LF / MF – Next Step For U.S. Amateurs (Part 3)

Continuing with the important sections of NPRM (FCC 15-50) affecting the future of LF/MF assignments in the U.S.A. ...

We also seek comment on the applicability of IEEE 1613-2009 – IEEE Standard Environmental and Testing Requirements for Communications Networking Devices Installed in Electric Power Substations ... ARRL claims that PLC systems complying with IEEE-1613 “would virtually guarantee that there would be no interaction between amateur stations and PLC systems,” and that compliance with the standard has been required by the Commission’s since 2002.  As background, the Commission’s rules require that PLC systems conform to engineering standards promulgated by the Commission and adhere to industry approved standards designed to enhance the use of PLC systems. Is compliance with this IEEE standard required by the Commission’s rules (i.e. is this an industry approved standard designed to enhance the use of PLC systems)? Would compliance of PLC systems with this standard facilitate the sharing of these bands between amateur stations and PLC systems? Are there PLC systems deployed that do not comply with this standard?
Would compliance with this standard obviate the need for amateur stations to maintain a specific separation distance from transmission lines?

We recognize that the separation distance required for PLC systems and amateur stations to coexist will depend on the power at which the amateur stations are permitted to transmit. We propose that amateur stations in the 135.7-137.8 kHz band be limited to a maximum EIRP of 1 W, as is required by footnote RR 5.67A, and which we adopted in the WRC-07 R&O. Is this EIRP limit appropriate for facilitating sharing between PLC systems and amateur stations? For the 472-479 kHz band, we propose to adopt transmitted power limits consistent with RR 5.80A. Amateur stations will be limited to an EIRP of 1 W in the portion of Alaska within 800 km of the Russian Federation and will be permitted to transmit at up to 5 W EIRP elsewhere. Is this EIRP limit appropriate for PLC systems and amateur stations to share this band? Should amateur stations be required to reduce their EIRP below 5 W when close to transmission lines and at what distances? We seek comment on these proposals.

We also seek comment on the practical application of a separation distance requirement, and, specifically, what resources and information amateur radio operators will need to comply with our rules. Amateur licensees will have to determine the location of transmission lines in their vicinity to determine if they are permitted to operate stations using these frequency bands. The amateur licensees will need to differentiate transmission lines from the electric distribution lines that connect distribution substations to customer or house wiring. High voltage transmission lines are typically attached to large steel towers that are easy to identity. However, lower voltage transmission lines are typically attached to wooden poles. Although the wooden poles used for transmission lines are usually taller than the wooden poles used for distribution lines, we recognize that distinguishing the two types may not always be straightforward. We seek comment on whether amateur licensees will be able to identify the transmission lines in their locality. If amateur licensees are not able to reliably identify transmission lines, should we require amateurs or ARRL to affirmatively verify the locations of transmission lines with utilities or UTC before an amateur station begins transmitting?

Lastly, we seek comment on additional service and operational rules that would be appropriate for amateur operations in these bands. According to ARRL, the tallest antenna that should reasonably be considered for an amateur station is 200 feet, because antennas with greater heights would
be required to obtain prior FAA approval and have to comply with FAA painting and lighting requirements. We note that adopting a maximum antenna height for amateur stations in these bands will aid in sharing of the spectrum with PLC systems by limiting the number of transmission lines that would potentially be in direct line-of-sight of amateur station antennas. We seek comment on what maximum antenna height, if any, we should adopt for amateur stations in these bands. 

We also invite comment on whether to adopt transmitter power limits for amateur stations, in addition to the EIRP limits we are proposing. If so, we seek comment on what the power limits should be. We observe that, in the 2002 Amateur Radio NPRM, the Commission proposed to limit the maximum transmitter power in the 135.7-137.8 kHz band to 100 W PEP because of the possible difficulty of measuring the EIRP of an amateur station in this frequency range. Also, in 1998, ARRL submitted data for the 135.7-137.8 kHz band showing that relatively short antennas can only produce ranges of EIRP that are well below the ITU’s 1 W EIRP limit (i.e., 10-40 mW for a 100 foot antenna and 1-4 mW for a 50 foot antenna) with a transmitter power output of 200 W PEP. The Commission did not consider either power limit at that time, because, as noted above, it decided not to adopt an allocation for amateur operations in this band. Given that we have adopted such an allocation in the WRC-07 R&O above, do either the 2002 Amateur Radio NPRM or ARRL’s 1998 study provide a basis for determining transmitter power limits now? Should these transmitter power limits vary depending on antenna height – e.g. we could allow a 200 W PEP limit for antenna heights not exceeding 30.5 meters while permitting only 100 W PEP for taller antennas. Should the transmitter power limits differ between the 135.7-137.8 kHz band and the 472-479 kHz bands?

In response to the WRC-07 NPRM, commenters addressed a number of steps that could facilitate amateur use of the 135.7-137.8 kHz band. Amateur operator John H. Davis (Davis) proposed that no amateur station should be automatically controlled to ensure that the amateur operator is able to quickly terminate transmissions if necessary. Davis also suggested that it may be appropriate to also prohibit software-driven modes that determine their own operating frequency without human intervention.
Should we adopt Davis’s suggestions? ARRL’s states that there is no rationale for limiting the occupied bandwidth in the 135.7-137.8 kHz band to less than the full 2.1 kilohertz, and that a stricter limit would not be conducive to experimentation with narrowband data emission modes in the future. Should we adopt any bandwidth limitation for either of the frequency bands? In the WRC-07 NPRM, the Commission requested comment on whether it should limit operating privileges in the 135.7-137.8 kHz band, e.g., to Amateur Extra Class licensees. None of the commenters believe that such a restriction would better facilitate Amateur/PLC sharing of the band. In particular, we note that ARRL states that it would be consistent with Commission policy to make this frequency band available to Amateur Extra, Advanced, and General Class licensees. Should we limit operating privileges for these bands in accordance with ARRL’s statement? Should we propose to authorize CW (international Morse code telegraphy), RTTY (narrow-band direct-printing telegraphy), and data emissions throughout the 630 and 2200 meter bands as we did for our 2200 meter band proposal in 2002? We also seek comment on amending Section 97.3 by adding definitions for the terms effective radiated power, isotropically radiated power, and LF.

Other Allocated Uses. Other radio services use the 135.7-137.8 kHz band. In the U.S. Table, the 130-160 kHz band is allocated to the fixed service (FS) and maritime mobile service (MMS) on a primary basis for Federal and non-Federal use ... The 126.7-141.7 kHz band is also used to track tagged salmon in the Pacific watershed. We seek comment on whether we need
to adopt exclusion zones or use other methods to protect these Federal uses of the band. Should we delete the unused non-Federal allocations from this band? To be consistent with the International Table, we also propose to require that amateur fixed stations operating in the 2200 meter band not cause harmful interference to stations in the FS and MMS that are authorized by other nations and require that these amateur stations take any and all corrective action, if harmful interference is reported to us. We seek comment on these proposals.

It would appear that the nature of enquiry is extensive but it is the next step needed before the LF / MF bands will become a reality in the U.S.

Following publication of the NPRM in the Federal Register (see daily updates here to see when it appears), stakeholders will have 60 days to make comments. Comments can be written or posted via their online comment page once it is opened. A thirty-day reply-to-comments period then ensues.

One source that I have read indicates that there is usually about 12-18 months before NPRM publication and rule enactment, should there be no major stumbling blocks. Whenever the final decision to implement comes will depend on how the enquiry proceeds.

I would urge all those interested in seeing these band become a reality to file comments when the opportunity becomes available, following the Federal Register posting. Comments could include your opinions on power levels, methods of stating / measuring power levels, restrictions on operating near power transmission lines, modes allowed, etc. It is particularly important for U.S. experimental stations to file a detailed report on their operations, including accurate descriptions of antenna systems and transmitter details. As well, I would urge Canadian amateurs that have had experience operating on either of these two bands, to file comments regarding your experiences, with particular emphasis on the lack of interference caused to PLC signals and the lack of interference caused by PLC signals to your own operation. Rest assured that U.S. power authorities will be putting their resources ($$) into one last lobby for as many restrictions as possible and it is not in our interest for the NPRM comments to be one-sided in their favor.

Lets all hope for a swift outcome to something that has been taking far too long.
Steve McDonald, VE7SL, is a regular contributor to AmateurRadio.com and writes from British Columbia, Canada. Contact him at [email protected].

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