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MAS Frequency Engineering
Frequently Asked Questions

What is an MAS system?

MAS systems are defined as Fixed Wireless, low-capacity, Point-to-Multipoint Systems where a Master Transmit Station will communicate to four or more remote facilities. The Master Stations are typically used to collect data from the remote stations and to send control commands to these remote stations. Typical MAS applications include utility company data collection; controlling railroad crossing signals; monitoring and controlling valves along gas and water pipelines; collecting data from ATMs and Lotto machines; and monitoring building security systems.

What companies manufacture equipment for MAS?

To locate an MAS equipment manufacturer, proceed to our VendorLocator. We will provide you with a list of companies and their contact information.

What spectrum is available for MAS operations?

There is a total of 3.2 MHz of spectrum in the 900 MHz band available for MAS usage. The specific frequency assignments are listed in Section 101.147 of the FCC Rules.

• 68 paired, 12.5-kHz channels in the 928-928.85 MHz and 952-952.85 MHz band. This 1.7 MHz of spectrum is commonly known as 928/952 MAS.
  
  
• 16 unpaired, 12.5-kHz channels in the 956.25-956.45 MHz band. This 200 kHz of spectrum is commonly known as 956 Unpaired MAS. This portion of the spectrum is reserved for simplex and half-duplex operation. Mobile operations, such as hand-held meter readers, often utilize this part of the spectrum. Though this type of system operates as a duplex system, it is licensed as simplex because the return frequency from the remote is an unlicensed frequency under FCC Rule Part 15.
  
  
• 6 25-kHz channel pairs in the 928.85-929 MHz and 959.85-960 MHz band. This 300 kHz of spectrum is commonly known as 929/959 MAS. These channels are designated for, and used primarily by, common carrier operations under Part 22 of the Rules and are authorized for private radio use on a co-primary basis, pursuant to certain sharing criteria. Limited system expansion currently exists in this band.
  
  
• 20 12.5-kHz channel pairs in the 932-932.25 MHz band and 941-941.25 MHz band. The five uppermost channels are designated exclusively for public safety and Federal Government uses. This 500 kHz of spectrum is commonly known as 932/941 MAS.
  
  
• 20 12.5-kHz channel pairs in the 932.25-932.50 MHz band and 941.25-941.50 MHz band will be geographically auctioned and licensed based on the U.S. Department of Commerce's definition of Economic Areas (EAs).
  

Who is eligible to own an MAS license?

FCC rule section 101.1301 defines eligibility for MAS. Rule section 101.1309(a) states that MAS systems licensed by Federal Government, Public Safety, and Operational Fixed Users should be used for internal business purposes only and are not to be employed to provide service on a for-hire or for profit basis.

What are my options if I am not eligible to operate an MAS facility?

Since MAS is a low-capacity band, a logical choice for operators who are not eligible would be to check their eligibility in the narrowband point-to-point bands in the 932.5-935 MHz and 941.5-944 MHz as well as the 953/956 MHz Band.

What are the interference criteria for MAS?

MAS interference criteria is distance based according to rule section 101.105(c)(3)(i).

Distance criteria is as follows:

Fixed - Fixed: 145 km
Fixed - Mobile: 113 km
Mobile - Mobile: 81 km

Comsearch can provide a preliminary and detailed interference analysis that determines if a proposed MAS facility meets the distance criteria.

What are my options if I cannot meet the required interference criteria for MAS?

If none of the MAS bands have clear frequencies available, you may consider trying to obtain a "Sharing Agreement." A sharing agreement is a mutual agreement between two or more MAS operators to have co-channel operation with substandard distances between facilities. Usually this can be agreed upon between carriers if there is significant terrain blockage between stations or if the distance between stations is just a few kilometers short of the criteria.

Comsearch provides the potential options for sharing agreements, and we can help provide support to make the sharing agreement a reality.

What are some of the operating requirements of an MAS facility?

• An MAS system must have at least four remote stations.
• EIRPs are limited according to FCC rule part 101.113. It is easy to inadvertently exceed the EIRP in the 932 MHz band. The EIRP limit in this band is 47 dBm.
• The Master frequency (by convention) is designated "high."

How do I license my MAS facility?

Most MAS facilities are licensed under CFR 47, Part 101 of the FCC Code of Federal Regulations. The licensing form is the FCC Form 601. Comsearch can provide filing services if you desire.

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