Proppy

This document describes the operation of the 'Proppy' web application and the capabilities provided to support on-demand predictions for Point-to-Point (P2P) and Area coverage in addition to monitoring conditions in real time.

Proppy comprises the following major elements;

Transparency is a fundamental design goal of the website, and wherever practical, the 'Source Text' toggle buttons may be used to inspect the ITURHFProp input and output files. Where this is not possible, i.e. due to multiple files being required to produce a single output, this document provides sample files.

The site has been developed using the responsive Bootstrap 4 framework for use on both Desktop and Mobile devices.

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 predictions for Signal Noise Ratio (SNR), Basic Circuit Reliability (BCR) and Signal Strength (S-Meter) predictions. In addition, the OPMUF, is displayed on the graph. ITURHFProp also supports the prediction of the Basic MUF (BMUF). The OPMUF is a higher value than the associated BMUF from which it's derived, accounting for propagation mechanisms at frequencies above the BMUF [ITU-R 1240-2] and is usually the preferred characteristic when planning HF links.

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

The main page comprises a map display used to select the transmit site and display the prediction results, a toolbar to control display format and a series of panels to define prediction input parameters. Both single shot predictions and animations over a twenty-four hour period are supported.

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 button is used to initiate the prediction. This button is enabled whenever the input panel settings becomes unsynchronised with the map overlay. A refresh indication is also displayed in the top right corner of the map whenever the map display does not correspond to the input values.

Alternatively, users may cycle through predictions for a twenty-four hour period by clicking the blue play button in the toolbar under the map. The animation may be stopped by clicking the pause button. The step forward/backward buttons will increment/decrement the value of UTC and perform a prediction.

3.2. Saving the Results

The download button below the map is enabled whenever valid data is displayed. Clicking the button open a panel to select image parameters;

Projection

Selects the map projection. Proppy currently supports Equidistant Cylindrical (Plate Carree), Azimuthal Equidistant and Mollweide projections. See Figures 1 to 3.

Scale

A decimal value in the range 1.0 (smallest) to 4.0 (largest) that defines the map's scale. Applies to Azimuthal Equidistant projections only.

LL Lat/Lng, UR Lat/Lng

Specifies the Latitude and Longitude of the Lower Left (LL) and Upper Right (UR) of the map. Applies to Equidistant Cylindrical (Plate Carree) projections only.

Overlay

Specifies the map's appearance. Select from a graphical overlay, a basic mono display or a basic display with colours to identify land and oceans.

Format

Select either .png or .pdf format. PNGs will be displayed in the browser window, PDFs will prompt a download.

The image may also be saved via the browser's print function. Media specific targets in the CSS file hide most of the page's content to reduce clutter, replacing the entry form with a title above the image.

The 'Beacon' page displays the NCDXF/IARU International Beacon Project's scheduled transmissions and performs propagation predictions for the current month between each beacon and a specified receive site. For details of the project, please refer to the 'NCDXF/IARU website

The beacons page provides a real-time view of the beacon's transmissions, as shown in Figure 5.

4.1. Beacon's Propagation Prediction Method

Each beacon comprises a 100W transmitter connected to a vertical (Cushcraft R5) antenna, operating at a forward power of 100W. The input file assumes a net radiated power of 90W (-10.46dBkW) to account for system losses.

Each beacon is assumed to be operating with a Cushcraft R5 antenna, employing a Type 14 antenna model.

Procedure 3. Beacon Predictions

1. Select the required SSN source. [ITU-R P.371-8] states that SSN values used with P.533 are derived from the 'Standard Curves' published by WDC-SILSO, Royal Observatory of Belgium, Brussels. Users may wish to explore the use of other SSN data sets published the WDC-SILSO by making the appropriate selection from the drop-down list, refer to Section 10.1 for further information. If in doubt, the default 'Standard Curves' should be used.

3. Specify the Receive location 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 map marker button () in the Rx. Site's entry panel. This will set the Rx. site to the user's current location (as reported by the browser).

4. Specify the receive antenna gain. The Receive antenna type is assumed to be a isotropic radiator, with a user defined gain (dBi).

Receive Antenna Gain

The main user interface permits the gain of the receive antenna to be defined which may be used to tune the model as a whole, e.g. setting the receive antenna gain to -0.17dBi is equivalent to setting the antenna gain at each end of the link to zero (0dBi).

PathName "Proppy Online HF Circuit Prediction: Beacon"
Path.L_tx.lat 9.083000
Path.L_tx.lng -67.833000
TXAntFilePath "path_to_data_directory/antennas/n14/o-cushcraft_r5.n14"
Path.L_rx.lat 51.482000
Path.L_rx.lng -3.179100
RXAntFilePath "ISOTROPIC"
RXGOS 2.16
Path.year 2018
Path.month  6
Path.hour 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24
Path.SSN 1
Path.frequency 14.100, 18.110, 21.150, 24.930, 28.200
Path.txpower -10.46
Path.BW 500
Path.SNRr 0
Path.SNRXXp 90
Path.ManMadeNoise "RESIDENTIAL"
Path.Modulation "ANALOG"
Path.SorL "SHORTPATH"
RptFileFormat "RPT_PR"
DataFilePath "path_to_data_directory"

The 'Planner' page allows a user to create propagation charts from a nominated transmit site to multiple receive sites on a single sheet, similar to those made available by the ARRL. The results are presented as a pdf download suitable for printing and retaining as a reference. All P2P plots on the chart are for a single Month/Year/SSN Value.

All plots present the Operational MUF (OPMUF) upon which the 'Overlay' selector may be used to specify additional data representing either; Basic Circuit Reliability (BCR), Signal-to-Noise Ratio (SNR) or Signal Strength (S-Units).

After processing, the user is prompted with a dialogue box containing a link to download the completed prediction. Predictions may be saved in .pdf, .png or .svg formats.

On supported browsers, lists of receive sites may be saved in local storage for later recall. This allows users to set up a predefined list of specific sites of interest and return monthly to produce updated predictions.

The RadCom predictions page has been produced in collaboration with the RSGB's Propagation Studies Committee (PSC) and allows users to create tailored versions of RadCom's monthly propagation predictions, reflecting their preferred modes and equipment. Predictions are performed between a user's transmitter site and thirty-two globally distributed DX locations. The results indicate predicted power received (S-Units^[1]) and Basic Circuit Reliability (%).

Transmit location is expressed as a Maidenhead Locator. If no transmitter position is defined, a default value corresponding to the centre of the United Kingdom is used. Locators may be provided in a four or six character format, the 4 character format typically being sufficient for HF circuits.

6.1. Results

Figure 7 shows a table generated by the RadCom prediction, displaying predictions for each hour of the day (00:00-23:00) for each of the amateur bands. Cell content is defined by the Basic Circuit Reliability (BCR), receive signal strength (P_r), the 'Probability of Propagation' (PoP) and man-made noise.

In cases where BCR and PoP are both greater than 10%, the cell's background colour is used to indicate predicted reliability as indicated by the colour map at the top of the tables. In addition, the cell's content indicates P_r (expressed in S-Units). A bold font is used when P_r exceeds the predicted level of man-made noise, a normal font is used otherwise.

In the event that either BCR or PoP are less than 10%, the cell is left blank. Actual values for BCR, PoP and Pr may be seen by hovering above the cell.

Path.L_tx.lat 52.000000
Path.L_tx.lng -2.000000
TXAntFilePath "/path_to_antenna_files/d10m.n14"
Path.L_rx.lat 55.755800
Path.L_rx.lng 37.617300
RXAntFilePath "/path_to_antenna_files/d10m.n14"
Path.year 2019
Path.month 2
Path.hour 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24
Path.SSN 3
Path.frequency 28.85, 24.94, 21.225, 18.118, 14.175, 10.125, 7.1, 5.33, 3.65
Path.txpower -10.00
Path.BW 500.00
Path.SNRr 0.00
Path.SNRXXp 90
Path.ManMadeNoise "RURAL"
Path.SorL "SHORTPATH"
RptFileFormat "RPT_BCR | RPT_PR"
LL.lat 55.755800
LL.lng 37.617300
LR.lat 55.755800
LR.lng 37.617300
UL.lat 55.755800
UL.lng 37.617300
UR.lat 55.755800
UR.lng 37.617300
DataFilePath "path_to_data_directory"

The 'SWL' page may be used to interrogate the current HFCC database of scheduled shortwave transmissions to access programming of interest. The underlying database is made freely available by the HFCC at http://www.hfcc.org/data/.

The main page comprises a map, used for defining the target location, and a 'Search Filters' panel incorporating filters for frequency, time, language and target CIRAF zones. Filters are enabled/disabled using the checkbox at the right-hand side of each entry field.

The Search button is used to initiate the search, displaying the results in a table below the filter panel. The table includes a search facility to further refine the results along with the ability to re-order the results by clicking on the table headers.

Results may be saved to file in either CSV (suitable for importing into Excel) or as a pdf document by selecting the required format at the bottom of the table and clicking the Save Table button.

The sites displayed in the table are also indicated on the map as shown in Figure 8 below;

Clicking on any of the sites in the main map will open a small information window providing additional data and initiate a propagation prediction between the transmitter site and the user received site. Clicking on the sites coordinates in the information window will open a new tab displaying the site's location on Google Maps. Note: Many of the site locations are taken from the site.txt file distributed with the HFCC schedules and are not necessarily precise enough to show the exact location of the site.

7.1. CIRAF Zones

CIRAF zones (`Conferencia Internacional de Radiodifusión por Altas Frecuencias') are used by the ITU to identify target coverage areas as shown in Figure 9 below;

Proppy determines the CIRAF zone by comparing the entered lat/lng values with 911 CIRAF test points defined by the ITU (https://www.itu.int/en/ITU-R/terrestrial/broadcast/HFBC/Pages/Reference.aspx).

7.2. Example Searches

Figure 10 shows a search configured to show all stations active at 10:42UTC on frequencies between 6.190-6.200 (e.g. 6.195MHz±5kHz).

Figure 11 shows a search configured to show all English language transmissions in the 25m band (11.600-12.100MHz) directed to CIRAF Zone 39 (Middle East).

Proppy may also be used as a web services, allowing HTML 'GET' parameters to be used to create images on demand. Only area type plots are currently supported, point-to-point plots are a planned enhancement. The area web service is available at the following URL, to which correctly formatted parameters shall be be appended.

https://soundbytes.asia/proppy/ws/area

A minimal example of a correctly formatted request is;

https://soundbytes.asia/proppy/ws/area?tx=23.1,-82.3&freq=10.26

Plots returned by the web service are in the Portable Network Graphics (PNG) format and may be saved in a browser or indeed called up as part of an image element in a web page.

8.1. Area

The Area Web Service returns area prediction plots in response to HTML requests. Input variable are defined in the URL e.g; The following request parameters were used to create the plot shown in Figure 12;

pwr=100&tx=23.1,-82.3&freq=10.26&ll=-50,-120.45&ur=50,0

The web service accepts the parameters listed below. When multiple parameters are used, the '&' character shall be used as a separator.

Encoding

The '&' symbol is a reserved character and requires encoding prior to sending to the server. Most browsers will perform the required encoding automatically when entering the URL in the address bar. However, client applications may need to explicitly encode the parameter string, . e.g. Python 3 uses the urllib.parse.quote() function to replace ampersand symbols with the corresponding 'percent encoded' equivalent ('%26').

tx

Required. A pair (lat, lng) of float values specifying the coordinates of the transmitter location. Positive values should be used to express North and East directions. Negative values should be used to express South and West.

Example: 'tx=54.23,2.4' specifies a transmitter located at 54.23°N, 2.4°E.

freq

Required. Float value [2.0-30.0] specifying the frequency of operation in MHz.

Example: 'freq=10.265' specifies a frequency of 10.265MHz.

pwr

Optional. Integer value [1-1000000000] specifying the transmitter power in Watts. Defaults to 100W if not specified.

Example: 'pwr=1000' sets the transmitter power to 1000W / 1kW.

bw

Optional. Float value [0.005-3000000.0] specifying the bandwidth of the traffic. See Section 12 for examples of recommended bandwidths. Defaults to 3000 if not specified.

Example: 'bw=500' sets the bandwidth to 500.

snr

Optional. Float value [30.0-200.0] specifying the snr required to support the traffic type. See Section 12 for examples of recommended SNR values. Defaults to 15 if not specified.

Example: 'snr=500' sets the required SNR to 500.

ssn

Optional. Integer value [1-311] specifying the ssn value to be used in the calculations. If no value for ssn is provided, the y and m parameters will be used to define the value from the SIDC Standard Curves dataset.

Example: 'ssn=6' sets the ssn to 6.

y

Optional. Integer value specifying the year for the prediction. Default value: Current year.

The month ('m') and year ('y') parameters are used to define the month for the prediction. If no value for ssn is provided, the m,y parameters will be used to retrieve the correct value of SSN. If ssn is provided, the y value will be used as a label only and have no influence on the calculations. Valid values define a month/year for which SSN values are available. The is generally the period January 2005 through to eleven months from the current date. Valid values are shown in the tables on SSN Data Page.

Example: 'y=2017' sets the year to 2017.

m

Optional. Integer value [1-12] specifying the month for the prediction. Default value: Current month.

Example: 'm=3' sets the month to March.

utc

Optional. Integer value [1-24] specifying the hour (UTC) for the prediction. Default value: Current time (UTC).

Example: 'utc=7' sets the time (UTC) to 07:00.

ll

Optional. A pair (lat, lng) of float values specifying the coordinates of the lower left corner of the plot. Positive values should be used to express North and East directions. Negative values should be used to express South and West. Default:-90,-180 (180°W, 90°S)

Example: 'll=10.25,-120' places the lower left of the plot at 10.25°N, 120°W.

ur

Optional. A pair (lat, lng) of float values specifying the coordinates of the upper right corner of the final plot. Positive values should be used to express North and East directions. Negative values should be used to express South and West. Default:90,180 (180°E, 90°N).

Example: 'ur=50,-60.1' places the upper right of the plot at 10°N, 60.1°W.

ptype

Optional. String value from the set ('bcr', 'snr', 'e'), representing Basic Circuit Reliability, Signal to Noise Ratio and Field Strength respectively. Default: bcr

Example: 'type=snr' specifies the display of Signal to Noise data.

The spaceweather page presents data extracted from the latest Geophiysical Alert Message published by NOAA at http://services.swpc.noaa.gov/text/wwv.txt. Updates to this data are typically published at three hourly intervals from around 00:00UTC.

:Product: Geophysical Alert Message wwv.txt
:Issued: 2017 Sep 09 0910 UTC
# Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center
#
#          Geophysical Alert Message
#
Solar-terrestrial indices for 08 September follow.
Solar flux 117 and estimated planetary A-index 96.
The estimated planetary K-index at 0900 UTC on 09 September was 2.

Space weather for the past 24 hours has been severe.
Geomagnetic storms reaching the G4 level occurred.
Solar radiation storms reaching the S1 level occurred.
Radio blackouts reaching the R1 level occurred.

Space weather for the next 24 hours is predicted to be moderate.
Geomagnetic storms reaching the G1 level are expected.
Solar radiation storms reaching the S1 level are expected.
Radio blackouts reaching the R2 level are expected.

Reports are retrieved every three hours and parsed to extract the data to drive a graphical display, as shown in the following screenshot.

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)).

S-Meter values are commonly used to express received signal strength. Proppy derives S-Meter values from the median available receiver power (P_r dBW) predicted by ITURHFProp^[2]. This value represents the summation of the the powers arising from the different modes, each mode contribution depending on the receiving antenna gain in the direction of incidence of that mode. The median received power levels are converted to S-Meter readings for ease of intelligibility. The conversion to S-Values follows the IARU Region 1 Technical Recommendation R.1, S9 for the HF bands to be a receiver input power of -103 dBW.

Proppy uses values of SNR and bandwidth derived from [ITU-R F.339-8] and [Lane 1997] as follows;

Proppy's calculation pages are offered in the following languages;

Language selection is made via the menu presented at the foot of each page. This will set a cookie ('locale') to preserve the user's language preference between visits.

In the event that a 'locale' cookie is not found, the value of the request header's 'Accept-Language' parameter is used to identify the required language.