Shure GLXD4 User Manual page 8

2.4 GHz Spectrum Overview
GLX-D operates within the 2.4GHz ISM band which is utilized by Wi-Fi, Bluetooth, and other wireless devices. The benefit of 2.4GHz is that it's a global
band that can be used anywhere in the world, license free.
Overcoming the Challenges of
2.4GHz
The challenge of 2.4GHz is that Wi-Fi traffic
can be unpredictable. GLX-D meets these chal-
lenges in the following ways:
• Prioritizes and transmits on the best 3
frequencies per channel (choosing from a
pool of 6 frequencies across the 2.4GHz
band)
• Repeats the most important information
such that one frequency can be taken out
entirely without audio interruption
• Continuously scans during usage to rank
all frequencies (both current and backup
frequencies)
• Seamlessly moves away from interference
to backup frequencies without audio
interruption
Note: Unlike analog TV band wireless which typically uses the same type of transmissions across manufacturers, all 2.4GHz wireless currently on the market use different
variations of wireless transmission. These differences make it more difficult to mix and match 2.4 GHz from multiple manufacturers successfully, as can be done with TV band
wireless solutions.
Tips and Methods to Improve Wireless System Performance
If you encounter interference or dropouts, try the following suggestions:
• Scan for the best available channel (press the channel button)
• Reduce transmitter to receiver distance - for example, place receivers
on stage with a line of sight to the front of the receiver.
• Change all GLX-D systems to Group 2, which is the most robust
wireless group
• Move receiver further away from Wi-Fi access points, computers, or
other active 2.4 GHz sources. Recommended distance is a minimum
of 3 meters (10 feet).
• Disable non-critical Wi-Fi on computers, cell phones, and other
portable devices
• If you plan to use Wi-Fi during a performance, turn on Wi-Fi prior to
turning on GLX-D and scanning for the best channel.
• Keep the transmitter and receiver more than 2 meters (6 feet) apart
• Avoid heavy Wi-Fi traffic activities such as downloading large files or
viewing a movie.
2.4 GHz Frequency Tables
The following tables list receiver channels, frequencies, and latency for each group:
Group 1: Channels 1-4 (latency = 4.0 ms)
Group/Channel Frequencies
1/1 2424 2425 2442 2443
2462 2464
1/2 2418 2419 2448 2450
2469 2471
1/3 2411 2413 2430 2431
2476 2477
1/4 2405 2406 2436 2437
2455 2457
8
Coexisting with Wi-Fi
If you plan to use Wi-Fi during a per-
formance, turn on Wi-Fi devices prior
to turning on GLX-D and scanning for
the best channel. GLX-D detects and
avoids other Wi-Fi traffic by scanning
the entire 2.4GHz environment and
selecting the 3 best frequencies to
transmit on. The result of this is reli-
able performance for your GLX-D wire-
less system as well as avoiding Wi-Fi
transmissions which may be important
as well.
"Bursting" Wi-Fi is harder to detect
as it is periodic; however, because
GLX-D repeats the most important
information, even bursts at very high-
levels don't have an effect on your
audio performance.
• Locate competitive 2.4 GHz receivers away from each other
• Avoid placing transmitter and receiver where metal or other dense
• Move the receiver to the top of the equipment rack
• Keep transmitters more than 2 meters (6 feet) apart - this is less
• During sound check, mark trouble spots and ask presenters or
• If there is a known strong source of Wi-Fi and you specifically want
Group 2: Channels 1-5 (latency = 7.3 ms)
Group/Channel Frequencies
2/1 2423 2424 2443 2444
2473 2474
2/2 2404 2405 2426 2427
2456 2457
2/3 2410 2411 2431 2432
2448 2449
2/4 2417 2418 2451 2452
2468 2469
2/5 2437 2438 2462 2463
2477 2478
Challenging Wireless Environments
Some environments are more difficult than others for
2.4 GHz wireless system performance. Additionally,
body absorption has a greater impact in the 2.4 GHz
spectrum, compared to the UHF spectrum. The sim-
plest solution in many cases is to reduce the transmit-
ter to receiver distance such as placing the receivers
on the stage with a clear line of sight.
Challenging environments include:
• Areas with few reflective surfaces such as:
• Outdoors
• Buildings with very high ceilings
• 3 or more GLX-D receivers in use
• Strong Wi-Fi presence
• Competitive 2.4 GHz systems in use
materials may be present
critical at shorter receiver to transmitter distances
Note: If transmitters are within 6 inches of non-GLXD transmitters or micro-
phone cartridges, audible noise is possible.
performers to avoid those areas
to use frequencies within that Wi-Fi channel, use the following
Group/Channel of GLX-D (best option listed first):
• Group 3/Channel 8, Group 3/Channel 4
Wi-Fi 1:
• Group 3/Channel 7, Group 3/Channel 5
Wi-Fi 6:
• Group 3/Channel 2, Group 3/Channel 1
Wi-Fi 11:
Group 3: Channels 1-8 (latency = 7.3 ms)
Group/Channel
3/1
3/2
3/3
3/4
3/5
3/6
3/7
3/8
Frequencies
2415 2416 2443
2422 2423 2439
2426 2427 2457
2447 2448 2468
2409 2451 2452
2431 2462 2463
2404 2473 2474
2435 2477 2478