South African amateurs
transmit digital voice on HF
Three South African amateurs made what is believed to be the first successful
transmission of a Digital Voice signal over HF amateur bands in the country.
The Digital Voice signal was transmitted at 11:16 on Sunday 8 August
by Andrew Roos, ZS1AN, and received by Dennis Wells, ZS1AU, with technical
assistance from Ettienne Vosloo, ZR1AHW. The transmission took place on
the 10 m band, with an occupied bandwidth of approximately 2,3 kHz.
On Tuesday 10th August, Dennis and Andrew successfully exchanged signal
reports on 15 metre, completing the first known digital voice QSO in South
Africa. The QSO was monitored by Sean White, ZR1BSD.
The software used in this experiment was HamDream version 2.4,
which is an open-source implementation of the Digital Radio Mondiale broadcasting
standard that has been adapted for amateur use by HB9TLK. It can be downloaded
free of charge from the SARL website, www.sarl.org.za.
For more information, see HB9TLK's website, www.qsl.net/hb9tlk.
All you need to explore this fascinating new mode is a PC with a full-duplex
soundcard, a soundcard/rig interface like those used for PSK-31 and similar
digital modes, and a PC headset and microphone that can be purchased at
any computer store for about R100.
So get QRV on digital voice and join the fun! Andrew and Dennis are keen
to make contact with other divisions using this exciting new mode. If
you would like to arrange a sked please send email to Andrew, zs1an@qsl.net
or Dennis, zs1au@absamail.co.za.
Andrew will be giving a talk on Digital Voice at the SARL "Radio
Technology in Action" Hamfest at the National Amateur Radio Centre
in Johannesburg on 21st August - see you there!
Courtesy of
The South African Radio League
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