Again AM power , A new view

Discussion in 'Amplitude Modulation' started by WA1HLR, Mar 20, 2018.

ad: L-HROutlet
ad: l-rl
ad: L-MFJ
ad: FBNews-1
ad: Subscribe
ad: Left-2
ad: Left-3
  1. SM0AOM

    SM0AOM Ham Member QRZ Page

    The amateur power limits are primarily set only by tradition.

    Originally they were derived from the interference potentials from spark transmitters.
    When international regulation first became implemented in 1927, the US viewpoint of limited power was carried over with a langage that exists still today:

    "25.7 ยง 4. The maximum power of amateur stations shall be fixed by the administrations concerned"

    Up to quite recently this line also was part of the Regulations;
    "having regard to the technical quaUfications of the operators and to the conditions under which these stations are to work."

    The US power limit of 1 kW input became some sort of bench-mark with most other countries adopting limits in this general range.

    This was however "yesteryear".

    If new amateur radio power limits would be derived "from scratch" taking general interference, EMC and EMF exposure into consideration, I am quite convinced that they would end up in the 50 or 100 W range.

    Amateur radio does not "need" any specific power levels, as we do not promise any coverage areas or circuit reliability figures.
    If we existed in a spectrum planned environment, there would exist an interval of power levels for each band.

    The outcome of the discussions at WRC-15 about 5 MHZ (60m) may serve as a guidance in these matters.

    KA0HCP and N2EY like this.
  2. AC0OB

    AC0OB Platinum Subscriber Platinum Subscriber QRZ Page

    AOM: "The amateur power limits are primarily set only by tradition."

    And were arbitrary even then, without any real basis in radio science.

    AOM: "If new amateur radio power limits would be derived "from scratch" taking general interference, EMC and EMF exposure into consideration, I am quite convinced that they would end up in the 50 or 100 W range."

    Again, which exposure study would you use to establish an exposure (limiting) basis? And would it be ERP or PO into a transmission line, or distance from antenna?

    Too many of these studies are based on the faulty "Precautionary Principle" and not good science.

    I have yet to see any study that shows unequivocal biological (genome) damage from the non-ionizing radiation for HF up to VHF for any of the powers used in ARS. For high power commercial FM to microwave, the studies have shown some cell heating only. In FM broadcast, we reduce transmitter power when working on FM antenna systems only because the length of the human body is close to its 1/2 wavelength.

    AOM: "Amateur radio does not "need" any specific power levels, as we do not promise any coverage areas or circuit reliability figures."

    For sure! But we're dealing with government bureaucracies.

    AOM: "The outcome of the discussions at WRC-15 about 5 MHZ (60m) may serve as a guidance in these matters."

    Let's hope not as the WRC does not represent us.

    Last edited: Apr 6, 2018
    K3XR likes this.
  3. K4KYV

    K4KYV Subscriber QRZ Page

    The punitive AM power limit was the result of the agenda of one individual who held the position as chief of the amateur rulemaking division at the FCC under various titles for over a quarter century, and who repeatedly displayed an obvious bias against AM. He hadn't been in that post for more than a couple of years, when he unveiled the infamous bandwidth docket 20777 in April of 1976 at the FCC Forum at the Dayton Hamvention. Titled "deregulation", it would have eliminated AM altogether on all amateur bands from 160m through 15m, by imposing a strict 3.5 kHz limit to occupied bandwidth. Largely due to the activism of a small core of members of the AM community, word was spread in those pre-internet days and a large number of opposing comments were submitted to the FCC in response, and the proposal was ultimately rejected. But during his tenure at the FCC, we lived through the "document-a-month" era in which a continual stream of ill-conceived, poorly thought-out rulemaking dockets were released, some of which would have radically changed the the very nature of amateur radio. "Coincidentally", many of those proposals "just happened" to include language whose collateral damage would have adversely affected AM. That's when the p.e.p. concept first reared its ugly head.

    One proposal, touted as "restructuring", would have limited Generals to DX-100 class power, and higher class would have suffered a substantial power reduction, under a p.e.p. input limit. A so-called "Plain Language" proposal would have re-written the rules to the same dumbed-down Q-A format as the CB rules, and would have imposed a 7 kHz limit to occupied bandwidth for AM. Another subsequent proposal would have included a p.e.p. output limit that would have cut AM power. None of those proposals made it into Part 97, until the 1983 docket specifically dedicated to the power issue was released, and it was immediately obvious that this one would be passed come hell or high water.

    Once the power limit was changed in the U.S., many other countries adopted copycat pee-e-pee rules as their amateur radio power standard as well.

    The AM power saga is fully documented and posted on the FCC's ECFS website:

    Part 1:

    Part 2:

    As well as here on
    N2EY likes this.
  4. K5UJ

    K5UJ Ham Member QRZ Page

    "RF Exposure" is mostly a crock. It matters when there is risk of skin contact with metal at very high power near field areas that can have voltage induced, and it matters at UHF for example tower riggers on TV towers and very high power FM broadcast. For ham it is utterly ridiculous except possibly in focused beams used for EME. RF energy is non-ionizing period and can do nothing to tissue at HF and medium wave energy levels apart from what has been mentioned previously. These are scientific facts and can't be disputed. Brain cancer from cell phones is nothing more than a cottage industry for a few quack researchers in need of money. FCC and others have simply caved to political correct pressure from the ignorant and emotionally driven over the reasonable. This is an example of what happens when FCC is run by lawyers who are political appointees. The most outrageous: Commissioner O'Rielly, in an interview with RadioWorld magazine said this in answer to a question about at least one Commissioner being an engineer: "No, I don't think an artificial requirement is the way to go. If that were a requirement, I might not have made the Commission. Hopefully I have brought some benefit to my time here so far." So, at least one commissioner thinks being an electrical engineer is an "artificial requirement" to sit on the Federal Communications Commission. If communications were still smoke signals I'd agree. By the way for the record, Commissioner O'Rielly does not have a law degree.
    Last edited: Apr 7, 2018
    WD4IGX, K4KYV and AC0OB like this.
  5. K5UJ

    K5UJ Ham Member QRZ Page

    I could not care less about the ITU. These regulatory bodies are hardly rational.
  6. K4KYV

    K4KYV Subscriber QRZ Page

    And even less so, the IARU (International Amateur Radio Union). Many hams confuse the two. ITU is a quasi-legal United Nations agency and many countries (including USA) closely follow its recommendations in their own national radio regulations, but the IARU has no legal bearing whatever. It's sort of an umbrella society comprised of national amateur radio societies like ARRL, Radio Amateurs Canada, RSGB, REF, etc. The IARU is to ITU international regulations as ARRL is to FCC rules. Compliance is voluntary, although the IARU "encourages" member countries to incorporate its band plans into their national amateur radio regulations.

    For example, the IARU band plans incorporate specific bandwidth limits to amateur signals, but the FCC has so far, steadfastly refused to incorporate them into Part 97. Germany has reportedly incorporated IARU bandwidth limits into their rules, in such a manner as to prohibit the use of AM.
  7. WA3VJB

    WA3VJB Ham Member QRZ Page

    I would really like to get this confirmed or disputed. No response to an email I sent last year to Germany's "Member Society" of the IARU, inquiring.
  8. W6RZ

    W6RZ Premium Subscriber QRZ Page

  9. K5UJ

    K5UJ Ham Member QRZ Page

    It certainly seemed like the now out of power Triumvirate, attempted to use IARU as a path to bandwidth control in the U.S.
  10. K4KYV

    K4KYV Subscriber QRZ Page

Share This Page