This page is a 'primer' for PARC members. It is 'work in progress' and liable to have significant changes as new information and links are added. Please use it as a starting point for your own investigations.

 Scroll down for HF Propagation 

VHF Propagation

  Tropospheric Ducting Forecasts

Tropospheric Conditions Near Real-Time

Scroll and zoom to the relevant location
VHF & UHF Line of Sight Calculator
Explanation of line of sight issues:

 VHF/UHF Area Prediction Tool
Online modelling application for local terrain
(incl. knife-edge refraction)

Enter a location and various parameters for a prediction of the likely path losses

Tephigrams for British Isles

Tephigrams are a vertical profile of temperature and dew point through the troposphere, taken by radiosondes (weather balloons), daily by the Met. Office at Watnall, England (and elsewhere).

The interpretation of tephigrams can appear complex and explanations are lengthy. If you are interested in the subject there are many online sources.

Here we present a link to daily tephigrams which we use to identify any temperature inversions that may result in enhanced tropospheric propagation - 'Lift Conditions' - at vhf (2m especially) over the East Midlands.
The things to look for on a tephigram are a sharp swings of the red line (temperature) to the right, which is usually associated with a sharp left-right swings of the blue line (dew point) indicating the tops and bases of cloud layers.

Temperature inversions at low or intermediate levels (900mb - 500mb / 2500 to 18000 ft) potentially give rise to 'Lift Conditions'. At much lower, or much higher, levels the effect may be less pronounced.

This is a complex subject so please do your own research.

Daily Tephigrams

Daily charts for several places in the British Isles are available on the following websites:



Also Ttry

Leeds University:

NOTE - This service was discontinuous in 2017 but is currently back online (March 2018). Met Office Watnall produce tephigrams at 00:00 and 12:00 UTC daily.

Tephigram for Nottingham (example)

28 December 2016 Nottingham 1200Z

Shows temperature inversions at 110m, 3000m & 5600m.

Click to enlarge

 Data source: Weather Online.
Diagram from Leeds University.

Pressure/height conversion

Level mB / hPa Height ft Height m
1000 364 111
925 2498 762
850 4781 1458
700 9882 3013
500 18289 5576
400 23574 7187
300 30065 9166
250 33999 10366
200 38662 11787

HF Propagation

Current HF Conditions

Global Ionospheric (Critical foF2)
Conditions Today (Live)


Hourly Area Predictions
Today (Live)
This HAP Chart produced by Space Weather Services, Bureau of Meteorology, Government of Australia gives a near-real-time view of the f0F2 conditions affecting the UK (London).

For fuller information please visit the webpage (link) where you can select other locations.

HAP Chart © Copyright Commonwealth of Australia 2016, Bureau of Meteorology

Local Area Mobile Predictions
Today (Live)

  This LAMP Chart is intended for use by UK Cadet Forces [presumably for 5MHz portable communications]. While precise data may need to be re-interpreted for Amateur Radio use the general principles do apply and illustrate changes on useable frequencies during the day.

For fuller information please visit the webpage (link) where you can select other locations.

LAMP Chart © Copyright Commonwealth of Australia 2016, Bureau of Meteorolog

Current British & Global K & Kp Geomagnetic Indices
Today (Live)

Recorded at UK Observatories by the British Geological Survey

Please visit the BGS Page:
'Current geomagnetic activity in the UK and across the globe'

G3YLA Real Time Propagation - Today (Live)

A very useful interactive website
provided by Meteorologist Jim Bacon G3YLA

This now includes foF2 observations from Chilton & RAF Fairford (UK) and Dourbes (Belgium). The additional stations give a broader picture of conditions across the UK and the Lowlands' but are a little bit cluttered for anyone interested especially in 'Inter-UK' conditions - a very good tool nevertheless

Current UK HF Band Conditions
Today (Live)

Example data - click image to go to the website. This page lands on ConUS - select your region at the bottom of the page.

This website is provided by K1BIZ with data from an un-named source which provides "HF Ionospheric Interferometry" using a methodology which is not described.

It is unclear how information about UK band conditions is generated so the snapshots may need to be treated with caution.

Other Information

UK Meteorological Office

The Met Office provides a concise synopsis of prevailing and forthcoming spaceweather conditions
Example (Geomag Impact Scale)

(c) Crown Copyright / The Met Office

Please visit

Note on K & A Indices
K & A Indices
    K & A Indices give a 'health check' on the geomagnetic stability of the ionosphere. /font> As a general rule, lower values indicate more stable conditions which usually lead to 'better' (more predictable) MF & HF conditions. 
  • 'K' values represent an average of rolling 3 hourly measurements at specific locations; 'Kp' values are similarly obtained but values are averaged across the globe. So, K / Kp values indicate the extent of hourly fluctuations in the earth's geomagnetic field (see note below).
  • 'A' values indicate the daily trend in geomagnetic variations. They are an average of eight 'K' values: that means they are a 24 hour rolling average. 'Ap' values are average values for the globe.
  • Together, K & A (Kp & Ap) Indices indicate the 3 hour vs 24 hour fluctuations in geomagnetic conditions.  Values of less than K = 3  and A = 6 indicate 'settled' conditions that may give good propagation.

The British Geological Survey also produce a K(UK) value is a daily average of indices measured at 3 UK Geomagnetic Observatories (Lerwick, Eskdalemuir, Hartland).

Critical Frequency, MUF & Ionograms

foF2 / MUF Ionosonde Data

The UK Solar System Data Centre (see below) produces real-time ionosonde data every 10 minutes throughout the day using the UKSSDC Chilton Ionosonde.  An example is given below.

The ionosonde data is available in a number of formats including ionograms (see below) and tables. This information is very helpful in determining likely current HF propagation conditions across the UK and also helps work out the prevailing 'skip distances' for, say, 40m contacts. The conditions affecting other bands can also be deduced. As with other examples on this site, the information may need further personal research in order to fully understand what the data shows and how to best use it.

Real and hypothetical examples below
click to enlarge

Example ionogram from UKSSDC Chilton

The horizontal axis is the frequency of the ionosonde sweep (MHz); the vertical axis is the height in km.

Annotated example ionogram

This example shows some small differences to the Chilton - see below

Short Explanation of Ionograms

Importantly for Radio Amateurs the ionogram chart (left) shows the prevailing critical f0F2 frequency (6.052MHz), and the calculated MUF at various distances (D vs  MUF at the bottom). 

The coloured lines/zones represent electron densities at different heights (vertical axis) and the horizontal axis is the frequency of transmission by the ionosonde. The curves and cusps on the lines indicates zone of reflection and the values are used to compute the tabular information on the left hand side of the chart. The tabular information is primarily what we are interested in.

Longer Explanations of ionograms - best to read both:

 See the UKSSDC explanation here
(see the note below)

Note: an asymptote is a straight line that continually approaches a given curve but does not meet it at any finite distance

Alternatively see this NOAA page:

Comparison of foF2 in 2015 & 2016

for IO91/2

NB - very large image

UKSSDC (Chilton) Ionosonde Data

To access the Chilton ionograms registration is required. Use of the data for purposes other than research, or for re-publication, may require a licence. The Ionograms (and other charts) can be found at:

Registration can be done at:
UK Solar System Data Centre, Science and Technology Facilities Council
Rutherford Appleton Laboratory, Harwell Campus, Didcot,
OX11 0QX

More HF Propagation Predictions


ITURHFProp - Propagation Predictions

This up-to-date applications is the successor to the VoACAP Propagation Prediction suite produced by the ITU. It gives predictions of path reliability based on 'standard' seasonal and daily variations - however these do not include short term variables such as geomagnetic storms and sunspot activity.

VOACAP (Voice of America Coverage Analysis Program)

This has been overhauled recently to make it much maore useful

The original VoACAP application is still available online.

It provides predictions of path reliability based on 'standard' seasonal and daily variations - however these to not include short term variables such as geomagnetic storms and sunspot activity. 

Functionally it is very similar to the ITURHFPROP software but has a more useable interface, better tools and a much nicer interface in PARC's opinion.

Space Weather

Space weather is an increasingly 'hot' topic. Some aspects are complex, but there are many websites available: start at

European Space Agency
Space Situational Awareness

Of particular interest is the ROTI diagram showing ionospheric disturbance over Europe

Current images of the sun

Look at the AIA 193Å image on the FAR SIDE tab

NOAA Space Weather Enthusiasts Dashboard

A comprehensive set of tools provided by the

National Oceanic and Atmospheric Administration
Space Weather Prediction Center


Viewing the Aurora

A short explanation about when and where to see the Aurora Borealis

Northwest Research Associates
 Many useful plots together with on-page explanations. Features some nice comparative graphs - see this page: 

Other Stuff

Dourbes ionograms


European Digital Upper Atmosphere Server
(Registration required)