New releases of MULTIPSK (4.39) and Clock (1.11.8) - LMS6 #Multipsk

Patrick Lindecker

New release of MULTIPSK (4.39)


Hello to all Ham and SWL,


The new releases of Clock 1.11.8 and MultiPSK (4.39) are 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: f067765e48c16a056f90003861798aea

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


Clock 1.11.8  fixes a bug about the BBC day of week decoding.


The main improvements of MULTIPSK 4.39 are the following:


403 MHz LMS6 radiosondes decoding (experimental)


The LMS6 radiosonde is in service since about 2010. It equips the weather balloons used in meteorology (mainly in USA+Pacific), on the UHF frequencies around 403 MHz. It is a small box of 250 g, equiped with sensors, a GPS receiver (for its position) and a transmitter for data transmission. It is possible to monitor these radiosondes up to a range of 600 km, according to the reception equipment, whereas the weather balloons can travel up to 300 km, in general.


See for more information.


For Hams and SWL, the LMS6 signal can be received:

·                     either from the discriminator output of a classical UHF FM receiver via a direct connection to the PC sound card. However, the receiver must have a large reception bandwidth due to the high modulation speed,

·                     or with a SdR receiver (FunCube Dongle, RTL SDR,...) and directly demodulated by Multipsk. It is the most simple solution.


Note: Multipsk decodes the radiosonde position but not the telemetry (temperature, pressure etc).


This mode is available for licencied copies, only (otherwise, the decoding is stopped after 5 minutes).


See general specifications further on.


Transmission of positions in real time


For several modes receiving positions (APRS, EPRIB, 1382, BIIS and all radiosonde modes), if the "GPS" button is pushed, all the received positions are transmitted, via a $GPGLL or $GPGGA NMEA GPS frame, to any cartography application able to manage GPS frames in real time (as Google Earth). The user must first select a serial port (physical or virtual) in the "Serial port for GPS" menu, on the Configuration screen.

For an application on the same PC, it will be necessary to install a virtual serial link (with the "Com0com" program for example). A serial port will be configured on Multipsk and the other will be scanned by the cartography application.



Note about translation of Multipsk.exe and Clock .exe:  the 4.38.2 version of Multipsk has been translated to Spanish by Joachin (EA4ZB), from French.






Description of the LMS6 mode

Baud rate: 4800 symbols/second.


Modulation : GFSK ("Gaussian Frequency Shift Frequency").


Reception mode: FM


Bandwidth : about 5 KHz


Demodulation : not coherent


Synchronization for bits: automatic using the signal


Detection code: yes on a header of 48 bits


Interleaving : no


Scrambling: no


Each LMS6 frame is composed of 4800 bits but only 608 bits are useful for the geographical data. Data is integrated in a convolutional code and a Reed-Solomon code but Multipsk does not take profit of them by lack of details. The decoding is basic, without correction.

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