Best practices for UHF Series wireless systems

FAQ #3292 Updated September 20, 2012


How does Shure recommend using my UHF series wireless system to the best capabilities?


UHF Series Best Practices for a Successful Event


  1. Identify the city and state (or zip code ) of your event.
  2. Use this information on the Shure Frequency Reference Guide at:
  3. Select “UHF Wireless” series, use 50 mile (default) lookup radius, submit!
  4. Note the number of available channels in each frequency band.
  5. Choose the appropriate band to accommodate the required number of channels. If sufficient channels are not available or if more than one band is required, call Shure Applications Engineering at 800-516-2525 for assistance with frequency coordination.
  6. If additional UHF range wireless equipment will be used (other wireless microphones, in-ear monitors, wireless intercom, etc.) call Shure Applications Engineering for assistance with frequency coordination.

Setup: Receiver Antennas

  1. Determine area of operation of transmitters.
  2. Determine receiver antenna locations for best line-of-sight to transmitters.
  3. Locate receiver antennas no closer than 15 feet to nearest transmitter.
  4. From the receiver antennas, the most distant transmitter should be no more than four times as far as closest transmitter. Ideally, transmitters should all be at a similar distance from receiver antennas.
  5. Use ½ wave antennas for transmission distances up to 100 ft.
  6. Use active directional antennas for transmission distances beyond 100 ft.
  7. Using Shure antennas:
    UA820A, ½ wave antenna for UA range
    UA820B, ½ wave antenna for UB range
    UA820C, ½ wave antenna for M4 range
    UA820D, ½ wave antenna for J4 range
    UA870A, active directional antenna for UA range
    UA870UB, active directional antenna for UB range
    UA870WB, active directional antenna for ALL UHF ranges
  8. Elevate receiver antennas well above the audience or other obstructions.
  9. Locate diversity antennas at least two feet apart.
  10. Keep antennas at least one foot away from other metal objects.
  11. Keep antennas at least two feet away from RF noise sources such as digital audio processors, video devices, CD/DVD players, computers, etc.

Setup: Antenna cables

  1. Connect antennas to receiver rack using the shortest length of 50 ohm cable.
  2. Using Shure cables:
    UA825, 25 feet of RG-8/X, no amplifier necessary
    UA850, 50 feet of RG-8/X, use amplifier (UA830) at +3dB gain
    UA8100, 100 feet of RG-213/U, use amplifier (UA830) at +10dB gain
  3. Using Shure in-line antenna amplifiers:
    UA830A, in-line +3/+10dB amplifier for UA range
    UA830UB, in-line +3/+10dB amplifier for UB range
    UA830WB, in-line +3/+10dB amplifier for ALL UHF ranges
  4. Do NOT use excessive antenna system gain:
    UA870 must have at least 50 ft. transmission distance
    UA870 or UA830 @+3dB must use at least 25 ft. cable
    UA870 or UA830 @ +10dB must use at least 50 ft. cable
  5. Protect antenna cables from kinking, crimping or crushing.

Setup: Antenna distribution

  1. Choose antenna distribution devices appropriate to the receiver frequency range.
  2. Multiple ranges will require multiple distribution systems or a single wideband distribution system.
  3. Using Shure antenna distribution:
    UA221, passive 2-way splitter for two receivers in ALL UHF ranges
    UA844US, active 4-way splitter for up to four receivers in ALL UHF ranges
    UA845UA, active 5-way splitter for up to five receivers in UA range
    UA845UB, active 5-way splitter for up to five receivers in UB range
    UA845US, active 5-way splitter for up to five receivers in ALL UHF ranges
  4. Using multiple active splitters:
    1. One “top level” splitter UA844 (or UA845) can feed up to 4 (or 5) “second level” splitters.
    2. “Second level” UA844 (or UA845) splitters can feed up to 4 (or 5) receivers.
    3. “Second level” UA844 (or UA845) splitters may NOT feed additional active splitters.
  5. Connect A and B antenna cables (or antennas) directly to splitter A and B antenna inputs.
  6. Connect splitter outputs to appropriate receiver antenna inputs.

Setup: Receivers

  1. Program receivers with Group and Channel set from “Preparation” section.
  2. Programming Shure U4 receivers:
    1. Use only “Numbered Groups”: UA, Groups 1-7; UB, J4, M4, Groups 1-10.
    2. Within a given band, ALL systems should be set to the same Group and different CHANNELS within that Group. DO NOT MIX GROUPS!
    3. DO NOT USE LETTER GROUPS: A1-A9, B1-B4 unless specifically instructed by Shure Applications Engineering!
  3. Set output mic/line switches as necessary.
  4. Set front panel output level controls fully clockwise (recommended).
  5. Program receiver “Names” as necessary.

Setup: Transmitters

  1. Program transmitters to match receiver Group and Channel set.
  2. Set transmitter audio levels:
    1. U1 bodypack transmitter: set input attenuation switch on back to “0” or “-6” for lavalier microphone, “-6” for headworn microphone.
    2. U2 handheld transmitter and U1 bodypack transmitter: adjust gain control in battery compartment so that red LED peak light on U4 receiver just flashes on LOUDEST sound.

Pre-show Checkout

  1. Verify good batteries in each transmitter.
  2. Turn OFF all transmitters.
  3. Turn ON all receivers.
  4. Observe RF signal LED strings on receivers:
    1. 0-2 LEDs on either side: channel is OK
    2. 3 or more LEDs on either side: channel has excessive interference. Change to another compatible channel if available and change corresponding transmitter accordingly.
  5. Turn on each transmitter ONE at a time to verify signal at corresponding receiver. Transmitters must be at least 15 feet from any receiver antenna.
  6. Turn on all transmitters to verify signals at all receivers. Transmitters must be at least 15 feet from any receiver antenna AND transmitters must be at least 3 feet from each other.
  7. Conduct a walk around test for each transmitter throughout the performance area. If locations of low RF are found, reposition receiver antennas to compensate if possible. If set pieces or other fixed obstructions are problematic, the allowable performance area may have to be modified.

Show Operation:

  1. Turn on required receivers.
  2. Mute or turn off unused receivers
  3. Turn on required transmitters. Transmitters must be at least 15 feet from nearest receiver antenna.
  4. Verify reception at receivers.
  5. Place transmitters with participants.
  6. Using Shure U1 bodypack transmitter:
    1. Attach to participant as high on the body as possible: breast pocket of jacket, belt, etc.
    2. Do not fold or shorten bodypack antenna.
    3. Do not allow participant to sit on bodypack.
    4. Position lapel microphone as close as possible to mouth: knot of tie, collar, lapel, etc.
    5. Aim directional microphones (WL184, WL185, WL51) toward mouth.
    6. Position omnidirectional head-worn microphone at corner of mouth (WBH53, WCE6).
    7. Position unidirectional head-worn microphone slightly forward and to the side of mouth (WBH54, WH20, WH30, WCM16).
    8. Power lock transmitter if desired (press and hold “Mode” and “Set” buttons together).
  7. Using Shure U2 handheld transmitter:
    1. Do not place hand around or near antenna.
    2. Do not place hand around or near microphone grille.
    3. Maintain consistent mouth to microphone distance: 6-12 inches for talkers, 0-6 inches for singers.
    4. Maintain consistent on-axis orientation: within 130° for cardioid (SM58, SM86, Beta87C), within 115° for supercardioid (SM87, Beta 58A, Beta 87A).
    5. Power lock transmitter if desired (press and hold “Mode” and “Set” buttons together).
  8. Monitor RF levels during show, either on the receiver front panels or by UA111/UA888 computer interface.
  9. Monitor audio levels during show, either on the receiver front panels or by UA111/UA888 computer interface.
  10. Monitor audio directly on headphone outputs on receiver front panels.

General tips:

  1. TURN OFF ALL GSM DEVICES (mobile phones, Blackberrys, Trios, etc.) in the performance area. In particular, do not allow participants to carry active GSM devices. Units must be COMPLETELY OFF, not just on silent. It goes without saying (but we’ll say it anyway) that the engineer and any other staff near the audio equipment must not have active GSM devices!!!!!!!!!!!!!!!!!
  2. Do not allow any staff to operate two-way radio devices near audio equipment, particularly wireless receivers.
  3. Do not cue up un-occupied receivers in the sound system. Receivers without active transmitters should be muted or turned off.
  4. Do not set up system with some transmitters very close to receiver antennas and other transmitters far away. The nearby transmitters can desensitize ALL receivers.
  5. Regularly check center pins on all male BNC connectors, particularly ½ wave antennas.
  6. In the UHF range, line-of-sight is critical: elevate receiver antennas as high as necessary to “see” the transmitters at all times.
  7. Keep losses in antenna cabling to <5dB by USING short cables, low-loss cables, and/or amplifiers.
  8. Keep excess gain in antenna cabling to <10dB by NOT USING too much amplification or directional antennas at short range.
  9. The headphone output is pre-squelch so that non-tonekey signals may be monitored.
  10. Consider using the UA111/UA888 for PC computer hookup of U4 receivers:
    1. UA111 connects to a single U4D or U4S
    2. UA888 connects to eight U4D or U4S
    3. UA888 can be used in multiples for up to 64 receiver channels.
    4. Software allows scanning, walk around, and easy receiver setup.
  11. Consider using a third-party scanner such as WinRadio ( to evaluate the radio environment before and during the event.


“Selection and Operation of Wireless Microphone Systems”, Shure publication AL1247


Call Shure Applications Engineering at 800-516-2525.

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