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Hill, J. S.

Publications and source records attributed to Hill, J. S..

15 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1980

Analysis of airborne RF measurements from U.S.A. urban areas

The paper presents in-situ, airborne survey radio-frequency measurements, which were made over the 400-1000 MHz range in May 1977 during the ASSESS-II Space Shuttle/Spacelab simulation aircraft flights. Measurements were made from altitudes of 10,000 to 33,000 feet with a downward-directed 70 deg wide, half-power beamwidth receiving antenna pattern. Channel occupancy percentages are given within a 50 MHz spectrum width, and continuous spectrum-scan measurements are presented for selected locations on the USA West Coast, showing the channel occupancy environment within the 806-890 MHz mobile-service band.

Taylor, R. E.↗
NASA NTRS1979

Airborne East Coast/Midwest urban survey at 121.5/243 MHz

Results of an airborne RF interference measurement survey of the emergency-distress, Search and Rescue frequency bands at 121.5 and 243 MHz at an altitude of 25,000 ft over the U.S. East Coast and Midwest urban areas are presented. Included are a series of minutely median profile plots of antenna-noise temperature computed from RF interference power measurements at the output terminal of a quarter-wavelength monopole antenna, for both daytime and nighttime observations. The greatest value, 450,000 K, of minutely median temperature was recorded over New York City at 121.5 MHz during the day. East Coast urban areas exhibited a day-night effect at 121.5 MHz, where nighttime observations had a median value of 8.6-dB below daytime values; Midwest counterparts did not exhibit a significant day-night effect at 121.5 MHz.

Taylor, R. E.↗
NASA NTRS1979

Airborne surveys of USA urban areas at 121.5/243 MHz

In situ, aircraft flight measurements were made in 1976 and 1977 by NASA of the radio-frequency environment over USA urban areas within the emergency distress search and rescue frequency bands at 121.5 and 243.0 MHz. This paper analyzes test results reported previously for USA East Coast and Midwest flight surveys; presented also are test results obtained in May 1977 for the USA West Coast during the NASA, ASSESS-II, Space Shuttle/Spacelab simulation aircraft flights. The USA West Coast flight include data at 121.5/243 MHz during an extensive series of aircraft passes for the Los Angeles urban area. The USA East Coast/Midwest measurements show correlation with population count.

Taylor, R. E.↗
NASA NTRS1977

EMI survey for maritime satellite 1535-1645-MHz shipboard terminal

A 15,690-ton commercial container ship was selected as lead ship for an onboard electromagnetic-interference (EMI) survey prior to installation of 1535-1645-MHz (L-Band) shipboard terminals for communication via a maritime satellite. In general, the EMI survey revealed tolerable interference levels on board ship. Radiometer measurements indicate antenna-noise temperatures less than 70 K at elevation angles of 5 deg and greater at 1559 MHz at the output terminals of the 1.2-m diameter parabolic-dish antenna for the L-band shipboard terminal. Other EMI measurements include field intensity from 3-cm and 10-cm wavelength pulse radars, and conducted-emission tests of primary power lines to both onboard radars.

Taylor, R. E.↗
NASA NTRS1977

Airborne urban/suburban noise measurements at 121.5/243 MHz

An airborne measurement of the terrestrial, radio-frequency (RF) noise environment over U.S. metropolitan urban/suburban areas has been made at the 121.5/243 MHz emergency-distress search and rescue (S&R) communications frequencies. Profile contour plots of antenna-noise temperature for U.S.A. East Coast and mid-west urban/suburban areas is presented for daytime/nighttime observations at 121.5/243 MHz. These plots are helpful for compiling radio-noise environment maps; in turn useful for designing satellite-aided, emergency-distress search and rescue communication systems.

Taylor, R. E.↗
NASA NTRS1977

Aircraft measurement of radio frequency noise at 121.5 MHz, 243 MHz and 406 MHz

An airborne survey measurement of terrestrial radio-frequency noise over U.S. metropolitan areas was carried out at 121.5, 243 and 406 MHz with horizontal-polarization monopole antennas. Flights were at 25,000 feet altitude. Radio-noise measurements, expressed in equivalent antenna-noise temperature, indicate a steady-background noise temperature of 572,000 K, at 121.5 MHz, during daylight over New York City. This data is helpful in compiling radio-noise temperature maps; in turn useful for designing satellite-aided, emergency-distress search and rescue communication systems.

Taylor, R. E.↗
NASA NTRS1977

Aircraft measurement of radio frequency noise at 121.5 MHz, 243MHz and 406MHz

An airborne survey measurement of terrestrial radio-frequency noise over U.S. metropolitan areas has been made at 121.5, 243 and 406 MHz with horizontal-polarization monopole antennas. Flights were at 25,000 feet altitude during the period from December 30, 1976 to January 8, 1977. Radio-noise measurements, expressed in equivalent antenna-noise temperature, indicate a steady-background noise temperature of 572,000 K, at 121.5 MHz, during daylight over New York City. This data is helpful in compiling radio-noise temperature maps; in turn useful for designing satellite-aided, emergency-distress search and rescue communication systems.

Taylor, R. E.↗
NASA NTRS1976

A 0.4 to 10 GHz airborne electromagnetic environment survey of USA urban areas

An airborne electromagnetic-environment survey of some U.S. metropolitan areas measured terrestrial emissions within the broad frequency spectrum from 0.4 to 10 GHz. A Cessna 402 commercial aircraft was fitted with both nadir-viewing and horizon-viewing antennas and instrumentation, including a spectrum analyzer, a 35 mm continuous film camera, and a magnetic tape recorder. Most of the flights were made at a nominal altitude of 10,000 feet, and Washington, D. C., Baltimore, Philadelphia, New York, and Chicago were surveyed. The 450 to 470 MHz land-mobile UHF band is especially crowded, and the 400 to 406 MHz space bands are less active. This paper discusses test measurements obtained up to 10 GHz. Sample spectrum analyzer photograhs were selected from a total of 5,750 frames representing 38 hours of data.

Taylor, R. E.↗
NASA NTRS1976

0.4- to 10-GHz airborne electromagnetic-environment survey of United States urban areas

An airborne electromagnetic-environment survey of some U.S. metropolitan areas measured terrestrial emissions within the broad-frequency spectrum from 0.4 to 10 GHz. A Cessna 402 commercial aircraft was fitted with both nadir-viewing and horizon-viewing antennas and instrumentation, including a spectrum analyzer, a 35-mm continuous-film camera, and a magnetic-tape recorder. Most of the flights were made at a nominal altitude of 10,000 ft, and Washington, Baltimore, Philadelphia, New York, and Chicago were surveyed. The 450- to 470-MHz land-mobile UHF band is especially crowded, and the 400- to 406-MHz space bands are less active. Test measurements obtained up to 10 GHz are discussed. Sample spectrum-analyzer photographs were selected from a total of 5750 frames representing 38 hours of data.

Taylor, R. E.↗
NASA NTRS1975

Test plan and preliminary report of airborne electromagentic environment survey over USA urban areas 0.4 to 18.0 GHz

An airborne electromagnetic environment survey is described of five urban areas where terrestrially-generated radio-frequency interference was measured over the frequency range from 0.4 to 18.0 GHz. A chartered Cessna 402 aircraft contained necessary measurement test equipment, including the receiving antennas mounted beneath the fuselage. Urban areas including Washington, D.C.; Baltimore, MD; Philadelphia, PA; New York, NY; Chicago, ILL; and Palestine, TX were surveyed. A flight test plan and preliminary test results for the 0.4 to 1.4 GHz frequency range, are included; a final test report describes more detailed results.

Taylor, R. E.↗
NASA NTRS1975

L-band, 1.2 m parabolic antenna-noise temperature measurement

Extensive antenna-noise temperature measurements at 1.6 GHz (L-band) were made using a 1.2 m (4 ft. diameter) parabolic dish antenna mounted on the flying bridge of a modern 15,690-ton, commercial-container ship. Both in-harbor and at-sea radiometer measurements were made that indicated a steady background, antenna-noise temperature value slightly less than 70 degrees Kelvin (K) at elevation angles of 5 percent, and greater, at 1.6 GHz. A comparison of theoretical and measured values indicate excellent agreement within about 5K for at-sea data. These measurements are helpful to RF equipment designers of maritime, L-band shipboard terminals for operation with the two, geostationary, maritime satellites, Marisat-A and -B.

Taylor, R. E.↗
NASA NTRS1975

EMI survey for maritime satellite, L-band, shipboard terminal

The paper presents results of an onboard EMI survey of an L-band shipboard terminal for operation with two geostationary maritime satellites. Significant EMC results include: (1) antenna noise temperature measurements indicate a maximum of 70 K steady background component at 1.6 GHz at sea for elevation angles of 5 degrees and higher; (2) field intensity measurements from 1-10 GHz show that a L-band terminal can operate simultaneously with onboard S-band and X-band navigation radar; (3) radar transmitter case emissions, below deck, in-band from 1535-1660 MHz, at 1 m distance from the cabinet, are equivalent, or greater than above-deck emissions in the same frequency range; and (4) conducted-emission tests of a ship's power lines to both radars show both narrow band and broad band emissions are 15 dB to 50 dB higher than equivalent U.S. commercial power lines from 150 kHz to 32 MHz.

Taylor, R. E.↗
NASA NTRS1974

EMI survey for maritime satellite, L-band, shipboard terminal

The United States Lines 15,690-ton commercial-container ship, American Alliance, was selected as lead ship for an onboard EMI survey prior to installation of L-Band shipboard terminals for operation with two, geostationary, maritime satellites. In general, the EMI survey revealed tolerable interference levels onboard ship: radiometer measurements indicate antenna-noise temperatures less than 70 K, at elevation angles of 5 deg and greater, at 1559 MHz, at the output terminals of the 1.2-m-diameter, parabolic-dish antenna for the L-Band shipboard terminal. Other EMI measurements include field intensity from 3 cm- and 10 cm-wavelength pulse radars, and conducted-emission tests of primary power lines to both onboard radars.

Taylor, R. E.↗
NASA NTRS1971

Electromagnetic compatibility design guideline for STADAN

Procedures for achieving electromagnetic compatibility in electronic and electrical equipment for aerospace ground stations are investigated. The application of shielding theory to good design is treated and standards of good practice are outlined for bonding, grounding, wiring, and cabling. Some aspects of filter design are explained, and suggestions are given for the application of filters to electronic and electrical equipment.

Cowdell, R. B.↗