 2.4GHz band.

  5. “With a range of 40 miles, the 1 watt transceivers provide fantastic range”

    LoL …

    Do you have test it ?

    I sure 40 miles is a Lie.
    Which antenna do you use?
    1* Lambda dipol ?
    How big is the Fresnel-Area?
    Do you have test it from Mountain to Mountain?

    Try 1 Mile with a simple lambda/8 (1/4 and 1/2) Stick-antenna at flat ground !

      1. No, I have test a 169,4MHz 0,5Watt Module with two (for send/recive) lambda/8 rod antennas and with two lambda/2 dipole antennas.
        (the module can send with 1 Watt too, but this is not allowed her in germany)

        The maximum distance should be 25km (15,5 miles) , but I do not reach it under normal* conditions.
        I want to reach 6km (~4 miles) but this seems not to be possible.

        With the two lambda/8 antennas I only can send 800 Meter without any losses.
        With one lambda/2 dipole antenna I have a 12-15db stronger signal, but this is far away from good enough.

        * flat ground, no Hills or Mountains, antennas in a height of 2 meters

    1. To be fair, water range is a different animal… surface conductivity would mean you could send a signal 10db lower than that for 20+ miles over water and still receive it under calm conditions (ie… the Xtreme with the normal 2.1db gain antenna… the 12db high gain antenna [I think it’s around 12db] is entirely irrelevant for water operations compared to land).

  6. i want something like this for ground use over a couple urban blocks. also want fpv, so im not holding my breath for a solution that doesnt include half a second of lag, but if anyone has a reasonable idea..

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