The radio frequency spectrum is quite broad. You can use some of the different areas for your wireless equipment out of this whole spectrum. However, some of these areas are better than others, which keeps on changing. As a result, which radiofrequency one must choose is always a hot topic for discussion. You must know that a frequency spectrum has only a finite amount to share.
Besides, people working in the exact location must use different frequencies. Every country permits a particular frequency range for wireless devices. Thus, if you pick a wireless system in one country, it may not be legal in other countries.
Here is the wireless microphones frequencies chart that mentions the most common frequency ranges used in the US. Before that, let’s have a clear picture of the basics of wireless microphone operations.
Table of Contents
- Types of Wireless Microphone Operations
- The transition of Wireless Microphone Operations out of Certain Bands
- Wireless Microphones Frequencies chart (U.S)
- Conclusion
Types of Wireless Microphone Operations
Wireless microphones can operate under two conditions, either licensed or unlicensed.
Licensed microphone operations
According to the FCC rules, part 74, subpart H, some wireless microphone users can get LPAS （low power auxiliary station）licenses. With this license, users can operate unused TV channels in the television band. However, they have to share this band with other users.
Remember that users will get a secondary status under this license, protecting primary TV broadcast operations from any interference. In addition to this, they have to accept any interference from other operating users.
The users of the part 74 license include broadcasters and TV programs production units. In 2014, FCC made two new categories as eligible entities. One was large venue operators, and the other was professional sound companies. If one wants to get a license under this new category, applicants must use 50 or more LPAS devices daily. Further, one must use such devices for significant events and production.
Some wireless microphone users can also get a license under part 74 for other spectrum bands. These mainly include portions of the 900MHz band, the 1435-1525 MHz band, and the 6875-7125 MHz band. However, permitted categories must operate with some conditions. They must use 50 or more LPAS devices for their significant events or productions.
It is essential to protect licensed operations from unlicensed devices in the TV spectrum. The FCC permits the users to register their operations in the white space database. With this registration, wireless microphone users and other LPAS equipment users get protection. They can write their operations’ locations, channels, and times in the white space database. In addition, they will get interference protection from other unlicensed white space devices.
Image: a device for transmitting and receiving the radio signal
Unlicensed wireless microphones
In 2015, the FCC made rules for unlicensed wireless microphone users to use the TV spectrum. Today, many wireless microphone users work on an unlicensed basis. However, this permission comes with certain restrictions.
- Firstly, their power is low as compared to licensed operators.
- Secondly, they must not cause any harmful interference.
- Lastly, they must accept any interference from other users operating in this band.
Under the FCC part 15 rules, unlicensed users can also operate on other frequency bands. These frequency bands include the 902-928, 1920-1930 MHz, and 2.4 GHz.
The transition of Wireless Microphone Operations out of Certain Bands
FCC once made rules to reorganize the existing band for wireless broadband and public safety services.
Transition out of the 600 MHz Band
In 2014, the FCC organized an incentive auction for the broadcast television spectrum. This auction repurposed 617-652 MHz and 663-698 MHz bands for wireless licensees. As a result, this spectrum will not be available for the wireless microphone after July 13, 2020.
The FCC allowed a transition period of 39 months for all wireless microphone operators. However, they had a constraint with this. Their operations must not cause any harmful interference to the 600 MHz licensee’s operations. Further, they must stop their operations in areas where a 600 MHz service licensee has started its operations or is performing its first filed application testing. And they must get new equipment during this period and leave their operations from the repurposed 600MHz service band.
After this transition period, microphone operators can access the 600 MHz spectrum under certain conditions. These were:
- Don’t create any harmful disturbance to the already operating broadcast television operators or 600 MHz service licensees.
- Accept any interference from the users mentioned above.
The broadcast television channels 2-36 were using TV bands below 608MHz. However, the FCC allowed secondary use of this band for all licensed/unlicensed wireless microphone users. Other than this, specific frequencies (653-657 MHz) come under the 600MHz duplex band. Licensed wireless microphone users can operate on these frequencies.
Unlicensed wireless operators can also operate on a small portion of the 600 MHz band, i.e., from 614-616 MHz guard band and in the 600 MHz duplex gap (657-663 MHz).
Image: radio communication device, radio frequencies
Wireless Microphones Frequencies Chart–Transition out of the 700 MHz Bands
In 2010, the FCC banned the operations of all wireless microphones in the 700 MHz band. These devices included all wireless intercoms, audio instrument links, and in-ear monitors. As a result, the FCC banned the manufacture, import, lease, sale, and shipment of wireless microphones used in the 700MHz band.
Wireless Microphones Frequencies chart (U.S)
There is no frequency reserved for the wireless microphones systems. All the wireless microphones share their frequencies with other devices. The chart below helps you find which frequency is available for unlicensed users, available for licensed users, and unavailable for wireless microphones and personal monitors.
Image: wireless microphone frequencies chart
Source: https://www.shure.com/en-US
Conclusion
If you use a wireless microphone system, make sure you pick the right frequency. The frequency band that you use must match your country’s rules and regulations. If you need any help installing wireless microphone systems, we are here to help you. We also deal in high-quality cable assemblies to support your wireless plan.
