Transcript Intro to Hellschreiber

Intro to Hellschreiber
What was Old is made New again…
What is Hellschreiber?
• A method of fax-like teleprinting.
• A “fuzzy” mode which uses the brain
as part of the decoding process.
• A “live” person-to-person QSO mode
• On/Off keyed, PSK or Multitone, it’s
excellent for QRP and Stealth
operating.
What’s all this “Fuzzy” Business???
• For “fuzzy” modes, the human brain is an
integral part of the decoding.
• Morse is a fuzzy mode, as is FAX and
SSTV.
• A Hellschreiber transmission is literally
read off of paper tape or a video screen.
• The brain does pattern recognition and
QRM/N rejection when receiving Hell.
Dr. Hell’s “Clear Writer”
• Invented in 1929.
• Used by news services
worldwide 1930s1960s, SE Asia through
1980s.
• Various military uses
1930s-50s.
• Dutch amateurs began
restoring surplus
machines in the 1970s.
Feld-Hell
• Traditionally, on/off keyed CW or MCW
• 8.162 ms per element, 400 ms/character
• Great in active, post-storm solar condx
Global DX with Feld-Hell
Gary, WB3DSJ < > Felix, DP1POL
U.S.A. - Antarctica
PSK-Hell
• Phase Shift Keyed, cosine shaping
• 105 Hz / 245 Hz bandwidth, very sensitive
• Ionospheric Doppler effect resistant
World’s first PSK-Hell DX QSO, 21 Aug 1999 (10 W)
Courtesy Murray, ZL1BPU
FM-Hell
• Frequency shift keyed; 50 Hz / 123 Hz wide
• Extremely clear text reception, sensitive
• Overcomes pulse, crash noise quite well
MultiTone-Hell
•
•
•
•
First demonstrated in 1937
Works in the frequency domain with 5 to 16 tones
Concurrent MT allows high resolution fonts
Sequential MT superb in noisy band conditions
Hard and Soft
• Any 80286-or-better PC, DOS or
Windows 95, 98, XP
• G3+ Macintosh, OS 8.1+
• Same interface as PSK-31, or
HamComm
• Tape rig’s mic to a
PC
speaker!
Operating
• Tune-up for Feld-Hell is the same as Morse
• Treat other Hell modes just as you would
PSK-31; that is, don’t overdrive the rig (use
min. TX drive), no TX audio compression
• Most N.A. activity is on 20 meters, just
above the PSK-31 area, and below RTTY
• “Narrow” filters can help (as with anything)
• Call CQ, see who’s out there, and have fun!
Acknowledgements
Murray Greenman, ZL1BPU, and the
“Fuzzy Modes” website, provided
invaluable assistance in preparing
this presentation. Thanks, Murray!
And thanks to all of you who attended the
presentation today. We’ll see you in HELL!
73! Dave – K7CCC