USA Tour - best wireless frequencies for all cities

USA Tour - best wireless frequencies for all cities

Date Updated: September 25, 2019 FAQ #4018
Question:
What are the best wireless microphone and/or personal monitor frequency bands to provision for traveling and performing throughout the United States?
Answer:

Using a wireless microphone system on a nationwide tour is challenging due to the lack of dedicated, nationwide spectrum in the United States. Shure's Axient Digital wireless microphone system is the only Shure wireless microphone system that offers full coverage of the UHF TV band, from 470 MHz to 616 MHz (less TV Channel 37, 608-614 MHz, where operation has never been permitted), and is highly recommended for nationwide tours. Users who only need a couple of wireless microphones may want to consider the QLX-D and ULX-D systems in the J50A, which can operate in the nationwide LTE Guard Band between 614 MHz and 616 MHz.

Shure recommends that any anybody planning a nationwide tour coordinate frequencies for each tour stop well in advance of the tour to ensure that equipment on hand will work at each tour stop. Shure's Wireless Workbench tool can be used to do this quickly and easily. Remember that you will need to coordinate all wireless microphones, in-ear personal monitor systems, and intercoms that will be used at each tour stop, including equipment already at the venue. Doing this homework in advance will provide adequate time to schedule available equipment and if necessary to rent additional wireless equipment. It will also minimize set-up time at the venue. The needed TV broadcast information is readily available from Shure's Frequency Finder or Wireless Workbench.

The type of venue can affect the frequency selection process.  Here are some characteristics to keep in mind:

  • Is the venue an indoor or outdoor facility?  Because of their construction (steel and concrete), indoor venues sometimes provide attenuation of external signals that can interfere with wireless microphone operations. Outdoor venues can be more difficult due to direct exposure to TV broadcast signals. 
  • Where are the TV broadcast stations located with respect to the venue?  Frequently, but not always, the major and some of the low-power TV stations locate their transmitters and antennas in the same general vicinity.  If the venue is some distance away, there may be some additional flexibility in selecting frequencies due to reduced signal levels.  On the other hand, watch out for venues that are located near TV broadcast sites.  For example, some low-power broadcast stations whose transmitters and antennas are not located with the major broadcast stations, may be situated on tall buildings in a downtown area.  If the performance venue is in a downtown area, special care will be needed to avoid their strong signals.
  • What equipment is already on-site? Be sure to ask the venue for a list of equipment and frequencies in-use at the venue. Often times, lobby microphones and other wireless equipment in adjacent spaces may be forgotten, so follow-up and ensure your list is complete so that you can factor these into your equipment coordination.

When planning frequency assignments, be sure to perform band planning for each category of equipment.  For instance, best practice calls for operating personal monitor transmitters and intercom systems in different frequency ranges from microphones to prevent interference issues.

Proper placement of antennas is critical to successful wireless systems on tours. Locating receiving antennas closer to the wireless microphones will help improve the desired to any undesired signals received ratio.  While the ambient RF noise level will remain relatively constant throughout a venue, locating the receiving antennas closer to the microphone transmitters increases the received signal strength of the microphone transmitters (inverse square law), and in turn improves the desired signal-to-noise ratio.  Also, personal monitor transmitting antennas should not be placed close to the wireless microphone receiving antennas. The rule of thumb is to maintain at least 15 - 20 feet of separation.  This method minimizes chances for intermodulation distortion interference and receiver front end overload that can result in receiver de-sense, and resulting audio dropouts.  

In some cases, the technical support staff may need to carry some sort of RF Spectrum Analyzer to confirm the available frequency spectrum upon arrival at each venue. The spectrum analyzer tool can also be used to confirm or troubleshoot received signal strengths at the venue. Shure's AXT600 Spectrum Manager and our QLX-D, ULX-D, and Axient Digital receivers can be used to scan the spectrum and determine what frequencies are available for operation.

Following is a list of metropolitan areas that will be most challenging when doing frequency coordination.  These cities require special attention when planning compatible frequencies in what may be a limited amount of available spectrum.  Also keep in mind that some of these metropolitan areas are large enough geographically that broadcast TV signal levels may vary from one area to another.  In addition, some TV broadcast stations use directional antennas, which may cause some additional signal strength considerations, either good or bad.

Tier 1 "Most Challenging" Metropolitan Areas

  • Dallas/Ft Worth, TX
  • Houston, TX
  • Los Angeles, CA
  • New York, NY*
  • Miami/Ft Lauderdale, FL

Tier 2 "Somewhat Challenging" Metropolitan Areas

  • San Francisco Bay Area
  • Denver, CO
  • San Antonio, TX
  • Chicago, IL
  • Detroit, MI
  • Boston, MA
  • Philadelphia, PA
  • Baltimore, MD
  • Washington, DC
  • Atlanta, GA
  • Orlando, FL

*New York has a number of open UHF television channels, but because of the density of entertainment venues in the city, it can be challenging to find spectrum to operate on in a particular venue. It is recommend that users contact the venue in advance for information on the best frequencies and bands to operate in. Users of more than six channels of wireless may want to contact local New York-based audio vendors who can assist with frequency coordination and rental, if necessary. Operation near Midtown Manhattan may require coordination with the Society of Broadcast Engineers. Most TV stations broadcast from the Freedom Tower in Lower Manhattan, with backup facilities near midtown. Some TV stations broadcast from New Jersey. Avoid public safety channels.