skywave

For KiwiSDR owners

If skywavehf.com shows up in your Kiwi’s user list, someone is listening to your receiver through skywave, a free web app that plays public KiwiSDRs. Thank you for running it. This page says what skywave does on your receiver, the limits it keeps to, and how to keep it off.

What it does on your Kiwi

  • Each skywave listener takes one channel, the same as a listener on your Kiwi’s own page. The waterfall and the band scan ride on that channel; they never open a second one.
  • It asks for raw I/Q (about 12 kHz wide) and does the demodulation on skywave’s own server. I/Q is never compressed, so a skywave listener uses more of your upload than one on your Kiwi’s page: roughly 0.4–0.65 Mbit/s, depending on your Kiwi’s sample rate.
  • The connection comes from skywave’s server, not the listener’s browser, so your Kiwi sees the server’s address rather than the listener’s.

The limits it keeps to

  • One skywave listener per receiver at a time. A crowd can’t fill your channels: the next skywave listener is sent to another receiver.
  • Sessions end after an hour, and skywave as a whole holds only a small, fixed number of listeners at once.
  • Your API setting is respected. If you allow no connections from apps other than your Kiwi’s own page (ext_api 0 in the public list), skywave leaves your receiver out of its list and map, and your Kiwi turns it away if someone types your address.
  • A refusal is taken at its word. When your Kiwi says it’s full, needs a password or takes no apps, skywave’s automatic picker leaves it alone for 15 minutes.
  • Band scans are shared. A finished scan of your receiver is kept for 10 minutes for everyone listening there, and one listener can ask for a new one at most every 30 seconds.

Keeping skywave off your receiver

Either works:

  • Tell us. Open an opt-out request with your receiver’s address (a free GitHub account is needed). It goes on a blocklist that both hides your receiver and stops skywave’s server from connecting to it, whoever asks.
  • Change your Kiwi. Set the number of connections allowed from non-Kiwi apps to 0. That turns away skywave and every other app straight away, without waiting on us.

More

skywave is open source: github.com/thehashrocket/skywave. Questions, problems or ideas are welcome as issues.

Back to skywave