HF-START Web Tool Instruction Manual

Before using “HF-START Web Tool”, please check your browser setting to enable Javascript and Window-popup.
Our website support the following web browsers. MacOS Safari, Microsoft Edge, Mozilla Firefox, Google Chrome.

In this web tool for HF radio propagation, user can input parameter by themselves and check the results based on the inputs.

1. Calculation input window

Please input/select parameters for the simulation.

  1. Turn on the Ham radio mode if you like. The Ham radio mode is off by default.
  2. Select 3D electron density option.
  3. Choose date and time.
  4. Set transmitter point.
  5. Set tansmission angle, frequency or wavelength, and receiver point and click "Set ray path".
  6. Click "Run HF-START" to run the simulation.
    If the distance between the radio wave transmission / reception points is long, the calculation process may take several minutes.

2. Calculation result window

When the calculation is done, the result window will automatically pop up.
*If popup window is restricted, please change the setting to allow popup.

“Side view” and “Top view” images can be opened in larger size by clicking these images.

“Propagation information” can be scrolled.

3. Detailed information

3-a. 3D electron density option

There are 3 options: “GNSS tomography” or “GAIA model” or “IRI model”.
*“GNSS tomography” is a default option.

3-b. Target date and time (UTC)

You can set date and time (UTC) for calculation.
*The most recent date and time, which can be used in calculation, are set as default values. You can also click the “Latest” button to make sure that it is the most recent time for calculation. Date and time can be inputted freely in available data range.

3-c. Transmitting point for calculation

You can set transmitting point into fields.
*“Lon : 139.5,  Lat : 35.7” are set as default transmitting longitude and latitude. 
You can enter the transmitting point by numerical input of longitude and latitude or by selecting from major cities in Japan and the world. You can switch the format with the button at the top of the input field. **Selectable transmitting point differs between “GNSS tomography” and “GAIA model” and “IRI model” as shown in following table.

  GNSS tomography GAIA model IRI model
Tx lon [degree E] 128 to 147 -180 to 180 -180 to 180
Tx lat [degree N] 30 to 46 -90 to 90 -90 to 90

3-d. Transmission information and receiver point for calculation

You can set Transmission information and receiver point into fields, and these can be registered up to 10 sets by clicking “Set ray path” for the 1st set and “Add ray path” for the 2nd to the 10th set. Registered set can be removed by clicking “X” mark.
Depending on the ON/OFF of the Ham radio mode, you can input it differently as written below. At each mode, it is also possible to input with multiple formats by selecting the preferred option at the top of each input field.

[When Ham radio mode is OFF]

When you open the web tool, “Zenith: 30”, “Frequency: 6.055”, ”Rx lon: 130.6”, “Rx lat: 31.2” are set as default.

[When Ham radio mode is ON] When you open the web tool, “Launch angle: 60”, “Freq. band / Wavelength: 3.5MHz / 80m”, ”Hokkaido (@Sapporo)” are set as default.

**The available range for “GNSS tomography” ,“GAIA model” and “IRI model” are shown in following table.

GNSS tomography GAIA model IRI model
Zenith angle [degree] 0 to 79.9 0 to 79.9 0 to 79.9
Elevation angle [degree] 10.1 to 90 10.1 to 90 10.1 to 90
Launch angle [degree] 10.1 to 90 10.1 to 90 10.1 to 90
Frequency [MHz] 3 to 30 3 to 30 3 to 30
Wavelength [m] 10 to 100 10 to 100 10 to 100
Rx lon [degree E] 128 to 147 -180 to 180 -180 to 180
Rx lat [degree N] 30 to 46 -90 to 90 -90 to 90

3-e. Error massages

Dialogue title Dialogue massage Meaning
Service Unavailable Please try again later. Server connection was failed.
No density data Specified time's density data does not exist. For some reason, specified time's density data does not exist.
Time-out Error Your process has timed out. Calculation request has timed out.
Error on processing program Process ID: [ID] Calculation request was failed on [ID].
This server is too busy Please try again after a while. Currently, the server capacity is overflown.
Internal Server Error Unexpected error has occurred. Unexpected error has occurred.

3-f. Propagation information

The propagation information is available for every Tx-Rx paths. Information from each Tx-Rx path is started with “Pathxx”, where xx is path number (i.e. 01-10). Zenith angle (degree) and azimuth angle (degree) of the first hop, Tx latitude (degree) and longitude (degree), Rx latitude (degree) and longitude (degree), and the frequency (MHz) are listed.

Next, the propagation information from each hop is listed. At each hop, “Refraction point” indicates the highest point [latitude (degree), longitude (degree), altitude (km)], where the radio wave refracts back from the ionosphere. “Propagation time” in milliseconds indicates the time when the radio wave propagates in 1 hop from one point to another point on the ground. “Next launch” indicates zenith angle (degree) and azimuth angle (degree) for launching the next hop. “Reach point” indicates the point [latitude (degree), longitude (degree), altitude (km)], where the radio wave reaches the ground. It is also the position where the next hop will be launched. “distance to destination” indicates the nearest distance on the ground from the reach point to the Rx.

When no more hop can propagate to the Rx, the message “No more hop is possible from now.” will be displayed. The “Max hop” indicates the maximum hop number that the radio wave can propagate from Tx to Rx. Only the ground-to-ground propagation is counted as 1 hop.

4. Reference


4-b. GNSS tomography

4-c. GAIA

4-d. IRI