Audio
Dante Based STL For Japanese Radio Station
Broadcast Industry News: “…Glensound’s new Signature SD1s act as a silence detector, providing alarms and a switched backup should any loss of audio occur”
FM-Hi Shizuoka is the first customer of Glensound’s DARK 88 Dante audio interface in Japan.
Glensound’s Japanese partner, Maple Audio Technology Corp (MAT) installed 2 x DARK 88s as a studio to transmitter link across MATs leased dark fibres.
The DARK 88 is an 8 input, 8 output analogue interface with network connections to a Dante® network, or directly between two DARK 88s as in this application. The DARK 88 is particularly suitable for programme audio, not just because of the audio quality and system flexibility, but because of the level of redundancy offered. There are twin switch mode AC power supplies, then 4 network connections, a primary and redundant copper/CAT 5 link and a primary and redundant SFP slots for fibre links. This makes the DARK 88 an effective device when used as an STL link on MAT dark fibres.
The direct distance between the studio and the transmitter is only 800m, but with an actual fibre length of about 1.6km. The link is at 1Gbps, with a loss of about 7dBm. 20km Bi-Directional SFP modules were used for the fibre link, with a wavelength of 1330nm for one direction and 1550nm for the other.
The transmitter site is also connected to the studio via a long distance WiFi (IEEE802.11B) transceiver system as a backup, in case the fibre connection fails. Wifi was a suitable back up as the two sites are in line of sight.
MAT used the Luci Live software IP codec on a very low powered Celeron based fan-less PC to connect on the WIFI link. Even though the WIFI link is limited to 0.1watts, 2 x 13dB high gains ANT were used with a good coaxial cable. This works with no problems, and connections between sites run at a rate of 1Mbps. Reception level of Wifi power is around -53dBm which is very strong compared to most common WIFI receptions.
The link system also included one of Glensound’s new Signature SD1s to act as a silence detector, providing alarms and a switched backup should any loss of audio occur.
Marc Wilson from Glensound was impressed with MATs system design, “Shotaro at MAT has a perfect application for our DARK 88 Dante® units utilising his dark fibres. Dante systems are particularly suitable to broadcasters with the low delay high quality audio, partnered with the reliability and redundancy inherent in a Glensound designed unit. We can see many similar projects in the future.”
Shotaro Umezawa of Maple Audio Technology comments, “In the era of changing from traditional transmission technologies such as TDM based links (T1, ISDN or E1) to IP or Ether based audio transmission, where we have an access to dark fibres, it is cost efficient, stable and easier to realise the STLs utilising these links, rather than using IP codecs which is mostly an ISDN direct replacement. Dark fibres are just a “pipe” in between sites. For this station, we picked Glensound DARK 88 as it is so much low cost and it does not work with IP. Audinate’s Dante® patented sync system over Ethernet framing is better for STLs. People always think a replacement of TDM leased line is IP, and it is not always true. IP has its own advantages, but in a short distance transmission, Layer2 might work a lot better than Layer3, and there are more ways to handle transmissions.”
The DARK 88 Dante Audio Interface is available now
– http://www.glensound.co.uk/product-details/dark88-mkii/
The Signature SD1 Silence Detector is available now
– http://www.glensound.co.uk/products/signature-series/
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