radio propagation

here you can find a collection of many websites and resources related to radio propagation reports and predictions.

My first intention is to collect them but also to explain how to interprete data and terms. The focus is mainly on HF ionospheric radio propagation.

Introduction to HF radio propagation

added on 07-Jan-2021

The first step to understand how the HF radio waves propagate and the tools listed in the following articles  is to have a clear idea about what is the ionosphere and what are the ionized layers involved in the radio waves reflection.

I found this educational page of SWS really useful and well made to explain the main concepts.

added on 03-Jan-2021

This is probably the table that is widely known related to HF/VHF propagation prediction, it is not a static picture but a realtime status in your location???

The first column reports some “mysterious” numbers used to produce the more intuitive visual results in the second and third columns. Details of each table section can be found in the below tabs.

added on 03-Jan-2021

In the HF Systems section of the Australian Government Bureau of Meteorology you can find the Ionospheric Map.

This is a critical ionospheric frequency (foF2) map produced using automatically scaled ionogram profiles around the world. The map shows colour contours of foF2 in units of MHz.

Ionospheric Station of Rome - AIS INGV Ionosonde

added on 03-Jan-2021

My Country is Italy, so here I present the data available from the ionosonde located in Rome; the main results are the critical frequency (foF2), the maximum usable frequency (MUF) and the height of layers responsible of radio waves ionospheric reflection.

If you compare the foF2 frequency of the plot below and the value of the Australian Bureau of Meteorology from the map above you should find comparable results.

Below the daily plot of:
  • Critical Frequency (f0F2)
  • Maximum Usable Frequency (MUF)

Other interesting data that I found really useful are the daily plots of  f0F2 and MUF of the last 6 days; these plots clearly indicate the ionization effect of the sun exposure during the day, both frequencies are higher in the central part of the days.

Below the plots of critical frequency (f0F2), the white line is a monthly median expected value:

Below the plots of Maximum Usable Frequency (MUF): - a direct way to check the real time propagation (of Your signals)

added on 07-Jan-2021

There is also a “direct” way to verify the radio propagation, in this case the realtime performance of your station.

The main concept is to send a beacon message (CW, WSPR, FT8, PSK31, RRTY, etc)  that includes your callsign and check on pskreporter map how far your signal goes.There is nothing magic, it is achieved by gathering and organizing data of all the SDR receivers that are connected on internet.

Here my favorite ways to send beacon signals:
  • if you have a rig capable to automatically transmit a CW message you can send a message like this: CQ CQ CALLSIGN/B CALLSIGN/B at a speed of around 20WPM, this is the easiest way because you don’t need a PC;
  • if you are a fan of FT8 you can send a WSPR beacon or directly a FT8 CQ message with WSJT software.
This tool can be very useful also to evaluate and compare the performance of your antennas, for example the image below show my first FT8 tests with a 3W QRP radio and an Outback 2000 mobile vertical antenna placed on my balcony.

Here some tips to visualize just the information you need...

  • if you want to check how far your transmitted signal is received select the “sent by” option (red circle), otherwise you’ll see also the station received by you (if  you’re playing with WSPR/FT8 for example).
  • to have a clean view of the map start by checking the “display options” like in my image example, the default map shows also the location of all the receivers and lead to confusing results.
  • you can monitor several bands, they are showed in different colors.

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