Configuring PskScope


Select the Menu item "Config/Parameters" to open the configuration dialog.





Enter the fully qualified communications port to which the pskmeter is attached.  On windows that would be COM1, COM2 etc.  On Linux use the fully device driver path as in /dev/ttyS0 or /dev/ttyUSB0.

R1    - this is the resistor (R1) value on your Psk Meter for high power (39 k) or the QRP (6.8 k) that is jumper selected.
PskScope computes and displays all power values as RMS for a transmitted IDLE signal.  This allows you to more easily adjust your output power to match an averaging SWR / Power Meter.  If you built your Psk Meter with the supplied resistor values you do not need to change this.  You may have opted for a much lower or higher power range and changed the resistors.  If so, then enter the actual values used.
 
Red - Inter Modulation Distortion (IMD) figure of merit above which the signal and spectrum display turn RED ... this is not desirable.  You will be seen, heard and disliked by all of the other psk operators on the band.

Yellow - IMD figure of merit above which the signal and spectrum display turn YELLOW ... try not to operate in the yellow.  You might be ok under really noisy conditions, but when the band is open and QRN is low your received signals will show the additional sidebands.

When the IMD is below the Yellow threshold your signal displays in GREEN ... nice ... try to keep it there.  You will be proud of your transmitted signal, it will be easier to decode, and give a higher percentage of printable characters.  Most important, you will not be interfering with other psk operators on the band.

TgtP -  The target output power (at idle) when automatic transmitter level conrrol is selected. (recommend 15 QRO)

The Psk Meter asynchronously samples the transmitted waveform.  It takes 64 8-bit samples spaced over the full cycle of the idle waveform when transmitting Psk31.  The data set must be rotated about itself to achieve what looks like a synchronous sample set.  During idle this nearly always produces a perfect sample set.  When characters are being transmitted the data set may or may not be useful for subsequent analysis.  Data set culling is used to insure that only valid sequences are used for analysis.  A valid sequence will have a complete first 1/2 cycle of the waveform available for analysis.  All samples are shown including those that do not qualify as valid for analysis.

Min - number of a/d bits required to declare the data set valid.  Increase this value if you have a large interfering signals on the antenna such as during field day.  A value of 4 insures that the transmitter really is on, but does not degrade any subsequent analysis.  Leave this number alone unless you can see the interference on the display

Filter - Coefficient for a simple first order difference equation used to filter the raw data values:

Vn = (alpha)*Vn-1 + (1-alpha)*Sn

change this to 0 if you do not want any filtering.  I find that 0.8 gives satisfactory results with my Delta II.


Pressing the SAVE button will create a "pskscope.ini" file in the same directory as the executable file.  This file will be read on subsequent program executions.


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