It says it in writing in the content summary about the origins of Part15 which Fry posted in the link above:In this longer edit of the thread John A. Reed, Senior Engineer in the FCC Office of Engineering and Technology, Technical Rules Branch explains...
-----------------(the following is a slightly edited portion of the full text)---------------------------------
"On July 18, 1957, in Docket No. 9288, the Commission provided specific provisions for unlicensed operation in the AM band in what would be designated as Sections 15.202, and 15.204 of its regulations. Section 15.202 stated that the field strength limits
shall not exceed 24000[/f(kHz)] uV/m at a distance of 100 feet. Section 15.204 was adopted as an alternative to the field strength limit
to avoid the difficulties in making field strength measurements, provided that the input power to the final stage did not exceed 100 mW and the combined length of the antenna plus connecting lead did not exceed 10 feet. While the Commission originally proposed to permit an input power of 200 mW in the AM band
(3rd Notice of Proposed Rule Making in Docket 9288 adopted November 8, 1956), the adopted limit was reduced to 100 mW to reduce the potential area of interference.
"In an Order adopted on November 12, 1974 (FCC 74-1221), the rules were again modified, redesignating 15.202 as Section 15.111 and Section 15.204 as Section 15.113. Section 15.113 was modified to include the length of the ground lead in addition to the length of the antenna and connecting lead in the 10 feet maximum. This change was added because the earlier rules had not contemplated anyone using an extended ground plane [lead] to extend the range. The change was made to stop this practice.
"On April 14, 1976, in Docket No. 20780, the Commission proposed several changes in Sections 15.111 and 15.113, but did not adopt any of these changes. Paragraph 16, however, made the Commission's intentions clear that it implemented the alternative power measurements in lieu of a field strength limit
to make it easier for home builders, that didn't have the means to perform field strength measurements, to demonstrate that their products complied with the standards. However, this rule was never intended to provide a greater operating range than the original field strength limit. The operating ranges were expected to be about equal, but improvements in efficiency were starting to result in increased range, and increased potential interference, for systems operating under Section 15.113.
"Finally, on March 30, 1989, in ET Docket 87-389, the Commission adopted the current regulations. Section 15.111 was incorporated into Section 15.209
without changing the radiated emission limits except to specify the measurement range as 30 meters instead of 100 feet. Section 15.113 was redesignated as Section 15.219
with the only change to the limit being to specify the combined length of the antenna, connection lead and ground lead as 3 meters instead of 10 feet.
The original intention
of the part15 rules really are not the major factor to be considered... Even John Reed admits that improvements in efficiency of the more modern part15 transmitters result in a greater range than what they ever expected to happen.. Intention is not always the actual results..
Rules are the result of intentions, but Intentions have no bearing on the actual results of the rules.
My point being.. It doesn't really matter !
But back to my original question, part of which has already been answered,
But what hasn't been answered, is why, (see original link above) in Flagstaffs NOUO back in 2005 was there only mention of 15.209, and no mention of 15.219 .. When in fact the Rangemasters were certified under 15.219, and not subject to the restrictions of the field strength limits imposed by 15.209?
Why was their Rangemaster cited for 15.209 to start with? - The Rangemaster is not even subject to it.