A Review of the L-Band Auction

In May 2008, Ofcom’s L-band auction concluded. This was Ofcom’s second combinatorial clock auction. The auction used an innovative format intended to encourage an efficient assignment of the 17 lots. Eight bidders competed for the lots. In sharp contrast to the first combinatorial clock auction, the 10-40 GHz auction, in which each of the ten bidders won spectrum, in the L-band auction there was a single winner—Qualcomm won all the lots. This note briefly reviews the auction.Auctions, spectrum auctions, market design, package auction, clock auction, combinatorial auction

Multi-frequency fine resolution imaging radar instrumentation and data acquisition

Development of a dual polarized L-band radar imaging system to be used in conjunction with the present dual polarized X-band radar is described. The technique used called for heterodyning the transmitted frequency from X-band to L-band and again heterodyning the received L-band signals back to X-band for amplification, detection, and recording

A Polarimetric Phased Array Antenna for E-SAR in L-Band

The design of a new L-band antenna for DLR’s airborne synthetic aperture radar system (E-/F-SAR) is presented. Beside operations in L-band new components for a system upgrade were developed. These components are intro-duced. Special interest of this paper is the development of the dual-polarized L-Band antenna with enhanced bandwidth of 150MHz. The antenna feed network is equipped with 2bit hybrid phase shifters to steer the beam between 25° and 40° in elevation. For mounting the antenna at the fuselage of a Dornier Do 228-212 aircraft a rack is described to house several antenna configuration

L-band multiwavelength erbium-doped fiber ring laser for sensing applications

In this work, a novel single-longitudinal-mode (SLM) four-wavelength laser configuration for sensing applications in L-band is proposed and experimentally demonstrated. This spectral region presents some advantages for the detection of dangerous gases. The sensor system presented here is based on ring resonators, and employs fiber Bragg gratings to select the operation wavelengths. The stable SLM operation is guaranteed when all the lasing channels present similar output powers. It is also experimentally demonstrated that when a SLM behavior is achieved, lower output power fluctuations are obtained

ATS-5 trilateration support

The development of an L-band trilateration network capable of locating the ATS-5 satellite, determining the satellite's orbital elements, and predicting the satellite position was investigated. An automatic tone-code ranging transponder was used to compare ranging measurements and communications reliability for the VHF and L-band. The L-band transponder network, analytical techniques, and the determination of the Kepler orbit parameters are described along with the calibration procedures, operation procedures, and verification of trilateration position

High Power, Continuous-wave Supercontinuum Generation in Highly Nonlinear Fibers Pumped with High Order, Cascaded Raman Fiber Amplifiers

A novel method for efficient generation of high power, equalized continuous-wave supercontinuum source in an all conventional silica fiber architecture is demonstrated. Highly nonlinear fiber (HNLF) is pumped in its anomalous dispersion region using a novel, high power, L-band laser. The L-band laser encompasses a 6th order cascaded Raman amplifier which is pumped with a high power Ytterbium doped fiber laser and amplifies a low-power, tunable L-band seed source. The supercontinuum generated 35W of power with ~40% efficiency. The Supercontinuum spectrum was measured to have a high degree of flatness of better than 5 dB over 400 nm of bandwidth (1.3 - 1.7 micron, limited by spectrum analyzer range) and a power spectral density in this region of >50 mW/nm. The extent of the SC spectrum is estimated to be upto 2 micronComment: 6 pages, 5 figure

Microwave remote sensing of soil moisture, volume 1

Multifrequency sensor data from NASA's C-130 aircraft were used to determine which of the all weather microwave sensors demonstrated the highest correlation to surface soil moisture over optimal bare soil conditions, and to develop and test techniques which use visible/infrared sensors to compensate for the vegetation effect in this sensor's response to soil moisture. The L-band passive microwave radiometer was found to be the most suitable single sensor system to estimate soil moisture over bare fields. The perpendicular vegetation index (PVI) as determined from the visible/infrared sensors was useful as a measure of the vegetation effect on the L-band radiometer response to soil moisture. A linear equation was developed to estimate percent field capacity as a function of L-band emissivity and the vegetation index. The prediction algorithm improves the estimation of moisture significantly over predictions from L-band emissivity alone

Distribution of dust clouds around the central engine of NGC 1068

We studied the distribution of dust clouds around the central engine of NGC 1068 based on shifted-and-added 8.8 - 12.3 micron (MIR) multi-filter images and 3.0 - 3.9 micron (L-band) spectra obtained with the Subaru Telescope. In a region of 100 pc (1.4") around the central peak, we successfully constructed maps of color temperatures and emissivities of the MIR and L-band continua as well as the 9.7 micron and 3.4 micron dust features with spatial resolutions of 26 pc (0.37") in the MIR and 22 pc (0.3") in the L-band. Our main results are: 1) color temperature of the MIR continuum scatters around the thermal equilibrium temperature with the central engine as the heat source while that of the L-band continuum is higher and independent upon distance from the central engine; 2) the peak of the 9.7 micron silicate absorption feature is shifted to a longer wavelength at some locations; 3) the ratio of the optical depths of the dust features is different from the Galactic values and show complicated spatial distribution; and 4) there is a pie shaped warm dust cloud as an enhancement in the emissivity of the MIR continuum extending about 50 pc to the north from the central engine. We speculate that material falls into the central engine through this cloud.Comment: 26 pages, 9 figures. Accepted for publication on Ap