Friday, April 4, 2014

It’s been a while, but here a new Tech Tip, straight from Shure:

GLX-D and the 2.4 GHz Frequency Band

A customer recently asked why Shure choose the 2.4 GHz band for the GLX-D wireless. As there is no perfect frequency band for a wireless mic system, let’s consider the pros and cons:

2.4 GHz Pros

a) No license required in any country.

b) No interference from local TV stations.

2.4 GHz Cons

a) Used for other wireless services, such as Wi-Fi.

b) Heavy RF traffic in this band can adversely affect performance. Symptoms can be short transmission range, frequent loss of signal, or inability to operate multiple GLX-D systems at the same time.

c) The human body efficiently absorbs and blocks transmissions in this frequency range. The short 2.4 GHz wavelengths (4.9 inches) make it essential to maintain line-of-sight between the transmitter and the receiver for the most reliable operation.

d) Microwave ovens can produce localized interference in this frequency band.

e) At 2.4 GHz, transmission distance outdoors is typically far less than indoors. Outdoors there is a lack of surfaces that will reflect the transmitted signal. Such reflections improve transmission distance indoors.

The pros and cons above apply to any wireless audio system that operates in the 2.4 GHz band. It is a matter of physics – not a matter of the product brand.

In theory, it is feasible to simultaneously operate up to eight GLX-D systems in one venue if the RF conditions are optimal. However, local interference in the 2.4 GHz band will often reduce this number to four or less.