New release of MULTIPSK (4.38) ("Extended Message" pseudo-mode and AERO) #Multipsk

Patrick Lindecker

New release of MULTIPSK (4.38)


Pour les francophones: la version en français de ce message se trouve sur mon site ( Il suffit de cliquer sur le lien "Principales modifications (courriel avertissant de la sortie de la nouvelle version)".

Hello to all Ham and SWL,


The new release of MultiPSK (4.38) is on my Web site (
The mirror site is Earl's, N8KBR:

The MD5 signature of the downloaded MULTIPSK_setup.exe file to, possibly, check (with WinMD5 for example), that the downloading works without error, is equal to: da63f8a4e0ab1bddd40e4f70b1d76e40

Multipsk associated to Clock are freeware programs but with functions submitted to a licence (by user key).


The main improvement of MULTIPSK 4.38 is the following:


"Extended Message" pseudo-mode

The EM (Extended Message) is a “pseudo-mode” because it can be used  in parallel of any mode (BPSK31...).

Its main use is to give the possibility to have simultaneous QSO (at standard speed) with different Hams, as messages are displayed on the waterfall. So everyone can see these messages and possibly answer.


This system can be used for a small meeting. The number of participants is limited only by the bandwidth.


The sensitivity is -14 dB comparable to Olivia or MFSK16, at 47 wpm. It is a free error transmission.

Example of an EM « CQ » message displayed on the waterfall.

To authorize the reception and transmission of these messages, one must click the "EM RX/TX" yellow button (in the left top part).

See general specifications below.


Other improvement:

·                     Experimental decoding of AERO 1200 bauds transmissions (R and T channels) in C band (3600 to 3629 MHz). These C band 1200 bauds transmissions (from planes to ground stations) are similar to the L band 1200 transmissions. However these are "burst" and not continuous transmissions. The decoding is proposed but has not been checked due to the difficulty to receive these transmissions.


Note about translation of Multipsk.exe and Clock .exe:  the 4.37 version of Multipsk has been translated to Spanish by Joachin (EA4ZB), from French.



"EM" description:


Baud rate: 10.766

Speed : 47 wpm maximum

Characters set: part of the ASCII (CHR(32) to CHR(95))

Modulation : 16MFSK (4 bits per symbol)

Bandwidth : 172 Hz.

Bit synchronization : automatic using the signal

Data synchronization : thanks to a detection code of 9 symbols transmitted before the Reed Solomon frame. It authorizes one symbol in error.

Correction code: Reed Solomon 63-47 of variable length (so possibly shortened) and containing a maximum of 47x6=282 data bits

Convolution code: no

Interleaving : no

Scrambling: no

Lowest S/N: -14 dB

Reception mode: sensible to the side (USB or LSB), USB is recommended.


For more details, EM specifications are given here:







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