Recorded radio exchanges

Winlink mail, in both directions

Selected examples show successful mail sends and receives using hfmodem. Play the recording, follow the waterfall and exchange timeline, or select a packet to inspect its signal and decoded bytes. Enable Listen to hear the audio.

A single data-loss incident cost the project significant development work and logbook material. Among the losses were the high-speed VARA receive recording and the original rig receive recordings for these ARDOP sessions. These examples use the recordings and session records that survived.

The VARA send reaches high speed. The retained VARA receive recording is speed-limited L4. The PACTOR-3 receive example reaches SL3. The ARDOP send used local 4FSK.200.50S data in a 200 Hz session; peer 4PSK.200.100 data is decoded in both ARDOP recordings. The ARDOP recordings show low-rate operation.

Open the curated static logbook →

The ARDOP recordings come from remote KiwiSDR witnesses. The WW2MI message reached its destination, but our subsequent receive parser failed: three offered messages were not fetched, and END was not confirmed. W6IDS delivered three messages and closed the link normally.

Original completed-message records establish mail direction and completion. Destination receipts establish delivery where explicitly stated; gateway acceptance and destination delivery are separate evidence. Remote gateways are interoperating stations, not demonstrations of native hfmodem at both ends.

Recordings and packet replay may have different coverage. A local monitor tap shows our audio, not reception at the peer; a remote witness shows what its receiver heard. Sender colors use the verified local transmit schedule. Read the implementation evidence for broader results and limits.