March 30th 2008
Mode to try: Hellschreiber

Description
===========

Hellschreiber or to give it it's proper name "Feld-Hell" is a fun
mode to try. It is an old invention and credited to Dr Rudolf Hell
in the late 1920's.

It is similar to a FAX transmission but rather than transmitting
a full picture it transmits individul characters as a series of
"columns" each containing 7 dots.

These days there are variants we can use on the amateur bands and
these include FM Hell and PSK Hell. Both are reported to give good
results and depending on conditions may be easier to copy than
regular "Feld-Hell".

If you have never tried Hellschreiber, give it a go and you might
just have a new favorite mode :) 


Specifications
==============

MultiPSK's help pages say this about Feld Hell....

Baud rate:     122.5
Speed:         25 wpm
Modulation:    On-Off keying of an audio tone
Sideband:      Doesn't make any difference but usually USB
Characters:    all ASCII printable characters except small letters,
               carriage return (+ line feed) and error correction 
               character.
Bandwidth:     About 300 Hz,
Pmean/Ppeak:   0.25
Lowest S/N:    -12 dB

Operating guide
===============

Hellschrebier signals are wider than PSK31 and sound very 
distinctive. I have heard people refer to it as the "sound
of chirping crickets".

Tuning is fairly tolerant and not as critical as PSK31 or
MFSK16.

Regular Feld-Hell operates with a very low duty cycle so
you can run the same power level as you would with CW.

FM Hell is a 100% duty cycle mode and PSK Hell is about the
same as PSK31. So when switching to these variants from Feld Hell
you may need to reduce your TX power to avoid excessive stress 
on your rig's finals.

Recommended Frequencies
=======================

Most activity on 30m is around 10.134MHz to 10.137MHz USB dial
frequency. I suggest that this Last Sunday event also follow
these common frequencies. That will still leave room for the PSK31
folks, however if you are careful to avoid QRM then transmitting
above 10.141MHz may also yield QSO's.

Availability
============

Just about every multi-mode program out there has
the Feld Hell mode. Many also have FM, PSK and other variants.

Some recommended Windows software to try:

IZ8BLY      Nino's Excellent Hell Software
MultiPSK    http://f6cte.free.fr/
MixW        http://www.mixw.net/

DM780 at this time doesn't support the Hell modes.

And for Linux, you could try

FLDigi      http://www.w1hkj.com/Fldigi.html

Spotting is encouraged and you can use the spot page at 
http://www.projectsandparts.com/30m/
or the dedicated Hellschreiber spot page at
http://www.projectsandparts.com/hell/
There is a dedicated club to Hellschreiber called the
"Feld-Hell Club" which issues FHC numbers. I am #227.

Sound Sample
============

Click here to listen to a Feld Hell signal (mp3 format)
Click here to listen to an FM mode signal (mp3 format)
And here to listen to a PSK Hell signal (mp3 format)

Nino's (IZ8BLY) website provides some interesting
information on Hellschreiber and links to Murray Greenman's
website which gives a lot of insight and
history into the mode.

CU IN HELL!

73 es GL!
Sholto, KE7HPV
Republic, WA.

Comments or errata to: KE7HPV