Ham Radio Digital Modes

Software-defined modes that squeeze messages through marginal HF propagation — email over radio, weak-signal text, and packet position reporting.

Winlink

Email over radio. Reaches any address worldwide.

rangeGlobal

bandwidthLow (data only)

costFree (software)

licenseHam

powerMedium

Global radio email system. A Winlink message sent via HF can reach any email address anywhere in the world without internet on the sender's end. Supports VARA HF, VARA FM, and Pactor modes.

Best for: Sending structured messages when local internet is down but HF propagation works

Limits: General class license for HF; requires radio + computer interface (Signalink USB or similar)

winlink.org Winlink Express (Windows)Pat (Linux/Mac)

JS8Call

Weak-signal keyboard messaging. Works 20 dB below the noise floor.

rangeGlobal (HF)

bandwidth~50 bps

costFree

licenseHam

powerMedium

Derived from FT8, designed for store-and-forward text messaging over HF. Can decode signals 20 dB below the noise floor — meaning it works when voice communication is impossible. Supports relay mode for multi-hop messaging.

Best for: Long-distance text when HF propagation is marginal and voice fails

Limits: Slow; requires HF radio and soundcard interface; keyboard-to-keyboard only

js8call.com

APRS

Real-time position and data on VHF packet radio.

rangeRegional (digipeater network)

bandwidth1200 bps

cost$100–300

licenseHam

powerLow

Packet radio system for real-time tactical information: GPS positions, weather data, short messages, object markers (shelters, road closures). Local digipeater networks continue to function even when internet IGates go down.

Best for: GPS position sharing, shelter markers, weather data during disasters

Limits: Short messages only; requires local digipeater infrastructure; 1200 bps is slow

aprs.fi

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