====== 1.9-cm primary focus receiver (13500-18700 MHz) ======

This is a 1-channel broad-band system used for spectroscopy. It has a linearly polarized feed. So far, only few test observations could be made to measure the variation of its parameters with frequency.

==== 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 ^
|13.75 |B |linear |1.5 |35 |1.1 |32 |39 |1.8 |61 |60.3 |Mar 2001 |
|15.42 |B |linear |1.7 |37 |1.2 |32 |41 |1.8 |64 |53.5 |Apr 2003 |
|18.00 |B |linear |1.2 |46 |0.90 |51 |32 |1.7 |53 |46.5 |Mar 2001 |

^ normalized Gain curve (G = A0 + A1·Elv + A2·Elv2)^^^ Observed in ^ confirmed ^
|A0=0.95912|A1= 2.5000E-3|A2=-3.8149E-5|Apr 2003|  |

**Comments:**
  * The values at 15.4 GHz could be derived from cross-scans during spectroscopic observations. Thanks to N. Nagar! 
  * Values at 18 GHz are a bit uncertain.

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

^ RX Name ^ Wavelength [cm] ^ Frequency (center) [GHz] ^ Nr. of Horns ^
| **P19mm 4-Box (13.5-18.7 GHz) ** | 2.2-1.6 | 13.5-18.7 | 1 | 
| **Version:** |   **Comment**   |||
|1. Cont./Line: 13,3-16,75 GHz (BW: 500 MHz) | VLBA IF Continuum and spectroscopy version, 1st freq. range |||
|2. Cont./Line: 16,55-18,5 GHz (BW: 500 MHz) | VLBA IF Continuum and spectroscopy version, 2nd freq. range |||
|3. Cont./Line: 13,5-16,95 GHz (BW: 100 MHz) | narrow band IF Continuum and spectroscopy version, 1st freq. range |||
|4. Cont./Line: 16,3-18,5 GHz (BW: 100 MHz) | narrow band IF Continuum and spectroscopy version, 2nd freq. range |||
| **Horn offsets** [arcsec]| -904.0, 1077.4 |||


==== 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\\
optical: optical fibre with 4 GHz of band width\\
BW: band width\\
TP: total power

^ 1.9cm PFK (Multi-RX-Box I) ^^^^
^ Channel ^ IF ^ Pol. ^ Comment ^
|  1  |  SB    |     linear    | TP A  |
|  2  |  BB    |     linear    | TP A  |
|  3  |  VLBA  |     linear    | TP A  |

==== Spectroscopy modes and resolution ====
^   BW ^ nchan ^    nu ^     Df ^     Dv ^     dv ^
^  MHz ^       ^   MHz ^    kHz ^   km/s ^   km/s ^
|  100 | 32768 | 13500 |    3.1 |  0.068 |  0.079 |
|  100 | 32768 | 14000 |    3.1 |  0.065 |  0.076 |
|  100 | 32768 | 14500 |    3.1 |  0.063 |  0.073 |
|  100 | 32768 | 15000 |    3.1 |  0.061 |  0.071 |
|  100 | 32768 | 15500 |    3.1 |  0.059 |  0.068 |
|  100 | 32768 | 16000 |    3.1 |  0.057 |  0.066 |
|  100 | 32768 | 16500 |    3.1 |  0.055 |  0.064 |
|  100 | 32768 | 17000 |    3.1 |  0.054 |  0.062 |
|  100 | 32768 | 17500 |    3.1 |  0.052 |  0.061 |
|  100 | 32768 | 18000 |    3.1 |  0.051 |  0.059 |
|  100 | 32768 | 18500 |    3.1 |  0.049 |  0.057 |
|  500 | 32768 | 13500 |   15.3 |  0.339 |  0.393 |
|  500 | 32768 | 14000 |   15.3 |  0.327 |  0.379 |
|  500 | 32768 | 14500 |   15.3 |  0.315 |  0.366 |
|  500 | 32768 | 15000 |   15.3 |  0.305 |  0.354 |
|  500 | 32768 | 15500 |   15.3 |  0.295 |  0.342 |
|  500 | 32768 | 16000 |   15.3 |  0.286 |  0.332 |
|  500 | 32768 | 16500 |   15.3 |  0.277 |  0.322 |
|  500 | 32768 | 17000 |   15.3 |  0.269 |  0.312 |
|  500 | 32768 | 17500 |   15.3 |  0.261 |  0.303 |
|  500 | 32768 | 18000 |   15.3 |  0.254 |  0.295 |
|  500 | 32768 | 18500 |   15.3 |  0.247 |  0.287 |

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 and Tsys measurements ====
{{:information_for_astronomers:rx:p19mm_tcal_from_specpointing_using_tau_spec.png?900 |}}
{{:information_for_astronomers:rx:p19mm_tsys0_from_specpointing_using_tau_spec.png?900 |}}
{{:information_for_astronomers:rx:p19mm_tau_from_specpointing_using_tau_spec.png?900 |}}
{{:information_for_astronomers:rx:p19mm_hpbw_from_specpointing.png?900 |}}