[Lowfer] multi mode sdr I/q transmitter for lowfer

[PAUL DAULTON]

Searching for a SDR transmitter suitable for lowfer, I found the HF I/Q
 SDR transmitter DT2
by YU1LM. See http://yu1lm.qrpradio.com/ for schematics and layout for PC
 board. I think there
is a corrected version at the end of the site called DT2A.
This is a transmitter capable of generating all modes via the computer
 sound card. Injection required is 
4x center freq. This could be accomplished with a 74hc4060 and a
 microprocessor xtal. 6.0mhz divided
by 8(750khz) would give a center freq of 187.5 khz. The generated signal
 could be +/- 24 khz of this freq.
Paired with his SDR rec this would make a good tranceiver project or a
 stand alone tx( with computer).
The DT2 is all standard parts, easily built, and  inexpensive. The author
 claims circuit is good from 30khz
to 30mhz.
I want to build the DR2a rec first as a dedicated lowfer rec. Then try the
 tx for multi-modes.
There is much info about SDR rec construction and software but little
 about software for transmitting. Can anyone 
suggest links to software for tx by SDR?
Thanks 
Paul K5wms