All,
I've been studying Hellschreiber screenshots to estimate
multipath delay. Delayed echoes via the ionosphere show up
in the pixels that make up the vertical part of each Hell
mode character i.e., letters appear as though they were
printed twice with one slightly above the other. The
location of the secondary print depends on how long the
delay is.
It's my understanding that each vertical axis pixel takes
4ms to print, so a delayed echo of the same duration should
cause an additional pixel to appear just above the last one
at the top of the character. An 8ms delay would print 2
pixel spaces above and so on.
Audio editors should be able to reveal multipath echoe delay
times with greater accuracy. Recorded Hell mode signals can
be played back and observed visually to find characters that
show multipath characteristics. The time difference between
the main signal pulse and the delayed pulse can then be
measured in ms.
I understand the basic concept of how Hellschreiber works,
but my interpretation of all this could throw-off everything
I've just said ; )
Comments welcome...
Tony -K2MO
PS: Screenshots of any Hell mode QSO's that exhibit
multipath characteristic, especially NVIS contacts, would be
appreciated.
