Traduction anglaise.
Hell 80 is a Hellschreiber mode. The Hellschreiber modes FELD HELL, PSK HELL, FM HELL and HELL 80 are graphical modes where characters are drawn and the interpretation done by the user. For FELD HELL, the transmission is done by On-Off keying (OOK) as in CW, by BPSK for PSK HELL and by AFSK in HELL 80 and FM HELL (MSK in fact).
This mode is included into the software MULTIPSK by Patrick F6CTE, there is the description of this mode and its variants as well as the specifications coming from his software :
Click on the copy of the screen in order to
listen to the corresponding audio
signal.
Creator : Siemens company in the 1960's
Description :
Baud rate : 315 (one pixel is 3.175 ms long)
Reading direction : column by column, from down to up and from left to right,
Matrix : height: 9 pixels et width: 7 pixels…so a total of 63 pixels per character. For each character, 2 lines and 2 columns are reserved for the frame.
Speed : 50 wpm (5 characters by second)
Modulation : FSK two tones with a shift between tones of 300 Hz. Normally, the white is at 1625 Hz and the black at 1925 Hz.
Receive mode : USB
Character set : all ASCII printable characters except small letters, carriage return (+ line feed) and error reset character. The used font derived from the one used for FELD HELL,
Shape of pulse : rectangular
Bandwidth : about 800 Hz (due to rectangular shape),
Synchronization : no need, each column is displayed vertically 2 times (but transmitted once)
Pmean/Ppeak : 1
Lowest S/N : - 4 dB
Note 1 : a start-stop mode also exists in the original system (not described here and not emulated by Multipsk).
Note 2 : it is added a "DX" and a "Super DX" sub-mods (provided also for FELD HELL and PSKHELL).
Additive F6CTE specification : when no character has to be transmitted, the power is reduced by a factor 9, this to keep the trace of the frequency associated to the white color, so as to signal that the transmission is still in progress.
Note: pieces of information about Hellschreiber modes can be found on the WEB site of ZL1BPU (Murray Greenman). Pascal F1ULT make a french translation of ZL1BPU's site on http://f1ult.free.fr.
Recommanded frequencies for HELL 80 (USB)
Valid also for FELD HELL, PSK HELL and FM HELL .
3580, 7035, 10135, 14063, 21063 and 28063 KHz