Can AM mode be used on the ham bands (Region 1)?

Discussion in 'Amplitude Modulation' started by SV3ORA, Mar 7, 2021.

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  1. SV3ORA

    SV3ORA Ham Member QRZ Page

    I would like to know if AM phone mode can be used legaly on the ham bands on IARU region 1 and in which segments of the bands?
    According to wikipedia, 6khz channels are not allowed, which also leaves out these homebrew DSB sets.

    Please give some light here.

    (A note to the forum admins, I still cannot receive emails when a reply is posted to any of the posts I do)
  2. KS2AM

    KS2AM Ham Member QRZ Page

    According to the most recent IARU band plan I'm familiar with, AM phone can be used in the phone sub-bands in Region 1. See

    I believe that there is semi-regular AM activity in Europe and some of those stations are regulars on
  3. G8FXC

    G8FXC XML Subscriber QRZ Page

    You also need to distinguish between the IARU band plan and the terms of your licence. The band plan has no legal force, your licence does. It's bad manners to transmit AM in the middle of a designated CW sub-band, but there is probably nothing in your licence that says you must not do it...

  4. SM0AOM

    SM0AOM Ham Member QRZ Page

    The most common bandwidth restriction on HF is 8 kHz in the European regulations. Some countries have no limits at all, only the band edges.

    IARU Region 1 band plans are sometimes incorporated by reference in the regulations, but their legal force is quite uncertain.

    The closest to a ban on DSB-AM (A3E) is found in the German regulations, where for bands below 28 MHz, a maximum occupied bandwidth of 2700 Hz is prescribed.

    It is however unclear if this is actually enforced,
    but in Germany "Befehl ist Befehl"...

    KD2ACO likes this.
  5. K4KYV

    K4KYV Premium Subscriber Volunteer Moderator QRZ Page

    And remember the distinction between occupied and necessary bandwidth:

    Occupied bandwidth: The width of a frequency band such that, below the lower and above the upper frequency limits, the mean powers emitted are each equal to a specified percentage B /2 of the total mean power of a given emission. Unless otherwise specified by the CCIR for the appropriate class of emission, the value of B /2 should be taken as 0.5%. [NTIA] [RR] (188) Note 1: The percentage of the total power outside the occupied bandwidth is represented by B . Note 2: In some cases, e.g. , multichannel frequency-division multiplexing systems, use of the 0.5% limits may lead to certain difficulties in the practical application of the definition of occupied and necessary bandwidth; in such cases, a different percentage may prove useful.

    Necessary bandwidth: For a given class of emission, the width of the frequency band which is just sufficient to ensure the transmission of information at the rate and with the quality required under specified conditions. [NTIA] [RR] (188) Note: Emissions useful for the adequate functioning of the receiving equipment, e.g., the emission corresponding to the carrier of reduced carrier systems, must be included in the necessary bandwidth. (188) (See Annex J of NTIA Manual of Regulations and Procedures for Federal Radio Frequency Management for formulas used to calculate necessary bandwidth.)
  6. SV3ORA

    SV3ORA Ham Member QRZ Page

    I should find first the local regulation, I guess. I will ask at local clubs, although I am not sure they will know for this old mode.
    WA3VJB likes this.
  7. G3YRO

    G3YRO Ham Member QRZ Page

    Do you not have an actual Licence you can read?

    Our British Licence allows us to use proper A.M. (ie Double Sideband, full Carrier) on all the main bands . . . and there is no actual restriction on what part of the band you can use.

    And it may be an "old mode" . . . but it's still used on the Medium Wave and Long Wave broadcast bands . . . as well as by all Aircraft on VHF !

    Roger G3YRO
    WA3VJB and K4KYV like this.
  8. SM0AOM

    SM0AOM Ham Member QRZ Page

    According to information at the RAAG website, the Greek Ministry of Transport and Communications rules;
    ΥΑ-38200_1136-Κανονισμός-λειτουργίας-ερασιτεχνικών-σταθμών-ασυρμάτου.pdf incorporates the IARU Region 1 band-plan by reference.

    Here, a maximum bandwidth of 2700 Hz on HF is stated, but a footnote further states that DSB-AM is also permitted.

    If I may have a theory, the Authorities have more profitable matters to worry about...

  9. K4KYV

    K4KYV Premium Subscriber Volunteer Moderator QRZ Page

    Of past legal bandwidth proposals in the US, the infamous Docket 20777 would have outlawed DSB AM by imposing a strict 3.5 kHz limit to occupied bandwidth. The ill-fated ARRL Regulation-by-Bandwidth petition appeared to have defined band segments in terms of necessary bandwidth. The difference is crucial, as explained above (see msg #5).

    Regulation by necessary bandwidth would not inherently limit occupied bandwidth, so carefully-worded necessary-bandwidth regulation in itself would not affect the legality of AM nor impose specific limits to transmitted bandwidth using any mode. "Necessary bandwidth" could be a way of lumping together various emission types without having to spell out an exhaustive list.

    Unfortunately, most countries that have included "bandwidth" in their rules have defined it in terms of occupied bandwidth. For example, Canada has a 6 kHz limit to occupied bandwidth, although I have never heard of any attempt to enforce it, and Canadians running AM never elaborate on any attempts they have made to limit their occupied bandwidth beyond the standard practice used in the US and elsewhere. Germany has imposed a specific 2700~ limit to occupied bandwidth, apparently outlawing AM, similarly to the US proposal under Docket 20777.

    Attached Files:

  10. WA3VJB

    WA3VJB Ham Member QRZ Page

    Actually, German government regulators have NEVER imposed a specific limit against AM, according to a fairly recent check by someone questioning the status. (thanks, Frank N.) There is a widespread misunderstanding in that country that the non-binding, outdated suggestions from the IARU are the same as a "real" rule, but history has documented an explicit bias against AM in that group years ago among uninformed volunteer planners.

    In the PDF, above, you can see the hobbyist group has included a "footnote" in its non-binding suggestions, that acknowledges unrestricted use of AM, in accordance with German government regulations.

    For our Greek correspondent SV3ORA who originated the question here, your government has apparently referred to the same suggested band plan, which would have the same "footnote" that avoids restricting AM.
    Last edited: Mar 10, 2021

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