General Statistical Information on Antenna

Coordinates

Latitude (geodetic1) 18° 20' 36.6" North
Longitude (geodetic1) 66° 45' 11.1" West
Latitude (astronomical) 18° 21' 13.7" North
Longitude (astronomical) 66° 45' 18.8" West
Declination range -01:24:00 through +38:00:00
Azimuth Slew Rate 0.4 deg/s, 1440 deg/hour
Elevation Slew Rate 0.04 deg/s, 144.0 deg/hour
Zenith angle range 1.06 - 19.69 degrees
Magnetic Dip 50°
Magnetic declination 8° 30' West
Height of reflector center of curvature above MSL 1630 ft (497 m)

1Earth Ellipsoid "Mercury 1960", with semimajor axis 6378166 m and inverse flattening 298.3

 

Reflector and Structure

 Type  Fixed reflector, movable feeds
 Diameter of reflector  1000 ft (304.8 m)
 Area of aperture  18 acres (73,000 sqare m)
 Shape of surface  70° spherical cap
 Radius of curvature  870 ft (265 m)
 Surface accuracy  2.2 mm rms

 

 

Typical Gregorian Performance

 -

 Effective Aperture

 

 Forward Gain

 Freq. (MHZ)

 ZA = 15°

ZA = 20° 

 

ZA = 15° 

ZA = 20° 

327

  10.5 K/Jy

9 K/Jy

 

55.5 dB

53.1 dB

430 

 11 K/Jy

 10 K/Jy

 

55.5 dB

55.5 dB

610 

 11 K/Jy

10 K/Jy

 

60.9 dB


1400

 11 K/Jy

10 K/Jy

 

68.3 dB

67.2 dB

2380

 10 K/Jy

  8 K/Jy

 

72.4 dB

71.2 dB

3300

  8 K/Jy

  6 K/Jy

     

5000

  7 K/Jy

 5.5 K/Jy

 

78.3 dB

76.8 dB

7000

  4.5 K/Jy

 4 K/Jy

 

8500

  4 K/Jy

  3 K/Jy

     

 Noise Contributions ( excluding receiver noise )

 -

 ZA = 15° 

 ZA = 20°

 Spillover

 4 K

 6 K

Blockage

4 K

4 K

Atmosphere

3 K

3 K

Cosmic Background

3 K

3 K

Total

14 K

16 K

Peak Sidelobe Level ( with blockage )

 -

ZA = 15°

ZA = 20°

 250 MHz

- 12.2 dB

 - 11.2 dB

500 MHz

- 13.5 dB

- 12.5 dB

1000 MHz

- 15.1 dB

- 14.2 dB

5000 MHz

- 16.0 dB

- 15.0 dB

 -

 ZA = 15°  ZA = 20°
 Cross - Polarization - 28 dB

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Beam Squint Circular Pol. 0.01 HPBW

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 Feed Cluster Size 430 MHz 1

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( see discussion ) 1400 MHz  3 ( or 7, without 1 dB gain reduction )

 -

 5000 MHz 7

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1 One Kelvin/Jansky (K/Jy) corresponds to 2761 m2 effective aperture.