Welcome to RF Current, a weekly electronic newsletter focusing on Broadcast technical and F.C.C. related issues. This newsletter is part of The RF Page @ www.transmitter.com, a web site devoted to TV Broadcast RF engineering. For more information see the What is... guide to the R.F. Page site.

This page contains stories from RF Current issues published in October 1998. Links referenced in the articles were current when published but by this time may have changed. If you find a bad link, try connecting to the home page of the publication or company and look for an archive of past articles. If you find a changed link, I'd appreciate it if you'd let me know by dropping me a note indicating the new location at dlung@transmitter.com.

October 26, 1998 - Issue 139 Final Edition

FCC - Electronic Comment Filing System Replaces RIPS (Oct. 26)
In a Public Notice (pnmc8063) released today the FCC said it was replacing its Record Imaging Processing System (RIPS) with the Electronic Comment Filing System (ECFS). ECFS is now the main source for copies of documents filed in docketed and rulemaking proceedings. It allows Internet access to these documents using Version 3 or later of Netscape or Internet Explorer. Documents can be viewed at http://www.fcc.gov/e-file/ecfs.html.

FCC Revises Experimental Radio Rules to Promote New Services (Oct. 22)
The FCC has made several changes in its Experimental Radio Service rules. Significant changes include longer license terms (up to five years), blanket licensing of related multiple experiments. easier rules for Special Temporary Authorizations (STAs) for temporary experiments, and allowing issuance of licenses to schools, as well as to individual students, for student experiments. Licensees will be allowed to change modulation/emission characteristics without filing a modification application, provided they stay within their authorized maximum emissions envelope. The FCC will also now recognize the use of electronic signatures on experimental applications.

More information is available in the FCC Engineering and Technology News Release - Report ET 98-9. The full text of the Report and Order (FCC 989-283) was not available on-line.

FCC Changes Broadcast Rules to Require Electronic Filing and Institute Random Audit Enforcement (Oct. 22)
The FCC's Mass Media Bureau has adopted new procedures for radio and television applications. While many of these do not directly affect broadcast engineers, some of the procedures adopted will affect the way they deal with the FCC. The FCC plans to make the fifteen major broadcast forms available for electronic filing over the next six months. Once a form becomes available in electronic format, electronic filing will become mandatory after six months. Narrative exhibits will be replaced with the use of certifications. Compliance with the certifications will be backed up with strong enforcement. The FCC plans random audits of up to 5 percent of pre-grant and up to 5 percent of post-grant applications. Applicants that fail to comply with FCC rules will be subject to "significant serious sanctions".

The Commission extended the construction permit time period to three years for all services. Full text of the Report and Order (FCC 98-281) was not available on-line. See the Mass Media Bureau News Release (nrmm8034), Report MM 98-15, for additional information.

FCC Releases Report and Order on Universal Licensing System (Oct. 21)
Refer to September 21, 1998 RF Current for a summary of the Report and Order on the Universal Licensing System (ULS). The FCC this week released the full text of its Report and Order on WT Docket 98-20, WT Docekt No. 96-188 and Rulemaking RM-8677, Amendment of Parts 0, 1, 13, 22, 24, 26, 27, 80, 87, 90, 95, 97 and 101 of the Commissionls Rules to Facilitate the Development and Use of the Universal Licensing System in the Wireless Telecommunications Services and Amendment of the Amateur Service Rules to Authorize Visiting Foreign Amateur Operators to Operate Stations in the United States.

The Report and Order is quite long and includes details licenses regulated under the FCC Parts listed above must know when submitting applications and requests. The FCC is using ULS to facilitate electronic filing of applications. Indeed, the Report and Order stated the FCC "will no longer accept letter requests as a substitute for authorizations that can be requested on ULS formats." While most of the document concerns filing and application procedures for station and operator licenses and permits, there are some modifications to technical rules. For example, Part 95 GMRS fixed stations will be limited to fifteen watts output, regardless of location. Small base stations will continue to be restricted ot five watts. There is no longer a distinction for urban areas. The Wireless Bureau is also requiring applicants and licensees to convert their location coordinates from NAD27 or local datums to NAD83. Databases will be converted to NAD83 at the same time they are converted to the new ULS format.

Over forty forms have been consolidated into four forms. Form 601 for initial licensing applications, modifications, renewals or STA applications. Form 602 is to be used for submitting initial and updated ownership information. Form 603 is used for applications for license assignments and transfers of control. (This form also includes the proposed 604 form.) Form 605 is a quick form application for Ship, Aircraft, Amateur, Restricted and Commercial Operator and General Mobile Radio Services (GMRS) authorizations. Old forms may be used until six months after the effective date of these rules.

Refer to the full text of the Report and Order for more information. The document is available in ASCII text format - fcc98234.txt; WordPerfect format - fcc98234.wp, and as a compressed WordPerfect file fcc98234.zip.

DTV - Scientific Atlanta Announces Products for Broadcast and Cable HDTV (Oct. 20)
Scientific Atlanta (SA) announced a range of products designed to support the national rollout of HDTV in November. Products included in SA's end-to-end DTV solution include PowerVu HD™ and PowerVu Plus™ compression systems, the Prisma™ Digital Transport system, Prisma™ Dense Wave Division Multiplexing (DWDM), the SP-1D signal processor and an HD version of SA's Explorer® 2000 digital set-top box.

Of particular interest to broadcasters are SA's solutions to the problem of 8VSB over cable systems. The model SP-1D signal processor enable cable operators to deliver broadcast DTV programming over cable. The unit can frequency translate any 8VSB off-air signal to any designated cable channel iin the 50-890 MHz range. These units are available immediately. SA's HD version of its Explorer 2000 advanced digital set-top box will include an HD decoder to translate the cable HDTV signal into a format acceptable for use by HDTV sets. Availability on the HD set-top box is January, 1999.

More information is available in the Scientific Atlanta Press Release.

DIGITAL TELEVISION STATION APPLICATIONS - See ap981026.txt for more information
Call (DT) Ch. Licensee Location ERP (kW) HAAT (m) Antenna
WHSH 23 USA Station Group Marlborough MA 100 332
KWBP 33 Acme TV Licenses Salem OR 750 523 Scala 772-419
WTVS 43 Detroit Educ. TV Detroit MI 200 318 Dielectric TFU-18GBH-R04

DIGITAL TELEVISION STATION ACTIONS - See ac981022.txt for more information
Call (DT) Ch. Licensee Location ERP (kW) HAAT (m) Antenna
WFMZ 46 Maranatha Broadcasting Allentown PA 50 293
WPVI 64 ABC Philadelphia PA 500 390
WISH 9 Indiana Broadcasting Indianapolis IN 15.86 284
WCPO 10 Scripps Howard Cincinnati OH 13.7 280
WPXI 48 WPXI, Inc. Pittsburgh PA 501 289 Dielectric TFU-30BGH-R0=-06
KXLY 13 Spokane Television Spokane WA 23.3 936
KIRO 39 Cornerstone Seattle WA 603 230

DIGITAL TELEVISION STATION ACTIONS - See ac981020.txt for more information
Call (DT) Ch. Licensee Location ERP (kW) HAAT (m) Antenna
WETA 27 Greater Wash. Ed. TV Washington DC 75 177 Dielectric TFU-8JST-R03

OTHER Items of Interest

October 19, 1998 - Issue 138 Final Edition

DTV - NCTA Outlines Cable Industry Position on Digital Must Carry (Oct. 15)
The National Cable Television Association outlined its position on FCC "Must-Carry" regulations for broadcast digital TV. NCTA asked "During the eight or more years while broadcasters are transmitting two over-the-air television signals, should the FCC mandate a "double dose of must carry" and require cable systems to carry both the analog and digital signals of every broadcaster?" NCTA's answer? "We believe -- as a matter of law and a matter of public policy -- that the answer must be 'no.'" Why? "Fundamentally, there is no reason that every broadcast station should be regarded as more important than any cable network."

NCTA is concerned that if DTV Must-Carry is enacted, cable networks could be "relegated to permanent second class status", resulting in cable networks being dropped from cable systems with limited channel capacity, "even though few people will initially buy new digital TVs and broadcasters will not offer more than a few hours of digital programming a week." NCTA said "Even when cable systems have more capacity, there’s no reason for the government to mandate a 'broadcaster first' policy."

Aside from these considerations, the NCTA position paper questioned the legal authority of the FCC to require carriage of both the analog and digital signals from broadcast stations during the transition period.

Read NCTA's Cable Industry Position on Digital Must Carry for more information. NCTA used quotes from several broadcasters to support its position, including CBS President Mel Marmazin, NBC's Charlie Jablonski, WTHR-TV VP/GM Rich Pegram, WFAA News Director John Miller and Nat Ostroff, VP Engineering, Sinclair Broadcasting.

SPACECRAFT - SOHO Nearly Back In Business - New Photos Released (Oct. 14)
NASA and the European Space Agency (ESA) said the Solar and Heliospheric Observatory (SOHO) was "nearly back in business", with its sensors again producing pictures of the Sun. Joseph Gurman, U.S. project scientist for SOHO and co-investigator on the Extreme Ultraviolet Imaging Telescope (EIT) said "It's very exciting to see these images again after so many weeks of concern. We hope that all of the SOHO scientific instruments can be returned to the same level of health, so we can resume normal scientific operations in the near future."

Nine of the twelve instruments on board SOHO have been turned on. Four are fully functional and the rest are undergoing "careful rescommissioning". ESA project scientist for SOHO Dr. Bernhard Fleck said "...so far no signs of damage due to thermal stress during the deep freeze have been detected. I tip my hat to the engineers who built this spacecraft and these sensitive but robust instruments."

Much more information, including some of the first images from SOHO after its restoration, are available on the web. Refer to the NASA Press Release - SOHO Is Nearly Back in Business, SOHO EIT images (NASA), SOHO MDI image (Stanford), NASA SOHO Recovery.

FCC Will Not Change Decision Prohibiting New TV Permittees from Operating on Channels 60-69 (Oct. 13)
The FCC released its Memorandum Opinion and Order in the Matter of Reallocation of Television channels 60-69, the 746-806 MHz band, ET Docket No. 97-157. The FCC declined to change its decision to allocate no new television permittees to operate on channels 60-69. The Commission also declined to change the status of low-power TV and TV translators operating on these channels.

With regards to the LPTV and TV translator stations, the FCC said "We have also taken a number of steps to accommodate low-power TV stations in the DTV Proceeding." The Order listed rules changes such as allowing these stations to apply for replacement channels on a non-competitive basis, deletion of some taboo restrictions, and allowing use of Longley Rice terrain dependent propagation prediction methods. It also noted that LPTV and TV translator stations could bid for the channels in the commercial part of that spectrum and thus gain primary status.

The Order used quotes from the Budget Act to support the FCC's conclusion that "we have both general and specific authority, granted by Congress, to make channels 60-69 available for public safety and commercial use as soon as feasible, and to take such actions as may be necessary to facilitate such availability." Refer to the full text of the Memorandum Opinion and Order in the Matter of Reallocation of Television channels 60-69, the 746-806 MHz band, ET Docket No. 97-157 for more information.

DTV - Real-Time MPEG-4 Video Over Satellite Link Demonstrated (Oct. 13)
Lockheed Martin Global Telecommunications, in conjunction with an international grouping of leading broadcast service providers, laboratories, and development facilities, successfully demonstrated "the first real-time MPEG-4 over satellite link" at the 45th meeting of the International MPEG Committee. Lockheed commented that with MPEG-4, "the customer's television set has the ability to match its processing power to the incoming video information. The new standard enables content providers to design feature-rich programs that let customers with lower bandwidth choose the elements they most desire - such as the audio from a signal, or a central image (of a tennis player, for example, without background), or just the overlay text services of any given program."

More information is available in the Lockheed-Martin Global Telecommunications Press Release.

DTV - Acrodyne Applies for Patents for ACT and DTV Transmitter Technology (Oct. 13)
Acrodyne announced it has applied for five US Patents covering its Adjacent Channel Technology (ACT™) and "conceptual and practical aspects of adjacent channel television transmitters, channel steering, signal correction and filter economy." Additional on-line information was not available.

DIGITAL TELEVISION STATION APPLICATIONS - See ap981019.txt for more information
Call (DT) Ch. Licensee Location ERP (kW) HAAT (m) Antenna
WPSD 32 Paxton Media Group Paducah KY 906 492 Harris TWSC-29

DIGITAL TELEVISION STATION ACTIONS - See ac981016.txt for more information
Call (DT) Ch. Licensee Location ERP (kW) HAAT (m) Antenna
WTHN 10 WTNH Broadcasting New Haven CT 7.99 342

OTHER Items of Interest

October 12, 1998 - Issue 137 Final Edition

SATELLITE - PanAmSat Orders New Satellites / New Launches (Oct. 12)
PanAmSat announced today it had ordered three new satellites from Hughes, for launch over the next 15 months, and three ground spares for use as replacement or supplemental satellites. Arianespace was selected to provide two additional launches, one of which will be used to deploy Galaxy XI. Galaxy XI is an HS 702 satellite. It has 64 transponders and is designed to provide coverage of North America and Brazil. Initially, it will be positioned at 88 degrees West Longitude to replace Galaxy IV, until the Galaxy IV-R satellite can be deployed. The launch is scheduled for March or April of 1999.

PanAmSat also released its schedule for launching seven other statellites, including PAS-8 (see Other Items, below) in November, PAS-6B in December and Galaxy IV-R and Galaxy X-R sometime in the 4th Quarter of 1999. A complete table of the satellites, launch dates and launch vehicles is contained in the PanAmSat Press Release.

DTV - NIST/ATP Work Planned to Develop Technology for Improved Indoor DTV Reception (Oct.)
GE Corporate Research and Development is sponsoring a project to "Develop and demonstrate improved receivers, antennas, and transmitters that will enhance indoor reception of digital television signals, stimulating the rapid adoption of this technology by broadcasters, expanding access to information, and creating new business and jobs." The total project cost is estimated at over three million dollars, with slightly more than one and a half million dollars of ATP funds requested.

GE Corporate R&D will lead the development team. The first task will be to characterize the complex indoor reception environment. After this, "advanced receiver technology will be developed, including improved techniques for estimating channel conditions, new algorithms for adjusting equalizer filters, and low-cost adaptive antennas." Other team members include the National Broadcasting Company (NBC); Comark Communications, Inc.; and Thomson Consumer Electronics. More information is available in an NIST Project Brief.

FCC Seeks Comments on Petition for Declaratory Ruling on Streamlining Antenna Struction Clearance (Oct. 9)
The FCC is seeking comments on a request by Teletechb for declaratory ruling on the Commission's streamlining of its antenna structure clearance procedure and revision of the Commission's rules concerning construction, marking, and lighting of antenna structures, implemented by Report and Order in WT Docket 95-5, released November 30, 1995. Teletech asked for clarification of the requirements to state:

  1. "the acceptable form of measurement;
  2. the accuracy requirement of the survey device;
  3. the accuracy standard to which an antenna site owner must measure the geodetic latitude and longitude and elevation of the antenna structure."

Teletech also asked for guidance on registration requirements for multiple antennas in hypothetical cases "for multiple antennas on single building sites and in which different parties own buildings and building-mounted antenna structures or different parties own antenna structures and surmounting antenna structures." Comments are due October 23, 1998. Reply comments are due November 2, 1998. Refer to Public Notice DA98-2042 for more information.

PEOPLE - Geza Dienes Elected as Fellow of IEEE (Oct. 6)
Andrew Corporation announced today that Geza Dienes was elected a Fellow of the Institute of Electrical and Electronic Engineers (IEEE). Some of Geza Dienes' broadcast TV accomplishments include development of Andrew's TRASAR® traveling wave antenna and the taming of circular waveguide with the GUIDELine® single mode circular waveguide.

On a personal note, I owe much of what I know about TV and RF engineering to the patience and knowledge of the engineers I've had the privilege to meet and work with over the past thirty years. Geza Dienes is one of those engineers. I first met Geza when I was started building TV stations for Telemundo. Among other things, he took time to explain how he solved some of the then common problems with traveling wave antennas and, later, how his GUIDELine worked. As you can imagine, I was quite happy when heard I his name announced as an IEEE Fellow at the IEEE Broadcast Technical Society banquet in Washington DC two weeks ago. Congratulations!

You can read more about Geza Dienes in the Andrew Press Release.

DIGITAL TELEVISION STATION ACTIONS - See ac981009.txt for more information
Call (DT) Ch. Licensee Location ERP (kW) HAAT (m) Antenna
WCAU 67 NBC Stations Philadephia PA 112 262 Dielectric TLP-16A(C)

OTHER Items of Interest

October 5, 1998 - Issue 136 Final Edition

SATELLITE - NASA says Leonids Meteor Threat Elevated but Not Serious (Oct. 5)
A NASA News Release issued today said "The November 17 Leonids meteor storm will present an elevated, though not serious, threat to spacecraft in the vicinity of the Earth for about half a day, according to NASA and Department of Defense experts, who have been studying the potential risk." NASA's Johnson Space Center Orbital Debris Program Office in Houston and the Air Force Deputy Chief of Staff for Air and Space Operations reported Comet Tempel-Tuttle passed perihelion eary in 1998, "setting the stage of a probable meteor storm in 1998 and perhaps again in 1999."

As a precaution, NASA said the Space Shuttle will not be in orbit during the Leonids storm and the launch of the first element of the International Space Station will not take place until after the storm subsides. The Hubble Space Telescope will be positioned so that the opening to its mirrors and instruments is pointed away from the approaching meteors during the storm. These are not the only steps being taken to reduce the risk of damage to satellites from the meteor storm:
Other measures being taken by U.S. government satellite operators to reduce spacecraft risk from the Leonids include minimizing the spacecraft cross-section (including solar arrays) to the meteors; reorienting sensitive spacecraft surfaces away from the direction of the Leonids; powering down non-critical systems; developing contingency and recovery plans to counter the likely effects of electrical discharge; minimizing communications to the spacecraft during the threat period; and augmenting crews at spacecraft operations centers during the period of intense Leonids activity.
These steps are similar to those previously announced by Intelsat (see The Leonid Meteroid Storm: INTELSAT's Risk Mitigation Stragegy) and GE Americom (see GE Leonid Meteor Showers Information Sheet) to protect their fleets.

NASA's Marshall Space Flight Center has updated their "Leonid Fluence Calculator" to incorporate results from 1998 observations of the Leonids. You can find it at http://see.msfc.nasa.gov/see/models/lsfc/lsfc.html. Other sites with Leonids information may be found at http://www-space.arc.nasa.gov/~leonid and http://www.spacecom.af.mil. The latest press release on that site is Threat to Spacecraft From Leonid Meteor Storm Said to be Elevated But Not Serious. See the July 27, 1998 RF Current for additional links.

DTV - ATSC Comments on Australian DTTB Selection Panel Report Recommending DVB-T (Oct. 1)
In comments released today, ATSC said that "Members of the ATSC with expertise in digital modulation techniques examined the test data from the Australian lab and field tests, and found that, in many cases, the data supported different conclusions than those reached in the Australian recommendation." ATSC said it was not trying to reverse the recommendation, but wanted to provide ATSC's perspectives on the tests to non-Australian readers of the report.

ATSC Chairman Robert Graves said "We are currently engaged with broadcasters and goverment officials in many countries whom we believe will find our report to be compelling reading. We believe that for many, the Australian test results make a clear case for choice of the ATSC DTV Standard and its 8-VSB modulation system." The ATSC comments highlight the superior threshold performance of the ATSC system and its robustness in the presence of impulse noise. They also point out that the DVB-T COFDM modulation system achieves better static multipath performance at the cost of deteriorated threshold performance, limiting its use to strong signal environments. The comments also point out the "Blue Rack" receiver used for the ATSC tests does not represent state of the art ATSC reception capability.

There are many other points that make the comments interesting reading. For more information, see the ATSC Press Release. The comments may be downloaded in Word 6.0/95 format from the Cover Page - Comments on DTTB. Also refer to the Results Summary for Australian 7 MHz Laboratory Tests of DVB-T and ATSC DTTB Modulation Systems or download the full text of the report and tests results from the Australian Communications Lab Digital TV Reports page. For information on tests conducted at the BBC on LSI Logic's DVB-T COFDM demodulator chip, see Results of initial performance tests with the LSI Logic L64780 DVB-T COFDM demodulator chip.

FCC Releases First Report and Order and Third NPRM on Public Safety Use of UHF TV Channels (Sept. 29)
The FCC today released its First Report and Order and Third Notice of Proposed Rulemaking on Wireless Docket 96-86, The Development of Operational, Technical and Spectrum Requirements For Meeting Federal, State and Local Public Safety Agency Communication Requirements through the Year 2010 and Establishment of Rules and Requirements For Priority Access Service, hereafter refered to as the First Report. Comments are due 60 days after publication in the Federal Register and reply comments 90 days after publication.

In the First Report, the FCC established "a band plan and adopted service rules necessary to commence the licensing process in the newly-reallocated public safety spectrum at 764-776 MHz and 794-806 MHz." The First Report also adopts "certain technical specifications that enhance spectrum efficiency, promote nationwide interoperability, and minime harmful interference." The FCC proposed technical criteria to protect GPS navigation and full service analog and digital television service during the transition to DTV. The First Report also establishes rules to ensure that "the new spectrum will not be subject to harmful interference from television broadcast licensees.

The FCC adopted a 40 dB desired-to-undesired (D/U) signal strength ratio to protect TV/DTV stations and public safety users from interference to each other. The D/U ratio for adjacent channel operations was set at 0 dB. Public safety applicants can choose one of three ways to meet the TV/DTV protection requirements:

  1. Utilize the geographic separation specified in the Table
  2. Submit an engineering study to justify other separations which the Commission approves
  3. Obtain concurrence from the applicable TV station(s)

Conventional UHF-TV stations can no longer apply for channels 60-69 or modifications in these channels "which would increase the stations' service areas".

Public Safety power levels and antenna height limits in the 700 MHz band will be the same as the 800 MHz limits in Section 90.635 of the rules - a maximum power of 1 kW and maximum height above average terrain of 304 m for trunked and "urban" systems and 500 watts and 152 m for suburban-conventional systems. Hand held transmitters are limited to 3 watts and mobile and control transmitters to 30 watts, with automatic power control.

The FCC's band plan divided the 24 MHz of spectrum into 1920 6.25 kHz narrowband channels and 240 50 kHz wideband channels. Equipment will generally be required to use digital modulation, although mobile and portable units may have analog modulation capability as a secondary mode in addition to the primary digital mode. Recognizing the need for standards for the interoperability channels in the 700 MHz band, the FCC established a Standards Development Process. (See the full text for details on this.) The FCC charged the National Coordination Committee with establishing receiver specification requirements, along with other work to develop standards.

The First Report and Third Notice of Proposed Rulemaking contain also proposals for interoperability in other frequency bands and year 2000 computer compliance. It is impossible to summarize all the issues raised in this Report. Download the full text of the First Report and Third NPRM (FCC98-191) in ASCII text - fcc98191.txt or WordPerfect - fcc98191.wp file format. Appendices A through G are also available in ASCII text - f98191ag.txt or WordPerfect - f98191ag.wp formats. Appendix H contains the channelization plan for the 700 MHz Public Safety band. Download the ASCII text - fc98191h.txt or WordPerfect - fc98191h.wp versions.

SATELLITE - Loral Skynet Postpones Launch of Telstar 6 (Sept. 29)
Yesterday Loral Space and Communications announced it was postponing the launch of Telstar 6. The launch was originally scheduled for October 15, 1998 and is expected to be rescheduled for the end of November. The manufacturer of the traveling wave tubes (TWTs) used in the satellite, AEG of Germany, notified Space Systems/Loral that the tubes may be susceptible to thermally induced fatigue. The tube modification and additional testing will be done at the Proton Launch base in Baikonur. Loral said Telstar 4 and Telstar 5 use a different version of the TWTs and are operating normally. Terry Hart, president of Loral Skynet stated "We believe it is prudent to stand down temporarily from the scheduled launch of Telstar 6 until we are certain that the satellite meets all specifications. This delay will not affect our ability to continue to meet commitments to our customers for satellite transmissions." Information obtained from Loral Press Release.

DIGITAL TELEVISION STATION APPLICATIONS - See ap980929.txt for more information
Call (DT) Ch. Licensee Location ERP (kW) HAAT (m) Antenna
WGFL 28 Budd Broadcasting High Springs FL 200 259 Andrew ATW30H3H
KFOR 27 New York Times Oklahoma City OK 352 489 Dielectric TFU-30GTH
WMPH 20 Mississippi Ed. TV Jackson MS 1552 4 Acrodyne AUD-2S
WHA 20 Board of Regents Madison WI 50 453 Dielectric TFU-30-GBH-R-DC

DIGITAL TELEVISION STATION ACTIONS - See ac981001.txt for more information
Call (DT) Ch. Licensee Location ERP (kW) HAAT (m) Antenna
KWHY 42 Harriscope Los Angeles CA 165 873 Dielectric TFU-26DSC-RS180

OTHER Items of Interest

Other Issues Available:



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Last modified October 28, 1998 by Doug Lung dlung@transmitter.com
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