Korean VLBI Network (KVN)

Antenna Beam Size & Aperture Efficiency

Site Band (GHz) HPBW (arcsec) Aperture Efficiency (%) Beam Efficiency (%)
KVN-YS 22 119 55 39
43 61.5 60 45
86 31.5 57 43
129 23.4 37 35
KVN-US 22 120 60 43
43 61.6 56 42
86 32.5 46 37
129 22.9 30 27
KVN-TN 22 123 59 44
43 62.1 62 48
86 31.5 52 39
129 21.9 40 33

1. Elevation dependency
Aperture efficiency varies with elevation. The elevation dependency of KVN antannas represented as gain curve is described in next section. Those in the above table are the maximum values.

2. Frequency dependency of beam efficiency
Beam efficiency varies with beam size. The measured HPBWs are tabulated in the above table, which are almost the same as the theoretical ones(= wavelength / diameter of antenna). In order to get a beam efficiency at 90 GHz, you have to multiply (86/90)2 to that at 86 GHz.

3. Quantization correction of single-dish spectrum data
In case you are reducing single-dish spectrum data, you need to multifly a factor of 1.25 before applying efficiency corrections. This is to compensate for the effect of the digital filter and spectrometer.

The above table can be applied for the following observing season.
    - KVN-YS : from OCT 2012 - now
    - KVN-US : from OCT 2012 - now
    - KVN-TN : from MAR 2012 - now


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Korean VLBI Network (KVN)