Road Access: Open road from Longyearbyen to Mine 7 and extension road to the radar
Electrical power: 22 kV line serving Mine 7, step-down transformers, emergency generator on site
Building: Operations building close to the antenna, consisting of transmitter hall, instrument and control rooms as well as office, workshop, laboratory, storage and personnel facilities rooms. Fully shielded for minimum radio frequency interference and electromagnetic compatibility. Constructed for severe Arctic climate conditions.
Frequency: Centre: 500 MHz Bandwidth: ±2 MHz (transmit) ±10 MHz (receive)
Temperature range: -55 ÷ +25 C Operational wind speed: less than 27 ms-1 Survival wind speed: 50 ms-1 Ice warning system Slewing rate (elev. + azim.): 1.5 s-1 Slewing acceleration: 1 s-2 Slewing range: elev.: 0 - 180 azim.: ± 270 Pointing accuracy: less than 0.05 Feed system: Secondary focus, waveguide, 2 rotary joints Polarization: Circular (right-hand transm. left-hand receive) Gain: 42 dBi Sidelobes: -16 dB (1. sidelobe) -24 dB (2. sidelobe) -34 dB (3.-5. sidelobes) less than -40 dB (others) VSWR: less than 1.20 Ant. temperature: 45 K at 90 elevation (Sky-, preamp. noise etc.) 60 K at 10 elevation Max. power: 2 MW peak, 500 kW average
The single modules base on standard television transmitters employing external cavity vapor cooled klystron tubes yielding 62.5 kW RF-power. A beam pulse modulator is added.
The transmitter is being constructed by Harris Allied Broadcast Division, Cambridge, UK (delivery for tests in Tromsø in summer 1993). The klystron tubes will be supplied by 2 independent vendors, Philips, Germany, and EEV, UK. These klystrons have typical lifetimes of about 25000 hours.
Power: 250 kW peak obtained by combining 4x62.5 kW Power bandwidth (-1dB): 4 MHz Duty cycle: 25 % max. Input power: 10 mW Load VSWR: less than 1.2 Harmonic emission: -60 dBc Spurious emission: -50 dBc Interpulse noise: less than -155 dBm/Hz Pulse length: 1 µs ÷ 2 ms Rise/fall time: less than 0.5 µs Voltage droop (at 2ms): 3 % Pulse rep. rate: 0.02-2 kHz Interpulse period: 0.5 ms min. Modulation: amplitude and phase Dynamic range: 20 dB Mains voltage: 3-phase 400 V HV for klystron: 23-27 kV Power combiner (2x125 kW): switchless Harmonic filter Security: Obey standards on RF leakage, magnetic and electric fields, x-ray and materials Control and monitor: allow mostly unattended operation under automatic or remote control Cooling: air and water vapor Size (lxwxh): 5.2 x 4.2 x 3.1 m Klystrons: YK1265, EEV K3673BCD
Inputs: A 10 MHz clock signal (sinus), a 100 Hz synchronization pulse and a start command from the real time clock.
Program memory: The address space is 20 bits. This means that it may contain up to 1 M Word memory. This gives the maximum program size that will be possible with this design. How much memory that actually will be instal will depend on how much memory we can fit on a VME card in addition to the other circuits. The aim is to install at least 256 k word on the prototype.
The memory is organized so that each word contains a 32 bit control word section, a 24 bit dwell time section and 8 bits for internal control and program instructions. Outputs: 32 bit control word with 100 nanoseconds time resolution, 1 bit end of scan.
The three main subsystems of the receiver are:
(a) Front-end: low noise cooled GaAsFET preamplifier and high dynamic range first mixer. Physically located in the antenna cabin. Equipped with low noise local oscillators.
Flange noise temperature: less than 20 K Bandwidth (- 3dB): 60 MHz Overall gain: 40 dB Local oscillator step size: 2 (1) MHz Output band (each mixer): 70 ±5 MHz
There can be up to three, first mixers connected to the common preamplifier, each with its own local oscillator and its own IF distribution and back end.
(b) IF distribution: first I.F. stages and the second mixer(s). Physically located at a central point in the RF equipment area (possibly the transmitter hall). One independent IF distribution subsystem for each first mixer output from the front end.
Input band: 70 ±5 MHz
Number of outputs: up to 4
Output ban 7.5 ±2 MHz
or 5.0 ±4 MHz
2nd LO frequency: 77.5 MHz, 75 MHz
(individually selectable for each mixer/output)
Total gain: >130 dB
Output level: 2 V pk-pk into 50 ohms
(c) Back-end: sampler, A/D converter, complex digital mixer and FIR filters. These will be realized in all digital technology. One independent back end for each IF distribution channel output. More than one mixer and FIR filter can be connected to the same ADC over a broadcast mode data bus.
Receiver back end specifications:
Bus environment: VME Analog-Digital-Converter: Input power bandwidth (-3 dB): 25 MHz min. Sample rate (sustained): 10 MHz min. Resolution: 12 bits min. Input voltage for 1 MSB: 1.024 V Input impedance: 50 + j0 * Digital multiplier: Input bandwidth: 10 Mhz min. Frequency resolution: less than 0.01 Hz HW FIR filter: Input data rate: 10 MHz min. Number of taps: 512 min. Coefficient accuracy. 16 bits min. Decimation: 2,..., 512 min.
DSP specifications:
Bus environment: VME Host processor type: SparcEngine 2 or 68040 Lag profile processor: Chip family TMS 'C40 Input data rate/processor: 10 MHz max. Input data format: 16+16 bit complex Output data format: 32+32 bit complex or IEEE FP Processing rate (complex mpy/add): 30 MOPS/channel
The software will be divided into two main areas which will communicate via a data base system. The first area:
(a) will contain all the time-critical elements, while the second,
(b) will contain all the packages required to use the radar for scientific purposes.
The two areas will provide a logical separation between (a) the real-time tasks and (b) the user packages. A further series of interfaces to the database system will provide engineering information both for operational maintenance and long term monitoring.
The design philosophy behind the EISCAT Svalbard Radar system procurement exercise is to use high-technology industry-standard components and subsystems wherever possible. In-house design is tried to be kept at minimum, although the expertise of inhouse staff, acquired over many years of the EISCAT operation, is indispensable in defining, supervising and developing certain system partitions of the hardware and software. This is mandatory to allow a system design and development, which is exceptionally specialized as an advanced incoherent and coherent scatter radar system. Associates' institutions support on certain work packages, such as software design is also envisaged.
The design of the industry-constructed system parts will be in close coordination with experienced EISCAT staff and selected consultants from other observatories and Associates' institutions. The testing of many parts will be performed at the mainland sites before these will be installed on the site near Longyearbyen in 1994 and thereafter. Test operation is planned to start at the end of 1995, experiments should commence as soon as possible after successful testing. Later remote monitoring and control from an operations centre in the Longyearbyen community or at the land is planned to be added, when corresponding facilities and funds will be available.
Created : 6.11.93
By : Jürgen Röttger
HTML debugged and edited 02/08-95 by Bjørge; Brekke