🐸 Ribbit Header Codec

Compact message header encoding/decoding system for amateur radio data transmission.
Watch data flow from human-readable → binary → bytes → binary → human-readable

Header Structure (128+ bits):

Callsign - 48 bits [8 chars × 6 bits alphanumbit]
Timestamp - 31 bits [Year/Month(10) + Day(5) + Hour(5) + Minute(6) + Second(5)]
Gridsquare - 28 bits [Letters(5+5) + Numbers(4+4) + Letters(5+5)]
Emergency - 1 bit (boolean flag)
NTP - 1 bit (boolean flag)
GPS - 1 bit (boolean flag)
Name Length - 8 bits [FirstName 4 bits + LastName 4 bits]
Message Length - 8 bits (0-240 bytes)
Message Type - 2 bits (0-3)
FirstName - Variable (0-75 bits, 5 bits per char, max 15)
LastName - Variable (0-75 bits, 5 bits per char, max 15)
Message - Variable (0-1920 bits, UTF-8 encoded)
ACK - Variable (acknowledgement array)

📤 Step 1: Encoding

Encode Human-Readable Data → Binary

Callsign

Ham Radio Callsign (up to 8 chars)

Callsign (48 bits):
000000000000000000000000000000000000000000000000

Timestamp (UTC)

Year (2026-2111)

Month (0=Jan, 11=Dec)

Year+Month (10 bits): 0000000000

Day (0-30)

Day (5 bits): 00000

Hour (0-23)

Hour (5 bits): 00000

Minute (0-59)

Minute (6 bits): 000000

Second (0-29, 2s intervals)

Second (5 bits): 00000

Timestamp Combined (31 bits):
0000000000000000000000000000000

Emergency Flag

Emergency Mode Active

Emergency (1 bit): 0

Message ID Complete (80 bits):
Callsign (48) + Timestamp (31) + Emergency (1) = Unique Message Identifier

Gridsquare

Maidenhead Locator (6 chars: AA00aa)

Gridsquare (28 bits):
0000000000000000000000000000

Meta Flags

NTP Time Sync

NTP (1 bit): 0

GPS Location Active

GPS (1 bit): 0

Lengths and Type

First Name Length (0-15 chars)

First Name Length (4 bits): 0000

Last Name Length (0-15 chars)

Last Name Length (4 bits): 0000

Combined Name Length (8 bits):
00000000

Message Length (0-240 bytes)

Message Length (8 bits): 00000000

Message Type (0-3)

Message Type (2 bits): 01

Name

First Name (up to 15 letters)

First Name (0-75 bits):

Last Name (up to 15 letters)

Last Name (0-75 bits):

Message

Message (UTF-8, up to 240 bytes)

Message (0-1920 bits):

✅ Complete Encoded Bitstream

00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001

Total bits: 128 bits | Message ID: 80 bits

⬇ TRANSMISSION ⬇

📡 Step 2: Byte Conversion

Prepare for Transmission (Variable Length)

The header bitstream is padded to the nearest byte boundary for transmission. Minimum: 16 bytes (128 bits, no padding needed).

Byte Array:
[0b00000000]

Byte count: 16 bytes

⬇ RECEPTION ⬇

📥 Step 3: Decoding

Decode Binary → Human-Readable Data

Recompose Bitstream from Bytes

Extract Fragments

Callsign (48 bits): 000000000000000000000000000000000000000000000000

Timestamp (31 bits): 0000000000000000000000000000000

Emergency (1 bit): 0

Message ID Complete (80 bits)

Gridsquare (28 bits): 0000000000000000000000000000

NTP (1 bit): 0

GPS (1 bit): 0

Name Length (8 bits): 00000000

Message Length (8 bits): 00000000

Message Type (2 bits): 01

First Name (variable):

Last Name (variable):

Message (variable):

🐸 Ribbit Header Codec

Encode Human-Readable Data → Binary

Callsign

Timestamp (UTC)

Emergency Flag

Gridsquare

Meta Flags

Lengths and Type

Name

Message

✅ Complete Encoded Bitstream

Prepare for Transmission (Variable Length)

Decode Binary → Human-Readable Data

Recompose Bitstream from Bytes

Extract Fragments

✅ Decoded Values

Callsign: --------

Timestamp: 2026-01-01 00:00:00

Emergency: false

Message ID (80 bits): Callsign + Timestamp + Emergency

Gridsquare: ------

NTP: false

GPS: false

First Name Length: 0

Last Name Length: 0

Message Length: 0

Message Type: 1 - Chat

First Name:

Last Name:

Message: