- - Repeater -
-- - | -|
- keyboard - | -- c - , - Enter - ⇧ Shift - | -
- gamepad - | -- - - | -
- - | -- - | -||
- keyboard - | -- . - x - | -- keyboard - | -- / - z - | -
- gamepad - | -- - LB - | -- gamepad - | -- - RB - | -
- Second mouse button: Dah - | -
- - | -- - | -
- - Check (CK) round-trip times and audio functionality - by sending "CK" to the repeater and playing the returned signal. - - |
-
- - Fetch a fortune and play it locally. - This can help practice copying (hearing) Morse code, - without having to involve another person. - - |
-
Alphabet
-E . | -I .. | -S ... | -H .... | -4 ....- | -
V ...- | -3 ...-- | -|||
U ..- | -F ..-. | -|||
- | 2 ..--- | -|||
A .- | -R .-. | -L .-.. | -||
- | ||||
W .-- | -P .--. | -|||
J .--- | -1 .---- | -|||
T - | -N -. | -D -.. | -B -... | -6 -.... | -
X -..- | -||||
K -.- | -C -.-. | -|||
Y -.-- | -||||
M -- | -G --. | -Z --.. | -7 --... | -|
Q --.- | -||||
O --- | -- | 8 ---.. | -||
- | 9 ----. | -
- 0 ----- - 1 .---- - 2 ..--- - 3 ...-- - 4 ....- - 5 ..... - 6 -.... - 7 --... - 8 ---.. - 9 ----. -
- Over .-. - Correction ........ - ? / Say Again ..--.. -
Knobs
-- Dit length (iambic): - ms - -
-- Recieve delay: - ms - -
--
- Suggested receive delay: - | -- ms - | -
- Average round-trip time: - | -- ms - | -
- Longest recent transmission: - | -- ms - | -
- Your clock is off by: - | -- ms - | -
Vail
-- This is a CW repeater, - named after Alfred Vail, - who may or may not have invented what's called "Morse code", - but clearly had some role in it. -
- -- Just like a radio repeater, - anybody can connect and start transmitting stuff, - and this will broadcast it to everyone connected. -
- -Why Does This Exist?
- -- I need a place to practice CW with actual human beings, - and I want it to be as close as possible to what I'd experience on a radio. - Also, I don't want to make people buy a bunch of radio hardware. - Nothing else like this exists on the Internet, as far as I can tell. -
-How It Works
-- The Internet isn't exactly like radio waves: - it still goes at near the speed of light, - but there are multiple hops between endpoints, - which buffer up transmissions, and multiplex them onto a single uplink connection. - These repeaters (routers) - are also allowed to just drop things if they need to. - It's the responsibility of the communicating parties - to work out whether something needs to be retransmitted. - Because of this, - there's no telling how long it will take for a transmission to get to a destination. -
- -- Each Vail transmission (packet) consists of: -
- --
-
- timestamp (milliseconds since 1 Jan 1970, 00:00:00 in Reykjavík) -
- transmission duration (milliseconds) -
- The repeater does nothing but broadcast everything it gets - to every connected Vail client, - including the one that sent the packet. - When your client gets back the exact same thing it sent, - it compares the current time to the time in the packet. - This is the round-trip time: - the time it takes for a packet to get from your computer to the repeater and back. -
- -- When the client gets a packet it didn't send, - it adds the receive delay to the timestamp, - and schedules to play the tones and silences in the packet - at that time. -
- -- By adding the maximum round-trip time to the longest recent transmission - (the length of a dah, hopefully), - your client can make a guess about how much time needs to be added to a received timestamp, - in order to have it play back in the future at the time it comes in. - This is just a guess. - If you're communicating with somebody with a higher round-trip time than you have, - you'll need to raise your receive delay to account for it. -
-Why do I hear a low tone?
-- This is the "drop tone", and will be accompanied by an error. -
- -- This means the packet arrived so late, it can't be played in time. - In technical terms: the timestamp of the packet plus the receive delay - is less than the current time. - It can't be scheduled to play, because we can't go back in time. -
- -- This could be happening for three reasons: -
- --
-
- You (the person hearing the drop tone) need a larger receive delay -
- The receiving computer's clock is in the future (running fast) -
- The sending computer's clock is in the past (running slow) -
- Make sure your clock is synced with an Internet time server. - Accurate time is very important to how Vail works. -
-How can I help?
--
-
- Improve the source code -
- Email me and let me know you're using it -
- Neale Pickett kd7oqi -
- -