Does anyone know how I can convert the output from a speaker/headphones jack
from a Laptop into a suitable input to the Mic socket of a TS430S? It's for
running SSTV

I have not been able to find anything on the net - probably 'cos I'm asking
the wrong question.

have u actually tried connecting the output of your speaker directly
into the mic input? i bet you a 2n3904 that it would work. you can cut
down the audio output using the volume control applet.

Getting proper, fine control of the volume level might be very
difficult with this approach.

even if you do horribly overdrive the transceiver, you dont have to
sweat because the SSB filter will clean out any out-of-passband
distortion. and sstv does not use any amplitude variations (i am not
aware of the newer SSTV modes) so clipped audio will not be very
different to the remote receiver.

Hmmm. How about intermodulation issues? That might cause a fair big
of gunk even within the audio passband.

as usual, i guess, you should simply plug in the sound card output
into your mic input to see what happens.

i have used my homebrew on PSK31 without any attenuation. it works
pretty well.

How the the signal actually look (and measure) on the far end? How
were the IMD levels, and how far did the PSK31 signal's sidebands
extend?

Even if it "works pretty well", I'd be concerned about shoving audio
distortion products out well away from the signal. This might not be
too much of an issue for SSTV, which is using voice-grade bandwidth,
but I _really_ wouldn't want to do it when working PSK31. One of
PSK31's benefits is its extremely narrow spectrum width, when tuned
properly.

I've seen some really beautiful (narrow and clean) PSK31 signals on
the band. I've also seen 'em with sidebands blasting out in both
directions, across the full width of the spectrum/waterfall display,
as a result of people overdriving their audio inputs or forgetting to
turn off their compressor/processor or driving their RF finals up to
get the last little bit of power out of their TX. When this happens,
the narrow-bandwidth spectum-sharing benefit of PSK31 go right out the
window, and the signal can become harder to copy reliably.

As to the original poster's question: there are a number of commercial
products designed for PC/rig interfacing, and numerous homebrew
circuits as well. The simplest designs simply include a resistive
attenuator (a fixed resistor pair, or an audio-taper potentiometer) to
drop the speaker output level down to mic levels. More complex
designs often include transformer isolation in both the TX and RX
audio paths, to break ground loops and keep RF out of the audio path.

Any interface designed for PSK31 would probably work very well for
SSTV as well. See http://www.qsl.net/wm2u/psk31.html for schematics
of both resistive and transformer-isolated versions.

On the commercial side, the best-known are probably the RigBlaster
(http://www.westmountainradio.com/) and the Rascal / GLX
(http://www.buxcomm.com).

I've used a Rascal (pre-GLX version) quite successfully, to operate
both PSK31 and VHF packet from my Dell laptop.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
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