I was thinking of this aspect as well, for SMT Hell modesl. Most
stations do not transvert, so soundcard output gives a problem.
The parallel port is difficult, though not impossible, to utilise in
this way through Windoze so I cam to the conclusion that the serial port
is once again the optimum route. It may mean constructing a bit of
hardware, but this need only be along the lines of a shift register/
latch and possibly a D/A converter to drive a varicap across a crystal.
Alternatively, one of the many serial D/A converters around now could
probably be driven directly from the serial port if this has its lines
toggled in a non-standard way to match the serial format needed by the
D/A - this may give Windoze software authors a headache but it can be
done.
The best route of course is just to use the serial port to control a DDS
- and HF-Instruments has now supplied around 100 suitable DDS modules.
Andy G4JNT
-----Original Message-----
From: Alberto di Bene [mailto:[email protected]]
Sent: 2001-03-07 09:40
To: [email protected]
Subject: LF: RE: Transcontinental modes - what next?
Hi all,
which would you all prefer as a way to
frequency-shift your TX ?
With frequency shift I mean many steps, separated by a
fraction of an Hertz.
The first two possibilities that come to my mind are an audio
output from the
sound card (requiring then a mixer to bring the tone to the
wanted freq.),
or a binary value output from, say, the parallel port, which
then would require
a small external board with a DDS or a microcontroller to
drive the TX.
No linearity requirements will be needed. I need your input
to not start in a
false direction. TNX for any advices.
73 Alberto I2PHD
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