PortaPack Mayhem's interface and its whole app suite, running on your PC against an Ettus USRP B200 — with more bandwidth, better filters and a real CPU behind it.
Tested on real hardware. Run against a physical Ettus USRP B200 (serial EDR04ZDB2, 2026-08-03): all 67 radio apps run on the device, the backend self-test passes across 100 MHz – 2.44 GHz with zero dropped samples, and the ADS-B app decoded real aircraft off the air. Details in Status and caveats.
This project is looking for people. It works, it decoded real aircraft off the air, and it is one person's work so far. If you want a portable version of this to exist, or you design PCBs, or you just want to try it — see Where this goes next and How you can help. Telling me you want it is genuinely useful; a star on this repo is the cheapest way to do that.
All captured from the running application with the Ettus USRP B200 connected
(the green B200 in the status bar). Mayhem's own fonts, palette and 240×320
layout, drawn to a host framebuffer.
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 |
 |
|---|---|---|
| Home — the icon-grid menu | Receive — 33 RX apps (one of several pages) | Transmit — 26 TX apps |
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 |
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| Spectrum — live FM band off the B200 | ADS-B — real aircraft decoded off the air (17 valid frames) | FM Radio — WFM broadcast receiver |
Download the latest Windows build →
Grab the mayhem-b200-<version>-win64.zip, unzip it anywhere, and run
mayhem-b200.exe. It is self-contained — the UHD and Visual C++ runtime DLLs
and the B200/B210 firmware/FPGA images are bundled, so no separate UHD, Boost
or Visual Studio install is needed.
There is one manual step, once per PC: bind the WinUSB driver to the
B200 with Zadig (every USRP needs this on Windows).
Full instructions are in READ-ME-FIRST.txt inside the zip. After that, plug in
the B200 and the status bar shows a green B200.
Prefer to build it yourself? See Building.
Mayhem is firmware. It runs on the PortaPack's LPC43xx — a dual-core Cortex-M with a 240x320 LCD, a five-way switch and an SD card — and it drives a HackRF One over an SGPIO bus.
A USRP B200 has none of that. It is a USB peripheral: a Spartan-6 FPGA, a Cypress FX3 USB controller and an AD9364 transceiver. There is no application processor to run firmware on, no screen, and no buttons. You cannot flash Mayhem onto a B200, and anything claiming to do so is claiming something the hardware cannot do.
So this is the other half of the idea: Mayhem's UI and apps, rebuilt as a host application, with UHD and the B200 standing in for the SGPIO bus and the HackRF's front end. The window is a real 240x320 framebuffer drawn with Mayhem's own fonts, palette and widget layout; your keyboard and mouse are the five-way switch, the encoder and the touch panel.
The parts of Mayhem that were hardware-independent — geometry, fonts, painter, focus manager, theme, the spectrum palette — are used unchanged. See NOTICE.md for exactly which files, and what was modified.
- Up to 56 MHz of instantaneous bandwidth instead of the HackRF's 20 MHz, so the spectrum app shows a live wide span rather than a swept one.
- A real CPU for the DSP, so the channel filters are designed at run time for whatever sample rate you pick instead of being fixed tap tables.
- LO offset tuning, which moves the direct-conversion LO spike out of the displayed band — the PortaPack has the same artefact and no way to avoid it.
- Capture while listening. Recording taps the same samples the demodulator is already using, so IQ recording is not an exclusive mode.
It is not pocket-sized and it needs a host. That is what the next section is about.
The obvious question is whether this can become a handheld again. It can, but not the way a PortaPack does, and it is worth being precise about why.
A PortaPack works because the HackRF already contains the computer. The PortaPack is a screen, a control wheel and an audio codec on a header, and the HackRF's own MCU runs Mayhem. A B200 mini has no such processor — it is a USB device and it needs a USB host. So a portable build is not a PortaPack; it is a small computer, a B200 mini and a battery in one enclosure, running this software.
That makes the concept roughly:
| Part | Why |
|---|---|
| SBC with real USB 3 | The B200's high sample rates need it; USB 2 caps you near 16 Msps |
| B200 mini (or clone) | The radio |
| 240x320-and-up display | The UI is drawn at PortaPack resolution and scales cleanly |
| Five-way + encoder + audio | So the existing input mapping just works |
| Battery and power path | Radio plus host is watts, not milliwatts — this is the hard part |
| Carrier PCB | Ties the above together instead of a nest of adapters |
Two things have to happen before the PCB is the interesting problem:
- A Linux port. Today the display is Win32/GDI and the audio is WinMM. The
platform-specific code is contained to three files —
src/ui/window.cpp,src/audio/audio_out.cppandsrc/audio/audio_in.cpp— out of ~108k lines, because everything above them is Mayhem's own portable UI core. This is a contained job, not a rewrite, but nothing runs on an SBC until it is done. - Evidence that people want it. A carrier board costs money and somebody's evenings. Before that, the same machine can be built from off-the-shelf parts and adapters — ugly, but it proves the idea and it costs the project nothing. If a handful of people build one, the PCB is worth designing.
That is the honest order of operations. I would rather say so than take money for a board nobody has run the software on.
I am one person and this needs more than one. In rough order of how much it would unblock:
- Try it and say something. Open an issue — "this worked", "this decoded nothing", "I would buy the portable one" are all useful. Star the repo if you want it to continue; that number is the only signal I have.
- A Linux port of the three platform files above (SDL2 or DRM/KMS + ALSA/PipeWire). This is the single highest-leverage contribution and it unlocks everything portable.
- A PCB designer. If the handheld gets past the proof stage I need someone who has done power paths and USB 3 layout properly. Talk to me before it is urgent — the enclosure and the board argue with each other early.
- RF testing. Almost every decoder here is unit-tested but has never met a real signal (see Status). If you have a POCSAG pager, an AIS receiver's view of a harbour, a weather sonde overhead — running one app and reporting what happened is real work I cannot do alone.
- Transmit verification, if you are licensed and have a dummy load. Nothing in the TX chain has ever radiated.
Funding. There is no donation link yet and I am not going to put one up to collect money for a product that does not exist. If the interest is there it will go here, and it will be for parts and prototype boards, itemised. If you want to fund something specific in the meantime, say so in an issue.
| Hardware | Ettus USRP B200 (B210, B200mini and B205mini should also work — every limit is read from the device, not hard-coded) |
| OS | Windows 10/11 x64 |
| Compiler | MSVC 2022 (Build Tools are enough) |
| UHD | 4.x with headers and uhd.lib — the stock Windows installer |
| Boost | headers only; UHD's public headers include <boost/format.hpp> |
| CMake | 3.20+ |
No other dependencies. The window is plain Win32/GDI and the audio is WinMM, so there is no SDL, Qt or FFTW to install.
cmake -S . -B build -G Ninja -DCMAKE_BUILD_TYPE=ReleaseIf UHD or Boost are not in the default locations, point at them:
cmake -S . -B build -G Ninja -DUHD_ROOT="C:/Program Files/UHD" -DBOOST_INCLUDE_DIR="C:/vcpkg/installed/x64-windows/include"Then build and test:
cmake --build buildctest --test-dir build --output-on-failureuhd.dll is copied next to the binary automatically, so the build tree runs
as-is.
build\mayhem-b200.exe| Option | Meaning |
|---|---|
--args=<uhd args> |
Pick a device, e.g. --args=type=b200,serial=31C9297 |
--scale=<1..6> |
Window magnification (default 2) |
--list |
List attached USRPs and exit |
--help |
Usage |
The app starts and stays usable with no radio attached — it shows no dev in
the status bar, and Radio setup → Reconnect picks the device up when you
plug it in. You do not need a B200 to look around, which is the easiest way
to decide whether you care about this project.
| Input | PortaPack equivalent |
|---|---|
| Arrow keys | five-way switch |
| Enter / Space | Select |
| Escape / Backspace | Back |
| Mouse wheel | rotary encoder |
| PageUp / PageDown | encoder, one detent |
| Left mouse button | touch panel |
| F11 | cycle window scale |
In the audio app, Left/Right tune by the current step no matter which control has focus. Select on the frequency field cycles the step size (1 Hz through 1 MHz, including 6.25 / 12.5 / 25 kHz).
The full PortaPack Mayhem app suite is ported — ~103 apps across the same category menus Mayhem uses, all reachable from the icon-grid home screen:
- Receive (33): Audio (AM/NFM/WFM/SSB/CW), ADS-B, AIS, APRS, POCSAG, FLEX, Radiosonde, Weather/TPMS, ERT, ACARS, AFSK, RTTY, SSTV, Morse, NOAA APT, WeFax, VOR, Scanner, Signal Hunter, Detector, Level, Time Sink, FM Radio, Tetra, SubCar, 2-Tone, NRF, EPIRB, FPV Detect, Analog TV, gfxEQ, Fox hunt.
- Transmit (26): Mic, OOK/Encoders + OOK Editor/Brute, RDS, APRS, RTTY, Morse, POCSAG, FLEX, SSTV, Signal gen, 2-Tone pager, Soundboard, GPS Sim, VOR, ADS-B, EPIRB, Jammer, KeeLoq, Keyfob, Security+, BHT, BurgerPgr, BLE, cart lock.
- Transceiver (2): Mic TX, KISS TNC.
- Utilities (17): Capture IQ, Replay/Playlist, Playlist Editor, File Manager, Freq Manager, Notepad, IQ Trim, Calculator, Antenna Length, Metronome, Stopwatch, Tuner, Random Password, WAV Viewer, Waterfall Designer, Wardrive Map.
- Games (10): Snake, Tetris, 2048, Breakout, Space Invaders, Blackjack, Battleship, Dino, Morse Practice, DOOM (shell).
- Settings / Debug: Radio Setup, Settings, About, Hard Reset, Audio Test, Font Viewer, Debug PMem, plus honest "N/A on B200" screens for the PortaPack-only apps (MCU Temperature, Ext Sensors, SD-over-USB, Wipe SD card, App Manager) that explain why the hardware does not apply.
Every app with decode/encode logic is tested against known protocol data (CRC vectors, round-trips through the modulators, documented frames). TX apps that radiate illegal signals (jammer, GPS sim, ADS-B/EPIRB TX, spam family) carry an on-screen legality warning and never transmit without an explicit action.
Recordings and frequency lists go under
Documents\mayhem-b200\CAPTURES and ...\FREQMAN.
DOOM is a shell that reports whether a WAD is present, not a playable port. Analog TV and some wideband 2.4/5.8 GHz apps (BLE, NRF, FPV) sit at the edge of the B200's range and their pipelines are ported and unit-tested but, like everything here, unproven on real RF (see Status).
UHD ──► UsrpRadio ──► lock-free ring ──► ReceiverModel
(streaming (NCO → channel FIR
threads) → demod → audio
filter → de-emph
→ AGC → resample)
│
┌─────────────────────────────────────────┤
▼ ▼
waveOut spectrum tap
│
Win32 window ◄── framebuffer ◄── Painter ◄── widget tree ◄── FFT ───┘
(keyboard/mouse) 240x320 (Mayhem) (Mayhem)
src/ui— Mayhem's UI core plus the host display, window and inputsrc/dsp— filters, FFT, demodulators, resampling, ring bufferssrc/radio— the UHD backend and the receive chainsrc/audio— WinMM output and capturesrc/apps— navigation and the app viewssrc/core— string formatting, paths
The DSP is not a copy of Mayhem's fixed-point M4 code; it is float, and the filters are designed at run time so they track the sample rate. The modes and their bandwidths deliberately match Mayhem's labels.
1986 tests, no framework dependency:
build\tests\mb200_tests.exeThey cover the string formatting (locked to the firmware's exact output,
including its slightly surprising -0042 sign padding), the DSP against
analytically-known results (FM deviation scaling, SSB opposite-sideband
rejection, FFT bin placement, resampling ratios, squelch hysteresis), the
display's scroll-region arithmetic, widget behaviour, and every no-device path
in the radio layer.
The receive path is verified on a physical USRP B200 (serial EDR04ZDB2,
2026-08-03). A hardware self-test (tools/hw_selftest.cpp, build target
mb200_hwtest) opens the device, reads its capabilities (42 MHz – 6.008 GHz,
0–76 dB, up to 16 Msps on USB 2), sweeps gain (−69 → −15 dBFS across 0–60 dB),
tunes and streams at eight frequencies from 100 MHz to 2.44 GHz, and sustains
2.40 Msps for 2 s with zero overflows, drops or errors — all checks pass.
The GUI has been driven live: the spectrum shows the real FM broadcast band, and
the ADS-B app decoded real aircraft off the air (17 CRC-valid Mode S frames,
2 aircraft, real ICAO/callsign/speed), which exercises the full
tune → stream → demod → CRC → parse chain on live RF.
What is still unverified on hardware:
- Transmit. Nothing has been transmitted. The TX chain and encoders are unit-tested only.
- Most individual decoders beyond ADS-B — their logic is unit-tested against known data, but a live decode depends on a signal being present locally.
- USB 3 rates. The test device was on a USB 2 port (16 Msps ceiling); wide spans and high sample rates are untested.
- Audio demodulation was confirmed to stream and measure correctly but not verified by ear.
The UI, DSP and file handling are exercised directly by the unit tests (1986, all passing) and by running the application.
GPL-2.0-or-later, inherited from PortaPack Mayhem. See NOTICE.md for attribution and LICENSE.GPL-2.0-or-later for terms. No warranty.
This is an independent project. It is not affiliated with or endorsed by the PortaPack Mayhem project, or with Ettus Research / NI. Any hardware that comes out of it ships under the same licence, source included.
You are responsible for what you transmit. Most of the B200's tuning range is licensed to somebody.