Welcome to Tropical band

To most people the phrase "tropical bands" bring a pretty clear picture to mind - a bunch of shirtless guys playing calypso music. But to experienced shortwave DXers those two little words express the most challenging and enjoyable part of the radio hobby. The phrase kindles memories of a DXer's best catches and favorite QSLs, of exotic stations, music and of early morning listening sessions. (Don Moore)
I like the "Tropical band" name for new 60m allocation. (OK1RP)

Effective from 1st Jan 2017 please paper QSL via OM-bureau only.

Friday, December 27, 2013

Studies of Ionograms show supremacy of the 5MHz band

ICASA has extended the SARL 5 MHz license till the end of January 2014. This follows SARL application for ICASA to review the license and grant facilities up to at least the start of the WRC 2015. Currently  the SARL holds a pilot license for 5 250 and 5 260 kHz. While the SARL applied for extension of the license for a further period it also appealed to the Chairperson of ICASA, Dr Stephen Mnube, to consider issuing the SARL with a long term authority to use these two frequencies to continue propagation research till at least the WRX15 conference.

The SARL is currently analysing the results of the special weekend 5 MHz activity event held in early November. The winner of the book prize is Barry Newton ZS2NF of Uniondale.



The ionograms generated by the South African ionosonde network clearly illustrate the supremacy of the 5 MHz band for short range, near vertical incidence  skywave (NVIS) communications under certain conditions. These typically happens during the morning and late afternoon when the 7 MHz band does not support short range, sky wave communications and the 3.5 and 1.8 MHz bands suffer from high noise levels. 
During the middle of the day the 7 MHz (and 10 MHz during high solar activity) band is typically the most effective medium for short range, sky wave communications.

Permanent access to the 5 MHz band will ensure that the amateur radio community can efficiently contribute to emergencies requiring short distance communications beyond line-of-sight as typically required in hilly and mountainous terrain.

The South African ionosonde network is unique in Africa and place South African radio amateurs in the very fortunate position to monitor reigning, short range propagation conditions and to improve their skills and experience accordingly.

An article by Hannes Coetzee illustrated with ionograms is available for download  here

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