Tuesday, February 14, 2023

Have You Worked Any Feld Hell on Radio?

I am sure some of you veteran hams have... but I think today I had my second Feld Hell (Hellschreiber) QSO. See videos below of actual signal and the decoding. I was using Ham Radio Deluxe for the QSO.

Here is some history regarding Feld Hell that I learned after the QSO. My interest was peaked and I thought it would make a good post for our website. The source of the information below was from these two websites.

Introduction To Hellschreiber Modes


"The traditional method of sending Hellschreiber by radio is to key a Morse-type (CW) transmitter ON for every black spot in a text character,and OFF for every white place. Different parts of each character are sent at different times. The technique is still in use by interested Amateurs, communicating world-wide. This mode is now called Feld-Hell (Field-Hell), since the pre-war format still used was originally used for field communications by the German Army. Feld-Hell offered good immunity to interference and provided a clandestine transmission capability, because nothing was transmitted until a key was pressed. Commercial variations of Feld-Hell could still be heard occasionally on HF up until the 1980s, transmitting Chinese and Korean characters."

"Feld-Hell characters are sent as a series of dots at 122.5 pixels/sec, using a CW transmitter, or these days, by sending tones to an SSB transmitter. Black dots are represented by a CW dot (key down), and white spaces by a space as long as one dot (key up). The timing requirements are quite precise, like FAX, but Rudolf Hell developed a simple but clever technique, which involves printing the text twice, which can negate the effects of phase and small timing errors, thus avoiding the need for true synchronism."


Here are videos from my QSO with NV1O Craig in Apache Junction AZ. I will be looking for more FELD HELL signals!



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