This page transmits. Holding the control, or holding
space, asks the adapter for the RF path. You are on air only when
the band says ON AIR — that comes from the adapter, not from the
fact that you are holding the key. Releasing stops. So does losing focus,
switching tabs, or closing the page.
Your callsign is required. It is your identity in the room, and
it is the name the roster and every refusal will use. Two browsers on
the same identity collide: the SFU evicts one, and the survivor can come
back without its subscription, with no error shown anywhere.
connection: -
identity: -
idle
Your microphone is live. Everyone in the room hears you whenever
you speak, and you hear them. There is no RF on this server, so there
is no push-to-talk.
-
What you are publishing to the room, measured on your own captured
audio before anything downstream touches it. It is the same
signal the RF leg gets, but not the same numbers: the adapter
resamples to 8 kHz and low-passes at 3.8 kHz on the way to USRP.
Peak hold and the clipped count do not reset — they are there so
a single loud moment is still visible after it has passed.
Everyone here hears everyone.
RF hears one station at a time.
A second operator talking during someone else's transmission is
audible to browsers and inaudible to RF, with no error anywhere.
The reaching RF column below says, per person, which side of that
they are on — and their own page says the same thing about them, because
a non-holder has no other way to learn that the radio cannot hear them.
participants
none yet
SELF-TEST MODE. Nothing is wrong. This page was opened with
?selftest, which holds the audio-recovery control open so it
can be clicked deliberately. The red banner below is shown on purpose.
AUDIO IS BLOCKED. You will hear nothing until you click below.
Audio IS arriving. You cannot hear it. This is the browser blocking
playback, not a problem with the net.
playback enabled.If you hear nothing from here on, rx and level will not tell you why.
The likeliest cause on a desktop browser is a muted tab or a muted system,
and no web API can detect it.
Every line above can be green and you can still hear nothing.
If this tab is muted, or this site's sound is blocked, or the system volume
is down, or audio is going to another device, then rx still climbs,
level still reads real energy, play still says AUDIBLE, and
nothing on this page changes. Confirmed on Chrome 152 / macOS, 2026-09-03.
No web API exposes it. Check the tab's speaker icon, this site's
Sound setting, the system volume, and the selected output device.
What this page can and cannot know.
It never paints from its own key state. Every state below the
control is derived from the adapter's slot, rf,
ptt_granted and ptt_refused broadcasts. A page
that turns red on key-down is asserting something it does not know, and
a refused operator would then talk confidently into nothing.
A refusal can never name the RF station. Nothing identifying
crosses the USRP hop — talkgroup 0, no callsign field — so
Refused: RF is transmitting is as specific as it can get.
That is a property of the bridge, not a gap to be filled later.
The RF indicator clears before the door opens. The adapter clears
the display on a 200 ms silence inference and holds the refusal until a
terminator arrives or a 5 s bound expires. So a refusal can arrive while
the RF band has already gone. That divergence is designed, and the
refusal says how long is left.