HamShield: VHF/UHF transceiver for Arduino

HamShield lets your Arduino talk to far away people and things using amateur radio bands (Coverage: 136-170MHz, 200-260MHz, 400-520MHz)

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HamShield lets you transmit voice and data over FM on amateur radio bands (144/220/440) and has wideband transceiving coverage: 136-170MHz, 200-260MHz, 400-520MHz. HamShield is an open hardware project and we are seeking backers to take it to mass production. currently on Kickstarter:

We have also written a powerful library to control it, featuring voice modes, packet radio, APRS, SSTV, morse code, and more. HamShield can also be solar powered for building emergency communication networks.

HamShield is a FM voice and data transceiver Arduino shield for three amateur radio bands (144MHz, 220MHz, and 440MHz) with wideband transcieving capability across 136-170MHz, 200-260MHz, 400-520MHz. It connects the FM transceiver to the ADC and PWM lines (filtered) and also features a TRRS jack for use with a smartphone headset.

The HamShield is based on a new variation of the RDA 1846, the Auctus A1846S and features a power amplifier to offer 250mW of filtered FCC/CE compliant RF output. This is a trade off between cost, heat, and adequate power output for use with an antenna or input to a larger power amplifier.

The HamShield also can operate at low power. We have used a 2.5 watt solar panel (4.5" x 7") to power the HamShield while transmitting a test morse code signal. You could easily build a solar powered packet radio station with a similar setup. Adding a battery charging circuit would help power the HamShield during less optimal sun exposure or overnight.

We have a powerful library that lets you write radio sketches fast! It supports control of every aspect of the radio, from power output level, transmit and receiving control, sub audio tones (CTCSS/CDCSS), RSSI detection and tone generator and detector circuits. In addition to voice, we have packet radio data capability using 1200 baud AFSK. Our library supports AX.25 frames as well as the popular APRS mode. There is work being done to bring 9600 FSK to the library, as the hardware is capable of higher bitrates.

We have also have a sketch that turns the Hamshield + Arduino into a serial controlled radio. This means you can connect it to a computer. We have written some Chrome browser applications that use the serial port to offer functionality such as packet radio in a web browser (APRS Text Messenger!) and another Chrome app that lets you operate the radio and talk to repeaters.

  • 1 × A1846S Radio SoC, successor to the RDA 1846

  • HamShield in Production!

    Casey Halverson03/24/2016 at 17:59 1 comment

    It has been a few months since I have updated our project log. Here is what has happened over the past couple of months.

    The power boost stretch goal was a bit more difficult than anticipated, and also resulted in several unexpected problems: ground loops, noise, and I2C bus capacitance tolerances! It has been a wild ride, but we finally resolved these in February.

    We ordered PCBs (about 1500) and delivered them to our manufacturer near Seattle in early March. The production run has started, and we tested the first panel off the line. It worked great! We authorized construction of the rest of the panels.

    This means we should have HamShield shipping by early next month! Our first shipments will go to Kickstarter backers and then off to our pre-orders. After this is all done, we will be able to fulfill orders in real time until we work out some sort of distribution agreement. Our HamShield team is small, and we would rather focus on improving HamShield and making new related products than work with shipping logistics.

    We learned a lot about Kickstarter, RF hardware, and other aspects of the project that I hope to talk about in a future update.

    Take care,


  • Pre-Order HamShield & Amplifier Updates

    Casey Halverson08/05/2015 at 01:03 0 comments

    We have a system to accept pre-orders for HamShield:

    Things are coming along nicely. We are getting a power amplifier test board revision back shortly with a new two-stage amplifier design that will really boost our power. We also are integrating this into the complete board and running the PCBs. If the amplifier stage works as planned, we can immediately start testing rev 4 of the complete board. Once this testing is complete, we can send the design off for manufacturing.

    We are also shopping around our BOM again (we have blown well past what we originally had quoted out) to see if we can get a better deal on components. This will allow us to save some more cash for further board revisions, improvements, and to prototype some really cool stuff we have planned in the future.

    HamShield is also allowing us to prototype these things :)

    But before we get ahead of ourselves, the focus is to make sure to deliver our hardware on time. So far, we are on schedule.

  • HamShield: Only 3 hours left on Kickstarter

    Casey Halverson07/30/2015 at 04:28 0 comments

    Wow, what an amazing month this has been. We have had incredible support for the HamShield.

    If you haven't had your chance to pledge for your HamShield, this is your last call!

    After our Kickstarter is complete, I will be posting more technical details on sourcing hardware, manufacturing logistics, and even some lessons learned. Hopefully this will be a good resource for anyone else looking to launch a successful open source hardware project.

  • Wow! Only 3 days left on Kickstarter!

    Casey Halverson07/27/2015 at 01:53 0 comments

    What outstanding support we have had over the past month. We are closing in on $100,000 -- that is a lot of HamShields!

    Thank you everyone for your support in making this happen.

    In August, we will be ordering all of our parts and sending the HamShield off to manufacturing. Other than making our suppliers and contract manufacturing company very happy, there will be no issues scaling up production of HamShield.

    I am working on our Chrome apps for HamShield as well as a demo for a WiFi-enabled HamShield using the ESP8266 and a smart phone. It will take a me a little while to finish both, but I will update everyone on the progress as we go along!

  • HamShield Library!

    Casey Halverson07/14/2015 at 04:42 0 comments

    As promised, here is the GitHub link to our growing open source library! Special thanks to Stephen Olesen / VE6SLP who made a lot of this possible! If anyone is looking for an amazing developer, I can put you in touch with him. This guy had half of this working before I could even get a prototype shipped to him.

    Remember, it is still in development, but I am too excited so I *must* show you!

    Things are still going full steam ahead with development, but this should give you a great idea of where things are headed. As we expand the library, expect to see more and more examples that leverage the new capabilities.

    Even better, we hope you contribute to our library and growing example base! We are working on a breadboard schematic so some of you can rig up what we have on the HamShield and develop even before your HamShield arrives!

    Here are some highlights of our library's capabilities:

    • General radio functions (Frequency, transmit, receive, VOX, RSSI, etc)
    • Programmable power amplifier (has non-linear performance, but still cool!)
    • CTCSS (PL tone) and CDCSS (DCS digital tones)
    • Disable emphasis / de-emphasis / etc (potential "discriminator" tap mode)
    • Single and Dual Tone detection (On chip DSP)
    • Single and Dual Tone generation (On chip DSP)
    • AFSK 1200 baud packet modem (Transmit and Receive)
    • AX.25 packet radio framing support (Transmit and Receive)
    • APRS support (Transmit and Receive)
    • KISS TNC support! (Turn your Arduino into a KISS compatible TNC)
    • Morse code functions (ie: morseOut("HELLO WORLD"); !)
    • DDS (Direct Digital Synthesis) waveform framework for custom digital modes
    • Martin 1 SSTV (slow scan television) with bitmap support
    • PSK31
    • QPSK63
    • Wait for empty channel
    • White space channel finder
    • Radio scanner
    • Weather channel finder and tuner
    • MURS/FRS/GMRS tuning support

    Some library roadmap and a few neat ideas we are kicking around:

    • A low power mesh messaging framework for off-grid / solar operations
    • Improved packet radio support
    • 9600 baud FSK (still *very* experimental, cannot promise anything yet. But maybe!)
    • Experimental trunked radio mode
    • HamShield daisy chaining support for repeater and duplex configurations
    • Digipeter support
    • Weather station support
    • More neat features

    We already have some great examples in our library, including our serial port controlled radio, APRS messenger, and KISS TNC packet radio sketch.

    Also, this week I am expanding on my solar powered experiment I did last Sunday. I hope to have another video soon!

    - Casey

  • HamShield Progress

    Casey Halverson07/13/2015 at 22:45 0 comments

    Over the last year, we have been developing the HamShield.

    Here is a view of our first prototype:

    The next revision had far less greenwiring:

    And finally, our final revision:

    We have also built a neat attachment for computer use. Here is our Chrome browser app with the HamShield + Arduino clipped on the back for mobile text messaging anywhere over amateur radio (APRS Messenger):

    Here is the start of our solar powered HamShield. The hope is to make it possible to build off-grid communication networks using the HamShield technology:

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aaaaaa wrote 04/15/2023 at 17:46 point

it is compatible with reticulum or meshtastic?

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mstalcup75 wrote 05/08/2018 at 03:02 point

Where do you get the APRS Messenger?

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cyber5tar86 wrote 09/23/2016 at 14:32 point

Hi! it's possible to use hamshield in PSK31 mode?

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gchatzisavvidis wrote 04/05/2016 at 08:08 point


what is the maximum distance module to module?  inside a city for axample

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Steve Smith wrote 01/22/2016 at 16:39 point

josephchrzempiec - Look up your countries national Amateur Radio Society or your local Radio Club. They will be able to advise you :-)

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polishplaya wrote 01/22/2016 at 15:04 point


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josephchrzempiec wrote 11/14/2015 at 05:11 point

I have one Question don't you know a license of some kind like a ham license?

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Saabman wrote 01/20/2016 at 00:42 point

yes you need amature/ham licence to transmit on amature/ham frequencies. 

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Grayson Schlichting wrote 10/15/2015 at 04:53 point

I can't wait to get mine - what a Great Team there in Seattle.

I'm behind in getting ready for it, and know that they are going to have to sit patiently  in their factory wrapper, calling out to me from the distance: "I can't wait to see what you are going to make with ME..."

Haven't been this excited since I ordered my FT101-EE HF Rig 40 years ago!  Maybe HS can show utility by revitalizing 220 with it possibly being the Band-of-Choice for experimentation of new "things" and protocols for advancement of technology, operating practices, and forums to foster off-the-wall applications and neat new coms protocols.

-Grayson, W5ANM, Austin, TX USA

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