Forecasting Propagation

Online Help Index

PropView uses the selected forecasting engine and technique to predict band openings between your station and a DX stations over the course of a specified UTC day. This prediction is driven by settings that you enter in the Conditions, Your Station, DX Station, Prediction Direction, and Prediction Path panels on the Parameters tab of PropView's Main window. The resulting prediction is graphically displayed on the Prediction tab of PropView's Main window.

Conditions panel

Date

the day for which a forecast is to be generated, in the format dd-mmm-yyyy

  • double-clicking on this textbox enters the current UTC date

  • if the Show Current Time box is checked, the date will automatically be kept current

SFI the current solar flux index 

SSN

the current smoothed sunspot number 
K-index the geomagnetic K-index 
Avail % the required circuit reliability, expressed as a percentage representing the likelihood that signal quality will be acceptable, in the range of 1 to 99
SNR the required Signal-to-Noise Ratio, expressed in decibels, in the range of -30 to 99
Mode selecting a mode sets the SNR to the Required SNR specified for the mode in the Mode-dependent Settings panel

 

Your Station panel

Latitude

specify the latitude component of your station's location, in standard geographic format

  • an invalid Latitude will be highlighted in red font

  • if DXView is installed, PropView sets this component to your QTH latitude

  • strike the Enter key to update your station's Grid Square

Longitude

specify the longitude component of your station's location, in standard geographic format

  • an invalid Longitude will be highlighted in red font

  • if DXView is installed, PropView sets this component to your QTH longitude

  • strike the Enter key to update your station's Grid Square

Grid Square optionally set your station's Latitude and Longitude by specifying a Grid Square and striking the Enter key
  • an invalid Grid Square will be highlighted in red font
TakeOff your transmit antenna's minimum takeoff angle, in degrees  (disabled when From the DX Station is selected)
Power your transmitter output power, in watts (disabled when From the DX Station is selected)is selected)
Man-made noise level specifies the level of RF noise in your location (disabled when To the DX Station is selected)

 

DX Station panel

Latitude

specify the latitude component of the DX station's location, in standard geographic format

  • an invalid Latitude will be highlighted in red font

  • strike the Enter key to update the DX station's Grid Square

Longitude

specify the longitude component of the DX station's location, in standard geographic format

  • an invalid Longititude will be highlighted in red font

  • strike the Enter key to update the DX station's Grid Square

Grid Square optionally set the DX station's Latitude and Longitude by specifying a Grid Square and striking the Enter key
  • an invalid Grid Square will be highlighted in red font
Track DXView Loc when checked with DXView running, the DX Station's Latitude and Longitude automatically track the selected location in DXView
Power the DX station's output power, in watts (disabled when To the DX Station is selected)
Man-made noise level specifies the level of RF noise at the DX station's location (disabled when From the DX Station is selected)


Prediction Direction panel

Prediction Path panel

Propagation Web Sites panel

You can populate each box in this panel with a URL that provides timely propagation information; clicking a box's Go button directs the specified web browser to display the box's URL.

Solar and Geomagnetic Parameters panel

The buttons on this panel provide access to historical, current, and forecast parameters that influence HF propagation:

History when clicked, directs SpotCollector to display its 31-day history of Solar and Geomagnetic indices
Current when clicked, downloads and displays the report from the Current Solar and Geomagnetic Conditions URL (if accessible) and updates the SFI and K-index
Forecast when clicked, downloads a 31-day forecast for Solar and Geomagnetic indices from the Predicted SFI and A-index URL (if accessible) and displays it graphically

 

Beacon panel

Clicking the Monitor button displays PropView's Beacon Monitor window, which can be used to assess actual propagation by monitoring beacons in the NCDXF/IARU Network.

 

Generating a Propagation Forecast

To determine where and when you can hear a DX station at a particular location,

  1. select the desired Forecasting Engine and technique

  2. set the Prediction Direction to From the DX Station

  3. specify settings on the Main window's Parameters tabs:

  4. Set the Prediction Path panel to Short for a prediction of short path propagation, or to Long for a prediction of long path propagation
  5. Click the Predict button

To instead determine when and where a DX station at a particular location can hear your station, set the Prediction Direction to To the DX Station, specify your station's TakeOff angle and Power in the Your Station panel, and specify the DX station's Man-made RF noise level in the DX Station panel. If the Frequency-dependent Settings panel's Enable box is checked and  Commander is running, PropView will set TakeOff and Power from the Frequency-dependent Settings as a function of your transceiver's current band.

 When you click the Predict button, PropView will create the scripts required to drive the selected forecasting engine, and then direct that engine to generate the prediction. When the forecasting engine has completed its computation, PropView will render the generated numeric forecast graphically on its Main windows Prediction tab. If the selected forecasting engine is IONCAP (a DOS program), execution can take several minutes on slower machines running some versions of Windows. The identity of the engine used to generate a forecast is displayed in upper-left corner of the Main windows Prediction tab, along with the forecast date.

The forecast graphically displayed on the Main window's Prediction tab shows time on its horizontal access, and frequency on its vertical access. A frequency scale labeled in MHz is provided along the left margin, and a wavelength scale labeled in meters is provided along the right axis. If a prediction To the DX Station was generated for a specific band, a magenta ball appears to the right of the primary transceiver's current band, if that band is present in the forecast. Otherwise, if Commander is running, a magenta ball appears to the right of the primary transceiver's current band, if that band is present in the forecast. 

A line of text immediately above the graphical prediction specifies

Below the graphical prediction's time axis, PropView displays two horizontal bars indicating the solar position at your station and at the DX station; in these bars, yellow means "sun is up", black means "sun is down", and grey means "twilight"; to display a Solar Colors  panel that provides a color key for each of these conditions, check the Prediction tab's Show Color Keys box.

The brown Vertical Time Index line 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, and to automatically update the Date.

If the Plot Critical Frequencies box is checked, PropView displays the following frequencies hour-by-hour

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.

For forecasts generated by any forecasting engine's LUF & MUF technique,

For forecasts generated by VOACAP's SNR & Prob technique,

Allowing the mouse cursor to hover over an opening forecast by VOACAP's SNR & Prob technique will display three parameters for the selected time and band:

  1. the predicted Signal-to-Noise Ratio, in decibels

  2. the percentage of days of the month that the Required SNR will be achieved

  3. the predicted number of hops among ionospheric layers

You can generate new short path or long path predictions by clicking the Prediction tab's Predict SP or Predict LP buttons respectively.

 

Interpreting PropView Graphs generated by any Forecasting Engine's LUF & MUF technique

After generating a prediction for propagation between two locations, check the Plot Critical Frequencies box and uncheck the Show Open Bands box.

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. To display a Critical Frequency Colors  panel that provides a color key for each critical frequency color, check
Prediction tab's Show Color Keys box.

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, use the red curve for this purpose.

To make it easier to see what ham bands are open when, uncheck the Plot 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 "Plot Critical Frequencies", the relationship between horizontal lines and critical frequency curves should be apparent.

 

Online Help Index