SARL 5 MHz propagation research project

Page last updated on: Saturday, November 1, 2014

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SARL 5 MHz propagation research project

The 5 MHz propagation research project show unexpected results.

One of the most interesting findings is the inconsistency in the results of Near-vertical-incidence sky wave propagation (NVIS).

Comparing a communications path between two amateur stations, ZS6KN and ZS6KTS (a distance of 51 km) it is interesting to note that in June 2014 there was a good communications path from just after 05:00 until approximately 16:30 after which the signals disappeared. The pattern for July was the same, but signals were considerably stronger than during August and September.

During September, a strong dip in signal strength can be seen. The other interesting observation from the graph is that propagation “opens” earlier and closes later as we go into summer which indicates variations in the ionisation of the D layer of the ionosphere as the sun rises earlier and sets later.

Not enough data has been collected to make any meaning full conclusions. If the path was a pure ground wave, the signals would have been more or less constant throughout the day and night.

The article will be published in the November/December edition of EngineerIT and is already available on the web. You can find the link on, click on propagation research. You will find links to the article as well as a report of the first six months.

The South African Radio League

via SARL 5 MHz propagation research project.


The South African Radio League (SARL) has found some unusual results from its recent test cycle of the 5 MHz band.  According to SARL officials, there was much inconsistency in Near Vertical-Incident Skywave Propagation (NVIS) and the discovery that 5 MHz “opens earlier and closes later as we go into summer…, indicating a variation in the ionization of the D Layer of the atmosphere.”  The SARL notes that is hasn’t collected enough data “to make meaning full conclusions.”

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Aloha es 73 de Russ (KH6JRM).

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