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SDRLab H4M (HackRF PortaPack) — Complete Guide

One-liner: the H4M is the current-generation PortaPack for the HackRF One — a 3.2″ touchscreen case that turns a 1 MHz–6 GHz SDR transceiver into a standalone handheld radio lab that runs on battery, with no computer attached. The Mayhem firmware turns it into an audio receiver, spectrum analyzer, signal recorder and much more.

What's in the box​

ItemTypical content
PortaPack H4MExtension case with 3.2″ matte touchscreen, rotary wheel, speaker, microphone
HackRF One (or R10C)The SDR board the H4M mounts on
AntennasWideband telescopic (40–6000 MHz) + band-specific (5dBi, 12dBi, 8dBi, 35dBi variants)
CablesUSB-C cable, SMA male-to-male
Extras (kit-dependent)20 dB power amplifier, batteries, cases

Specs at a glance​

HackRF One (the radio core)​

ItemSpecification
Frequency range1 MHz – 6 GHz
Operation modeHalf-duplex transceiver
Sample rates2 – 20 Msps (quadrature)
Resolution8-bit I / 8-bit Q
InterfaceHigh-Speed USB (USB-C on H4M bundle)
Antenna portSMA female, 50 Ω
Antenna port powerSoftware-controlled, max 50 mA @ 3.0–3.3 V
Max RX input-5 dBm (exceeding it can permanently damage the device!)
Max TX output+10 dBm (10 mW); typical 0 to +5 dBm
ClockCLK IN / CLK OUT for synchronization

PortaPack H4M (the shell)​

ItemSpecification
Display3.2″ 240×320 matte LCD touchscreen
ControlsArrow keys, 360° rotary wheel (flat design), select buttons, power button
AudioBuilt-in speaker, built-in microphone (toggle switch), 3.5 mm headphone/mic jack
StoragemicroSD card slot (required for apps, logs, recordings)
Battery2500 mAh rechargeable with management IC + status display
ChargingUSB-C, with a proper on/off switch
ExpansionGPIO port (I2C-capable) for add-ons like GPS receivers
CaseTransparent ABS injection-molded shell

What's new on the H4M vs the older H2​

USB-C instead of Micro-USB, a real on/off switch, built-in speaker + microphone with auto-switching, I2C-capable GPIO port, battery info shown in firmware, and a flatter design.

Concept: how the H4M works​

The HackRF digitizes the spectrum; the PortaPack provides the human interface; Mayhem firmware provides the apps. No PC involved — the H4M is the whole lab.

Mayhem firmware​

The H4M runs the open-source Mayhem firmware (portapack-mayhem/mayhem-firmware), the community continuation of the PortaPack software with hundreds of apps: spectrum analyzer, audio receiver/transmitter, signal recorder and replay, ADS-B, APRS, GPS simulator, and more.

Step 1 — Prepare the microSD card​

  1. Format a microSD card (16 GB is comfortable) as FAT32.
  2. From the Mayhem releases page, download the COPY_TO_SDCARD archive matching the release you'll flash.
  3. Extract it to the card root. This is what puts the apps, maps and assets on the card.

Step 2 — Update the firmware (three ways)​

Option A — Flash Utility (recommended):

  1. Copy the FIRMWARE_mayhem_*.bin from the release archive to the microSD card root.
  2. Insert the card, power on the H4M.
  3. Utilities → Flash Utility → select the file → confirm. The device reboots.

Option B — hackrf.app: connect USB-C (data cable), open https://hackrf.app/ in a WebUSB-capable browser, click Connect Device, choose your PortaPack, and let it flash.

Option C — classic CLI (Linux/macOS):

sudo apt install hackrf          # Debian/Ubuntu/Kali; brew install hackrf on macOS
hackrf_info                      # confirm the board is seen
hackrf_spiflash -w portapack-h1_h2-mayhem.bin

Expected hackrf_info output:

Found HackRF board.
Board ID Number: 2 (HackRF One)
Firmware Version: git-... (API:1.02)

⚠️ In HackRF mode the H4M is a plain HackRF — the PortaPack UI is bypassed. Keep the COPY_TO_SDCARD content in sync with the firmware version.

Quickstart — hear the world​

  1. Charge the battery (USB-C) until the indicator shows full.
  2. Insert the prepared microSD card.
  3. Attach a suitable antenna to the SMA port.
  4. Slide the power switch on. The Mayhem menu appears.
  5. Open Audio RX (or FM Broadcast RX), tune to a local FM station (88–108 MHz). Adjust the gain; audio comes from the built-in speaker.

Command-line spectrum check (as plain HackRF)​

hackrf_transfer -s 8M -f 100M -g 20 -r /dev/null

If the device streams without errors, the radio core is healthy.

Example project — spectrum around you​

  1. Spectrum Analyzer app → sweep 88–108 MHz: you should see the FM broadcast band as several bright peaks.
  2. Tune the center on the waterfall and note the station callsigns with Audio RX → FM.
  3. Try 1090 MHz (ADS-B): install the ADS-B app and watch aircraft positions stream in.

Compatibility​

PlatformSupportNotes
Standalone (PortaPack)✅The whole point — no PC needed
Linux / macOS (as HackRF)✅hackrf tools, GQRX, SDR# with ExtIO
Windows (as HackRF)✅SDR# / SDR++ with HackRF source
SDR software for the PortaPack✅Mayhem ecosystem apps

Responsible-use note​

The H4M is a transceiver: with the right antenna it can transmit on amateur bands and beyond. Radio laws vary by country — transmitting without a license, or on frequencies you're not authorized for, can be illegal and can interfere with critical services (aviation, emergency). Great for listening and lab experiments; think carefully before pressing TX.

Troubleshooting​

ProblemCauseFix
Won't power onFlat battery / stuck modeCharge 10+ min; hold power button; try USB-C to PC
Apps missingmicroSD missing or staleExtract the matching COPY_TO_SDCARD to a FAT32 card
No audioWrong output / gainUnplug headphones to re-route to speaker; raise gain; check mode (WFM for FM)
PC doesn't see a HackRFNot in HackRF modeSwitch to HackRF mode in the UI before USB tools
Noise floor everywhereNo antenna / overloadAttach antenna; lower gain; max RX input is -5 dBm

More help: the SDRLAB troubleshooting hub.