To Transmit, the output from the LINE OUT socket of the computer is connected to the Mic socket of the radio via an ATTENUATOR. The Attenuator is a must as the line out level from the Computer sound card is way too high to feed directly into the Microphone socket of the Radio
The connections to and from the computer and Radio, together with the Attenuator may be built into a small enclosure. The interface, once built, can be used for most of the common Data programs,
for example :- PSK31, RTTY, SSTV, WSPR.
If required, a small stripboard circuit can be built to switch the Transceiver into Transmit using signals from the Serial port, this can also be incorporated into the interface enclosure.
Another way to switch the Tx is to use the VOX function on the TX.
Click HEREfor simple Attenuator circuit - or
Click HERE to build a complete Data interface
If you do not wish to 'homebrew', there are ready made Interfaces on the market -
Signalink, Rigblaster, Buxcomm "Rascal" etc.
Some Software downloads for Data Modes :-
PSK - Digipan, MultiPSK. RTTY - MMTTY, TrueTTY. SSTV - MMSSTV.
An interesting site for checking propogation - Weak Signal Propogation Reporting - WSPR
If all else fails and you can't transmit for any reason, try this Program CQ100 from QsoNet
Check latest Band Plans as some frequency allocations have changed.