The following programs need the Matlab Compiler Runtime (MCR) to be installed.
MSRX is a receiver for meteor scatter for use parallel to WSJT.
In contrast to WSJT the confidence of the decoded characters is encoded in the visibility
(bold black for high confidence, light gray for low confidence.
Additionally MSRX also decodes PSK2k.
Therefore you could use FSK441 to reply to a CQ received in PSK2k.
Download MSRX_UserGuide (280 kB)
Download MSRX.zip (4 MB)
MSRX V3 has the new option to simulate meteorscatter signals very near to reality.
An example is here:
Download sim_example_1.wav (320 kB)
MSRX V3.0 decodes it to (which makes the great difference between FSK441 and PSK2k visible):
A further example is the decoding of some recordings at my holiday location in OH0:
Download OH0-Decodings (710 kB)
PSK2k is an advanced digital mode for meteor scatter with secure communication by Error Correcting and Error Detecting Codes.
Auto-Modes for automatic QSO running and automatic reply to received calls are integrated.
This program can operate in parallel to WSJT on the same PC on the same soundcard.
So you decode FSK441 and PSK2k on the frequency in use.
PSK2k can decode very weak signals. Here an example which has two pings at seconds 3 and 8.
After automatic accumulation of both pings the decode is CQ de DJ5HG QTF=rndH period= 15s rx1st *6
Download weakping.wav (100 kB)
Download PSK2k_UserGuide.pdf (460 kB)
Download PSK2k_Documentation.pdf (320 kB)
Some Comments on Reliability and Validity of PSK2k-QSOs
Download PSK2k.zip (6 MB, includes the UserGuide)
SlowPSK and EMEpsk
SlowPSK is an advanced digital mode for weak signal communication below -28 dB.
The program is not quite ready for general use, but running as a test version V0.0 beta.
A special version EMEpsk also was designed.
The new specification and UserGuides are available:
Download SlowPSK_UserGuide.pdf (315 kB)
Download EMEpsk_UserGuide.pdf (60 kB)
Download SlowPSK_Documentation.pdf (170 kB)
HDCW was designed as an RTTY-type mode for use on radio channels with great frequency spreading as in aurora.
Indeed, in case of aurora-signals HDCW is more sensitive than any human CW-operator at the same speed.
If the frequency spreading is as low such that PSK31 decodes, then these coherent digital modes outperform HDCW.
But also on none-spreading channels HDCW may be very useful by two reasons:
(1) it is very robust against QRM, and
(2) it decodes all incoming signals within the usual SSB-bandwidth in parallel.
HDCW has the options FSK and ASK (for aurora).
The characterrate can be chosen in a wide range to adapt to the specific application.
The following example shows the result of a very weak simulated aurora signal (-11 dB).
Here two audio examples:
The sound of HDCW in ASK at 87 characters/minute (normal CW-speed, text sent is 'CQ DJ5HG'):
Download HDCW audioexample1 (131 kB)
The sound of HDCW in FSK at 22 characters/minute for non-spreading channels (text sent is 'DJ5HG'):
Download HDCW audioexample2 (406 kB)
Download HDCW_UserManual.pdf (380 kB)
Download Version 2.2 HDCW.zip (6.4 MB, includes the UserManual)
The record of the simulated aurora signal in ASK at 87 characters/minute with SNR=-11 dB is here:
Download HDCW aurora audioexample -11 dB (650 kB)
The same information is sent at the same speed and the same SNR=-11 dB in CW here via the same aurora.
You surely can identify the signal.
even can dig this signal out of the noise. But reading remains difficult compared to the display of HDCW above:
Download CW aurora audioexample -11 dB (650 kB)
CWP is a CW-comptible digital mode.
It exactly sounds like CW (hear the audio example below).
The only diffenence is that the carrierphase is inverted at every key-down.
The coherent decoder of CWP therefore can much better differentiate between a dash and two dots than this is possible in normal CW.
Signals at SNR = -20 dB (see the figure) can well be decoded.
The CWP-receiver decodes all signals in a bandwidth of 2000 Hz.
The confidence of the decoded characters is encoded in their visibility.
In the following example the receiver finds two additional signals of very low confidence at a level of -28 dB.
There is only a test version of CWP.
It was programmed just for fun.
Digital modes with Forward-Error-Correction (FEC) like JT65 are more sensitive .
Here the sound of CWP:
Download audioexample of CWP (12s)
Download Version 2.0: cwp_n.zip (4.0 MB)
A very simple transmitter for FSK441 as an example of Digital Signal Processing
discussed in CQ-DL Spezial Digital 2011, pp.11-15.
Download FSK441GUI.zip (120 kB)
The complete Matlab source code is not very large. Here it is for inspection:
Download sourcecode of FSK441TX (40 kB)
Papers Concerning Digital Modes
Download the VERON Lecture on Digital Modes, Dwingeloo 2007 (3.3 MB)
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