A Digital HF Mode By N4UFP Marc Tarplee Tweaks by K7AGE
Randy Hall K7AGE Pacificon 2012 k7age@k7age.com
I was first licensed in 1968 I’ve been around video since high school Built a TV camera as high school electronics project Worked on remote TV broadcast as cameraman and engineer Worked at college TV studios Work for broadcast equipment manufacturers Belden/Miranda/NVISION and Grass Valley Group First Youtube video in August 2006, now over 6 years 76 videos Over 2.2 million views 6400+ subscribers My WHAT THE HELL video has over 83,000 views 4
“ Typenbildfernschreiber ” that is: a character ‐ image tele printer (writer) named after its inventor, Rudolf Hell Wikipedia provides further background for the use of the term “HELL” "Hellschreiber" translates into English as "Light Writer," "Bright Writer," or "Clear Writer," and is a pun on the name of its inventor (Rudolf Hell) Hell (the adjective) is German for "light," the adverb is "bright." 5
Developed By Dr. Rudolf Hell of Germany Dr. Rudolf Hell (1901 ‐ 2002) was one of the most important German inventors of all time. E.g., with Prof. Dieckmann he invented the Photoelectric Image Scanning Tube (TV camera tube, patented in 1925); Electronically controlled "Klischograph" half ‐ tone photo ‐ engraver in 1951 First practical fax machine in 1956, Color scanner in 1963 Computerized CRT type ‐ setter in 1965, and many technical processes. 6
What is Hellschreiber? A simple fax mode No ‐ decoding, you do the the decoding Developed back in the late 20s Uses by German military along with Enigma during WWII Used into the 80s by news wire services Intelligible communications over poor circuits Feld Hell, for Field Hell Today, another one of the many digital modes Free software Uses typical PSK ‐ 31 sound card interface 7
Developed as an alternative to the teletype machines Less moving parts Less sensitive to synchronizing Simpler radio interface Intelligible communications over poor circuits We will see examples as we go along 8
Can you count the number of parts? Complex to maintain Let’s watch it run….. 9
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A lot less parts 11
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Does not send data Does not send text, as data Does not synchronize sender and printer It does send pixels, one at a time 13
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one ring for each character of the Hell-font the pixel bit-sequence is wrapped into a ring the rings are combined into a cylinder - the “ character drum ” The character-drum is the character-set “font” memory 15
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Motor pulls the paper tape Motor turns the cork screw print head Audio decoded to trigger a solenoid at each pixel The solenoid hits from below the paper opposite the print head for each pixel Printed! 17
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Feld ‐ Hell PSK ‐ 31 RTTY 122.5 Bd 31.5 Bd 45.45 Bd telegraphy signaling rate * 35 WPM 50 WPM 60 WPM necessary bandwidth 367.5 Hz 62.5 Hz 270 Hz duty ‐ cycle 6 ‐ 39% 80 ‐ 100% 100% error correction or no no no data redundancy large (60+ pix/char) no no Useable with CW Xmtr? yes no no (On ‐ Off ‐ Keying) Requires very stable no yes no TX/RX freq? Very comfortable typing speed. 19
Feld ‐ Hell (raised ‐ cosine) PSK ‐ 31 RTTY (45.45 Bd, 170 Hz shift) PSK31: normal modulation 20
Able to read weak signals, they just get faint 21
There is no synchronization between sender and printer Phase differences causes the text to print at a slant Two lines, means YOU can always read the text 22
Today, like some many other modes Implemented in the computer with Sound card Software Easy to get on the air. Look at the software 23
Windows Simple 2004 Free http://anoninoporcino.xoom.it 24
Windows Mac Linux All in one program Switch easliy between PSK, Hell, and other modes Free www.w1hkj.com 25
Windows Do All Program You may be using this now Switch easily between PSK, Hell, and other modes Free to $$s www.hrdsoftwarellc.com 26
IZ6HPJ, Bronzi Luca 27
HF radio USB mode Computer with software Sound card interfaced to radio If you are on PSK ‐ 31 you are set to go Find the activity A challenge But …….. 28
Feld Hell Club Monthly Sprint Contests Simple fun time Nov 17 Turkey Shoot 16:00 ‐ 18:00 UTC Lots of stations, short time for the contest Get on and have fun, easy Free to join and get your Feld Hell number Google Feld Hell Club for website Frequencies 29
160 METERS 1.804 80 METERS 3.574 to 3.584 40 METERS 7.077 to 7.084 30 METERS 10.137 10.144 (Region I) Below the PSK 20 METERS 14.063 (PREFERRED), 14.073 (Note 1) waterfall! 17 METERS 18.104 15 METERS 21.074 12 METERS 24.924 10 METERS 28.074 6 METERS 50.286 Note 1: For 20 meter ops, the FHC calling frequency is 14.063 and UP to 14.069. PSK31 ops are on 14.070 and the QRP club uses 14.060 as their calling frequency. We do not wish to cause interference to each other. A reminder, QRP is a power reference, not a mode. If using 14.073, be sure to avoid interference with the JT65 area at 14.076. Even though some may encroach on our segment, we need to be be the good guys! Hellschreiber is a Fuzzy Mode, classified as J2B. As such Hellschreiber may be transmitted on CW or phone amateur radio frequencies. The list above is a starting point for your activities. The club expects that operators will operate with the high ideals of Ham Radio in mind, and be vigilant against 30 QRMing our fellow hams.
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Easy Try a new mode Learn something new Interesting to watch text printing If you are on PSK ‐ 31 Get the free software and try it out Join in a simple short contest Lots of activity FUN With a 80 year old mode brought up to date 32
k7age@k7age.com Thanks to N4SPP Frank Dörenberg Very in depth Hellschreiber website www. hellschreiber .com Lots of data, graphics, animation, and text Your thoughts and questions? 33
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