PropView forecasts the minimum and maximum useable frequencies between a transmitter in one specified location and a receiver in another specified location over the course of a specified day. This forecast is driven by settings that you enter on the Conditions, Transmitter, and Receiver panels in PropView's Parameters tab.
Date |
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SFI |
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Avail % |
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Latitude |
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Longitude |
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TakeOff |
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Power |
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Path |
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Latitude |
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Longitude |
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Man-made noise level |
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When the above settings have been specified, click the Predict button. If the Frequency-dependent Settings panel's Enable box is checked and Commander is running, PropView determines your transceiver's current operating frequency and updates the Transmitter panel's Takeoff and Power settings based on the values specified in the Frequency-dependent Settings panel for that band; if the Frequency-dependent Settings panel's Enable box is not checked, or if Commander is not running, then the Transmitter panel's Takeoff and Power settings are not modified. PropView then creates the scripts required to drive IonCap and then initiates IonCap. When IonCap has completed its computation, PropView scans the generated numeric forecast and renders it in a graphic display on its Prediction tab. Because IonCap is a DOS program, its initiation and execution can take several minutes on slower machines running some versions of Windows.
The generated display shows time on its horizontal access, and frequency on its vertical access. A frequency scale labeled in mHz is provided along the right margin, and a wavelength scale labeled in meters is provided along the left axis. Below the time axis, PropView displays two horizontal bars indicating the solar position at the transmitter and receiver locations; in these bars, yellow means "sun is up", black means "sun is down", and grey means "twilight".
The brown Vertical Time Index shows the current UTC time, but can be dragged to any time of day; check the Show Current Time box to make the Vertical Time Index resume tracking the current time.
If the Plot Critical Frequencies box is checked, PropView displays the following frequencies hour-by-hour
the lowest useable frequency (LUF) in black
the 90%-confidence maximum useable frequence (MUF) in blue
the 50%-confidence MUF (in green)
the 10%-confidence MUF (in red)
If the Show Open Bands box is checked, PropView displays horizontal lines for each amateur band for which propagation is possible. The width of each line indicates the likelihood that propagation will occur:
if the band is higher in frequency than the LUF, and lower in frequency than the 90%-confidence MUF, then its associated line is 3 pixels in width
if the band is higher in frequency than the LUF, and higher in frequency than the 90%-confidence MUF, but lower in frequency than the 50%-confidence MUF, then its associated line is 2 pixels in width
if the band is higher in frequency than the LUF, and higher in frequency than the 50%-confidence MUF, but lower in frequency than the 10%-confidence MUF, then its associated line is 1 pixels in width
After generating a
prediction for propagation between two locations, check "Show Critical
Frequencies" and uncheck "Show Open Bands".
The black curve represents the lowest useable frequency (LUF) as a function
of time. Any frequency lower than the black curve will not support
communications due to absorption.
The blue, green, and red curves provide a statistical range for the maximum
useable frequency (MUF) as a function of time. The actual MUF will be at or
above the blue curve with 90% confidence, at or above the green curve with
50% confidence, and at or above the red curve with 10% confidence. Any
frequency above the actual MUF will not support communications, due to
insufficient reflection.
So at any specified time, you can identify which frequencies will likely
support communication between the specified locations: they
are bounded on the low-end by the black curve, and on the high-end by the
statistical range between the blue and red curves. You can use the green
curve as a kind of "expected MUF" curve; if you're an optimist,
you use the red curve for this purpose.
To make it easier to see what ham bands are open when, uncheck the
"Show Critical Frequencies" box and check "Show Open
Bands". Horizontal lines represent ham bands lying between the LUF and
statistical MUF. The thickest lines indicates openings based on the 90%
confidence MUF (the blue curve), and the thinnest lines indicate openings
based on the 10% confidence MUF (the red curve).
If you now check "Show Critical Frequencies", the relationship
between horizontal lines and critical frequency curves should be
apparent.