Technical Specifications


A brief technical summary of the Thoth Technology 46 m antenna on the site of the Algonquin Radio Observatory (ARO) in the Province of Ontario, Canada is provided. 


The antenna is located at 45 deg 57 min 19.8 sec latitude, 281 deg 55 min 37.0 sec east longitude, 260.4 m elevation.

Antenna Performance

The following table presents the estimated performance information for the 46 m antenna at ARO.

Table 1 Antenna Performance, 46 m Antenna at ARO

Aperture efficiency

0.42 at 10 GHz (full surface); 0.29 at 22 GHz (inner solid surface)

Area gain

74 dBi at 10 GHz

Effective aperture gain

70 dBi at 10 GHz, 69.1 dBi at X-band, 68.6 dBi at S-band

RF/IF Specifications

    (a) Hydrogen maser time and frequency reference: frequency stability 1014 to 1015

    (b) Dual frequency S- and X-band front end receivers with concentric LCP feeds for simultaneous S- and X-band observations. L-band capability.

    (c) Closed cycle helium cooling system for front end receivers.

    (d) System temperatures approximately 55 deg K for X-band and 60 deg K for S-band

    (e) S-band IF

    i. S-Band first LO is 2020 MHz

    ii. Maximum receiver noise power density: -44 dBm Hz-1 at 191 MHz

    iii. 3 dB points at 173 MHz and 283 MHz

    iv. 10 dB points at 132 MHz and 437 MHz

    v. 20 dB points at 132 MHz and 462 MHz

    vi. Linear portion of passband from 191 MHz to 425 MHz

    (f) X-Band IF

    i. X-Band first LO is 8080 MHz

    ii. Maximum receiver noise power density: -49 dBm Hz-1 at 152 MHz

    iii. -3dB points at 83 MHz and 317 MHz

    iv. -10dB points at 60 MHz and 613 MHz

    v. -20dB points at 37 MHz and 920 MHz

    vi. Linear portion of passband from 132 MHz to 902 MHz

    (g) L-Band IF

    i. L-Band first Local Oscillator is 1010 MHz

    ii. Receiver Noise Temperature 0.78 COLD, 2.983 HOT.

    iii. IF output frequency 285 MHz, 110 MHz bandwidth (3 dB)

    iv. LNA noise temperature 31 degree K and gain of 39 dB.

    v. Passband 1150 to 1750 MHz

    (h) VLBI data acquisition system backend. Dual Frequency X- and S-band operation with USB and LSB outputs for both RF channels. Baseband bandwidths variable from 250 kHz to 16 MHz. 1- and 2-bit sampling and recording.

    (i) GPS active control point (location reference station).

The Antenna Structure

The following table presents information on the structure of the 46 m antenna.

Table 2 Antenna Structure, 11 m Antenna at ARO

Antenna diameter

150 feet (45.8 m)

Focal length

Prime focus 60 feet (18.3 m)

Parabolic reflector

Inner surface of 0.635 cm (1/4 in) thick steel plate, 36.6 m (120 feet) in diameter. Outer surface of panels of galvanized steel square mesh of 1 mm diameter wire with 10 mm spacing, 4.55 m (15 feet) in radius width all round. The solid surface is adjustable with one adjuster screw at every 4-corner intersection of the steel plates


Both prime focus and Gregorian capability with 10 foot (3 m) diameter elliptical subreflector

Focal ratio

F/D = 0.4 for full surface and F/D = 0.5 for inner solid surface

Feed support

Tetrapod feed legs supporting prime focus aerial cabin. Prime focus cabin: cylindrical 2.5 m diameter by 3.7 m length

Gregorian focus

Located in the Vertex Room: cylindrical 5.8 m diameter by 6.4 length

Surface accuracy

rms departure from best fitting paraboloid = 0.85 mm. Maximum departure from best fitting paraboloid = 0.32 mm (inner solid surface) = 0.64 mm (outer mesh surface)

Antenna Operations and Control

The following table presents operations and control information for the 46 m antenna at ARO.

Table 3 Operations and Control, 46 m antenna at ARO

Altitude/Azimuth antenna mount

Computer controlled pointing

Azimuth range of motion

215 degrees in Azimuth centred on an Azimuth of 112.5 degrees West of North

Elevation range of motion

102 degrees (-5 degrees to 97 degrees) in elevation

Maximum operating wind velocity

80 kmhr-1 (50 mph)

Extreme operational temperature range

-46oC to +40oC

Azimuth slewing

Variable in rate up to 24 degrees per minute

Elevation slewing

Variable in rate up to 10 degrees per minute ascending and up to 15 degrees per minute descending

Pointing accuracy

Current performance 20 arc sec. With enhanced pointing model in place 10 arc sec