SkookumLogger Panadapter


If you have a radio with a video output port, you can display that video in a window on your Mac managed by SkookumLogger. You will need a video capture device that converts between the radio video output format and USB. When using the K4 TCP radio type in SkookumLogger, you can view either unadorned video that you configure as you prefer, or allow SkookumLogger to configure the external display, with the benefit that SkookumLogger can then draw overlays on the panadapter display and control the radio with gestures in the display. To enable the later, turn on the Enable K4 Panadapter option in Logging preferences. When you toggle this option, you will also need to disable and re-enable the K4 TCP connection.

A panadapter is a display that shows signal information over a range of frequencies. One type of display is an x-y plot with frequency along the x axis and signal amplitude along the y axis; this is often called a spectrum plot. Another type of display is the waterfall, also with frequency along the x axis, but with time along the y axis and colors associated to signal amplitude. The SkookumLogger Panadapter window displays the K4 EXT window like this:

SkookumLogger extends the usefulness of this display in several ways:


The Panadapter window is resizable with constrained aspect ratio and heights between 270 and 1080 pixels. SkookumLogger sets the waterfall height to 80%, so the y-axis range of the waterfall is about 45 seconds. SkookumLogger sets the waterfall colors to grayscale to improve the clarity of colored graphical overlays.

Known calls from the appropriate Activity table are identified by thin vertical lines at their frequencies, with the calls shown in staircase fashion in the waterfall area. The fonts and colors of the lines and calls are determined by their needed status. You define those fonts and colors in the Logging pane of SkookumLogger preferences. The use of color cues for needed status is the reason that grayscale is more appropriate than “heat map” colors in the waterfall display.

The known calls lines are interrupted near the boundary between the spectrum plot and the waterfall to avoid obscuring the waterfall traces for the most recent few seconds of activity. The K4 A panadapter reference level is displayed tucked in at the left just above the spectrum/waterfall divider, -121dBm in the example (yes, I have a rather poor noise floor).

The blue bar in the spectrum area is located at the main receiver frequency. The width of the bar matches the receive bandwidth. The red line in the spectrum area is located at the transmit frequency. Both of these cursors are drawn by the K4, and correctly account for RIT/XIT states and offset.


The SkookumLogger Panadapter has been tested with an Epiphan Systems HD video grabber, and with Pengo Technology 1080p HDMI to USB Type-C video grabber. Connect the K4 HDMI video output to the grabber input. Connect the output to a USB3 computer input.

Start SkookumLogger. SkookumLogger will discover the video grabber; no configuration is necessary.

You may want to fuss with the WTR CLRS setting for the EXT display in K4 DISPLAY, which seems to affect the dynamic range of the signal amplitude grayscale in the waterfall. Mine is set at 1.5.


Frequency Grab Cursor
Panadapter Control

Window ► Panadapter opens the SkookumLogger Panadapter window. The panadapter provides nearly-instant situation awareness at a glance. Locate the window near your Log window where you can inspect it without turning your head. The window is associated with Radio 1.

Frequency Grab Cursor

Click inside the Panadapter window to make the window active and to show the grab cursor:

The grab cursor is a vertical white line that spans the height of the window. The line follows your mouse as you move left and right within the window, updating the frequency display for the horizontal location of the grab cursor. If the frequency is near a known activity, the call is also drawn above the frequency.

Click to set the radio to the grab cursor frequency and make the Log window/Pounce entry active. If the “Fills QSO entry from nearby activity” option is on in Activities preferences and the grab cursor is near a known activity, the activity information is loaded into the Pounce entry fields. If instead the “Creates activity from QSO entry and clears entry” option is on and the Pounce QSO entry box is not empty, the click creates an activity. Use the first setting when your activity table is filled with many known signals. Use the second setting when you want to add unknown signals to your activity table.

Shift-click to set the radio to the grab cursor frequency and make the Log window/Run entry active. Use this to begin CQing on a new frequency that appears to be clear.

Pandapter Control

The "Pan" items in the Radio 1 menu control the tracking mode, span, and center frequency of the K4 EXT panadapter. Open External Devices ► Panadapters to establish values for the span and center frequency choices. These are discussed in more detail in the Panadapter topic of SkookumLogger Help.