• The Free Radio Frequencies



    Recently I learned that the FCC is proposing to change a few things in the personal radio service.

    Some History:
    At one time, the only free personal radio service was the CB (Citizen Band) radio service. It is located in the 27 MHz (11 m) area and is limited to 4-Watts of AM (amplitude modulation) or 12-Watts (PEP) for Single Side Band (SSB) output, The basic 27 MHz CB we know today was created in 1958, though it only had 23 channels back then, not the 40 we have had since 1977. The first 22 channels were originally in the Amateur Radio Service band which was moved to 29 MHz and is now called the 10-meter band.



    Changes to CB:
    The big proposed change to CB is the removal of the current distance limit of 155.3 miles. So if you can "skip" across country or even out of the country, I guess it will now be legal. Other changes include being able to use hands-free devices with your CB rig. No power limit change is in view.

    More History:
    The FCC started the FRS (Family Radio Service) in 1996 because CB had too much interference. The FRS changed that by using UHF frequencies and FM (frequency modulation), which is far less interference prone. UHF is also more propagation-predictable and is able to deliver the same short distances of CB with far less power. The frequency range is in the 462 MHz and 467 MHz sections of the UHF (ultrahigh frequency) band with 14 channels. The first seven are shared with the GMRS (General Mobile Radio Service); the next seven are called interstitial channels meaning they are in between the GMRS channels and so were not part of the original GMRS. Last, the power output is limited to 500 mW or 0.5 Watts. While the GMRS is allowed outside antennas and higher power, 50 Watts, there is a downside that it is a licensed service and costs about $70 for a ten-year license.



    Problems cause Changes to FRS:
    The problem in recent years is that, for some reason, the manufacturers have made combined walkie-talkies for FRS and GMRS use. These have 22 channels (some of which are GMRS only) and a user would need a $70 license to use them. While most ethical sellers do inform the buyer of this fact, almost no one bothers to get the license if using these walkie-talkies when using the GMRS-only frequencies. So, the big changes are that these walkie-talkies will now be considered FRS and some of the former FRS/GMRS frequencies will be allowed to transmit with up to two Watts of output power. You can check the references below for the proposed frequencies and power limits, but when the dust settles it may be a little different. I thought that all FRS channels might end up at two Watts of output power, but that remains to be seen because there may be other reasons that the GMRS channels 08 through 14 were limited to 500 mW in the GRMS radios and so that may not be changing. So we see that channels 08 - 14 are still limited to 500 mW but they are now also part of the GMRS. Channels 01 - 07 and 15 - 22 are also now for both FRS and GMRS, and the FRS is allowed to use these frequencies at two Watts of output power. The GMRS can use these frequencies at an output power of up to five Watts for channels 01 - 07 and 50 Watts for channels 15 - 22. By the way, FRS is allowed digital communications modes but Iíve never heard anyone making an FRS radio that does so.

    The Other Free Radio Service, as of Fall of 2000:
    The almost unknown free radio service in the US is the Multi-Use Radio Service or MURS. The big difference here is the "Multi-Use" moniker which means it can not only be used for voice, AM (Amplitude modulation), FM (Frequency modulation), and Angle modulation, it can also be used for data (think WiFi) communications. The frequencies are in the 150 MHz range. There are only 5 channels with two Watts of output power. But, unlike the FRS, one is allowed outside antennas not just the antenna attached to the walkie-talkie and thus the possible range of use is extended for both mobile and home use. The propagation for the 150 MHz range is different from that of both the CB 27 MHz and the FRS 460 MHz frequencies.

    The bottom line is that now the free radio users have some similar choices as Ham (amateur) radio users. We can now use HF (high frequency) using the CB service at 27 MHz, or VHF (very high frequency) MURS at 150 MHz, and the UHF (ultra-high frequency) FRS frequencies in the 460 MHz range and thus choose the service that best fits the task at hand.

    References:
    FCC Personal Radio Service Revisions Will Affect GMRS, FRS, CB, Other Part 95 Devices

    Unlicensed (Part 95) operation:
    CB: Citizens band radio - Wikipedia
    MURS: Multi-Use Radio Service - Wikipedia
    FRS: Family Radio Service - Wikipedia
    FRS/GMRS combined channel chart - The RadioReference Wiki

    Licensed (Part 95) operation:
    GMRS: General Mobile Radio Service - Wikipedia


    All my blog articles are listed at: Karras' Corner
    or
    Karras' Corner Article Links on my KE3FL web site.

    Like what you've read? Register and leave a comment...
    Already registered here? Type away!