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information_for_astronomers:rx:s7mm_db

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

This are preliminary results from first tests and can easily be off by 10 or 15 %.

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
35.75 A LCP 7.5 77 0.76 102 26 1.6 47 24.4 May 2018
35.75 B RCP 6.9 83 0.75 112 26 1.6 47 24.5 May 2018
38.25 A LCP 9.3 90 0.62 145 22 1.6 38 22.5 May 2018
38.25 B RCP 9.1 94 0.66 143 23 1.6 40 22.6 May 2018
42.75 A LCP 9.5 84 0.76 110 26 1.5 50 20.9 May 2018
42.75 B RCP 8.7 85 0.77 111 27 1.5 50 21.1 May 2018
44.1 (narrow band)A+B LCP+RCP 13 100 0.66 140 23 1.67 40 19.5 Dec 2019
45.25 A LCP 8.5 99 0.63 156 22 1.5 42 19.7 May 2018
45.25 B RCP 8.2 103 0.65 159 22 1.5 47 19.8 May 2018
normalized Gain curve (G = A0 + A1·Elv + A2·Elv2) Observed in confirmed
A0 = 0.897 A1 = 5.93E-3A2 = -8.52E-05Below 40 GHz, Aug 2018
A0 = 0.897 A1 = 7.85E-3A2 = -1.5E-04Above 40 GHz, May 2018

Comments:

  • The new gain curves were corrected for opacity.
  • Opacity correction was done with a zenith opacity of 0.06-0.08. 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.

information_for_astronomers/rx/s7mm_db.txt · Last modified: 2020/05/18 10:36 by akraus