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.

Issues are dated each Monday, although recently I've needed an extra day or two to complete each issue. Articles may be posted earlier if time permits or if there is a major, breaking story.

<<< Back to August 7 - Issue 226

August 14, 2000 - Issue 227 Final Edition

SATELLITE - DIRECTV renames Satellite Fleet (Aug. 10)
DIRECTV announced it is renaming four of the five satellites in its existing fleet to the name "DIRECTV" followed by the numeric identifier. All future spacecraft will use similar numbering. David Baylor, executive vice president, DIRECTV, Inc., explained, "The 'DBS' identifier is generic terminology in the industry and does not reflect the nature of ownership or clearly identify the DIRECTV satellite fleet. With DIRECTV-branded satellites, we will eliminate confusion over identity of the spacecraft and bring them into line with our effort to continually strengthen our brand name and competitive position. The name change is especially important as we continue to expand our fleet to provide our customers with more programming.With DIRECTV-branded satellites, we will eliminate confusion over identity of the spacecraft and bring them into line with our effort to continually strengthen our brand name and competitive position. The name change is especially important as we continue to expand our fleet to provide our customers with more programming."

Satellites will be named as follows:
Original Name Orbital Position New Name

This information is from the DIRECTV Press Release DIRECTV Renames Satellite Fleet.

FCC Experimental Application Grants for March 1 to June 1, 2000 (Aug. 8)
The FCC Office of Engineering and Technology has released a list of experimental applications granted between March 1 and June 1, 2000. Some of the more interesting licenses include one granted to Montech Systems to operate in the 1720-2065, 2194-2495, 2505-2850 and 3155-3400 KHz medium/shortwave spectrum in all 50 U.S. states to develop a trailer tracking and asset monitoring communications system. David Hysell received a license to operate on stepped frequencies in the band 2000-12000 KHz for atmospheric study in Pendleton, SC. Orbital Communications was granted a license to operate in the 137-138 and 148-150.05 MHz bands for development of a repeater system for testing LEO satellite equipment in the continental U.S. Northrop Grumman was allowed to use 143, 150.65 and 2360-2390 MHz to test, develop and demonstrate mobile robots under a Navy contract. Andrew Corporation was granted a license to operate in the 150 - 58,000 MHz spectrum for development and testing of antennas at an outdoor test range in Orland Park, IL.

Two companies were granted licenses to operate in the TV broadcast spectrum. Rockwell Collins received a license to operate in the 180-210, 476-608 and 614-788 MHz bands for test, development and demonstration of a military radio communications system at sites in Georgia, New Jersey, Texas and Iowa. Lockheed Martin's license covered the 512-608, 614-650 and 650-806 MHz bands for training and evaluation of telemetry under an Army contract in Orlando, FL.

Other interesting licenses included one issued to Transcom to operate on 915.75 MHz for the test, development, and demonstration of an autmoatic vehicle. Gamut Electronics, LLC was allowed to use 2450-2483.5 MHz for testing of Part 90 video equipment mobile in San Diego County, CA. Lockheed Martin was granted a license to use 21200-23600 MHz for investigation of bandwidth efficiency techniques to improve terrestrial line of sight capacity by a factor of two. Finally, Marconi Astronics, Inc. received a license to operate on 94 GHz for testing a radar system for runway imaging in the continental U.S.

See the FCC Experimental Actions Public Notice for a complete list of all experimental grants and more information on the applications listed above.

Technology - Hands Free Kit Reduces Cell Phone EMF Exposure (Aug.)
A release from the United Kingdom Mobile Phones - Hands Free Kit Reduces EMF Exposure confirmed that use of personal hands free kits (PHF) for portable phones does "offer substantial reductions in exposure compared to the normal use of a mobile phone." British E-Minister Patricia Hewitt said, "Today's report confirms that hands-free kits reduce exposure for mobile phone users. It is important that the public is provided with clear and unambiguous advice about the use of hands free kit."

The study, conducted by SARtest Ltd., was commissioned to carry out tests on PHF kits following reports from the Consumers Assocation that the ear-piece wire used in the kits acted as an aerial and 'channelled three times the level of radiation to the head.'

The complete report in Adobe Acrobat format (355 kb) is available at www.dti.gov.uk/cii/sartest.pdf. Details of the testing procedure can be found on the SARtest web site. Also see the EE Times article linked to in Other Items below.

Technology - "Completely new amplification technique" - the Syncrodyne(tm) Amplifier (Aug.)
An Office of Naval Research (ONR) news release contained an interesting paragraph on "a completely new amplification technique for communication signals." The new technology is a result of work in nonlinear dynamics by NextWave Technologies in Columbia, MD and supported by ONR.

The description of the technique in the ONR release is not clear and no additional information was found on either the ONR or the NextWave Technologies web site. The ONR release said the Syncrodyne amplifier "is capable of provide enormous power gain while operating at 90 percent efficiency or better." Operation is described as follows: "Using a nonlinear oscillator, the technique converts signals' trajectories into symbols that can be recognized by the receiver and amplified. The breakthrough allows only the symbols to be regenerated and amplified, not the entire signal and any accompanying noise." ONR Program Officer Michael Shlesinger explained, "The fact that the trajectory is chaotic gives it the richness to represent many symbols. It's also inherently an encoded signal because the transmitter and receiver can only communicate if they are paired in terms of frequency and nonlinear oscillation."

The next step, according to NextWave researchers, is to build a "fully integrated communications system that will demonstrate the technique's distinct advantages." Do any readers have more information on this technique? Send a note to dlung@xmtr.com. Why does this remind me of a super-regenerative receiver, which uses quenched oscillation/regeneration to achieve very high gain?

OTHER Items of Interest

>>>>Next August 21 - Issue 228

RF Current Index

Return to The RF Page @ www.transmitter.com

Last modified August 20, 2000 by Doug Lung dlung@xmtr.com
Copyright ©2000 H. Douglas Lung