New release of MULTIPSK (4.45) - PSKR modes #Multipsk

Andrew OBrien

Very useful additions 

Andy K3UK

Patrick Lindecker

New release of MULTIPSK (4.45)


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 releases of MultiPSK (4.45) and Clock (1.11.10) are on my Web site (
The mirror site is Earl's, W8BR:

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:


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


Clock 1.11.10  fixes a bug about the BBC week number decoding.


The main improvement of MULTIPSK 4.45 is the following:


PSK125R/250R/500R modes coding/decoding


The "R" means "Robust", this because the modulation is the PSKxyzF one, at which it is added an interleaving.
The PSKR modes (initially created on the Fldigi program) are fast, robust and sensitive.

The advised frequencies are 1838, 3570, 7070, 14070, 18101, 21070 and 28120 kHz.


These modes are in freeware, so without time limitation.

See general specifications below.


Other improvements:

·                     new POCSAG.TXT file for correspondences "Address - Name" managed by the user.

Note that, for the ones who want to connect the SDRUno program to Multipsk (in SdR demodulation) through I/Q signals , Fred wrote this guide:


Note about translation of Multipsk.exe and Clock .exe:  the 4.44.1 version of Multipsk has been translated to Spanish by Joachin (EB4Z), from French.



PSK125R/250R/500R modes description

Created by: John Phelps (KL4YFD) in 2013 on Fldigi


Baud rate : 125 for PSK125R, 250 for PSK250R, 500 for PSK500R

Speed : 84 wpm (average) for PSK125R, 168 wpm for PSK250R, 336 wpm for PSK500R

Modulation : DBPSK

Reception mode: indifferent (LSB or USB)

Character set : ASCII characters + almost all ANSI extended characters + a backspace character ("Varicode" characters)

Shape of pulse : raised cosine 

Bandwidth : about 260 Hz for PSK125R, 500 Hz for PSK250R, 1000 Hz for PSK500R

Synchronization: automatic using the signal

Correction code: no

Convolution code: R(Rate)=1/2, K (Constraint length)=7 with Viterbi type decoder, both coder outputs being sent successively,

Interleaving : on 82 bits with 40 diagonal interleavers in series, on a square elementary matrix 2x2 for PSK125R, on 162 bits with 80 interleavers for PSK125R,on 322 bits with 160 interleavers for PSK500R

Drift tolerance : 2 Hz/sec (depending on signal-to-noise ratio) for PSK125R, 4 Hz/s Hz for PSK250R, 8 Hz/s for PSK500R

Pmean/Ppeak: 0.79

Lowest S/N: - 9 dB for PSK125R, - 6 dB for PSK250R, - 3 dB for PSK500R