Make the first hour productive
This radio covers an enormous tuning span, but a disciplined setup beats maximum gain. Begin with known public signals, prove the signal chain, then add antennas and decoders one band at a time.
Your first 30 minutes
Hardware truth table
| Exact H4M vendor claims | 100 kHz–6 GHz receive/tune range, LPC4330, iCE40 UltraPlus FPGA, MAX2831/MAX5865 chain, 25 MHz 0.5 ppm TCXO, USB-C, extra shielding/surge protection. |
|---|---|
| HackRF architecture reference | Half-duplex SDR, up to 20 MS/s in conventional 8-bit complex I/Q, software-adjustable gains/filters. Confirm derivative-specific advanced modes and host/firmware compatibility on your unit. |
| What “100 kHz–6 GHz” means | The synthesiser can tune there. It does not promise flat sensitivity, immunity to overload, a suitable antenna or legal access to every signal. |
| Urban Sydney reality | Strong AM/FM, mobile and local transmitters can create intermodulation and false signals. Attenuation, a band-pass/notch filter and a better antenna often outperform an LNA. |
| Data rate | At conventional 8-bit I + 8-bit Q: 10 MS/s ≈ 20 MB/s ≈ 1.2 GB/min; 20 MS/s ≈ 40 MB/s ≈ 2.4 GB/min, before filesystem/container overhead. |
What is worth trying now?
Recommendations use Sydney local time, approximate sunrise/sunset, your selected solar state and optional VHF propagation scenario. They are probability hints, not reception guarantees.
Manual mode. Live loading is optional and sends a request only to NOAA SWPC.
How to read the conditions
Best candidates under the selected conditions
63 things to hear, see or measure
Frequencies are practical guides, not permission. For changing local assignments, use ACMA RRL, Airservices, AMSA, SatNOGS and SondeHub immediately before listening.
Build capability in layers
No single “100 kHz–6 GHz antenna” performs well everywhere. A sensible kit combines broad discovery antennas with narrow, filtered antennas for weak targets.
1 · Discovery
A discone outdoors and high covers local VHF/UHF well enough to find air, marine, amateur and utility activity.
2 · LF/MF/HF
A tuned ferrite/active loop for LF/MF plus a 10–20 m receive wire or passive magnetic loop for HF. Add static protection and common-mode control.
3 · VHF/UHF local
A dual-band 2 m/70 cm vertical complements the discone with more gain on amateur/APRS/radiosonde/UHF work.
4 · Weather satellites
A 137 MHz QFH or turnstile sees circularly polarised LEO weather downlinks across the sky. Put a filtered LNA at the antenna only after overload is controlled.
5 · AIS & ADS-B
Use a 162 MHz marine vertical for AIS and a dedicated 1090 MHz antenna + band-pass filter + LNA for aircraft. These are excellent measurable upgrades.
6 · L/SHF
Short-feed patch, helix, panel or dish antennas for 1.5–1.7, 2.4 and 5.8 GHz. Feedline loss rises rapidly, so put electronics near the antenna.
Antenna length calculator
Free-space wavelength λ ≈ 299.792458 ÷ f(MHz) metres. The factor shortens a practical conductor; real resonance also depends on element diameter, feedpoint, ground, enclosure and surroundings.
Filter before amplifying
Use AM/FM notches, high-pass or target band-pass filters to stop strong out-of-band stations driving the wideband front end into non-linearity.
LNA at the antenna
An LNA is most useful when the desired band is already clean and coax loss is significant. At 1–6 GHz, keep coax short and place the filtered LNA near the antenna.
Static, lightning & bias power
Disconnect outdoor antennas during storms or when unattended; use appropriate grounding/static discharge. Verify voltage, polarity and current before powering any active antenna—the official HackRF reference is 3.3 V/50 mA, but confirm the H4M implementation.
A software stack that grows with you
Use one general tuner, then add purpose-built decoders. Keep original I/Q only when it adds value; otherwise save decoded metadata, screenshots and short representative samples.
Daily receiver · SDR++
Fast general tuning, spectrum/waterfall, recording and plugins. Start here. If a duplicate Soapy source causes a HackRF conflict, disable that source rather than changing drivers blindly.
Decoder workbench · SDRangel
Integrated demodulators and channels for ADS-B, AIS, DAB, digital modes, mapping and more. More complex, but unusually broad.
Build your own · GNU Radio
Flowgraphs for signal processing, experiments and custom decoders. Radioconda is a practical way to obtain a coherent Windows radio-science environment.
Satellites · SatDump + Gpredict
Predict passes, correct Doppler and process live or recorded weather/telemetry downlinks. Confirm current spacecraft status with SatNOGS.
Ships · AIS-catcher + OpenCPN
Decode both AIS channels, expose NMEA/web output and plot vessels. It is educational—not a certified navigation chain.
HF digital · WSJT-X + fldigi
Weak-signal FT8/FT4/WSPR plus CW/RTTY/PSK and other modes. Synchronise Windows time and route SDR audio cleanly.
Own-device analysis · URH
Visualise and annotate pulse/radio protocols from devices you own or are authorised to test. Keep access/security systems out of open-air experiments.
Digital trunking · sdrtrunk
For lawful, unencrypted and non-sensitive systems. Do not bypass encryption, follow individuals or publish operational talkgroup activity.
DAB+ · welle.io / SDRangel
Sydney DAB+ is a useful wideband test. Hardware-source support varies, so SDRangel may be the simplest HackRF route.
Recommended setup order
I/Q storage calculator
Capture only the bandwidth and duration you need. A SigMF sidecar can preserve frequency, sample rate, time, hardware, antenna and notes without locking you to a proprietary application.
Mayhem application encyclopaedia
151 current entries from the verified app inventory, including receivers, transmitters, core tools, diagnostics, games, settings and HackRF Mode. High-risk transmit functions are described only at a safety level.
Pro_v2.4.0 based on Mayhem 2.4.0 and need matching SD APPS. The official Mayhem page showed a nightly dated 2 August 2026 when this guide was checked on 4 August 2026. Nightlies are pre-release; external .ppma apps and firmware must match. Preserve the vendor image and update firmware + SD assets together.Safe update checklist
- Photograph the current About/build and calibration screens.
- Make a sector or file-level backup of the entire SD card.
- Save the exact vendor firmware/recovery bundle locally.
- Confirm the target release supports this derivative and obtain its matching SD package/external apps.
- Verify checksums where published; use the documented DFU/recovery path.
- After update, test receive-only apps, storage and calibration before any authorised bench transmission.
Normal-use TX policy
Use App Manager and TX Limit to disable or restrict transmit functions. Leave Jammer/Hopper and safety/access simulators disabled. A TX-limit setting is a guardrail, not legal permission.
Observe systems without becoming part of them
The useful skill is not “collect everything”. It is disciplined inference from the minimum lawful data: frequency, bandwidth, timing, location, direction, modulation family and authoritative licence/allocation records.
The eight-step receive workflow
Hard boundaries
Authorised RF bench checklist
For legitimate transmit development: remove the antenna; terminate into a correctly rated 50 Ω dummy load; add fixed attenuation; use a shielded enclosure; monitor leakage with a second receiver; set restrictive TX limits; document authorisation; stop immediately if energy escapes. Some safety/jamming simulations should not be run at all outside a professionally controlled facility.
This is educational guidance, not legal advice. Australian interception and radiocommunications law is fact-specific and changes; consult the current legislation and ACMA for a real project.
Six weeks from waterfall to insight
Tasks are saved only in this browser via localStorage. The sequence deliberately begins with strong public signals before weak-signal, satellite and protocol work.
Turn listening into evidence
A good log separates observation from identification. Entries stay in localStorage on this browser and can be exported as CSV or JSON.
| Time | Frequency | Signal | Mode | Antenna / level | Conditions | Confidence / notes |
|---|
Start with authoritative sources
Links appear on relevant cards throughout the guide. This index groups them for deeper study. Volatile frequencies, software versions and laws should always be rechecked.
Regenerate or extend this guide
The prompt forces current-source verification, Sydney-specific propagation, a complete Mayhem inventory and safety boundaries. Replace the hardware, location or goals as needed.
You are an expert radio-spectrum educator, SDR engineer, Australian radiocommunications researcher, antenna designer and technical web author.
Create a current, evidence-based, receive-first field guide for this exact setup:
• Radio: OpenSourceSDRLab HackRF Pro H4M Pro / PortaPack-style handheld, advertised tuning coverage 100 kHz–6 GHz.
• Location: Sydney, New South Wales, Australia (approximately 33.87° S, 151.21° E).
• Computer: Windows 11 Pro.
• Goals: learn radio from first principles; listen to public and amateur services; investigate propagation; receive aircraft, ship, satellite and weather telemetry; perform lawful civil spectrum intelligence and interference hunting; analyse only my own or explicitly authorised devices; use the current Mayhem firmware safely in standalone mode.
• Date: verify all volatile information at the time you answer and state the verification date.
Use primary or authoritative sources wherever possible: the exact product/vendor documentation; Great Scott Gadgets HackRF documentation as an architectural reference while clearly distinguishing it from the third-party H4M derivative; the official PortaPack Mayhem repository/wiki/releases; ACMA spectrum plans, class licences, Register of Radiocommunications Licences and current legal guidance; the current Federal Register versions of relevant Australian legislation; WIA Australian band plans; Airservices Australia AIP/ERSA; AMSA marine/AIS guidance; Bureau of Meteorology Space Weather Services; NOAA SWPC; current satellite databases such as SatNOGS; SondeHub; and official software repositories.
Research and explain, without assuming that tuning range equals useful sensitivity:
1. Hardware reality
• Clearly separate advertised tuning coverage, instantaneous bandwidth/sample rate, ADC/quantisation, dynamic range, gain stages, clock accuracy, half-duplex behaviour, bias power and USB/storage requirements.
• State which facts are documented for the exact H4M Pro and which come from the official HackRF Pro architecture and therefore need confirmation on this derivative.
• Explain overload, intermodulation, images, aliases, DC artefacts, gain compression and why an urban Sydney receiver often needs attenuation and filters before an LNA.
• Give conservative starter settings and a troubleshooting path.
• Estimate I/Q storage per minute at common sample rates.
2. A comprehensive “what can I receive?” catalogue
Cover practical signal families from 100 kHz to 6 GHz, not merely a list of allocations. Include at least:
• LF/MF beacons and AM broadcast;
• HF broadcasting, time/frequency stations, weather fax, marine/aviation HF, amateur 160/80/40/30/20/17/15/12/10 m, CW, RTTY, FT8/WSPR and propagation beacons;
• Australian 27 MHz CB, 6 m, FM broadcast, VOR, civil airband, ACARS, 137 MHz weather satellites, APRS including Australia and ISS use, 2 m, marine VHF, AIS, DAB+, digital-TV spectrum;
• radiosondes, 406 MHz distress beacons, 433 MHz sensors, 70 cm, Australian UHF CB, wireless microphones, and high-level treatment of P25/DMR/TETRA/paging with strict privacy limits;
• 915–928 MHz Australian low-power devices, ADS-B/Mode S, navigation pulses, GNSS, public L-band satellite/weather downlinks, 1420 MHz hydrogen-line radio astronomy, amateur/CubeSat telemetry;
• BLE advertisements, own-device nRF24 and Wi‑Fi spectrum occupancy, 5.8 GHz analogue FPV on my own equipment, 5 GHz Wi‑Fi spectrum, weather-radar pulse presence, solar radio bursts and local EMI hunting;
• mobile/cellular spectrum occupancy only, with no subscriber/content interception.
For every catalogue entry provide:
• frequency/range and modulation;
• what can realistically be heard or measured in Sydney;
• best local time of day, season or pass/event condition;
• effect of solar flux, Kp/geomagnetic storms, solar radio blackouts, grey line, sporadic-E, meteor scatter and coastal tropospheric ducting as relevant;
• recommended antenna, filtering, LNA/attenuation and feedline;
• Windows software and matching Mayhem receive app;
• difficulty;
• legal/privacy/safety boundary;
• contextual source links.
Do not invent a frequency. Where local assignments or schedules change, point to current ACMA RRL, Airservices, AMSA, SatNOGS or SondeHub instead of copying an old frequency list.
3. Sydney propagation planner
• Use Australia/Sydney local time and calculate approximate sunrise/sunset and grey-line windows.
• Explain day/night band migration on HF.
• Let the reader choose or load current F10.7 solar flux, Kp, NOAA R/G scales and local propagation scenarios.
• Produce “good things to try now” recommendations, but label them as probabilistic rather than guarantees.
• State that VHF/UHF/microwave work is usually line-of-sight and weather/geometry dependent rather than controlled by the solar cycle.
4. Antenna system
• Recommend a staged antenna kit: LF/MF tuned loop; HF receive wire or passive magnetic loop; discone; 2 m/70 cm vertical; 137 MHz QFH/turnstile; 162 MHz AIS vertical; filtered 1090 MHz ADS-B chain; 1.5–1.7 GHz patch/helix/dish; 2.4 and 5.8 GHz patches/panels.
• Include quarter-wave and dipole-length calculators.
• Explain polarisation, antenna height, ground/common-mode control, lightning/static disconnection, bias-power compatibility, low-loss coax above 1 GHz, band-pass/notch filters and when an LNA makes reception worse.
• Include simple original diagrams.
5. Windows 11 software and workflow
• Evaluate current versions/official sources for SDR++, SDRangel, HackRF tools, GNU Radio/Radioconda, SatDump, Gpredict, AIS-catcher, OpenCPN, WSJT-X, fldigi, Universal Radio Hacker, SigMF, sdrtrunk and DAB software.
• Give a safe installation/order-of-use workflow, HackRF Mode steps, driver cautions, audio routing, frequency correction, sample-rate strategy, recording practices and a repeatable method for identifying unknown signals.
• Make clear that protocol analysis is limited to my own or authorised devices.
6. Complete Mayhem standalone application encyclopaedia
• Re-read the current official Mayhem app inventory and include every receiver, transmitter, transceiver, core tool, utility, diagnostic, game, setting and HackRF Mode entry available in that current build.
• For each app give a concise purpose and a status badge:
“receive/public”, “privacy caution”, “legacy/region-limited”, “utility”, “authorised TX”, “shielded lab only”, “do not radiate”, “illegal interference”, or “destructive”.
• Research app-specific limitations such as obsolete NOAA APT live reception, region-specific ERT/SAME/TEDI functions, and external .ppma app/build matching.
• Explain that the exact H4M vendor firmware may use a customised Mayhem base and matching SD app bundle. Compare the vendor-recommended build with the current official stable/nightly release, state the checked date, and provide a backup/recovery/update checklist.
• Do not provide operational instructions, waveform parameters, code sequences or frequency lists that would facilitate jamming, spoofing, access-control bypass, unauthorised replay, safety-system simulation or interference.
• Treat Jammer/Hopper as illegal open-air interference; treat ADS-B, GNSS, VOR, EPIRB, P25-control and similar simulators as conducted, attenuated, shielded laboratory functions only; recommend disabling/removing dangerous transmit apps for normal field use.
7. Lawful civil spectrum-intelligence method
Teach a disciplined workflow:
detect → characterise → compare with authoritative allocation/licence data → record minimal technical metadata → decode only public/own/authorised content → document antenna/time/SNR/solar context → protect personal data → never decrypt, impersonate, replay, jam or interfere.
Distinguish public reception, spectrum-only observation, privacy-sensitive signals, safety-of-life services and licensed transmission.
Link current Australian legislation and ACMA guidance, and say the guide is educational rather than legal advice.
8. Learning tools
• A progressive six-week learning roadmap.
• Searchable/filterable signal catalogue and Mayhem app list.
• Field log stored locally in the browser with CSV/JSON export.
• Source index grouped by topic.
• A copyable version of this prompt.
Output one polished, responsive, accessible HTML file. Embed all CSS, JavaScript and original SVG illustrations directly in the file; do not require a build system. It should open locally in a modern Windows browser. External links are allowed only for contextual authoritative references and optional live space-weather data. Include print styles, keyboard focus states, no tracking, no external fonts and no third-party JavaScript. Use Australian English, exact dates, clear caveats, and a welcoming dark technical visual style.
Safety boundary: receive-first education and defensive RF analysis only. Do not teach private-message interception, encryption defeat, credential extraction, access bypass, cloning/replay against real systems, spoofing, jamming, evasion or harmful transmission.