ac4msite
 
The PSKAM10 mode is PSKAM transmitted at 10 bauds. The speed is about 6 wpm. This mode permits only to chat at slowly speed but down to very weak S/N (-19.5 dB)...it can be used in LF transmissions. The bandwidth is about 40 Hz

The PSKAM31 mode is PSKAM transmitted at 31.25 bauds. The speed is about 20 wpm. This mode permits to chat down to a weak S/N (-14 dB). The bandwidth is about 110 Hz

The interleaved PSKAM50 mode derives from PSK10  mode for the modulation and for AMTOR FEC for the repetition of the characters (time diversity). The speed is 50 bauds but each character is transmitted twice at an interval of five characters (example: A X B Y C A D B). The speed is about 31 wpm. This mode permits to lower appreciably the number of errors due to HF radio conditions (without transmitting random characters). The bandwidth is about 180 Hz. The lowest S/N is -11.5 dB (for a PC at 166 MHz or higher).

Created by : Patrick Lindecker F6CTE (2002/2003)
Description :
Baud rate : 10 (PSKAM10) , 31.25 (PSKAM31), 50 (PSKAM50)
Speed : 6 wpm (PSKAM10), 20 wpm (PSKAM31), 31 wpm (PSKAM50),
Modulation : DBPSK
Reception mode : indifferent (LSB or USB)
Character set : 56 fixed length characters A..Z 0..9 <CR> <SPACE> . , : - = + ? $ ( ) ! / @ % with an error reset character and an idle character (displayed by >). Small characters are transformed in capital characters and special characters as are transformed in standard capital (in the example above: E )
Shape of pulse : for PSKAM10 and PSKAM50: rectangular but the transition between 2 successive different bits is done by a decreasing sine then by an increasing sine (each one during a quarter of period)
for PSKAM31: raised cosine
Bandwidth : about 50 Hz (PSKAM10), 80 Hz (PSKAM31), 260 Hz (PSKAM50),
Demodulation : coherent,
Synchronization : automatic using the signal
Correction code : no
Convolution code : no
Interleaving : no
Repetition : each character is repeated 5 positions later (0.8 s in PSKAM50, 1,28 s in PSKAM31 or 4 s in PSKAM10) between 2 transmissions of the same character) (example: A X B Y C A D B). This time diversity allows the correction of an erroneous character. Its detection is easy due to the particular content of a character (5 space and 3 mark ).
Automatic Frequency Correction : from +/-3 Hz to +/- 10 Hz depending on signal level,
Drift tolerance : 60 Hz/mn for PSKAM31 and PSKAM50 and 40 Hz/mn for PSKAM10 (depending on signal-to-noise ratio)
Pmean/Ppeak : 0.86 for PSKAM10 and 50, 0,79 for PSKAM31
Lowest S/N : -11.5 dB for PSKAM50, -14 dB for PSKAM31 and -19.5 dB for PSKAM10


For all the modes
+Pretty senstive
-Not used hardly ever


Mode Menu
PSK AM 10/31/50
Mode Audio Sample
FFT Window Screenshot
PSKAM
PSKAM
PSKAM
VIDEO OF AN ACTUAL QSO IN PSKAM10,31 and 50 HERE