[SMCARA] RTTY

[Clarke, Tom AIR4.0P NATOPS]

Bill,

Make sure in your email options you do not have the "Sign" block checked.  Some sites will reject signed messages.  That happens to me on SMCARA when I send from here at work.

Just a quick note on RTTY.  RTTY consists of two frequencies or tones, a Mark and a Space and they have to be in the correct order.  In true FSK, the carrier is shifted up and down to produce the Mark and Space.  When using SSB, the M & S signals are produced by sending a discrete audio tone to the transmitter.  A single tone will then produce a carrier and the other tone will produce the shifted carrier.  To decode or be decoded, you must have the correct order, called Mark High or Mark Low.  We can change those by either changing the software to reverse the tones or by selecting USB or LSB.  Lots of combinations there to get wrong!  In other modes (PSK, etc.) either it doesn't matter or the software automatically compensates for the inversion.

Tom

Tom Clarke
P-3/C-130 Program Support, PEO(A)
USN/USMC National Airworthiness Office
Naval Air Systems Command, AIR-4.0P
(301) 995-3793/DSN 995-3793
Fax: (301) 342-3276
Cell (301) 904-2053
frederic.clarke at navy.mil

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