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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

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
44.1 (narrow band)A+B LCP+RCP 13 100 0.66 140 23 1.67 40 19.5 Dec 2019
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-3A2 = -1.046E-04Below 40 GHz, Oct 2021
A0 = 0.7852 A1 = 1.126E-2A2 = -1.475E-0440-45 GHz, Oct 2021
A0 = 0.7608 A1 = 1.487E-2A2 = -2.310E-0445-50 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.

information_for_astronomers/rx/s7mm_db.txt · Last modified: 2021/10/21 20:58 by akraus