Wireless networking at shows
Point to Point / Point to Multipoint Links
Point to point links are typically used for passing information between ethernet enabled devices or via protocol converters – such as sound desks, lighting desks, and computers to backstage or around an arena for passing audio or allowing remote configuration of delay towers etc.
We can offer fault tolerant links with automatic fallback to independent equipment, automatic frequency changing systems to avoid interference and a range of antenna to suit every configuration you require.
Wireless is used in shows to run point-to-point links for several reasons:
- As a multicore replacement, where it is difficult or uneconomical to run a control cable from the desk to the dimmers.
- As a feed to a moveable object onstage, where wires would interfere with its free movement.
Non DMX based systems
These systems use wireless for control of motors and lighting circuits and are designed to allow mobile objects to be controlled. These systems are used for systems such as controlling car headlights etc on stage. Rather than transmit the DMX signal, individual channels are controlled.
An example of this is the Theatrewireless RC4 system which works on the 900MHz band. Theatrewireless: www.theatrewireless.com
An increasing number of manufacturers are producing Zigbee transmitters. Zigbee is a low speed, low power mesh type system which can jump from unit to unit to work over long ranges and with its low cost can be fitted to a large number of lighting/control units. The difficulty with the system is its low operating speed which limits its usefulness where time critical switching is needed.
DMX/802.11b/g Systems
These typically work by converting the DMX to an ethernet stream which is then passed over a standard wireless bridge link.
These systems are better used where interference is not expected to be an issue.
Martin Pro Diversity: www.martin.com -
A typical example is the Martin system which uses 802.11b and has a combined DMX to Ethernet and bridge.
Luminex Ethernet -DMX8: www.luminex.be is another example of a combined protocol converter and Wireless access point.
Avolites: www.avolitesshop.co.uk/avo/products/edmx.htm.
Avolites eDMX is an example of a combined protocol converter/ Access point which uses a standard access point to extend the range by using the
separate WAP as a middle hop.
Artistic Licence NetLynx: www.artisticlicence.com
This system use a separate DMX - ethernet converter and then can be used with a standard Wireless Access point which adds the flexibility of operation in the clearer 5.8GHz band.
802.11 Systems
Rather than the normal 802.11bg DHSS (spread spectrum) These use the 802.11 frequency hopping system which is more resistant to interference. Typically an 802.11b/g system will have to wait until an 802.11 transmitter is idle before it can work.
Examples of this are
Goddard Designs DMX-Link: www.goddarddesign.com This uses a
separate protocol converter and an 802.11 access point,
and City Theatrical WDS: www.citytheatrical.com
DMX/Proprietary RF systems
These systems use DMX, but avoid using the 802.11b/g standard and are less likely to be interfered with by Wireless Lan users. This tends to also mean their range is larger as there is less background nose on their operating channels.
An example of this is W-DMX which whilst working on the license free 2.4GHz band uses different protocols and centre frequencies. W-DMX: www.wirelessdmx.com
