====== 7mm secondary focus receiver (33500-50000 MHz) ======

This is a 4-channel two horn system for continuum, spectroscopy and VLBI observations.\\
Attention: When frequencies lower than 35 GHz are selected, the receiver operates in 
double sideband mode for some parts of the observed bandpass. Please contact staff for
advice.

==== 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 ^
|36.25 |A/B |LCP/RCP |10.6 |124 |0.78 |160 |27 |1.7 |44 |23.0 |Oct 2021 |
|38.75 |A/B |LCP/RCP |15.0 |144 |0.73 |197 |26 |1.8 |40 |21.2 |Oct 2021 |
|41.25 |A/B |LCP/RCP |12.2 |110 |0.64 |171 |23 |1.7 |38 |20.7 |Oct 2021 |
|43.75 |A/B |LCP/RCP |10.8 |136 |0.60 |228 |21 |1.6 |36 |19.7 |Oct 2021 |
|46.25 |A/B |LCP/RCP |10.2 |125 |0.59 |214 |20 |1.6 |36 |19.1 |Oct 2021 |
|48.75 |A/B |LCP/RCP |10.0 |187 |0.51 |369 |18 |1.6 |32 |18.1 |Oct 2021 |

^ normalized Gain curve (G = A0 + A1·Elv + A2·Elv2)^^^ Observed in ^ confirmed ^
|A0 = 0.8349 |A1 = 8.312E-3|A2 = -1.046E-04|Below 40 GHz, Oct 2021 | |
|A0 = 0.7852 |A1 = 1.126E-2|A2 = -1.475E-04|40-45 GHz, Oct 2021 | |
|A0 = 0.7608 |A1 = 1.487E-2|A2 = -2.310E-04|45-50 GHz, Oct 2021 | |

**Comments:**
   * **Please note, that Tsys and SEFD are given for zenith. For sensitivity calculations, please take the atmosphere's opacity into account!**
   * The data was corrected for sky opacity with observations from the WVR. Typical zenith opacities under good weather conditions are around 0.07 to 0.1 at 42 GHz. 
   * For informations about the old parameters please contact Uwe Bach (ubach_at_mpifr.de).

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

^ RX Name ^ Wavelength [cm] ^ Frequency (center) [GHz] ^ Nr. of Horns ^
| **S7mm double beam RX ** | 0.7 | 33.5-50.0 (42.0) | 2 | 
| **Version:** |   **Comment**   |||
|1. Continuum (BW: 2.5 GHz) | Broad Band Continuum |||
|2. Line (BW: 2500 MHz) | Spectroscopy/Continuum using optical IF |||
| **Horn offsets** [arcsec]| 107.7,-451.8; 219.2,-451.8 |||


==== 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


^ 7mm SFK dual horn receiver ^^^^  
^ Channel ^ IF ^ Pol. ^ Comment ^ 
|  1  |    2.5 GHz    |     LCP    | TP A, horn 1  | 
|  2  |    2.5 GHz    |     RCP    | TP B, horn 1  | 
|  3  |    2.5 GHz    |     LCP    | TP A, horn 2  | 
|  4  |    2.5 GHz    |     RCP    | TP B, horn 2  | 


==== Spectroscopy modes and resolution ====

To be done.

==== Tcal and Tsys measurements ====

To be done.