Proppy

User Documentation

The Proppy documentation is available for download in pdf format.

Abstract

This document describes the use of the proppy web-application to perform HF Circuit analysis for both Point-to-Point Circuits and Area Coverage. Predictions are performed in accordance with the with ITU Recommendation P.533 (Method for the prediction of the performance of HF circuits) [ITU-R P.533] using the ITURHFPROP application, software method for the prediction of the performance of HF circuits implementing Recommendation ITU-R P.533-13.


Introduction

The Proppy web site is designed to serve as a convenient front end to the ITURHFPROP application; a software method for the prediction of the performance of HF circuits in accordance with Recommendation ITU-R P.533-13.

This document describes the operation of the web application and the procedures required to produce Point-to-Point (P2P) and Area Predictions. The prediction results are graphically presented in the browser. P2P predictions may be presented in either a conventional 2D graphical format or presented as a 3D 'surface' plot facilitating examination of P2P behaviour over time.

Point-to-Point Predictions

The Point-to-Point (P2P) page supports predictions for a specified path for a 24 hour period throughout a given month.

The main page comprises a map display which may be used to select the Transmit and Receive sites. Additional entry fields are provided to specify the input data set. Prediction results are plotted alongside the map.

The P2P page supports Signal Noise Ratio (SNR), Basic Circuit Reliability (BCR) and E-Field Strength predictions. In addition, the Operational Maximum Usable Frequency (OPMUF) is plotted on the graph. The OPMUF is the highest frequency that would permit acceptable performance of a radio circuit by signal propagation via the ionosphere between given terminals at a given time under specified working conditions [ITU-R P.373-9]. This may be compared to the Basic MUF which represents the highest frequency by which a radiowave can propagate between given terminals, on a specified occasion, by ionospheric refraction alone. The OPMUF is consequently (usually) a higher value than the associated BMUF from which it's derived via the application of a correction factor to allow for propagation mechanisms at frequencies above the basic MUF [ITU-R 1240-2]. Absorption effects at lower frequencies mean that communications are generally more efficient at the highest possible frequency supporting the required traffic, i.e. the OPMUF is of most interest when planning HF links.

Procedure 1. Point to Point Predictions

  1. Specify the Transmit location. The Transmit location may be specified using one of the following methods;

    1. Directly from the map by dragging the red map pin to the required location.

    2. Using the Latitude / Longitude entry fields in the Tx. Site Panel.

    3. Using the browser's geolocation support and clicking on the map marker button Tx. Site's entry panel. This will set the Tx. site to the user's current location (reported by the browser).

      Privacy

      Due to privacy concerns, most browsers only support geolocation services when securely connected to a site using https. Geolocation may not be supported when connecting to the site via http.

  2. Specify the Receive location. The Receive location may be specified using one of the following methods;

    1. Directly from the map by dragging the blue map pin to the required location.

    2. Using the Latitude / Longitude entry fields in the Rx. Site Panel.

    3. Using the browser's geolocation support and clicking on the blue geolocation icon in the Rx. Site's entry panel. This will set the Rx. site to the user's current location (reported by the browser).

      Privacy

      Due to privacy concerns, most browsers only support geolocation services when securely connected to a site using https. Geolocation may not be supported when connecting to the site via http.

  3. If required, toggle the Source Text button ON to reveal the raw ITURHFPROP input / output text files which may be useful for debugging purposes. Once displayed, this data may be copied to the system clipboard by clicking the clipboard icon in the Input File and Output File header bars.

  4. Specify the system parameters from the System panel;


    Date

    Specify the month / year for the prediction. Note: The datetimepicker is configured to only permit dates for which SSN values are available.


    Power

    Specify the net power, expressed in Watts delivered to the antenna.


    Traffic

    Specify the traffic type. Bandwidth and required SNR values for this entry field are derived from [ITU-R F.339-8] and [Lane 1997].


    Manmade Noise

    Specifies the level of man-made noise at the receive location.

  5. Specify the Transmit antenna gain using the Tx. Site Antenna Gain entry field. An isotropic antenna is assumed for P2P predictions. The default value of 2.16dBi corresponds to the gain of a dipole over an isotropic radiator.

  6. Specify the Receive antenna gain using the Rx. Site Antenna Gain entry field. An isotropic antenna is assumed for p2p predictions. The default value of 2.16dBi corresponds to the gain of a dipole over an isotropic radiator.

    Antenna Gain

    The current implementation uses the specified gain uniformly for all frequencies in the analysis (2-30MHz). This is likely to be an unrealistic assumption for most practical antenna types.

  7. Click the Run Prediction button to start the prediction procedure. The Run Prediction is enabled whenever the input panel settings become unsyncronised with the plotted results, providing a visual cue that the input data no longer corresponds to the plotted results.

Displaying the Results

The predicted results are displayed on a 2D plot adjacent to the map. The selected data set (SNR, BCR or Field Strength) is displayed on the background of the plot with the Operational Maximum Usable Frequency (OPMUF).

Area Predictions

The Area page provides coverage predictions for a specified transmit site and traffic.

The main page comprises a map display used to select the Transmit site and display the prediction results, a toolbar to select the data displayed and a series of panels to define prediction input parameters.

The map toolbar is used to define the data to display on the map (Basic Circuit Reliability (BCR), Signal to Noise Ratio (SNR) or Signal Strength (S-Units)). The Day/Night button activates the day/night overlay and the Run Prediction is used to initiate the prediction. This button is enabled whenever the input panel settings becomes unsyncronised with the map overlay. A refresh is also displayed in the top right corner of the map whenever the map display does not correspond to the setting in the input panels.

Procedure 2. Area Predictions

  1. Specify the Transmit location. The Transmit location may be specified using one of the following methods;

    1. Directly from the map by dragging the red map pin to the required location.

    2. Using the Latitude / Longitude entry fields in the Tx. Site Panel.

    3. Using the browser's geolocation support and clicking on the blue geolocation icon in the Tx. Site's entry panel. This will set the Tx. site to the user's current location (reported by the browser).

      Privacy

      Due to privacy concerns, most browsers only support geolocation services when securely connected to a site using https. Geolocation may not be supported when connecting to the site via http.

  2. If required, toggle the Source Text button ON to reveal the raw ITURHFPROP input / output text files which may be useful for debugging purposes. Once displayed, this data may be copied to the system clipboard by clicking the clipboard icon in the Input File and Output File header bars.

  3. Select the plot resolution from Low, Medium and High, corresponding to 15°, 10° and 5° respectively.

    High Resolution Images

    Increasing resolution significantly increases processing time. Low resolution plots specify 325 data points at 15° intervals. At High resolution (5° intervals) this increases to 2,701 data points.

  4. Toggle the Day/Night display as required. This input has no effect on the prediction. The displayed day / night regions correspond to the time of the displayed prediction.

  5. Specify the system parameters from the System panel;


    Date / Time

    Specify the month / year for the prediction. The datetimepicker is configured to only permit dates for which SSN values are available.


    Traffic

    Specify the traffic type from the drop down menu of options. The Bandwidth and SNR values in this menu are specified by [ITU-R F.339-8] and [Lane 1997].


    Frequency

    Specify the frequency in MHz of the radiated signal in the range 2 < f < 30.


    Power

    Specify the net power, expressed in Watts at the antenna.


    Manmade Noise

    Specifies the level of man-made noise at the receive location.

  6. Specify the Transmit antenna type using the Tx. Site entry panel.

    1. If an isotropic antenna is specified, an antenna gain may also be defined. The default value of 2.16dBi corresponds to the gain of a dipole over an isotropic radiator

    2. If a specific antenna type is selected, the bearing may also be defined.

  7. Specify the Receive antenna gain using the Rx. Site Antenna Gain entry field. An isotropic antenna is assumed. The default value of 2.16dBi corresponds to the gain of a dipole over an isotropic radiator.

    Antenna Gain

    The current implementation uses the specified gain uniformly for all frequencies in the analysis (2-30MHz). This is likely to be an unrealistic assumption for most practical antenna types.

Displaying the Results

The predicted results are displayed directly onto the map used to indicate the transmit site. When valid results are displayed on the map, the plot selection toolbar, located below the map, is enabled and enables selection of the plot dataset. The day/night display may also be toggled from this menu.

Surface Plots

Surface plots provide a method for exploring P2P predictions over extended periods of time by stacking individual plots on top of each other to provide a 3D view of the data set. The plot.ly library used to create the 3D plot supports dragging and zooming with the mouse, providing an interactive view of the display.

Processing Time

Surface plots are computationally expensive and take longer to process than P2P and Area plot types. Surface plots typically take 10-15 seconds to process.

Procedure 3. Surface Predictions

  1. Specify the Transmit location. Transmit locations may be specified using one of the following methods;

    1. Directly from the map by dragging the red map pin to the required location.

    2. Using the Latitude / Longitude entry fields in the Tx. Site Panel.

    3. Using the browser's geolocation support and clicking on the blue geolocation icon in the Tx. Site's entry panel. This will set the Tx. site to the user's current location (reported by the browser).

      Privacy

      Due to privacy concerns, most browsers will require a secure (i.e. https) connection to the site. Geolocation may not be supported when connecting to the site via http.

  2. Specify the Receive location. Receive locations may be specified using one of the following methods;

    1. Directly from the map by dragging the blue map pin to the required location.

    2. Using the Latitude / Longitude entry fields in the Tx. Site Panel.

    3. Using the browser's geolocation support and clicking on the blue geolocation icon in the Tx. Site's entry panel. This will set the Tx. site to the user's current location (reported by the browser).

      Privacy

      Due to privacy concerns, most browsers will require a secure (i.e. https) connection to the site. Geolocation may not be supported when connecting to the site via http.

  3. Select the plot type (Stacked MUF, Reliability, SNR or Signal Strength) from the dropdown menu. Select the required Depth, i.e. the number of months over which the prediction will be performed.

  4. Specify the system parameters from the System panel;


    Date

    Specify the starting month / year for the prediction.


    Power

    Specify the power, expressed in Watts delivered to the antenna.


    Traffic

    Specify the traffic type. Bandwidth and required SNR values are specified by [ITU-R F.339-8] and [Lane 1997].


    Manmade Noise

    Specifies the level of man-made noise at the receive location.

  5. Specify the Transmit antenna gain using the Tx. Site Antenna Gain entry field. An isotropic antenna is assumed for p2p predictions. The default value of 2.16dBi corresponds to the gain of a dipole over an isotropic radiator.

  6. Specify the Receive antenna gain using the Rx. Site Antenna Gain entry field. An isotropic antenna is assumed for p2p predictions. The default value of 2.16dBi corresponds to the gain of a dipole over an isotropic radiator.

    Antenna Gain

    The current implementation uses the specified gain uniformly for all frequencies in the analysis (2-30MHz). This is likely to be an unrealistic assumption for most practical antenna types.

Sun Spot Numbers (SSNs)

Determination of ionospheric characteristics related to HF propagation requires knowledge of the prevailing levels of solar activity [ITU-R P.1239-3]. The Sunspot Number (SSN), quantifying of the number of dark spots visible on the Sun’s surface, has historically served as the primary proxy of solar activity [Clette et al. 2015]. Records of SSNs date back over 400 years, providing a valuable insight into the sun's quasi periodic 11-year cycle of activity. Superimposed onto this cycle are shorter term variations that can result in large fluctuations in day-to-day values. More recent research suggests that the 11 year cycle is itself modulated by the interaction of two solar dynamos, accounting for the fluctuations in the level of activity observed during each cycle [Zharkova et al., 2015].

The figure below illustrates how daily values (yellow) may be averaged over month (blue) and monthly smoothed (12-month) (red) periods, eliminating complex short term variations to yield a more predictable indicator of solar activity. The preferred ionospheric metric when determining the critical frequencies of the various layers and the MUF factor M(3000)F2 is a 12-month running mean sunspot number, R12 [ITU-R P.1239-3]. R12 values are a function of sunspot values extending at least six months either side of the month of interest [ITU-R P.371-8]. (Note that this has the unfortunate side effect that an R12 value for a given month m cannot be absolutely determined until m+6 (six months later)).

Figure 1: Daily and Monthly Sunspot Number (last 13 years)
Source: WDC-SILSO, Royal Observatory of Belgium, Brussels

SSN Data

In accordance with Recommendation ITU-R P.371-8, the site uses SSN (R12) values presented in the ITU's Circular of Basic Indices for Ionospheric Propagation, derived from SSN data provided by WDC-SILSO, Royal Observatory of Belgium, Brussels. The SSN values used in Proppy are updated at the beginning of each month directly from the source data available at http://sidc.oma.be/silso/INFO/snmstotcsv.php (historical) and http://sidc.oma.be/silso/FORECASTS/prediSC.txt (predicted).

The SSN values used by Proppy are presented at https://soundbytes.asia/proppy/help/ssn. These values extend from 2005 to the latest available prediction date (typically 12 months ahead).

Bibliography

[Clette et al. 2015] Frederic Clette, Leif Svalgaard, Jose Vaquero, and Edward Cliver. 2015. The Solar Activity Cycle. 35-103. Revisiting the sunspot number. https://arxiv.org/pdf/1407.3231.pdf.

[ITU-R P.533] Recommendation P.533-13. July 2015. International Telecommunication Union. Method for the prediction of the performance of HF circuits. https://www.itu.int/rec/R-REC-P.533-13-201507-I/en.

[ITU-R F.339-8] Recommendation F.339-8. February 2013. International Telecommunication Union. Bandwidths, Signal-to-Noise Ratios and Fading Allowances in HF Fixed and Land Mobile Radiocommunication Systems. https://www.itu.int/rec/R-REC-F.339/en.

[ITU-R P.373-9] Recommendation P.373-9. July 2015 2013. International Telecommunication Union. Definitions of maximum and minimum transmission frequencies. https://www.itu.int/rec/R-REC-P.373/en.

[ITU-R P.1239-3] Recommendation P.1239-3. February 2012. International Telecommunication Union. ITU-R reference ionospheric characteristics. https://www.itu.int/rec/R-REC-P.1239/en.

[ITU-R 1240-2] Recommendation P.1240-2. September 2013. International Telecommunication Union. ITU-R methods of basic MUF, operational MUF and ray-path prediction. https://www.itu.int/rec/R-REC-P.1240-2-201507-I/en.

[Lane 1997] George Lane. 1997. Radio Science. 32(5). 2091-2098. Required Signal-to-Interference Ratios for Shortwave Broadcasting. http://onlinelibrary.wiley.com/doi/10.1029/97RS00843/pdf.

[Lane 2005] George Lane. 2005. Ionospheric Effects Symposium, Alexandria VA USA. 3B-4. Improved guidelines for automatic link establishment operations.. http://www.voacap.com/documents/GLane_ALE.pdf.

[Zharkova et al., 2015] V V Zharkova, S J Sheperd, E Popova, and S I Zharkov. 2015. Scientific reports. 5. Heartbeat of the Sun from Principal Component Analysis and prediction of solar activity on a millennium timescale. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4625153/.