Source: http://hraunfoss.fcc.gov/edocs_public/attachmatch/FCC-02-136A1.txt

Federal Communications Commission FCC 02-136 
Before the Federal Communications Commission 
Washington, D. C. 20554 

In the Matter of Amendment of Parts 2 and 97 of the Commission's Rules to Create a Low Frequency allocation for the Amateur Radio Service

Adopted: May 2, 2002: Released: May 15, 2002 
Comments Due: 45 days from publication in the Federal Register. Reply Comments Due: 60 days from publication in the Federal Register. 

By the Commission:


II. 135.7-137.8 kHz AND 160-190 kHz BANDS (RM- 9404) 

A. Background and Summary of Petition

C. Proposal

II. 135.7-137.8 kHz AND 160-190 kHz BANDS (RM- 9404) 
A. Background and Summary of Petition 
4. Internationally, the band 130-148.5 kHz is allocated to the fixed and maritime mobile services on a primary basis in all three International Telecommunications Union ("ITU") Regions.  In addition, in Region 3, the radionavigation service has a primary allocation in this band.  Within the U.S., the band is allocated to both the fixed and maritime mobile services on a primary basis for both Federal and non-Federal Government users.  The non-Federal Government services in this band are covered under Parts 23 and 80 of the Commission's Rules, respectively.  In the 135.7-137.8 kHz portion of the band, there are currently no non-Federal Government assignments and only one Federal Government assignment, as of January 25, 2002. The Federal Government assignment is for a coast station in the maritime mobile service communicating with ships in the Pacific Ocean.

5. The band 160-190 kHz is allocated on a primary basis to the broadcasting service in Region 1 and to the fixed service on a primary basis in Regions 2 and 3. 8 In Region 3, the aeronautical radionavigation service has a secondary allocation. In the U.S., the band is allocated to both the fixed and maritime mobile services on a primary basis for Federal Government users and also to the fixed service for non-Federal Government users. This service is regulated under Part 23 of the Commission's Rules.  As of January 25, 2002, there were no non-Federal Government assignments in the Commission's database for this frequency band. There are ten Federal Government assignments for coast stations communicating with ships at sea and several fixed service sites in this band. 

6. In addition, the LF spectrum is used by unlicensed devices. These systems do not have any allocation status, but are authorized to operate under our Part 15 Rules on an unprotected, non-interference basis with respect to all other users. Section 15.209 permits operation of authorized systems with field strengths of up to 4.9 microvolts/meter in the 9-490 kHz band. Additionally, Section 15.217 permits use of the 160-190 kHz band for general unlicensed operations limited to one watt total input power to the final radio frequency stage (exclusive of filament or heater power) with the length of the transmission line, antenna and ground lead not to exceed 15 meters.  Emissions outside of the 160-190 kHz band must be attenuated by at least 20 dB below the level of the unmodulated carrier. Section 15.113 permits Power Line Carrier ("PLC") systems on power transmission lines for communications important to the reliability and security of electric service to the public in the 10-1490 kHz band.  PLC systems are used to trip protection circuits if a fault, such as a downed power line, is detected in the power grid. 

7. In our preparations for the World Administrative Radio Conference 1979, we considered a request from ARRL for an amateur allocation in the 160-190 kHz band under Docket No. 20271. At that time we declined to allocate the spectrum to the amateur service because of concerns about interference to the PLCs.

See 47 C.F.R. 2.104 and 2.106. The U.S. is located in ITU Region 2. 
ITU- R Region 3 is generally the Asia- Pacific Region. See 47 C.F.R. 2. 104( b)( 3). 
ITU- R Region 1 is generally Europe, Africa and the Middle East. See 47 C.F.R. 2.104( b)( 1). 
See 47 C.F.R. 15.113, 15. 209 and 15. 217. See also 47 C.F.R. 2.106 footnote US294. 
See Report and Order, Docket No. 20271, 70 FCC 2d 1193 (1978). 

8. On October 22, 1998, the ARRL filed a Petition for Rule Making ("LF Petition") requesting that we amend Parts 2 and 97 of our Rules to create a domestic secondary allocation for the amateur service in the LF range of the spectrum in the 135.7-137.8 kHz and 160-190 kHz bands. ARRL states that there is no amateur service allocation in the LF spectrum range. Such an allocation, they argue, would enhance technical self- training in areas such as Morse Code and digital communications and experimentation in LF communications.  ARRL points out that numerous amateur radio and non-amateur radio operators in the U.S. are using the 160-190 kHz band pursuant to Section 15.217 of our Rules.  ARRL states that the power and antenna limitations of these rules, noted above, preclude or inhibit effective experimentation.  ARRL desires more liberal operating conditions, such as an output power limit of 200 W peak envelope power ("PEP") and 2 W effective isotropic radiated power ("EIRP"). These power limits would allow amateur radio operators to conduct antenna design and construction experiments, and long range propagation studies with continuous wave ("CW") telegraphy, RTTY, data, single- side band ("SSB") telephony and image emission types. In order to ensure that these experiments are conducted by knowledgeable operators, ARRL proposes that operators be required to hold a General Class license or above.

9. The LF Petition notes that, although there is no international allocation for the amateur service in these bands, the European Posts and Telecommunications Commission 20 ("CEPT") countries have provided a secondary amateur allocation in the 135.7-137.8 kHz band and limited power output to 1 W effective radiated power ("ERP").  In addition to the general CEPT decision, individual CEPT 

See Petition for Rule Making, RM- 9404, Public Notice (rel. November 23, 1998) Report No. 2306. The LF Petition specifically requests amendment of 47 C.F.R. 2.106; 97. 3 (b); 97.301( b), (c), and (d); 97. 303; 97. 305( c); and 97. 313( c).  In addition, the Commission received a petition for rulemaking from Mr. Nickolaus E. Leggett on November 27, 1998. This petition also requested the Commission consider a secondary allocation to the amateur radio service in the 135.7-137.8 kHz and 160-190 kHz bands. As these bands are the same as contained in the ARRL LF Petition (RM- 9404) which was placed on public notice for comment, we find that it is not necessary to put the Leggett petition out for comment as the record is adequate for the purposes of this Notice and Order. Thus, it will be treated as a comment in support of the LF Petition. 

See LF Petition at i. 
See LF Petition at i. 
These transmissions often only travel a fraction of a kilometer. However, amateurs experimenting with communications using continuous wave, RTTY or pulse transmissions can achieve distances of 160 to 480 kilometers under favorable propagation conditions.  In rare cases, with very well tuned devices, they can achieve distances of approximately 1300 kilometers. However, with an allowable power of 5W ERP, they can achieve transcontinental communications. See www.lwca.org, the Longwave Home Page, for more information. 

PEP is defined as the average power supplied to the antenna transmission line by a transmitter during one radio frequency cycle at the crest of the modulation envelope taken under normal operating conditions. See 47 C.F.R. 2.1. 
Continuous wave signals are unmodulated carrier frequencies. Information is transmitted by turning the carrier on or off in recognized patterns, such as Morse Code. 
RTTY is defined as narrow-band direct-printing telegraphy with specific emission designators. See 47 C.F.R. 97.3(c)( 7) for more information. 
The amateur radio operator licenses that are above General Class include the Advanced and Amateur Extra Class operator licenses. See 47 C.F.R. 97.9 for more information. 
CEPT is an organization under the European Union umbrella that deals with spectrum management issues. 
ERP and EIRP differ in magnitude by 2.15 dB. This is caused by a 2.15 dB increase in radiated power from a dipole antenna relative to an isotropic antenna.
Five member nations have instituted their own domestic rules. For example, Belgian radio amateurs are permitted to use up to 1 kilowatt transmitter output power.

10. ARRL states that a review of Federal Government frequency assignments in the 130-160 kHz and 160-190 kHz band shows that the U.S. Navy has assignments in both bands and the U.S. Air Force Groundwave Emergency Network ("GWEN") has assignments in the 150-175 kHz band.  ARRL asserts that, based upon information and belief, and upon inquiry of the Navy staff, incumbent primary status Navy operations in the LF range are increasingly inactive and other Federal uses of the band are being phased out in favor of other bands.  As additional evidence of this, ARRL states that groups of Part 15 experimenters in this band have logged signals heard in the 130-160 kHz and 160-190 kHz bands, and that no signals have been noted other than longwave broadcast signals, mostly from Europe.  Nevertheless, ARRL requests a secondary allocation to protect primary allocations in the bands. The petition also does not specifically address sharing with the primary fixed and maritime mobile services. 

11. Regarding sharing with Part 15 PLC operations, ARRL argues that such operations have no allocation status and thus do not merit protection from services with allocation status. Nevertheless, ARRL asserts that the interference potential of its proposed amateur operations to PLCs would be minimal. Specifically, ARRL indicates that power grid faults are detected through either Directional Comparison Blocking ("DCR") or Direct Transfer Trip ("DTT") PLC methods. The DCR method does not transmit a signal until there is a fault, and interference can cause adverse performance only if it occurs simultaneously with a fault. ARRL argues there is a low probability of an amateur station being close to a power line and transmitting simultaneously with a DCR ("guard") signal. On the other hand, the DTT method transmits a continuous guard signal, which is frequency shifted during a fault. ARRL argues that DTT systems will be protected because amateur service stations will detect the guard emission and avoid using that channel.  ARRL also points out that voice and data communications are performed over PLCs, but that interference to such uses are not serious because the communications can be repeated.

12. ARRL also claims that PLCs operating in the 135.7-137.8 kHz and 160-190 kHz bands are not likely to receive interference which might interrupt the power grid, even if co-frequency operation occurs.  ARRL's analysis shows that with its suggested EIRP of 2 W, a separation distance of about 1.3 km from PLC systems operating on 161 kV power lines is needed to avoid interference. The separation distance decreases to approximately 170 meters for PLC systems operating on 765 kV power lines.  ARRL contends that, at these frequencies and corresponding wavelengths, the antenna inefficiencies and ground losses would prevent amateur operations from generating interfering signals. ARRL states it could not find any record of false trips of PLC equipment and that a 1995 survey of the power utilities 

ARRL claims that the GWEN system is to be deleted and the transmitter sites are to be used for other purposes and managed by the U.S. Coast Guard. 
Typical amateur operations use a "listen-before-transmit" technique whereby the operator listens to ensure the channel is not in use before transmitting. 

The power grid is made up of a generating station, which outputs the electricity onto high voltage transmission lines (50 kV to 765 kV). These lines carry the power to a substation which reduces the line voltage to below 50 kV for use by businesses and housing subdivisions. These 50 kV lines are further reduced via local transformers to the typical 120/ 240 V used for providing electrical service to individual households. 

6 shows that interference from licensed systems is not a significant problem.  ARRL also asserts that an increasing number of PLC systems use synthesized transmitters that allow easy frequency changes and that many systems employ forward error correction ("FEC") digital transmissions of data, making the PLC system nearly immune to interference.

B. Comments 
13. Thirty-two parties filed comments on the LF Petition.  Comments from amateur operators generally support an amateur allocation in the LF range.  Galasso states that this secondary allocation would be very helpful and supports a 200 W PEP limit with no EIRP limit to permit experimentation to develop antennas with better efficiency. Rayburn also supports the LF Petition, indicating that the current amateur service operations have pioneered the use of binary phase shift keying ("BPSK") signaling and coherent CW in these frequency bands. 

14. Texas Instruments ("TI") and HID Corporation ("HID") express concern with ARRL's request for the 135.7-137.8 kHz band. These companies manufacture radio frequency identification ("RFID") equipment which operates in the nearby 121-134.2 kHz band under Part 15 of our Rules. TI and HID point out that RFID devices use inductive coupling and therefore rely on the magnetic-field ("H-field") component of a signal for communications.  HID and TI claim that amateur radio operators will likely use loop antennas because of space limitations. TI contends that the resulting magnetic field from a 200 W PEP amateur service transmitter fed into a loop antenna may cause interference into an RFID system.  HID also claims that amateur station signals can mix with HID's 125 kHz carrier frequency and pass into the RFID receiver.  Further, HID fears that amateur radio licensees will use transceivers with high harmonic content, causing interference to RFID systems.  TI proposes that, if this band is allocated to the amateur service, operations be limited to electric field antennas, power limited to 2 W EIRP, and interference be defined such that Part 15 devices are considered as not causing interference to any authorized amateur operations.

Hohn, J. W., et. al, POWER LINE CARRIER PRACTICES AND EXPERIENCES, IEEE Transactions on Power Delivery, Vol 10, No. 2, April 1995.

The LF Petition was placed on public notice on November 23, 1998. See Public Notice Report No. 2306. A list of commenters is in Appendix A. 
See, e. g., Ex parte Comments of Eyre- Eagles at 1, Ex parte Comments of Galasso at 2, Ex parte Comments of Leggett, and Ex parte Comments of Rayburn
Radio waves have both an electric and a magnetic component. In the LF spectrum, antennas (sensors) may be designed to utilize one or the other component for more efficient communication. 
See Comments of Texas Instruments

See Ex parte Comments of HID Corporation. Signals mix in the front end of a receiver and create sum and difference signals which may then be passed through the receiver's filter if they are close enough to the desired signal's frequency. For example, a signal at 125 kilohertz may mix with a signal at 135.8 kilohertz and create new 10.8 kilohertz and 260.8 kilohertz signals. If the receiver is looking for signals near 10 kilohertz, this new signal can interfere with the expected signal. 
HID asserts that loop antennas emphasize H-field coupling up to 1 wavelength (2.21 km) away and are prone to broadband harmonic emissions if not properly tuned. 
See Comments of Texas Instruments.  Defining interference in the manner proposed by TI would permit a Part 15 device to cause interference to operations of a secondary service.  However, Part 15 devices would not be protected from amateur stations operating under the proposed secondary allocation. 

15. ARRL replies that the typical amateur station EIRP in the 135.7-137.8 kHz band will be on the order of 0.5 W, which is significantly below the power limit used by TI in its analysis, and thus amateur radio operations should not cause interference to RFID systems. ARRL also states that the antenna bandwidth of amateur operations in this band would be "very low," so that adjacent frequency interference is unlikely.  ARRL argues that the Commission should not specify antenna types because that would stifle experimentation, and notes that amateur radio licensees will likely use long wire antennas that will emphasize electric field radiation to facilitate sharing with magnetic-field RFID systems.

16. A number of commenters raised concerns about the impact of the proposed amateur service operations on PLC operations in both frequency bands.  Commenters point out that PLC use of these bands is significant.  UTC indicates that there are approximately 10,000 PLC terminals operating in these bands.  It points out that the Commission has noted the importance of the PLC operations, and in 1978 declined to introduce new broadcast and amateur allocations to protect PLC operations in the LF region. 

17. The Institute of Electrical and Electronic Engineers ("IEEE") Relay Communications Subcommittee ("the Subcommittee") of the IEEE Power Systems Relay Committee indicates that the Subcommittee echoes the Commission's concerns about the possibility of interference to PLCs from amateur radio operations mentioned in Docket No. 20271. The Subcommittee claims that the ARRL LF Petition is mistaken regarding interference to PLC systems. It submits that, of the two different types of PLC systems, the ON/ OFF type is normally off except for short encoded bursts 1- 3 times per day.  It states that interference to this type of PLC system will cause unfaulted lines to disconnect from the power grid resulting in outages.  The Subcommittee argues that an amateur radio operator cannot rely on a "listen before talk" protocol to avoid the frequency being used by an ON/OFF PLC system because the system is normally off and no signal is transmitted. The Subcommittee submits that the second type of PLC system uses frequency shift keying ("FSK").  It indicates that with FSK systems, a fault causes a status signal to shift frequency which trips the relay. The Subcommittee states that it takes approximately 32 milliseconds to start the process, and it cannot be
stopped once started.  It further states that, in the FSK system, transmit and receive frequencies are different and the amateur radio operator will not be able to determine what frequencies to avoid since the shifted frequency is normally not used unless there is a 

 See Reply Comments of ARRL, at 3. 
 On March 30, 1999 ,ARRL filed a Motion to Strike ("Motion") comments from the IEEE Relay Communications Subcommittee, Michael McDonald, Paul Drum and ComEd because they were more than 30 days late and ARRL was not served in violation of Section 1. 405 (b) of the Commission's Rules. We believe that it is in the public interest to have as complete a record as possible in this proceeding. We further note that while ARRL was not properly served, their Motion included a substantive response to these comments and was considered by the Commission as well. Therefore we deny ARRL's Motion to Strike. 
 See Ex parte Comments of UTC at 2. 

 ON/ OFF keyed PLC systems are similar to DCR systems described in the LF Petition. 
 See Ex parte Comments of the IEEE Relay Communications Subcommittee, dated February 12, 2001 at 1. 
 FSK PLC systems are similar to DTT systems described in the LF Petition. 
 See Ex part Comments of the IEEE Relay Communications Subcommittee, dated February 12, 2001 at 1. 

 fault on the power system.  Commonwealth Edison ("ComEd") and other utilities support the Subcommittee's concerns.  
18. The Subcommittee also disagrees with ARRL's assessment that there is no risk of interference to PLC operations beyond 1.34 km from amateur stations operating with an EIRP of 2 W. It takes issue with the LF Petition's statement that the noise floor of the PLC system is 30 dBm on lower voltage lines such as 161 kV power lines and as high as 5 dBm on 765 kV lines per the IEEE 643- 1980 standard. The Subcommittee states that the IEEE standard for PLCs actually provides various noise data for both fair and adverse weather and indicates that the fair weather data is valid for more than 75% of the time. It notes that ARRL used the highest numbers in the adverse weather range for their analysis, and that this results in a 10- 15 dBm decrease in sensitivity for lower voltage lines and 20- 25 dBm for 765 kV lines.  The Subcommittee therefore argues that ARRL understates the necessary separation distances needed to protect the PLCs. 

19. The Subcommittee also states that while utilities may use fiber in new installations, it is not cost-effective to retrofit existing PLCs.  ComEd agrees with this assessment and also notes that forward error correction is not widely used.  The Southeast Reliability Council and the Florida Reliability Council argue that PLC communication is the only viable means of providing the protection, control and operation for many transmission facilities.  UTC asserts that utilities have experienced problems with their PLCs that could have been caused by interference, but sources of interference are often difficult to identify. In addition, UTC states that many cases of interference are not documented, because most facilities do not have the monitoring equipment necessary to determine the cause of the tripping of breakers if no fault is found in the power grid. UTC submits that one utility, CP& L, did investigate interference to their network and determined that the false signals were coming from stray radio signals.  

20. ComEd asserts that amateur radio licensees may have difficulty in calculating EIRP, the power measurement suggested by ARRL. It argues that because ARRL suggests no restrictions on antenna size or design, it would be difficult to anticipate the gain of the antennas used.  The Subcommittee notes that a Dutch amateur radio licensee has developed a kite-borne 900-foot antenna with higher efficiencies that allows the amateur station EIRP to be in the range of 10-15 W with a transmitter output power of 150 watts.

 See, e.g., Ex parte Comments of Commonwealth Edison, dated March 8, 1999, at 4, and Comments of Alabama Power, Georgia Power, Gulf Power, Michigan Power and Savannah Electric at 1. 
 See Ex parte Comments of the IEEE Relay Communications Subcommittee, dated February 12, 2001, at 3. 

 See Ex parte Comments of the IEEE Relay Communications Subcommittee, dated January 29, 1999, at 1. 49 See Ex parte Comments of Commonwealth Edison, dated March 8, 1999, at 4. 
 See Ex parte Comments of Southeast Reliability Council at 1 and the Ex parte Florida Reliability Council at 1. 
 See Ex parte Comments of UTC at 4. 
 See Ex parte Comments of Commonwealth Edison, dated March 8, 1999, at 3. 
 The longer the antenna, the more radiated power that can be achieved with the same transmitter output power. By attaching a wire to a kite, the Dutch amateur radio operator effectively created a long- wire antenna much closer in length to ideal quarter-wave monopole length. The higher the efficiency of an antenna, the more power can be radiated from it for a given transmitter output power. For example, under the current antenna length limit of 15 m (See 47 CFR 15. 217) antenna efficiencies are 

 21. In reply ARRL, states that its analysis assumes zero ground loss between the amateur stations and PLC systems and thus leads to overstatement of the separation distance necessary to protect a PLC system; the actual distances should be much less.  ARRL states that an amateur LF station would have to be mounted on a utility pole to cause co-channel interference.  Lastly, ARRL claims that amateur service stations would not exceed power limitations because the antenna efficiency would limit radiation from a 200 W PEP transmitter to under 0.5 W EIRP. Further, ARRL notes that its proposal would limit access to the LF allocation to licensees who have demonstrated competence by passing an examination, and that it would publish a LF handbook for amateur radio operator's use.

C. Proposal 
22. We are persuaded by ARRL's arguments to consider whether a secondary amateur service allocation in the LF range of the spectrum would serve the public interest because amateur experimentation could lead to a better understanding of communication techniques in this frequency range. As discussed below, we are proposing to allocate the 135.7-137.8 kHz band to the amateur service on a secondary basis. This allocation would allow amateur radio operators the ability to experiment more freely with propagation, antenna design and antenna construction. However, we are concerned about potential interference to PLC systems in the 160-190 kHz band. We declined previously to provide an allocation for the amateur service in the 160-190 kHz band because of potential interference to PLC systems, and we believe that PLC use of this band continues to pose sharing problems with an amateur service allocation. Therefore, we are not proposing an allocation in the 160-190 kHz band, although amateur use of the 160 kHz band may continue under our Part 15 rules.

23. Incumbent use of the 135.7-137.8 kHz band is relatively light and thus a secondary amateur service allocation in this band raises few concerns. An analysis of a portion of the UTC database of PLC systems by Commission staff shows that PLC system density is significantly less in the 135.7-137.8 kHz band than in the 160-190 kHz band. 58 Consequently, there should be many areas where PLC systems would not be in close proximity to any future amateur operations. Further, domestic primary services in this band would be minimally affected by an amateur service allocation. The Government Master File ("GMF") and Commission's databases identify only one Federal Government assignment in the 135.7-137.8 kHz band. The amateur service has extensive experience in operating on a secondary basis with primary status services in frequency bands with long range capabilities and we believe the same would apply here. We expect that interference would be rare because amateur radio operators have apparently demonstrated their effective use of the "listen-before-transmit" protocol, which also can be utilized with the primary users of this band. Regarding the RFID uses in the lower adjacent band and the approximately 0.02%. If the allowable antenna length is increased to 60 m, then the efficiency increases to 1%. Thus an EIRP of 0.04 W radiating from a 15 meter antenna increases to 2W when a 60 meter antenna is used. See LF Petition at 13. 

 See Ex parte Comments of The IEEE Relay Communications Subcommittee, dated January 29, 1999, at 1 
 UTC maintains a database in accordance with 47 C.F.R. 90. 35 (g). This database was established in order to provide information on PLC use by utilities and also to assist in coordination with other primary uses of the 10-490 kHz band. Our analysis showed that there were approximately 430 PLC systems in operation in 400 locations in the United States in the 135.7-137.8 kHz band.

 PLC use in-band, we propose technical rules that are intended to minimize any impact from these amateur station operations on unlicensed equipment use. We seek comment on this assessment. 

24. While there is no international allocation to the amateur service at 135.7-137.8 kHz in the International Table of Allocations, we note that the European Posts and Telecommunications Commission ("CEPT") has allocated this band to the amateur service on a secondary basis and individual administrations are granting amateur radio operators additional technical flexibility for their LF operations. We also note that Canada has recently proposed a secondary allocation of the 135.7-137.8 kHz band for the amateur service in Region 2, which may be considered at the 2003 World Radio Conference ("WRC- 03").  We believe that a domestic secondary amateur service allocation in the 135.7-137.8 kHz band would provide a chance to harmonize amateur LF allocations and promote international exploration of a common band.  In the absence of an international allocation, however, we propose to adopt certain technical limitations on amateur radio operations in this band so that they should not cause interference to primary services outside of the United States.  We request comment on whether there are any specific spectrum sharing concerns between amateur station operations and domestic or international primary allocation operations in the 135.7-137.8 kHz band. 

25. We propose to require that amateur stations in the 135.7-137.8 kHz band meet the technical limits suggested by Canada in the WRC-03 preparatory process, noted above.  As provided in the Canadian proposal, we believe that sharing of this spectrum would be facilitated if the amateur station is limited to an EIRP of 1 W and the transmission bandwidth is limited to 100 Hz. Because of possible difficulty in measuring the EIRP of the amateur station in this frequency range, as noted by ComEd, we additionally propose to limit amateur output power in this band to 100 W PEP. We seek comment on whether these limits on EIRP and PEP are appropriate. We propose no restrictions on antenna size or design for amateur stations because such restrictions would inhibit experimentation, and we believe that interference to other users can be adequately addressed by the proposed power limitations. We also propose to limit access to this band to amateur operators holding a General, Advanced, or Amateur Extra Class license, as requested by ARRL, as a way to insure amateur operations would be conducted in a manner that minimizes the interference potential to other users. We note that with an allocation of only 2.1 kilohertz of spectrum in this band, amateur radio operations may be limited to propagation experiments, telegraphy and low speed data applications. Nonetheless, this allocation would benefit amateur experimentation of the LF range. We seek comment on all of these proposals for a secondary amateur service allocation in the 135.7-137.8 kHz.

26. In declining to propose a secondary amateur service allocation for the 160-190 kHz band, we observe that while the number of incumbent primary users in this band has decreased over the years, the record and Commission staff analysis shows that significant PLC use continues in this band in many locations.  The wider bandwidth in the 160-190 kHz band increases the number of PLC systems potentially impacted. Further, while newer technologies may be implemented where possible, PLC systems are not being replaced or retrofitted with these new technologies in many areas. Therefore, we continue to be concerned about the interference potential that a secondary amateur service allocation would have on PLC systems. We also observe that, unlike the situation with the 135.7-137.8 kHz band, there does not appear to be interest internationally in adding amateur services in the 160-190 kHz band. 

 See Document PCC. III/ doc. 2171/ 02, Draft Proposals for the Work of the Conference WRC- 03 Agenda Item 1.1, submitted by Canada, dated February 11, 2002. A copy of this document will be placed in the docket file. 
 Our analysis showed that there were approximately 4900 PLC systems in operation in 3000 locations in the United States in the 160-190 kHz band. 

27. Amateur radio operations in the 160-190 kHz band under the Part 15 rules will not be affected. Under these rules, amateur operations must meet certain power and antenna length requirements, but they also are allowed to build and operate some equipment of their own design.  We thus note that amateurs do have some flexibility to achieve wideband communications and thus, the need to provide a secondary amateur service allocation in the 160-190 kHz band is reduced. We seek comment on our tentative decision to not provide the allocation in this band that ARRL requested. 

28. Finally, we recognize that spectrum in both the 135.7-137.8 kHz and 160-190 kHz bands could be used more efficiently if potential operators knew where other users of the spectrum were located and could avoid them.  UTC has maintained a database of PLC locations in order to notify primary Federal Government users of PLC operations.  We request comment on whether this database provides sufficient information for use by amateur operators and how such access could be provided.