Absolute Radio was reporting live to the Christian O’Connell Breakfast Show from the ‘Two Years To Go’ event at the impressive Olympic Stadium earlier this week, and we were even fortunate enough to get interview with Lord Coe live to air.

A live broadcast from a site such as this poses some problems, mostly that it is not a completed structure with the facilities and connectivity that you would get at a completed venue. As such the Technology team at Absolute Radio had to think carefully about the method of relaying live audio from the stadium to the studios at One Golden Square, balancing cost, reliability, quality and ease of use. Broadcasting from large metal objects, such as a stadium, causes particular problems for any wireless equipment as there are lots of reflections and ‘sash’, but in this case it was the only option.

The team considered using a Nera M4 satellite kit and a long run of Cat5e cable to connect the ISDN codec in the stadium with the satellite kit that could be outside of the main structure with a clear view of the sky and they also considered using a 3G IP codec, although previous results with 3G connectivity have not been encouraging. However, they eventually opted to use a new piece of equipment that was supplied by a company called Wired For Sound, who have an inventive way of combating the inherent problems with 3G networks.

The equipment, known as the ‘Mediahub’, comprises of three 3G modems that can act independently and across a variety of different networks, providing a much more resilient connection to the Internet. For our broadcast we opted to use three different networks, O2, Vodafone and Three (which performed the best by far, if you’re interested) and a TieLine IP codec, with built in mixer facilities for our microphones and headphones, that connected to a matching TieLine unit at One Golden Square. The ‘cool bag’ sized over the shoulder Mediahub, with 3G aerials built into the case, is battery powered and is able to run for around four hours, or it can be powered from the mains or even a car battery.

The main benefit of the Mediahub is the networking that it is capable of. For audio traffic (provided by the IP codec) it can be configured to send the exact same packet across all three mobile networks to an assembler, at a wired location (such as your office) with lots of connectivity, where it will only take and use the first correct packet that arrives. This therefore means that the networks with the most latency (which changes dramatically with usage on a 3G network) are not used, and you always use the fastest packet – this facilitates a much smaller buffer size on the IP codec, meaning that round trip delay is kept to a minimum and that a two way interview can then be conducted. Quite often with 3G networks you lose throughput entirely, and this kit copes with that nicely, considering it’s ‘first correct packet’ scheme that doesn’t mind if only one correct packet is ever received. The unit even comes with a laptop (separate to the over the shoulder bag) that allows you to monitor the state of the networks, allowing you to see signal strength and the quality of the network.

The Mediahub also has another few clever tricks up its sleeve. Firstly, it has the ability to multilink 3G networks for data traffic, separately to diversified audio traffic. We know that for voice it will diversify packets across all three networks, but for data traffic it will combine the three networks to give you effectively three times the throughput than a standard 3G connection. Wouldn’t it be really excellent if you could then connect a laptop to the Mediahub then and transfer audio via FTP, access emails, etc? Well that’s the second trick that this nifty piece of equipment can do – it has a built in wireless hotspot allowing you to do just that.

We used the equipment for the full four hours that the battery could handle and found it to be very reliable and hugely cost effective compared to using a satellite kit at roughly £5 per minute. The ‘Mediahub’ also has a bigger brother that features more 3G modems and an ADSL modem, which is perfect for more established venues where using 3G is a backup to a wired connection.

Wired For Sound can be contacted on +44 (0)20 8880 4840, or alternatively can be found at their website.

- Stuart Edwards