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Multipsk 4.38 - Test version 2 - "Extended Message" pseudo-mode to test #Multipsk

Patrick Lindecker
 

Hello to all,

 

I proposed a pseudo-mode called “Extended Message”, in this test version 2:

http://f6cte.free.fr/MULTIPSK_4_38_test_version_2.zip

 

Paste this address in your Internet Explorer or equivalent. Download the file.
Extract the ZIP file and replace the “official” Multipsk.exe and the two chm files (manuals) with this test version. Before, make a copy of the “official” Multipsk.exe, in case of.

You can also simply extract this ZIP file in a test directory (C:\TEST for example) and start Multipsk.exe.

 

Once Multipsk started up, the user clicks on the buttons « RX/TX screen » and then "EM RX/TX" (yellow button in the upper part). The user types his/her message in the first editor on top of the small window, then types the <Enter> key once the message ready to be transmitted.

The answer is waited on the waterfall and so on. Macros can be used.
Note: this function does not need user key.

Frequencies for test

The following frequencies are suggested for the test: 3590, 7042, 10148, 14075, 144620 kHz, in USB.

Quick description of EM

 

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 (minimum Signal to Noise ratio) is -14 dB comparable to Olivia or MFSK16, at 47 wpm max.

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

As soon as an EM is received, Multipsk:

  • displays the message on the waterfall, ,
  • also displays the message on a specific panel ("RX" part).

This identifier is transmitted in 3.7 to 9.9 sec and has a bandwidth of 172 Hz. It is composed of a detection code followed by a sequence of data inside a Reed Solomon frame.

To authorize the reception and transmission of these messages, one must click the "EM RX/TX" button.

It is a free error transmission, i.e in presence of an EM message, there are two solutions:

  • either it is not received because the signal is too weak,
  • or it is received and it is correct, the probability of detection of a wrong EM message due to radio noise being almost nil.

EM specifications (project) are integrated in the ZIP file.

Thanks to post your observations or reports on the group IO.

 

73

Patrick

 

 




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