Table of Contents
2cm double beam secondary focus receiver (12000-18000 MHz)
This receiver is a two horn system for continuum, spectroscopy and VLBI observations.
Overview
| RX Name | Band | Frequency range [GHz] | Polarisation | Nr. of Horns | Horn position relativ to center of focus cabin |
|---|---|---|---|---|---|
| S20mm | K | 12.0-18.0 | dual-circular | 2 | Horn 1: Az: -525 arcsec, Elv: 63 arcsec, Horn 2: Az: -762 arcsec, Elv: 63 arcsec |
Calibration Information
| Frequency [GHz] | Feed | Polarisation | Tcal [K] | Tsys [K] | Sensitivity [K/Jy] | SEFD [Jy] | Aperture Eff. [%] | TMB/S [K/Jy] | Main Beam Eff. [%] | FWHM [arcsec] | Last update |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 14.25 | 1 | LCP | 2.1 | 34 | 1.36 | 25 | 48 | 2.18 | 62 | 52.5 | Jun 2024 |
| 14.25 | 1 | RCP | 2.1 | 34 | 1.36 | 25 | 48 | 2.18 | 62 | 52.5 | Jun 2024 |
| 16.75 | 1 | LCP | 2.8 | 45 | 1.30 | 35 | 46 | 2.22 | 59 | 44.3 | Jun 2024 |
| 16.75 | 1 | RCP | 2.8 | 45 | 1.30 | 35 | 46 | 2.22 | 59 | 44.3 | Jun 2024 |
| normalized Gain curve (G = A0 + A1·Elv + A2·Elv2) | Observed in | confirmed | ||
|---|---|---|---|---|
| A0 = 0.9818 | A1 = 1.179E-3 | A2 = -1.906E-5 | Dec 2022 | — |
Comments:
- Note that the system temperature at this frequency depends on weather conditions!
- For technical reasons, no spectroscopic frequency-switch observations are possible!
- Below 13 GHz, there is strong interference due to communication with satellites.
Available receiver versions (for OBSINP)
| Version | Description | Details |
|---|---|---|
| continuum_5ghz | standard continuum backend with 2 basebands | 13.0-15.5 GHz & 15.5-18.0 GHz |
| cont_spec_5ghz | includes the WFFTS with 2x2x64k channels | 13.0-15.5 GHz & 15.5-18.0 GHz |
Below here: Information is currently updated.
Version description for OBSINP
| RX Name | Wavelength [cm] | Frequency (center) [GHz] | Nr. of Horns |
|---|---|---|---|
| S20mm Double Beam RX | 2.0 | 12.0-18.0 (15.0) | 2 |
| Version: | Comment | ||
| 1. Continuum (BW: 2 GHz) | Broad Band Continuum | ||
| Horn offsets (Azi, Elv, from center of SFK) | Horn 1: -525" ; 63" – Horn 2: -762" ; 63" | ||
| relative offset of horn 2 from 1 (Azi, Elv) | -237" ; 0" | ||
Receiver Bands
The receiver delivers the data in two 2.5GHz-wide IF-subbands, which can be shifted in to cover the 12-18 GHz range.
Spectroscopy modes and resolution
Low-res mode (2 basebands for each of 2 feeds and 2 polarizations)
Note, that due to technical reasons the LSR correction has to be applied via software (regridding). This will decrease the effective spectral resolution to some degree.
TODO: update numbers!
| BW | nchan | nu | Df | Dv | dv |
|---|---|---|---|---|---|
| MHz | MHz | kHz | km/s | km/s | |
| 2500 | 16384 | 18000 | 152.6 | 2.541 | 2.948 |
| 2500 | 16384 | 20000 | 152.6 | 2.287 | 2.653 |
| 2500 | 16384 | 22000 | 152.6 | 2.079 | 2.412 |
| 2500 | 16384 | 24000 | 152.6 | 1.906 | 2.211 |
| 2500 | 16384 | 26000 | 152.6 | 1.759 | 2.041 |
| 2500 | 32768 | 18000 | 76.3 | 1.271 | 1.474 |
| 2500 | 32768 | 20000 | 76.3 | 1.144 | 1.327 |
| 2500 | 32768 | 22000 | 76.3 | 1.040 | 1.206 |
| 2500 | 32768 | 24000 | 76.3 | 0.953 | 1.105 |
| 2500 | 32768 | 26000 | 76.3 | 0.880 | 1.020 |
| 2500 | 65536 | 18000 | 38.1 | 0.635 | 0.737 |
| 2500 | 65536 | 20000 | 38.1 | 0.572 | 0.663 |
| 2500 | 65536 | 22000 | 38.1 | 0.520 | 0.603 |
| 2500 | 65536 | 24000 | 38.1 | 0.477 | 0.553 |
| 2500 | 65536 | 26000 | 38.1 | 0.440 | 0.510 |
BW … band width
nchan … number of spectral channels
nu … center frequency
Df … Channel separation (in frequency)
Dv … Channel separation (in velocity)
dv … Velocity resolution (dv=1.16*Dv)
Hi-res mode (?? basebands)
TODO: update numbers!
| BW | nchan | nu | Df | Dv | dv |
|---|---|---|---|---|---|
| MHz | MHz | kHz | km/s | km/s | |
| 300 | 16384 | 18000 | 18.3 | 0.305 | 0.354 |
| 300 | 16384 | 20000 | 18.3 | 0.274 | 0.318 |
| 300 | 16384 | 22000 | 18.3 | 0.250 | 0.289 |
| 300 | 16384 | 24000 | 18.3 | 0.229 | 0.265 |
| 300 | 16384 | 26000 | 18.3 | 0.211 | 0.245 |
| 300 | 32768 | 18000 | 9.2 | 0.152 | 0.177 |
| 300 | 32768 | 20000 | 9.2 | 0.137 | 0.159 |
| 300 | 32768 | 22000 | 9.2 | 0.125 | 0.145 |
| 300 | 32768 | 24000 | 9.2 | 0.114 | 0.133 |
| 300 | 32768 | 26000 | 9.2 | 0.106 | 0.122 |
| 300 | 65536 | 18000 | 4.6 | 0.076 | 0.088 |
| 300 | 65536 | 20000 | 4.6 | 0.069 | 0.080 |
| 300 | 65536 | 22000 | 4.6 | 0.062 | 0.072 |
| 300 | 65536 | 24000 | 4.6 | 0.057 | 0.066 |
| 300 | 65536 | 26000 | 4.6 | 0.053 | 0.061 |
BW … band width
nchan … number of spectral channels
nu … center frequency
Df … Channel separation (in frequency)
Dv … Channel separation (in velocity)
dv … Velocity resolution (dv=1.16*Dv)
Tcal measurements
Mar 2020
Tcal and Tsys
Opacity and Tebb (WVR+AATM)
T0
Antenna model
Nov 2019
Tcal and Tsys
Opacity and Tebb (WVR+AATM)
T0
Antenna model
