diff --git a/static/devel.html b/static/devel.html new file mode 100644 index 0000000..34b8339 --- /dev/null +++ b/static/devel.html @@ -0,0 +1,549 @@ + + + + Vail + + + + + + + + + + + + + + + + +
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+ + Vail + +
+ + +
+
+ +
+ Repeaters + +
+ Local Practice + +
+ +
+ +
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+ +
+ +
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+
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+ + volume_off +
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+

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+ + + + + + + + + + + + + + + + +
+

+
+ +
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+ Straight Key + Iambic + Tools +
+
+ + + + + + + + + + + + +
+ +
+ keyboard + + c + , + Enter +
+ gamepad + + Bottom button + Right button +
+
+
+ + + + + + + + + + + + + + + + + + + + +
+ + + +
+ keyboard + + . + x + + keyboard + + / + z +
+ gamepad + + Left Button + LB + + gamepad + + Top Button + RB +
+ Second mouse button: Dah +
+
+
+
+ +

+ Send CK (check) to the repeater, and play when it comes back. +

+
+
+
+ +
+
+
+ +
+
+

Notes

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+ +
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+ +
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+

Alphabet

+
+
+
+ Dichotomous Key + List +
+
+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
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 ----.
+
+
+ A .- + B -... + C -.-. + D -.. + E . + F ..-. + G --. + H .... + I .. + J .--- + K -.- + L .-.. + M -- + N -. + O --- + P .--. + Q --.- + R .-. + S ... + T - + U ..- + V ...- + W .-- + X -..- + Y -.-- + Z --.. +
+ 0 ----- + 1 .---- + 2 ..--- + 3 ...-- + 4 ....- + 5 ..... + 6 -.... + 7 --... + 8 ---.. + 9 ----. +
+ End of transmission .-.-. + Over -.- + Correction ........ + ? / Say Again ..--.. + Speak Slower --.- .-. ... +
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+ +
+
+

Knobs

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+

+ Dit length (iambic): + ms + +

+

+ Receive delay: + ms + +

+
+ + + + + + + + + + + + + + + + + + + +
+ Suggested receive delay: + + 0ms +
+ Average round-trip time: + + 0ms +
+ Longest recent transmission: + + 0ms +
+ Your clock is off by: + + ??ms +
+
+
+ +
+
+

Documentation

+
+
+
+ About + FAQ + Geek Stuff +
+
+

+ 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 needed a place to practice CW with actual human beings, + and I wanted it to be as close as possible to what I'd experience on a radio. + I also didn't have a lot of money to spend on equipment, but I did have a computer, phone, and gamepad. + Nothing else like this exists on the Internet, as far as I can tell. +

+ +

What does "local" mean next to the repeater name?

+

+ It means this repeater doesn't repeat anything: + nothing you key in will be sent anywhere. + These are to help people practice and learn, + without worrying about anyone else hearing them fumble around. +

+ +

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: +

+
    +
  1. You (the person hearing the drop tone) need a larger receive delay
    2. +
  2. The receiving computer's clock is in the future (running fast)
    3. +
  3. The sending computer's clock is in the past (running slow)
    4. +
+

+ Vail attempts to correct for clock differences, + but making sure your computer has correct time, + down to the millisecond, + can help with reliability. +

+ +

How can I help?

+
    +
  • Improve the source code
    • +
  • Email me and let me know you're using it
    • +
  • Vail costs me 50¢ a year to run: you could buy me a cup of coffee every 5 years or so to offset the expense
    • +
+ +

Who made this?

+

+ Neale Pickett kd7oqi +

+
+ + +
+

+ 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. +

+
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+ +
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+ + + diff --git a/static/vail.css b/static/vail.css index 44675f4..d7b6ecd 100644 --- a/static/vail.css +++ b/static/vail.css @@ -82,6 +82,12 @@ code { padding: 0.1em; } +textarea.notes { + width: 100%; + min-height: 10em; + font-family: sans-serif; +} + img { max-width: 20em; }