I started this project back in the beginning of 2014 as the Raspberry Pi Repeater Controller Project but that quickly evolved into the Open Repeater Project. It’s the same project but as some things change like working on making the project open source, building a community around the project, and expanding out to other embedded Linux boards, a name change was a no brainier.


I started this project as a small proof of concept idea but as I worked on it, it’s potential started to become more evident. In the beginning I spend some time deciding if I wanted to take a commercial route with the project or make it open source. GREAT NEWS FOR HAMS…the project is Open Source!

Goals & Features

In setting out to develop this project my primary goals and features are to develop a low cost, low power, but feature rich duplex repeater controller suitable for setting up a temporary / emergency repeater systems with radios that can be run on portable power. However with a more complete feature set and a modular design, it could also be used as a primary or a backup controller for a permeant installation repeater. With the low cost, modular design, it would make it easy to keep backup hardware on site for easy service swap-outs.

The additional circuitry required to interface a SBC to the radios would ideally mount on a “cape” or “daughterboard” style circuit board that would mount on top of the SBC by plugging into the GPIO connector. This repeater setup is initially intended for use on Amateur Radio, but could be potentially useful on other radio services such GMRS, Commercial, etc.

  • Low Cost
  • Modular Design
  • Low Power Consumption
  • Flexible connectivity to various radios

Purpose of SBC (Raspberry Pi 2/Others)

  • Provide all logic control of repeater operation
  • Timers (Timeout, Identification, etc.)
  • Voice Synthesis for identification
  • CW Generation for identification
  • Playback of courtesy tones (user selectable)
  • Web server Interface for controlling settings – Will be provided by built in ethernet jack.
  • DTMF Decoding
  • CTCSS Encoding/Decoding
  • Optional EchoLink connectivity (requires connection to internet)

Purpose of External Circuit Board

  • PTT control for transmitter
  • COS Control
  • OPTIONAL – Real Time Clock to maintain time if not connected to the internet. This would be useful for time announcements and logging/statistics.
  • OPTIONAL – Extra Control Relay(s)
  • OPTIONAL – Power Lose Detection

79 thoughts on “About the Project

    • Aaron Crawford says:

      Hello and Thanks for your comment and interest. Yes I think it will have a lot of potential. I have the core of the python program done, so I hope to post a video to YouTube soon demonstrating what I have so far.


  1. Mike Rice says:

    My club is looking to replace its older repeater setup. I’ll keep an eye on this as some of the members think any money spent is too much, but some also like wielding their soldering irons. Also, cool toys/project!

    • Aaron Crawford says:

      Mike, Thanks for your interest and support. The project is at a pivotal point right now…deciding between open source and commercialization (read my reply to Erik). Definitely check back for updates in the future. 73s, Aaron.

  2. Justin - VK2HJA says:

    Love it!!

    Keen to do some testing if you need another set of hands…..Just building a 6m repeater now…

    • Aaron Crawford says:

      Thanks for your interest and support! I am working on some circuitry design at this point and my next step is to build a functioning prototype connected to radios. Check out some of my other replies I just left. The project is at pivotal point in its development right now. If I choose to open source the project, I will definitely be reaching out to those that are expressing interest in helping.

      Aaron – N3MBH

    • Aaron Crawford says:

      Hello Erik. At this time I am keeping any code under wraps because I haven’t decided yet what path to take with the project…Open Source or Commercial. There would be advantages and disadvantages to both. GPL would allow me to make it a community project and crowd source it to many, but I run the risk of diluting the code with forks and such which would make consistency and support an issue. Commercializing it would help support its continued development financially and provide support over the long haul while maintaining a consistent product. If I went the commercial route, I know that I lack the resources to effectively develop the hardware and bring it to market, so I would have to find a partner company to assist with that. I have some feelers out right now to see if there are any small commercial US based amateur electronic manufacturers that would be interested in this endeavor.

      This is a pivotal decision point for the project. I have a ton of hours in this project so far and plan to invest many more. My ultimate goal is to make something easy to use and setup on the surface (Web UI) and that supports the amateur radio community, probably something you don’t find a lot of. I would also like to keep it as affordable as possible too. There are many ways this project could go which are up in the air at the moment, but hopefully in the next couple months I will make a decision and be able to offer updates here. Thank you for your support and check back for updates.

      73s, Aaron

  3. Nick says:

    Just a thought, are your plans to make this a single port unit or would you consider having multiple (expandable) repeater ports to control/link multiple repeaters from a single controller.

    Also, are you working on a “flat” audio path or are you using de-emphasized audio?

    • Aaron Crawford says:

      Initially my plans are to keep it simple. So probably single port and flat audio. But I have though about multiple ports as an option or even echo link. I got to get the basic prototype working first then I will see where it evolves from there.

  4. Justin - VK2HJA says:

    Have you looked into using a cheap USB interface like the URI from dmkeng.com?

    these units have been working well for quite a while now.

    • Aaron Crawford says:

      Hello Justin,
      Thanks for the suggestion. I looked at the site and it is pretty vague. I cannot seem to find any additional information or specs on these. Kind of pricy, especially if I ended up needing 2. The goal is to make a simple but cost effect controller that is easy to configure. I won’t rule it out completely, just not the direction I am looking to go right now. Thanks for your interest and your input.

  5. Joe says:

    This will be a great contribution to the ham community no matter if it is open sourced or not. Keep up the good work. Looks brilliant! KD8WZU

  6. Michael - KE4EST says:

    Been following this for a couple of months now. I have myself been tinkering with a Raspberry Pi as a repeater controller. I used an old Atari 130xe for years as a controller, but the thing just requires to much power and hard to keep a drive functioning for it. A few months ago I go the idea of using a Raspberry Pi and in researching have came across your project. I love having some sort of computer running the repeater, cause I can change or add functions/features pretty easy by changing some code. Looking forward to see where you go with this.

    • Aaron Crawford says:

      Thanks for the support. I hope to get back to this project soon. I have some other things going on and some springtime and home projects to knock out of the way first.

  7. Angel says:

    Hi Aaron.
    Great project, can not wait to see when you finish it, since I entered because I was looking in google just what you’re doing.
    The raspberry, offers many opportunities to change the states of others, please do not forget to include options to add a fan and an extra battery.
    You know that SD cards are often corrupted by you exceed your limits of writing, I have my toy with the / root on a USB.

    If you need a beta tester I have some time now two motorolas GM340 and ready to run a couple of very boring raspberrys ….

    You have my email, I’m at your disposal. EA5HNU / Angel Tomas

    • Aaron Crawford says:

      Hello. Thanks for the interest. Stay tuned…I am looking into open sourcing the project.

    • Aaron Crawford says:

      Hi, Nothing has been physically interfaced as of yet. In the video demo, the breadboard is a proof of concept for the hardware/software interoperability via the GPIO pins on the Pi. There will be a circuit board that will replace that which will actually interface with the radios. Right now I am in the beginning process of open sourcing the project and getting a GitHub repository going and posting some circuit designs. I have a number of people that expressed interest in help develop and test the project. If you are interested, be sure to sign up to the mailing list at the top of the page. I will be sending details out to those interested soon. Thanks for your interest.

  8. stevmills says:

    Hi! I am excited about this project.. it is exactly what I was looking for – a way to use my Raspberry Pi as the controller for a GMRS repeater. I plan to run the repeater to provide an alternative means of communication for my family/extended family in the event of an emergency, and would also be very interested in helping with any kind of beta testing effort, if you go that route, as I have work experience as a Software QA Engineer. Thanks for your work on this!

    – WQTY571

    • Aaron Crawford says:

      Thanks Steve for your interest in the project. I am in the process now of open sourcing the project. I will be posting a blog entry and sending out a message via the mailing list as soon as I have things in order.

  9. Donald says:

    This is very cool. I think it would be very nice to be able to upload a MP3 of the Rain report or Amateur Radio Newsline and have it run on a cron job or something like that…

    de W5DRO

    • Aaron Crawford says:

      Hey Donald. Thanks for your interest and I will keep that in mind as I make improvements. 73s

  10. Joseph Colson says:

    Aaron my up most respect for making this open source! I look forward to beta testing your product.

    • Aaron Crawford says:

      Hello Bruno. Definitely still alive. I hope to be getting some code out in the wild here soon. Been busy with the spring an summer months. I see you are on the mailing list which is how I plan to reach out to those interested. If you can fill out the contributor form also. Thanks.

  11. mark says:

    how soon till we can download it???? also it would be awesome the get it working with allstarnode as well.

    good luck 73

    • Aaron Crawford says:

      Mark, I am hoping to have something out to developers here soon. Once I do that hopefully the process will move along a little faster. If you can, fill out the contributor form so I can keep you in the loop.

  12. roy says:

    Can’t wait to see how this project gets going I wonder if a kickstarter would be good for circuit design and distribution, I’d love to buy a prefab board that is made to be plugged into the RPI and has a socket for Baofeng radios… even if we have to assemble the board.

    Looked at the rPi B+ this has good specs for a solar driven repeater! can’t wait to see how this project progresses.

  13. Michael Moller says:

    I’ve been trying to accomplish a Baofeng to Baofeng repeater for a few weeks now. The problem is that there is no COS out from the RX radio. Using the Raspberry Pi as a controller would solve this problem of mine by creating the COS needed to pass the audio to the TX radio. The only problem I see is that the Raspberry Pi has no mic port/jack. IRLP uses a CM119 based USB sound card for the Pi. I can’t wait to see and use the Open Repeater Project software!

  14. Larry Ellsworth says:

    I have a Mastr II and an MSF5k sitting here waiting for a controller. THis is the one I would like to use. Also have 3 PI’s with the adafruit 16×2 displays sitting on them that would be great for status visuals. Anyway to intergrate that into the code using Python?

    • Aaron Crawford says:

      Hi Larry and thanks for your interest in the project. As of right now there are no immediate plans to incorporate a display. That could be an addon module later maybe. It would probably need to tie into the SVXLink. There will be simple LED status for PTT.

    • Aaron Crawford says:

      Hello Brian,
      Thanks for your enthusiasm for the project and I agree. I’ve recently release the code to some of the developers and we are getting the GitHub project repository up and going to manage the code and schematics. Once we have a chance to do some bug squashing and come up with some basic circuit designs, I will feel more confident releasing the project to everyone. I don’t have an exact date, but I want to get something out there as soon as I can.

      Even if you don’t have much development experience, I would still recommend signing up for a free GitHub account so you can participate in discussions (called “issues”) on the GitHub repository.

      Also, be sure to sign up for the mailing list so we can send you updates. 73 for now.

  15. tobiasdh1tw says:

    The control via WebInterface is a cool idea. However the idea with the two Baofeng radios won’t work in real life, except TX and RX are octaves separated (i.e. 70cm – 2m). For Inband (e.g. 70cm repeater), the Baofengs lack proper filters. Even with a commercial 6 cavity 70cm Duplexer the Baofengs start blocking at approx -20dBm. This restricts significantly the radius of your repeater.

    • Aaron Crawford says:

      Hello Tobias,
      Yes, I agree that the Baofengs would probably not work for same band repeat and that there are probably better choices (like Motorola). It’s just a graphic I threw together really quick at the beginning of the project. I hope to get around to some marketing stuff here soon like a project logo. I will likely change that graphic at that time so there is no confusion. Thanks.

  16. Frank says:

    Hi. I just joined the project.
    Could you please consider replacing the speech synth. with user-uploaded wav files.
    There is nothing more annoying than synthesised voice announcements.
    I have built a couple of repeaters and would like to help build the ultimate controller.

    Do you envisage using external CTCSS hardware? (Such as the Comspec TS-64) as the UK repeaters heavily rely on CTCSS.

    We also need to think about repeater linking in the spec.


    • Aaron Crawford says:

      Hi Frank,
      Welcome to the project!

      Yes, it is in my plans to add an option to allow user upload-able WAV files for ID. In theory this is entirely possible. I’ve already built the PHP side to process uploaded audio files into the proper WAV format for SVXLink and create the TCL overrides based upon user selection.

      I’ve already done some programing to create the overrides for the ID to add CW ID. I just need to work on that section more to add more user selectable options. I hope to allow the user to choose CW only, Voice Synth Only (with option to append CW), and WAV file ID only (with option to append CW). I even plan to add a feature to allow the user to change the pitch and WPM of the CW.

      Same goes for courtesy tones. You currently can choose your tone, but I also plan to add options for a basic beep and no tone. This would allow each operator to custom taylor the controller to suit their own preferences with out having to conduct rocket science to do so.

      Currently, I don’t have any plans to implement CTCSS in hardware as this is already handled in software by the SVXLink Core. I do have to do a little more testing and refining of my front end and how this builds the config files. CTCSS is pretty common here in the State for both TX and RX.

      As for the linking specs (radio linking), SVXLink does support this. It is just a matter of building a logical front end for it. You can add as many ports as you like it is just limited by how many sound channels you have going in and out and system resources. I was thinking it would be cool to build a block interface that could be wired together much like Yahoo Pipes. I think it needs to be visual, but this could be a lot of work. This may be some time off.

      The next major milestone for the project is getting some good schematics for basic hardware interfaces designed, tested, and available on GitHub for those wanting to test the project. I am relying on some help from others to do this. Once we have a foundational system, then we can build upon it.

      Also, need to prove that the current iteration of the Raspberry Pi is a viable option. It might not be up to snuff. I think the Beaglebone Black and some other SBCs would be better options.

      Thanks for you interest and your desire to help make this project great!

      Aaron, N3MBH

  17. Frank Johnson says:

    Hi Aaron.
    Thanks for the reply. It all sounds very exciting.
    The reason I suggested hardware CTCSS is performance.
    The hardware units mange decode at very poor signal/noise ratios (3-6dB) which is what is required. They also decode after just a few cycles of tone.
    Can we replicate this level of performance?
    Frank, g0gsr

    • Aaron Crawford says:

      Frank That still remains to be seen on the software CTCSS. There is a pretty good following around SVXLink already which lead me to believe it fairly reliable. Feel free to jump in the discussion on this GitHub issue: https://github.com/OpenRepeater/OpenRepeater/issues/11
      I copied our previous comments in there for group reference. That is where the action is happening at the moment. Right now we are trying establish some ground framework and get the ball rolling to ensure the success of the project. Thanks.

  18. Vincent Pichot says:

    Dear Aaron,
    very nice to see how your project is running. In fact i’m looking for HW to replace old controller for an intercom repeater (UHF repeater coupled with one simplex VHF frequency). The frequency output on VHF is programmable through dtmf on UHF and should take into account vhf repeater shift. the Rpi should eb the smartest solution. Ready to make some tests and build hw interface for the project. Txs for yourgreat job.
    best regards.
    Vincent / F5LUZ

  19. john.weland says:

    This is awesome. I’m a new HAM KG5ECM, I actually never thought about HAM before until I joined my counties SAR team which they are trying to get a handful of members HAM certified. I’d like to build a repeater for them as currently we use a repeater from one of the local clubs.

    I am a web developer by trade, but have been tinkering with the RasPi for about a year now. What are the regs for setting up a repeater? Does it use the owners call sign or do you test and apply for it to have its own callsign? I know this is all stuff I could ask my local group but they tend to get cranky.

    • Aaron Crawford says:

      Hello John,
      Sorry for the slow reply. Welcome to the hobby! This project is still in it’s early development so we don’t quite have a turnkey solution just yet. As for who’s callsign gets used, It could be either an individual or and club callsign, depending on the setup. Repeaters should ideally go through a coordinator to avoid conflicts with other repeaters. There is some good information here: http://www.repeater-builder.com/rbtip/ Might not be the prettiest site, but it has a wealth of info. 73s N3MBH

      • john.weland says:

        Hey thanks for the reply. Will there be a board that does the RX/TX you know its own radio board or will there simply be a usb link to connect to some handy talkies like a couple of small Baofengs r5’s?

        Having a nice board to do the radio itself would be much slicker. Also maybe working multiple bands eg 2M vox and a separate solution that can be hooked up for ARPS or digital. Set it up, hook up your antenna (antenni?… antennas?) and be able to utilize the whole lot (within the scope of your licensing.) I am the SAR teams tech guy and sort of fringe science guy. They want me to make technology work for them and since HAM is a requirement I’m hoping to set them up something nice.

        • Aaron Crawford says:

          I’ve considered SDR and onboard radios; however, I think it is best to start with something more traditional and build a solid core. Also since the receiver and transmitter in a duplex repeater will be operating at the same time, the chances are much higher for desense with SDR and onboard radios without proper filtering and shielding. Plus with many SDR type options you will need additional external amplifiers. With pre-made rigs, that is much simpler of a setup….radios are radios and the controller is handling interfacing and logic.

          • john.weland says:

            I guess I am confused at what make that SDR versus my little Baofeng HT. There is firmware that drives the hardware. What I had meant was a hardware hat (daughter board) for the Ras Pi that was both the transmit and receive radios and those frequencies, tones, squelch and offsets all handled via your awesome web interface rather than LCD screen of the radio. I imagine it would be a fair amount more work but it would be something that’s developed sort of as a bonus something that can be added.

            There would of course have to be an amp between the system and the antenna but that would be up to the operator to provide. I hope you don’t take this as arguing, I just think that after the core is built it could be a good route to go.

            Also let me know what I can do to help if any.

  20. roy says:

    I’m in process of creating my own EchoLink using a raspberry pi and found the easydigi interface; looks like the project may not need a circuit design, or maybe they’re interested in joining forces with your project to offer the hardware portion.

    Link to easydigi:

  21. Sam Nelson says:

    Excellent Start Aaron!
    I’ve been kicking around repeaters since 1971…Motorola, Vertex, Kenwood, etc. I was a coordinator here in Louisiana till I got tired of that, but still operate a few machines locally. Currently casting about looking for an external controller for the new Yaesu digital repeater, and tripped over your effort. Hope I can be of some assistance in recommending a feature set for serious repeaters.
    Not really interested in something that takes a couple of Walmart radios and makes them repeat.
    Sam, WA5VDM.

    • Aaron Crawford says:

      Thanks for the reply. Yes, this should be able to control “Real” repeaters also. Sorry for the late reply, I got tied up on some other projects. I’ve been working on some updates and tinkering with some hardware. I hope to post some updates after the new year. I will send out an email news letter once I do. 73s.

  22. Richard says:

    Great project, but I feel Echolink is a bit outdated and a new kids need to step up and take the technology forward. I stumbled on this project but I feel I will be re-writing the digital repeater book to use faster internet – friendlier firewall rules, UPNP configuration and audio encryption.

    • TJ says:

      I agree, I think Echolink is really outdated. I hope someone will write a new voip ham conference software both client and server, kinda like Echolink and teamspeak combined… where user can host their own conference server using their own vps server. I don’t mind paying for the conference server license if it’s a one time fee only, hehehe 🙂

  23. Matthew Jenne says:

    Would it be possible to get a demo release of the software and general design of the board you used in the test? I’ve been playing with RasPis for a little bit now and am looking to use them more as I have recently got my ham license. I’m not all that great with programming or hardware design yet, but would like a good project to tinker with. I’d be happy to share back anything I came up with.

    • Aaron Crawford says:

      Firstly, congrats on your recent ham ticket and welcome to the hobby. I do see you are on the mailing list. I am working on some tweaks to the software and coming up with basic hardware interface to get folks up and running. I hope to have some updates posted towards the beginning of the year. Stay tune!

  24. John Salsgiver says:

    Hi Aaron: I am not sure how much help I could be to you since I am not all that savvy when it comes to repeater controllers. The Cat1K I dealt with when I belonged to a club gave me fits. The best I could do is change the clock and manipulate the scheduler and update the CAT with new perimeters. I posted this to the comments at your You Tube page but will bring it up here for others who may wish to experiment. Based on your video, it appears you have enough bases covered( primarily FCC ID rules) to enable you to set up a simple simplex repeater; one transceiver, one antenna, no duplexer. I would imagine though that there is no script for the PI to act enable a simplex repeater mode of operation. Lastly, perhaps you could share your ideas with the people at http://www.repeater-builder.com/

  25. John Weland says:

    Just a heads up if you haven’t already heard The Raspberry Pi 2 mod B is out. Its about 6x more powerful (quad core, 1gb ram). Its still $35 however it is ARM v7 based which will mean a slight update to the host OS.

    • Aaron Crawford says:

      John thanks for the update. That’s news to me. I didn’t expect the Raspberry Pi Foundation to come out with a significant updates anytime soon. I’m currently developing on a Beaglebone Black Rev C…as time permits. Hopefully I will get a chance to pick up one of the newer RPIs in the next couple months.

      • Chris Berry says:

        any news yet? I do agree that the beaglebone is a bit more robust. just very anxious to try it out, 😉 (like a kid at Christmas excited)


        • Aaron, N3MBH says:

          Hi Chris,
          Sorry for the delayed reply. The project was put on hold for a while as I didn’t have any spare time. Me an another developer are working on it again and hope to get something usable soon.

          Yes the Beaglebone Black is a great platform and there are others that are emerging: Raspberry Pi 2 and just heard of another called “Chip”. There are getting more and more powerful which is a great fit for the project.

          Please make sure that you have filled out the contributor form so you can be added to the mailing list to be update when code is available. Thanks for your support.

  26. Mike Conner says:

    Hi John

    I am a trustee for a Solar powered New Zealand Repeater 147.3 zl1rod. This repeater is thirty years old and has no external control. Looking at what you have so maybe we could control Repeater TX OFF/ON, Repeater time out settings, etc via DTMF. Also be most useful to read voltage and announce on repeater tail etc and turn the repeater TX off is < 11vdc etc.

    Look forward to your progress and comments.

    Mike – ZL1MRC

    • Aaron, N3MBH says:

      Hi Mike,
      Sorry for the delayed reply. The project was put on hold for a while as I didn’t have any spare time. Me an another developer are working on it again and hope to get something usable soon. There will be a web gui, which is the primary ui, but the SVXLink core does have some dtmf functions and we may add some more down the road. Thanks for your support.

    • Aaron, N3MBH says:

      Hi Kato,
      Sorry for the delayed reply. The project was put on hold for a while as I didn’t have an spare time. Me an another developer are working on it again and hope to get something usable soon. Please make sure that you have filled out the contributor form so you can be added to the mailing list to be update when code is available. Thanks.

  27. Josh Rogers says:

    Radio control through the speakermic jack from the GPIO of the PI. The tricky part I foresee is writing a codeplug over serial. CTSS/DTMF/MDC1200 can all be done through already available decoding algorithms. I expect the Pi will have no trouble sending/receiving audio over the GPIO. If you do have a starting point, I’d love to have a framework to add to. Feel free to contact me if you think I can be of help.

    • Aaron, N3MBH says:

      Hi Josh,
      Sorry for the delayed reply. The project was put on hold for a while as I didn’t have any spare time. Me an another developer are working on it again and hope to get something usable soon. Please make sure that you have filled out the contributor form so you can be added to the mailing list to be update when code is available.

      The SVXLink core handles many options such as DTMF decoding and generating PL tones. The video at the time of this post is old. While the GUI concept is the same, the core functionality has changed. Thanks for the support!

  28. Bill Ardesson says:

    Still interested in this project. I’ve been working on a pi version using svxlink and a small HT with some success but I’m learning Linux as I do it. Can’t wait for an update and release. Best of luck.

    • Aaron, N3MBH says:

      Hi Bill,
      Thanks for the comment. We are working on it again and hope to have something soon.

  29. mois ragona says:

    Hi Aaron

    Great project, can’t wait to see it in action. Will keep checking for your update/publish of this useful tool. Would you have an estimated when it will be ready? 😉

    Thank you and keep up keep up the great work!

    • Aaron, N3MBH says:

      Thanks for the support. Stay tuned we hope to have some usable stuff out soon for beta testing. If you haven’t already, sign up for the contributor list, this will put you on the mailing list to keep you up to date. 73s

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