20 June 2015


18/06/15 10146.0 HB9AK Winlink Mail Server 0700  Winmor-500

The WINMOR (WINlink Message Over Radio) protocol is intended to be used for sending messages and binary data error free over a HF radio link. It is a Selective Repeat Automatic Retry reQuest (SRARQ) protocol where the Information Receiving Station (IRS) acknowledges receipt of the data to the Information Sending Station (ISS). Normally during a connection session the IRS and ISS exchange roles multiple times. The protocol is designed to handle the type conditions normally encountered in amateur radio transmission. WINMOR is not optimized for keyboarding or chat mode applications though this may be possible.

The WINMOR protocol uses basic OFDM (Orthogonal Frequency Division Multiplexing) modulation and a number of modulation modes and error correction schemes to adapt to changing channel conditions.
There is currently 2 operating bandwidths of 500 and 1600 Hz (@ 26 db below peak power output:
  • 500 Hz BW 2 carriers 46.875 Baud 4FSK or 93.75 baud PSK
  • 1600 Hz BW 8 carriers 46.875 Baud 4FSK or 93.75 baud PSK
Pic. 1a - WINMOR-500 data frames
Pic. 1b - 4FSK grid

I recently heard (18 June, Pic. 1) the WINMOR 500 Hz bandwidth mode around 0700z on 10146.0 KHz (center frequency). As said, the 500 Hz bandwidth mode use 3 modes PSK:
- 4PSK TCM, 8PSK TCM, 16PSK TCM  - 2 Carriers at 1406.25 Hz and 1593.75 Hz
and one 4FSK mode:
- 2 groups of 1 of 4 Carriers. (2 carriers active simultaneously)
  Group 1: 1312.5, 1358.375, 1406.25 and 1453.125 Hz
  Group 2: 1546.875, 1593.75, 1640.625 and 1687.5 Hz

A WINMOR frame is composed of a Pilot ("leader" of the frame) and Data. The Pilot is used to enable rapid identification of a transmission, to DSP tune the receiving station accurately, to establish symbol and frame sync and to indicate the frame type:
Data frames:
- Two carrier 8PSK (Pic. 2)
- Two carrier 4FSK (Pic. 3)  
Control frames:
- Connect ReQuest frame: 2 Car 4FSK
- Coded Control Frame: 2 Car 4FSK (Pic. 3,4,5)
- Ack: 2 Car 4FSK FEC (Pic. 4)

- ID frame: 2 Car 4FSK (Pic. 5)

Pic.2 - 16QAM data frame
Pic.3 - 4FSK data frame and control frames

Pic. 4 - control frame and ACK frame
Pic. 5 - control frame and ID frame

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