Japanese Radio Chooses the Sonifex DHY-03 Telephone Hybrid For a Marathon Event
13th May 2008
JORF (RF Radio Nippon), an AM radio station in Japan, is the official radio broadcaster of the Japanese ‘Hakone Ekiden’. The ‘Hakone Ekiden’ is a two day relay marathon from Tokyo to Hakone, and back again, a distance of 120km each way and this year was the 84th running of the event. All the runners were college students pre-selected from 15 schools that had won pre-event races.
This event was broadcast live by JORF between 8am and 2pm with the broadcasters running some of the distance with the students. However, because the broadcast needed to be over such a long distance and was partially set in Tokyo’s dense building conurbation, standard radio wave propagation would have been subject to shadow areas or loss of reception.
In an attempt to overcome these problems JORF set up numerous temporary RPU receiving sites along the marathon route. At each of the sites, there was an ISDN audio codec that sent audio to the Broadcasting Centre which then switched the appropriate audio source at the correct time, and sent it to JORF’s master control room by ISDN.
Although this procedure addressed many of the broadcasting difficulties, the ISDN often became disconnected and so, as a backup method, they used two Sonifex DHY-03 telephone hybrids with a simple telephone line connection. The Sonifex hybrids were sold and supported by Maple Audio Technology Corporation. CEO of Maple Audio, Brian Kreps, commented: ” As an engineer its very easy to tell a customer about the technical merits of this hybrid, but from what customers are saying, those specs really don't matter so much, because this is the best sounding hybrid they've used.”
The reasons why they chose the DHY-03 were that it gave the best performance when compared to other competing products. Also, when they tested the DHY-03 in a studio, they were not able to produce feedback loops, or audio ‘leaks’ , even when feeding too high a level of audio into the hybrid. The reason for this is that the DHY-03 uses acoustic and network echo cancellation to minimise the effects of potential feedback and also the accurate telephone line impedance matching provides excellent rejection figures, averaging typically 75dB on a complex waveform.
Whilst JORF may have hoped not to have had to use the DHY-03 hybrids, last year they were used twice to cover ISDN drop-outs.
For images of the DHY-03 click here >
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