====== 2cm secondary focus receiver (13600-15600 MHz) ======

This is a 2-channel system mainly for VLBI observations.

==== Calibration Information ====


^ Frequency [GHz] ^ Channel ^ Polarisation ^ Tcal [K] ^ Tsys [K] ^ Sensitivity [K/Jy] ^ SEFD [Jy] ^ Aperture Eff. [%] ^ TMB/S [K/Jy] ^ Main Beam Eff. [%] ^ FWHM [arcsec] ^ Last update ^
|14.60 |A |LCP |3.8 |50 |1.14 |44 |43 |2.2 |51 |50.8 |Okt 2017 |
|14.60 |B |RCP |3.8 |49 |1.14 |44 |43 |2.2 |51 |49.5 |Okt 2017 |

^ normalized Gain curve (G = A0 + A1·Elv + A2·Elv2)^^^ Observed in ^ confirmed ^
|A0 = 0.96053|A1 = 2.4319E-3|A2 = -3.7304E-5|Mar 2002| |
|A0 = 0.97099|A1 = 1.8327e-03|A2 = -2.8674e-05|Feb 2007| |

**Comments:**
   * The new gain curve (Feb 2007) was corrected for opacity.
   * If no other information about the opacity is available a typical zenith tau value of about 0.022 should do a good job. 

==== Version description for OBSINP ====

^ RX Name ^ Wavelength [cm] ^ Frequency (center) [GHz] ^ Nr. of Horns ^
| **S20mm Multifrequency RX ** | 2.0 | 13.6-15.6 (14.60) | 1 | 
| **Version:** |   **Comment**   |||
|1. Continuum (BW: 2 GHz) | Broad Band Continuum |||
|2. Line (BW: 100 MHz) | Spectroscopy/Continuum using narrow band IF + VLBI IF Polarimeter |||
|3. Line (BW: 500 MHz) | Spectroscopy/Continuum using VLBA IF + VLBA IF Polarimeter |||
|4. Pulsar (BW: 500 MHz) | Pulsar 500 MHz BW Version |||
| **Horn offsets** [arcsec]| -761.5,56.5 |||


==== Channel assignment in the MBFITS data files ====

Note that the narrow line and VLBA IF channels are usually only available when the specific line version of the receiver was selected. In addition for most receivers with narrow line channels the cables at the patch board need to be connected by the receiver group.

To select different channel numbers in OBSINP, the online plot, or the toolbox the numbers have to be specified like c(1)+c(2) to add channel 1 and 2. E.g. channel 1 and 2 contain the LCP and RCP broadband channels, then "OnlPlot pen='c(1)+c(2)'" or "toolbox use='c(1)+c(2)'" will select these channels. In OBSINP the pen can be directly specified in the receiver selection menu.

Abbreviations:\\
SB: narrow band channel (Schmalband-Kanal), 100 MHz band width\\
BB: digital broad band channel (Breitband-Kanal), band width varies for different receivers\\
VLBA: VLBA IF, 500 MHz band width\\
BW: band width\\
TP: total power

^ 2cm SFK single horn receiver ^^^^
^ Channel ^ IF ^ Pol. ^ Comment ^
|  1  |    SB     |     LCP    | TP A  |
|  2  |    SB     |     RCP    | TP B  |
|  3  |    SB     |     cross  | cos AB  |
|  4  |    SB     |     cross  | sin AB  |
|  5  |   VLBA    |     LCP   | TP A  |
|  6  |   VLBA    |     RCP   | TP B  |
|  7  |   VLBA    |    cross  | cos AB  |
|  8  |   VLBA    |    cross  | sin AB  |
|  9  |    BB    |     LCP   | TP A  |
|  10  |   BB    |     RCP    | TP B  |

==== Tcal and Tsys measurements ====
{{:information_for_astronomers:rx:s20mm_tcal_from_specpointing_using_tau_spec.png?675 |}}
{{:information_for_astronomers:rx:s20mm_tsys0_from_specpointing_using_tau_spec.png?675 |}}
{{:information_for_astronomers:rx:s20mm_tau_from_specpointing_using_tau_spec.png?675 |}}
{{:information_for_astronomers:rx:s20mm_hpbw_from_specpointing.png?675 |}}