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Author Topic: ICOM & RASCAL  (Read 2317 times)

Posts: 643

« on: September 15, 2004, 06:20:32 PM »

I am setting up my PSK31 again. I'm using a Icom - 728 with the RASACL (sound card)interface. In setting the xmit level, I get a very low power level reading on the RF output meter on the rig. I am running into the accessory connector using the supplied cables.
Regardless will be playing safe rather than sorry and setting RF power at the 25% rating CW.
Any ideas as to the low readings, or did I miss something?



Posts: 299

« Reply #1 on: September 19, 2004, 12:44:03 AM »


A lot of things could cause this so I think a little more info is required for figuring this out.

First, is the Rascal one of the kits or was it pre-built?  There have been numerous QC problems with Rascals and other issues of in correct schematics as well.  Don't know if this is the problem, but you have to keep it in mind when troubleshooting a Rascal soundcard interface.

Second, what software are you using and what digital mode are you testing with?

Third, on the soundcard, are you using the line-out or the speaker output for the transmit signal?  Sometimes the line-out input will be low on gain.

Fourth, what are the volume control's settings (master volume control and wave slider positions) for the specific output?

Last but not least, what version of Windows (you are using Windows, aren’t you?) are you running this on?

Normally for digital modes, when I adjust for a 50% duty cycle (on PSK) I initially set the rig’s power setting at 100%, I don’t worry about the rig’s mic gain (on my Icom the mic gain control does not effect the input on the ACC connector), and the computer’s line-out (the soundcard speaker output is too “hot” for my configuration) and wave output volume at 0.  Connect the rig to dummy load so as not to QRM while setting things up.  On the rig, turn off any compression, set the rig in SSB mode (duh!) and set the meter so you can observe ALC signal levels.  

On PSK, just set the software in transmit mode so you are getting an output carrier.  Increase the master volume control to 75%.  Start increasing the wave volume slider until you start to see ALC indicated on your meter, and then reduce the slider just a bit so NO ALC is observed.  Check you wattage output at this point.  If your output wattage is greater than 50 watts, keep reducing the wave and master volume control together until you are between 30-50 watts.  Recheck to make sure there is no ALC reading on the meter.  At this point you will have a good clean signal (low IMD) and enough watts to work the world on PSK.  On my setup, both the master volume control and wave sliders are at 30% of the scale.

If you do these things and still get no output, I would suspect the Rascal as being bad.  A word of the wise, don’t call Buck at Buxcom for support unless you want to be insulted and belittled.  He has a very bad reputation for terrible product support and never admits he or his products are at fault when a lot are.  Just read some of the reviews of the Rascal on  I have personally experienced his crappy customer service skills and I was so put off I gave away my Rascal and built my own (QST March 2002).

Hope this helps.

-Tim W4TME

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