Topband: Using DSP Software

[Herb Schoenbohm <herbs@vitelcom.net>]

Last week I sent S9SS a .wav file of his booming signal into North 
America on topband.  I tried to put myself in his shoes with the awesome 
QRN level he experiences.  On the tape were periods of very high QRN at 
my end and I wanted to clean up the files that I sent him a bit.  I had 
a 30 free evaluation copy of Cool Edit and began playing around with the 
digital noise reduction features and audio peak and notch features.  I 
was absolutely amazed at what could be done with the signal in noise 
using this over the counter software. I sent Charles two .wav files of 
his signal.  One was in noise without processing and the other sounded 
like he was coming out of a code practice oscillator!  Also I download 
the free version of Virtos  Software ( a German Company) "De-Clicker" 
and "De- Noiser" which can be run with either Cool Edit or Sound Forge 
audio processing software.  (Sound Forge is available on e-Bay for under 
$10 and can be used in the same manner as Cool Edit or Cool Edit Pro.  
Syntillium (Cool Edit) was recently purchased by Adobe so the price has 
increased significantly.) With "De Clicker" key click are gone without 
the roofing and pumping problem my IF NB gives.  The "De Noiser" 
eliminates most random noise such as QRN that it makes me wonder if I am 
listening to 160 meters which always has static crashes at my QTH.

I have not heard any discussion of the feasibility of running two sound 
cards and achieving "real time" processor with using the ham shack 
computer.  Indeed I could record and playback a processed signal  and 
dig the call  out in  less than a half minute. But that time lag would 
not be feasible in a pile up or during contests. 

So you already know my question, right.  Do you know of any audio 
processing software that will do a relative real time presentation?  The 
preliminary tests with the simple stuff that I have are very exciting.  
Additionally I will send you the two 750KB .wav files of Charles so you 
can hear the awesome difference.  Perhaps someone would be willing to 
put them on an amateur web site so I would only need to send out the 
link.  Just let me know.

BTW SGC offers a stand alone post audio amp DSP that was reviewed in QST 
last month.  It did not seem very versatile and the reviewer said "that 
using the noise reduction feature caused the signal to disappear in the 
noise."  My ear does better than that.  Is there a future in considering 
using the shack PC and inexpensive sound processing software to enhance 
weak signal in high static noise reception on top band?

73

Herb Schoenbohm, KV4FZ

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