Wireless intercom – too many strings attached?29 May 2013
Wireless technology has brought flexibility, convenience and movement to all areas of broadcast production, freeing presenters and crew from the restrictions of wires and cables. Despite more efficient processing and transmission-reception systems there is still the reality that radio equipment comes with a trade-off; the risks of interference and lower quality for the freedom to move around without physical hindrance.
Restricting intercom and talkback to wired units could be impractical, so wireless comms have their place, especially on large-scale productions, but they come with specific challenges and drawbacks. The practical business of setting up connections has become more difficult and involved over the last few years due to the reallocation of frequencies to make room for new 4G mobile services.
Not surprisingly many intercom manufacturers have an almost ambivalent attitude towards wireless technology. "While the demand had increased some years ago it seems many manufacturers as well as customers have learned where the mobility of a wireless intercom is a real advantage and where a wired intercom can provide a stable, trouble-free experience," comments Christian Diehl, product manager for intercom at Riedel. "Changes in spectrum allocation, the overcrowded WiFi frequencies and the associated uncertainty may have dampened the requests for wireless systems that operate in these frequencies."
In the last few years developers have looked at ways to integrate ‘traditional’ intercom technology with telecom formats, including smartphones and DECT (Digital Enhanced Cordless Telecommunications). But as the founder of Delec Audio and Video Technology, Donald Dilocker, observes, this has not provided immediate solutions to the underlying problem of connectivity: "DECT and smartphone subscribers have their limitations and the standard radio wireless beltpack requires bureaucratic frequency permissions, which is a reason why wireless technology is only used where it is needed. The majority of connections can and will be made over network cables, again offering a more cost-effective solution."
RTS offers both UHF and WiFi wireless technologies. The two channel, full duplex uncompressed BTR800 is aimed squarely at broadcast, with the capability to supply more frequency band options in what Nico Lewis, senior sales manager for RTS intercoms, describes as the "ever-changing UHF RF spectrum".
Last year RTS introduced the BTR-240, featuring wired interfacing options and licence-free 2.4GHz WiFi technology. Lewis acknowledges that because the system works in the 2.4GHz WiFi spectrum its use can be limited, depending on the situation and the number of WiFi users in the area.
The inherent difficulties of wireless intercom are reflected in the decision by Anchor Audio to concentrate its radio products in the home US market and not bring those products to Europe. "Offering a reliable wireless intercom in the European market has been difficult because of limitations on RF power output, inherent range limitations of the 2.4 GHz frequency and incompatible frequency allocations between countries," explains director of marketing Colton Jacobs. "Therefore, Anchor Audio has focused on offering its wired system in Europe."
Despite the difficulties involved the demand for wireless intercom continues because, in some situations, there is no other way to set up communications. "Wireless is becoming an important component of intercom systems because some situations demand it," says Mike Reay, product manager for TecPro at Canford. "Customers are asking for licence free, good RF coverage and simple interfacing to two wire systems. In practice the obvious choice of 2.4GHz is rapidly becoming overcrowded, with RF range the first thing to suffer. If customers can afford it, they should seriously consider UHF systems, which offer consistent reliably coverage and good audio quality without latency. However, you’ll have to buy a licence."
Raycom produces its own brand of walkie talkie-style wireless intercom for OB trucks, studios and theatre. General manager Chris Pemberton comments that standard base station systems are still the norm but that "an extension" is usually needed when the crew have to walk around over long distances. The Raycom units are semi-duplex, allowing only one person to talk at a time, which Pemberton says is sufficient when the majority of the communications is a director giving cues to the camera operators and sound engineers. Raycom is due to launch a new system in the autumn, with either two transmitters, two receivers or full duplex operation.
Clear-Com, with its parent company HME, claims to have the "largest portfolio of wireless production intercom systems". This covers units with no interfacing for a maximum of 15 users per base up to four to six or more intercom channels available in a user beltpack serving dozens of users. "Wireless intercom in some applications is the driving and sought after solution," says product marketing manager Vinnie Macri. "We don’t see our customers or potential customers telling us they prefer a wire. They pretty much know the benefits yet understand the challenges of wireless integration. People needing intercom will definitely continue to seek wireless in some way as part of their overall package."