>>>AA6YQ comments below.
-----Original Message-----
From: digitalradio@yahoogroups.com [mailto:digitalra...@yahoogroups.com]on
Behalf Of AC TALBOT
Sent: Tuesday, August 03, 2010 5:46 AM
To: digitalradio@yahoogroups.com
Subject: [digitalradio] Direct RTTY Generation
A back-to-basics question for once...
Is there any modern RTTY datacomms software that gives a single wire digital
output for driving an FSK transmitter? Looked in the MultiPSK and MMTTY
setup menus and nothing.
>>>MMTTY provides this "FSK signal" via the TxD pin of the serial port
specified in the "PTT & FSK" panel on the "Setup MMTTY" window's "TX" tab.
Since using this signal requires a serial port capable of 45 baud operation,
which some USB-to-serial-port-adaptors can't do, you can set the "PTT & FSK"
panel's port selector to EXTFSK, which displays a window that lets you
configure the generation of an FSK signal on a serial port's RTS or DTR
pins. In this latter configuration, the timing of the FSK signal is
software-generated, and thus less accurate than that generated by a 45 baud
serial port.
>>>Digital mode applications that use MMTTY as their "RTTY Engine" --
WinWarbler, HamScope, etc. -- thus offer this capability.
While I realise there may be little call for such a one-wire drive now
>>>Not true! Modern transceivers provide RX filtering for RTTY that is only
availalble when the transceiver is operated in RTTY mode, thus requiring the
"FSK signal" when transmitting. Icom's ic-7200, ic-7600, ic-7700, and
ic-7800 all provide a very nice twin-peak filter that is only available in
RTTY mode.
73,
Dave, AA6YQ
