FCC approves FM for CB Radio

Many thanks to SWLing Post contributor, Ron who shares the following news via the Southgate ARC:

FCC signals FM CB will be permitted on 27 MHz

63 years after the introduction of Class D 27 MHz AM CB Radio the FCC has agreed to permit FM to be used

From FCC Memorandum Opinion and Order on Reconsideration WT Docket No. 10-119, issued July 15, 2021:

What the Memorandum Opinion and Order on Reconsideration Would Do:

• Grant Cobra’s Petition requesting that the Commission allow FM as an optional modulation scheme for all existing 40 CB Radio Service channels (with AM remaining mandatory).

• Grant Motorola’s Petition requesting that the Commission allow automatic or periodic location and data transmissions in the GMRS and FRS. The Commission’s rules currently permit the transmission of location information and brief text messages initiated by a manual action and automatic responses of location information.

• Grant Medtronic’s Petition requesting the correction of typographical errors and rule changes in the Part 95 Personal Radio Services Rules Report and Order that inadvertently altered the substance of the Medical Device Radiocommunications Service (MedRadio) rules

The FCC say:

After considering this additional information, we conclude that allowing manufacturers to add FM as an optional modulation scheme will not substantially change the fundamental nature of the CB Radio Service and will improve the user experience, as described by Cobra and President. How people use the service will not materially change or be expanded. Further, Cobra states that AM is a “well established” operating mode that is unlikely to disappear, even if we permit operations in FM mode.

Continuing to mandate AM capability while permitting dual modulation will provide benefits to CB radio users who will have an additional modulation option, while maintaining the basic character of the service.

The addition of FM as a permitted mode will not result in additional interference because users who hear unintelligible audio on a particular channel can simply select another channel or switch modes.

Read FCC Memorandum Opinion and Order on Reconsideration WT Docket No. 10-119

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21 thoughts on “FCC approves FM for CB Radio

  1. Robert Clark

    The CB radio is great for outdoor use, for quick updating on what is going on currently. If you want to operate your small radio station, you can make use of the ham radio.

  2. Bear

    Here in the UK, we had several years of illegal am/ssb CB in the 70s, with the commie UK govt. saying they would never legalise CB radio! Then in the autumn of 1981, they announced that CB would be legalised on the upper part of 27MHz, and fm only, plus 20 more fm channels on the near microwave frequency of 934MHz, so 60 legal CB channels in total. Many folks wanted to carry on with the am or am/ssb radios they already owned. As the years went on, we were allowed radios with the EU fm channels [same as the US channels], and eventually am and then ssb followed on those EU/UK channels 934MHz was closed down at the end of 1988, the equipment which worked very well, was so expensive to buy [up to £500 for a radio], people couldn’t afford it, so it never caught on. That said, there was more activity on 934 than 2m & 70cms combined, which remain untouched. These days, the original legal UK 27/81 channels as they’re known, remain our most popular CB channels – tho much less used than they were 40 years ago!

    1. yh. kim

      This is South Korea.
      I used 27MHz in 1987-1988.
      About 100 to 200 CB stations were active.
      I used the X-tal TRX, KRACO-1307 (4W-AM).
      I made and used 3ele yagi and GP. 16M high.
      Building Antennas is very fun.
      Nowadays, most CB are mobile stations & local communications.

  3. James A. Spruyt

    FM is a non-starter. CB is ch 35-40+ SSB. FM in a new band plan between 11 and 6m would have been cool. Mostly local with occasional skip openings using verticals. Still hoping for an 8m amatuer band in the USA but won’t hold my breath.

  4. DB

    Wait a minute…

    Some old CB radios like the SuperStar 3900, Cobra 148 GTL-DX, Stalker 9 DX, Uniden President Grant, President Jackson, and others *already had FM*, and they are all 1980’s radios made in the USA, afaik.
    Or were they made in Europe or Asia and I am utterly wrong?

    At least here in Argentina there were several of them in service, before VHF and UHF became the standard for land radios.

    1. Paul C.

      Those multimode sets such as the Cobra 148GTL-DX (a.k.a. Superstar 360 FM) and the Stalker 9-DX were never made in the U.S.A. nor were they legal to use here, or almost anywhere else for that matter. These units were variously made in Japan, Taiwan, and South Korea, before in later years production shifted to China. They were often referred to as “Export radios,” which is perhaps where some confusion might arise, since the same far eastern manufacturers also built plenty of FCC-compliant AM/SSB transceivers for the American market, which obviously were exported as well!

      Note: There was the Stalker ST-9F DX multimode which was sold in the U.K. and was legal to use there in its unmodified, factory form, since it could transmit only on the 40 U.K. FM channels which were assigned in 1981. It could also receive AM/SSB/FM on FCC/European channels, and was easily modified to restore transmit capability on those channels/modes, although doing so rendered it illegal to use, of course.

  5. John K5MO

    “The addition of FM as a permitted mode will not result in additional interference because users who hear unintelligible audio on a particular channel can simply select another channel or switch modes.”

    This is classic “bureaucrat speak” of the finest vintage!

    I’m surprised they didn’t say “no interference will be caused because the users who hear “unintelligible audio” (aka: Interference) can always turn the radio off”


  6. Dennis Dura

    I didn’t see any mention in the Docket about adding FM to a dual mode radio with AM/SSB now. If so, it’ll be easy for a few of the manufacturers that already offer 10 meter rigs with all three… Anytone and the variety of names they use on the same radio.

  7. Tha Dood

    YES!!!! It’s indeed about time to do NBFM on 27MHz CB’s in the USA. Should be less interference, lower power on the radio output finals, better S/N Ratios, possibly longer battery life on portables, etc. I see a big Win / Win here. But, you don’t have to wait on Cobra, there’s a dude in the UK that is making CB FM boards to modify your existing rigs, https://www.ebay.com/itm/283737307487 I’ve already bought two of these. Now, to decide which rigs to add FM too. They appear very straight forward and cleverly designed.

  8. K5MPH

    Its about time the FCC is sometime way behind times in all this radio stuff and what we call a hobby,this may bring a new life into CB radio………..

    1. Ryan

      thanks for the links!
      It seems the link for the confidential history of ham radio is the same for the CB radio. Could you please tell me which issue it is in, I would love to read it

    2. Michael Black

      May 1969 Electronics Illustrated, page 68 “Skeletons in CB’s Closet”. Some history of what 27MHz was used for before CB.

      Don’t forget that about 1947, there is as “CB” at 450MHz. But equipment too expensive at that frequency and time, so it didn’t get many users. GMRS is kind of descended from it.

      Canada waited a few years after the US before creating a “General Radio Service” that was mostly the same as CB in the US. I thought FM was allowed, but it’s been a long time. A significant difference was a few channels were not allowed in Canada, so a tiny 11 metre ham band continued. It didn’t get removed until April 30th 1972, when the missing channels became CB. I don’t think there were antpy Canadian made CB sets, so it relied on sets for the US market. Since there were 23 channel sets before 1972, I wonder if people were really good about not using those extra channels.

  9. 13dka

    Well… that took a while. 🙂

    In Germany, the first 12-channel (500mW) radios with FM came in 1977, an expansion of the band to 22 channels in 1981 brought the first mode limitation to FM for the new channels, based on concerns about interference through AM. In 1983 the regulator allowed 40 channels FM with 4W and the old 12 channels in between with 1W AM, the 8-fold TX power compared to the initial regulations clearly helped with the adoption of the formerly much despised mode.

    10 years later, the only channel still being used in AM on a regular basis was CH9, FM wasn’t so bad after all: People had realized that you could get away with much higher illegal power levels than you ever could in AM. 🙂

  10. rtc

    Keep in mind that 60 years ago (1958) the “state of the art” was still tube based and FM gear
    was bulky and expensive.That’s why the first generation CB gear was crystal controlled single channel with
    a super-regen tunable (broad) receiver.
    A quick search of the internet shows that most CB websites feel that Cobra and President are just looking to
    sell new radios with the FM mode.
    We’ll see.

  11. mangosman

    In Australia, this was an option a long time ago and was dropped because very narrow band FM performance approaches AM in the 27 MHz. We have 476.4250 and 477.4125 MHz FM CB radio which is now much more popular than 27 MHz. These UHF frequencies are used in the Americas and Europe for TV.
    In the 27 MHz band, SSB (12 W)/AM (6W) is used instead. The use of SSB means a doubling of the available channels compared to AM and FM. The range is increased because all of the battery power is used for the voice signals and not wasted on an AM carrier and for FM the power output of the transmitter is constant. With SSB silence means no power transmitted and the greater the volume of the sound the greater the power transmitted.

    As Desmond mentioned CB radio is very old, and has been replaced by digital two way radios in many professional situations such as the emergency services, mining companies….. The advantage is that they have selective calling better sound, 20 % increase in coverage and upto 50 % longer battery life.
    Check out two way radios for the VHF high band and UHF.

  12. Desmond Walsh

    Reading the FCC document I cannot see any reason why they did not adopt NBFM for CB 50 years ago. Lots of lines about FRS, UHF etc but little about 27MHz . Anyway it may interest a few people.
    Des Walsh EI5CD


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