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<h1 style="text-align: center;">Hell Modes</h1><div style="text-align: center;"><div style="text-align: left;"><div style="text-align: center;"><br>
<div style="text-align: left;"><p>
All Hellschreiber modes are based on character scanning, reproducing characters in a similar way to a dot-matrix
printer. This technique uses a digital transmission, yet allows the received result to be interpreted by eye, a similar
concept to the reception of Morse by ear. The character is scanned upwards, then left to right. There are typically 14 pixels
(transmitted dot elements) per column (although single pixels are never transmitted) and up to seven columns per character
including inter-character space.</p>
<p>
These remarkably simple modes are easy to use, easy to tune, and
although not especially sensitive, are entirely
suited to HF/VHF since they use no sync and the eye can discern the
text even in high levels of noise. fldigi can operate in the
following Hellschreiber modes:</p><table style="background-color: rgb(238, 238, 255); text-align: left; margin-left: auto; margin-right: auto;" border="1"><tbody><tr bgcolor="#eeffff"><td><b>Mode</b></td>
<td><b>Symbol Rate</b></td>
<td><b>Typing Speed</b></td>
<td><b>Duty Cycle</b></td>
<td><b>Bandwidth</b></td>
</tr>
<tr>
<td>Feld-Hell</td>
<td>122.5 baud</td>
<td>~ 2.5 cps (25 wpm)</td>
<td>~ 22%</td>
<td>350 Hz</td>
</tr><tr>
<td>Slow Hell</td>
<td>14 baud</td>
<td>~ 0.28 cps (2.8 wpm)</td>
<td>~ 22%</td>
<td>40 Hz</td>
</tr><tr>
<td>Feld-Hell X5</td>
<td>612.5 baud</td>
<td>~ 12.5 cps (125 wpm)</td>
<td>~ 22%</td>
<td>1750 Hz</td>
</tr><tr>
<td>Feld-Hell X9</td>
<td>1102.5 baud</td>
<td>~ 22.5 cps (225 wpm)</td>
<td>~ 22%</td>
<td>3150 Hz</td>
</tr><tr>
<td>FSK-Hell</td>
<td>245 baud</td>
<td>~ 2.5 cps (25 wpm)</td>
<td>~ 80%</td>
<td>490 Hz</td>
</tr><tr>
<td>FSK-Hell 105</td>
<td>105 baud</td>
<td>~ 2.5 cps (25 wpm)</td>
<td>~ 80%</td>
<td>210 Hz</td>
</tr><tr>
<td>Hell 80</td>
<td>245 baud</td>
<td>~ 5.0 cps (50 wpm)</td>
<td>100%</td>
<td>800 Hz</td>
</tr></tbody></table><p>Feld-Hell seems to be the most commonly used
and use can usually be found on 80 and 40 meters at the high end of the
digital sub bands. All of the Hellschreiber modes are described
in detail with both waterfall and sound clips in the <a href="Modes/index.htm">Sight and Sounds</a> section. Feld-Hell look like this when being received by fldigi:</p><table style="text-align: left; width: 100%;" border="0" cellpadding="2" cellspacing="2"><tbody><tr><td><img style="width: 269px; height: 317px; float: left;" alt="" src="images/feld-hell.png" hspace="5" vspace="5"></td><td style="vertical-align: top;">Feld-Hell, Slow Hell, Feld-Hell X5, and Feld-Hell X9 are all pulse
modes. Extreme linearity is required in the transmit path in order to
control the bandwidth of the transmitted signal. Feld-Hell X5,
Feld-Hell X9 and Hell 80 should probably not be used on HF in the US.
They can be used on VHF and UHF.<br><br></td></tr></tbody></table><p></p></div>
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