229 lines
12 KiB
Prolog
229 lines
12 KiB
Prolog
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/ A \
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===============/ \==============
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THE / R R \ LETTER
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VOLUME 4 \ / NUMBER 21
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===============\ /==============
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\ /
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\ L /
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\ /
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\/
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October 10, 1985
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The ARRL Letter is published bi-weekly by the Information Services Department
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of the American Radio Relay League, 225 Main St., Newington, CT, 06111; (203)
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666-1541. Larry E. Price, W4RA, President; David Sumner, K1ZZ, Executive Vice
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President; Dave Newkirk, AK7M, Editor; Debra Chapor, Circulation Manager.
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Information from The ARRL Letter may be reproduced in whole or part in any
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form including photoreproduction and electronic databanks, providing credit is
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given to The ARRL Letter and to the American Radio Relay League.
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The ARRL Letter is available in printed form from ARRL. Subscriptions,
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limited to ARRL Members, are $19.50 (U.S. funds) per year for First-Class
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Mailing to the U.S., Canada, and Mexico. Overseas air mail subscriptions are
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available at $31 (U.S. funds) per year. Sample copies are available for an
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s.a.s.e.
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In this issue:
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o FCC PREPARES TO NAIL RADIO PIRATES
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o ARRL FILES COMMENTS ON PR 85-22
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o ANOTHER HAM IN SPACE
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o ...and much more!
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-----------------------------------------
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PERIMETER PROTECTION SYSTEMS ON 6 METERS?
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-----------------------------------------
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In turning a Canadian company's petition for operation of a perimeter
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protection system into a Notice of Proposed Rulemaking, FCC appears to have
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deflected a potential threat to the Amateur Radio Service at 50-54 MHz. In the
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NPRM, General Docket 85-231, FCC responded to a request for a waiver of Part 15
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at 50-88 MHz by proposing 54-88 MHz instead.
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It all began with a bit of alphabet soup called "CTLFDS" and ended up
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"GUIDAR." "CTLFDS" stands for "coupled transmission line field disturbance
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sensor." Control Data Canada, Ltd. (CDC), developed one and called it GUIDAR.
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It's a system that can be used to provide security surveillance for prisons,
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and to protect high-risk sites such as nuclear power stations from terrorism,
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theft and vandalism. GUIDAR operates on a principle of guided radar whereby a
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detection zone is created between "leaky" or ported coaxial cables deployed
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around the protected area. The present GUIDAR system employs two parallel
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cables buried approximately five feet apart and nine inches below the ground.
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An RF pulse is transmitted into one cable; some of this energy is coupled via
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the ports (holes) in the outer conductor of this cable into the ground and air
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near the cable. Some of this energy is reflected by objects in the ground and
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discontinuities in the soil, and is coupled into the second, or receiving,
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cable. When a human or other large object crosses between the cables, the
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change in RF coupled from cable to cable is detected and triggers an alarm.
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Such systems may cover a perimeter up to 2 miles long.
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On June 24, 1984, CDC asked FCC for a waiver of Part 15 of its rules to allow
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the operation of GUIDAR at 50-88 MHz. (Part 15 is that part of the FCC Rules
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governing operation of unlicensed low-power communication devices. Familiar
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Part 15 devices include cordless telephones, 49 MHz walkie-talkies, garage-door
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openers, etc. Such devices must not interfere with any other service; they
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must tolerate interference from other services.)
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Why did CDC make a run at 50-88 MHz? The aim was improved performance of its
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GUIDAR. CDC indicated that the ability of the system to detect actual
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intrusions and to ignore objects that could cause false alarms is affected by
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the frequency of operation. Below 30 MHz, sensitivity of the system to humans
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drops dramatically. Operation above 100 MHz increases the system's sensitivity
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to small animals, resulting in numerous false alarms; also, above 100 MHz,
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signal loss in the cable is significant. CDC stated that such systems must
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operate somewhere between 30 and 100 MHz.
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CDC stated that the present rules in Part 15, Subpart F, allowing perimeter
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protection systems to operate in the range 40.66 to 40.70 MHz, do not allow for
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effective operation of a system such as GUIDAR. GUIDAR uses a pulsed signal
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with a bandwidth of 2.5 MHz. A pulsed signal is employed to allow
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determination of the exact location along a perimeter where intrusion has
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occurred.
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CDC proposed 50-88 MHz for GUIDAR. This range includes the amateur 6-meter
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band, TV channels 2-6 and radio astronomy and avigation at 72-76 MHz. CDC
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contends that its perimeter protection systems can operate in the 50-88 MHz
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range without causing interference to radio services on those frequencies.
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In the NPRM, FCC said that CDC's reasons for selecting 50-88 MHz, rather than
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30-50 or 88-100 MHz, were "unclear." Yet, "In view of the public benefits to be
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derived from improved security at facilities such as prisons and nuclear
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plants, we find it appropriate to accommodate such systems to the extent
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possible." Operation of CTLFDS on vacant VHF TV channels sits well with the
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Commission. But what about 6 meters? Said FCC, "We have reservations about
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also permitting these systems to operate in the 50-54 MHz am because these
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systems could extend for considerable distance around a large facility, thereby
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increasing the likelihood that an amateur transmitter could come in close
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proximity to some part of the system."
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What has been proposed by the Commission is a set of standards for perimeter
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protection systems allowing for operating at 40.68 MHz, 54-72 MHz and 76-88
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MHz. For systems operating between 54 and 88 MHz, strength of emissions is not
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to exceed 10 microvolts per meter at a distance of 30 meters -- the same
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limitation placed on computers for use in residential areas. FCC carved 50-54
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MHz and 72-76 MHz from CDC's original proposal: "Permitting operation on TV
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channels 2 through 6 should be more than sufficient, since this ensures that in
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any given area there will be at least two vacant TV channels on which a
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perimeter protection system could be set to operate."
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Comments on General Docket 85-231 were due by October 11, 1985, with the
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League to file in support of FCC's decision to keep these devices out of the
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6-meter band. Reply Comments are due on or before November 12.
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----------------------------------
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FCC PREPARES TO NAIL RADIO PIRATES
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----------------------------------
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The Federal Communications Comission's monitoring network is continuing to
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investigate and fine illegal radio operators on a number of frequencies.
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Through long-distance direction finding, unlicensed "pirate" radio operations
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have been identified near these cities: Richmond, Charlottesville and
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Staunton, VA; Youngstown, OH; Miami and Orlando, FL; Minneapolis, MN;
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Washington, DC; Louisville, KY; Waterbury, CT; Newark, DE; Grand Rapids and
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Lansing, MI; San Francisco, CA; Arkansas City, KS, and Fort Smith, AR.
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The operation of unlicensed radio stations is in direct violation of FCC
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Rules and Regulations. Their operation may endanger life and property by
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causing harmful interference to licensed radio operations.
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One such pirate station, "KRZY" of Arkansas, was located and inspected on
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March 9, 1985. As a result of the inspection, a $1000 Notice of Apparent
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Liability was issued for unlicensed and out-of-band operation. The same
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operator soon returned to the air, and on August 9, 1985, U.S. Marshals,
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accompanied by an agent from the FCC District Office in Dallas, served a
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warrant and seized transmitting equipment used by the radio operator. The
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search and seizure resulted from a close-in DF to his residence on August 16,
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1985, at which time the station was identifying itself as "KBBR" on 7440 kHz.
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If convincted of operating an unlicensed radio station, the operator faces a
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maximum penalty of one year imprisonment, a fine up to $10,000 and a possible
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forfeiture of radio equipment to the U.S. government.
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Persons having information that would assist the FCC in its effort to locate
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and close down pirate radio stations should contact: Engineer in Charge, FCC,
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P.O. Box 1588, Grand Island, NE 68802-1588; telephone (308) 382-4296.
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---------------------------------
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NEW ADDRESSES FOR TWO FCC OFFICES
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---------------------------------
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FCC's Anchorage District Office has moved to 6721 West Raspberry Road,
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Anchorage, AK 99502, telephone (907) 243-2153. The Honolulu Office has moved
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shop as well; their address is Waipio Access Road, Next to the Ted Makalena
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Golf Course, P.O. Box 1030, Waipahu, HI 96797. The telephone there is (808)
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677-3318.
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Both offices are open from 8 A.M. to 4:30 P.M. Public inquiries concerning
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telecommunications matters, complaints of electronic interference and schedules
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of commercial radio operator examinations should be directed to these
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addresses.
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-----------------------------------
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THAT THIRTY-DAY RULE ISN'T GONE YET
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-----------------------------------
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From the ARRL/VEC office comes this reminder for all ARRL- accredited
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Volunteer examiners: don't forget that the thirty-day wait rule remains in
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force until November 8. Don't risk your license by breaking the rule while it
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is still on the books. After November 8, each VEC entity may set its own
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waiting period. Once the ARRL Board has determined the cost impact of this
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rules change, ARRL/VEC VEs will be advised as to what the ARRL/VEC retest
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policy will be.
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-----------------------
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COHERENT CW ON LONGWAVE
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-----------------------
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Have you heard of the 1750-meter band? It spans 160-190 kHz, and U.S.
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experimenters there are allowed unlicensed operation with no more than 1 watt
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DC input and a 15-meter antenna. (Don't get out your calculators; that's like
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having QSOs on 80 meters with a wire just a hair longer than two feet!) It is
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possible to make electromagnetic hay on 1750, though -- especially if you jump
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into the experimental spirit of the band and its users. More and more
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1750-meter experimenters, or LOWfers, as they're nicknamed, are turning to
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uncommon technologies in their quest to span greater distances on the band.
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One such technology is coherent CW (CCW). What's coherent CW? There's quite a
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bit on the technique on pages 21-9 to 21-12 of the The ARRL 1985 Handbook for
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the Radio Amateur. Simplistically put, it's a method wherein transmit and
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receive frequencies, keying speed, and receiver bandwidth are synchronized,
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allowing something like a 20dB improvement in signal-to-noise ratio at 12 WPM
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over non-coherent CW systems at similar signalling rates. From the September
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issue of QEX, the ARRL Experimenter's Exchange, comes this report on 160-190
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kHz CCW:
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"Mike Mideke, WB6EER, and I have been experimenting with coherent CW in the
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1750-meter experimental band. My CCW beacon is located in Morro Bay,
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California, transmitting 10-baud CCW, while Mike is receiving with a Petit
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PCF-3 coherent CW filter (QST, May 1981). A digital dot is precisely 0.1
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second, while dashes, space and blanks between elements are 0.3 second long. A
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32-bit memory is used, making the entire ID 10.7 seconds. All experiments have
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been conducted on 176 kHz, as sufficient RF stability occurs with ordinary
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crystal control. 166.66667 kHz was planned, but carrier accuracy is far less
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stringent than first thought!
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"Phase-locking to 10-MHz WWV was discarded after the discovery that 100-kHz
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LORAN C signals were received while tranmitting on the same antenna, using a
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simple 100-kHz tuned circuit. A basic 100-kHz receiver is now needed with only
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a sample and hold output such that a phase lock can be achieved with a 1-MHz
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crystal. A commercial LORAN C unit was used for this initial try.
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"It is becoming more apparent that stabilities and complexities first thought
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necessary are not required when the communication experiment lasts for a few
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hours, or can be optimized by the operator on the spot. Both Mike and I are
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now look-ing for an experimenter in, say, the Hawaiian islands, to show what
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coherent CW and one watt of power can really do" -- Cliff Buttschardt, W6HDO,
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950 Pacific St., Morro Bay CA 93442.
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