ARLA/CLUSTER: África do Sul vai ativar beacon em 5250 kHz para estudos de propagação

[João Costa > CT1FBF]

SARL to take the next step in 5 MHz propagation research

The South African Radio League will activate a beacon on 5250 kHz by
the end of August. This was announced at the Radio in Action Symposium
held in Port Elizabeth yesterday, Saturday 27 July.

One of the HF transmitters at the National Amateur Radio Centre will
be programmed to send signals at regular intervals and radio amateurs
who have the relevant software will be able to record these signals
automatically on their computers.

The software that will be used is ALE, which is a complex
communications standard also known as MIL-STD 188-141 and USA
government standard FED-STD-1045.

In the past usage was limited to expensive military and commercial
equipment with built-in ALE controllers. Fortunately all of that has
changed with the development of software that runs on a PC and makes
use of the sound card. ALE is now in regular use by radio amateurs all
over the world.

ALE has the capability to call up a specific station, a group of
stations, a net or just a general call not directed to a specific
station (CQ). It is also possible to perform a sounding or short
transmission to allow receiving stations to determine the reigning
propagation conditions. The sounding can be (automatically) executed
at regular intervals. A sounding typically lasts for 10 seconds and
the repetition interval can be set in minute increments.

On the receiving side all the received soundings are displayed in
terms of call sign, Bit Error Rate (BER), received
Signal-to-Noise-Ratio (SNR) as well as the time that the signal was
received. The above information is invaluable to determine the
coverage and reception possibilities of a 60m transmission.

An article by Hannes Coetzee, ZS6BZP, explains the full operation and
will be posted on the SARL Propagation Research page on
www.sarl.org.za during the coming week. The ALE software is free and
has been included on the RTA CD. A link to where to download will also
be provided on the SARL Web.

It should be remembered that the use of 5250 and 5260 kHz is limited
to SARL members who have registered only. Full details on how to
register are on www.sarl.org.za, select the link on the right hand
side of the home page.