HF Prediction: Upper, Recommended, Second best and Lower frequency (URSL)
A common problem facing an HF communicator is to choose one, among several frequencies to establish a
communication link. This tool can be used to assist in this task. There is a help screen explaining the
various inputs needed (available HF frequencies, level of solar activity, and time of day/year, receiver
and transmitter locations). The output is a table of frequencies to use ranked according to upper,
recommended, second best and lower frequency.
The map seen on opening this window shows the location
of the solar terminator and the auroral oval. If the radio path between the two terminals intersects
either of these, there is a possibility of further signal degradation due to excess absorption, near the
auroral oval and steep electron density gradients, near the dawn terminator.
Anybody using HF for communications on a single link.
Typical users could be travelling in remote locations and be setting up a radio link back to base
(from peace-keepers to tourists, including mineral prospectors and small boat owners).
IPS F-region model; NPOES auroral oval
F-region model on demand, auroral oval updated hourly
Australian regional T index time series
This time-series plot shows the trend in the observed Australian regional T index over the past 30 days. The daily
values can fluctuate during disturbances. The dashed blue line represents the median of these daily values and is
an indicator of the quiet level of ionospheric support over the period plotted. The forecast daily T index for the
current UT day is shown as the unfilled rectangle. The T index is an equivalent sunspot number and is what the
sunspot number would have needed to be to best match the observed ionosphere with the empirical model of the
ionosphere used for Australian ionospheric predictions.
Any HF frequency manager using software requiring an improved sunspot index for input to manage an HF system.
Australian magnetometer network
Global T-index departures from monthly predicted levels
This image shows the difference between current observed hourly conditions and predicted monthly conditions for
the global ionosphere. The colours blue, green, yellow, red, correspond to "enhanced", "normal", "mildly
depressed" and "depressed" conditions respectively. Depressions and enhancements are with respect to the IPS
predicted monthly T index for that month. Thus if the monthly predicted T is far too high, the entire global map
will be red, which will warn a communicator that any frequencies scheduled using the monthly index are likely to
be too high. This situation can occur due to a poor monthly prediction or an ionospheric storm.
Any HF frequency manager using software requiring a sunspot index for input to manage an HF system.
Global ionosonde network