Providing the reins of command - in emergencies.
                                               - USAF MARS Mission

THE ARQ MODES (Connected)



Ever since the "handshaking" modes of Packet and Pactor were introduced in the late 1980s there have been efforts made to develop soundcard methods of producing ARQ communications without the need of expensive hardware TNCs. WINMOR stands for Winlink Message Over Radio and is a new transmission protocol by Rich Muething, KN6KB, of the Winlink development team. Unlike Pactor, only a simple computer soundcard to radio interface is required.and it runs as a virtual TNC together with host software such as RMS Express and /V4Chat.

WINMOR is distributed free with the software RMS EXPRESS found at

See the WINMOR Primer for a full discussion of the mode and instructions on setup and configuring. The set up will ask for a Federal Access Code if you use the program for MARS. That code number is 211576. Once all this is accomplished the WINMOR Primer will give you excellent step by step instructions for operation and setup.


DIRECT MODES FEC (Non-Connected)


The modes listed below are all included in the Software listed in the previous link. MixW, Fldigi, DM780 and Multipsk.

OLIVIA Is another MFSK mode that is one of the most robust methods of text keyboarding. It can perform superbly for long distance communications in ionospheric noise conditions where other modes fail. It is possible to communicate worldwide using Olivia with as little as a few watts of transmitter power. Olivia is different from some other types of amateur radio digital keyboarding methods, because it can often be decoded perfectly in the most poor signal-to-noise conditions, even when the human ear cannot discern the presence of the signal, and even when it cannot be easily seen on the conventional waterfall spectrum display. There are different combinations of formats. The variations are in the number of tones and the bandwidth. However The 2 most common formats are: Olivia 500/16 and Olivia 1000/32

MT63 is a DSP based mode for sending keyboard text over paths that experience fading and interference from other signals. It is accomplished by a complex scheme to encode text in a matrix of 64 tones over time and frequency. This overkill method provides a "cushion" of error correction at the receiving end while still providing a 100 WPM rate. The wide bandwidth (1Khz for the standard method and 2 Khz for faster transmission) makes this mode less desirable on crowded ham bands such as 20 meters. A fast PC (166 Mhz. or faster) is needed to use all functions of this mode. Army MARS use this mode for a number of reasons so AF MARS members are encouraged to stay familiar with MT-63 in order to achieve interoperability with our sister systems.