HzDrop

Ready

Send

0 bytes · —

Use this updated page on both devices. Auto speed + repair uses both microphones and speakers for larger transfers.

Receive

While listening, this device can reply through its speaker to help repair missing packets.

Received text appears here

Text or file

Signal & packet details

Spectrum

Audio inactive
02 kHz4 kHz6 kHz8 kHz

Microphone input while listening; generated signal while sending. The chart runs only while this panel is open.

Sending Ready

No payload selected.

Transfers are saved packet by packet, limited by available browser storage. Large transfers include SHA-256 in the final data packet. Text appears as it arrives; a red receiver border indicates a failed integrity check.

Lossless · used only when faster. Both devices need this version.

Receiving Not listening

Waiting for a valid packet header. All profiles are detected automatically.

No packet yet—

Data appears as it arrives. A red border means SHA-256 verification failed. Resend the whole transfer if needed.

Profiles

Fast uses DQPSK for close range. Balanced uses DBPSK and a longer echo guard. Resilient adds triple repetition and stronger correction. The new compact framing needs testing on your devices.

How it works

Both devices must use this version. Chirps identify a profile; a five-byte header carries packet length and flags with CRC-16 protection. Packed OFDM symbols carry the payload, CRC-32 and Reed–Solomon correction. Short packets use proportionally less parity.

Lossless raw DEFLATE is used only when it shortens estimated airtime. Small compressed messages fit in standalone packets. Larger transfers are saved incrementally and include a SHA-256 digest inside their final data packet. Browser storage limits transfer size.

Auto speed + repair applies to multi-packet transfers after compression. Start listening on the receiver first. Both devices need a speaker and microphone: a probe selects the initial profile, then small acknowledgements request only missing packets. Standalone messages and transfers with Auto disabled broadcast without replies.

Text appears as it arrives, with a preview of the first 64KB. Download the full transfer for the complete content. A red border means verification failed; interrupted transfers remain unverified. If the repair limit is reached, move devices closer and resend.

Microphone
Not opened
Input level
—
Screen lock
Inactive

Keep both devices close and their pages visible.