Maximum and Lowest Operational Frequency
from K1TTT's Java Applet

David Robbins, K1TTT, did a wonderful job writing a java applet for on-line Maximum and Lowest Operational Frequency (MOF and LOF) prediction (see below inset for definitions). Click here for K1TTT's detailed account of the program's development history.

Simply point to your QTH on the map and click. Then, hit the Compute button. Try also the very useful Polar QTH projection. The applet employs the values for solar flux and geomagnetic A-index & K-index previously obtained from WWV.
Next update in minute(s).

Legend: MOF LOF 10m 160m 15m 80m 20m 40m SP: Short Path LP: Long Path LP = SP + 180°

Definitions: Basic MUF(3000)F2 is the Maximum Useable Frequency for a 3000km single hop refraction off the F2-layer with a probability of about 50%. The value of basic MUF is independent of antenna gain, transmitted power, emission class or required information rate. MOF (LOF) is the Maximum (Lowest) Operational Frequency that will allow tropospheric radiocommunications with a probability of 90%. As a rule of thumb, MOF = 0.85 MUF. foF2 (not shown on this page) is the maximum (or critical) ordinary mode radiowave frequency capable of perpendicular reflection from the F2-region of the ionosphere.

publishes this great real-time world-wide basic MUF(3000)F2 map.

This image is automatically refreshed every 5 minutes. Next update in minute(s).
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For those living in Europe, a real-time European basic MUF(3000)F2 forecast map for the next hour, based on real-time ionosphere soundings has been reproduced below, by courtesy of , the Radio Communications Research Unit. Visit their website for more and future forecasts.

Monthly Propagation Charts

If you are living in Europe and not far from Belgium, you may also be interested in the monthly propagation charts of the UBA.

The ARRL provides a similar product for US amateurs here.