1.3cm secondary focus receiver (21600-24400 MHz)

This is a 2-channel system for VLBI observations.
This system has been replaced by the new double beam receiver.

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
21.73 A LCP 5.1 78 0.90 96 28 1.8 47 36.5 Jul 2007
21.73 B RCP 4.9 84 0.90 105 28 1.8 47 36.4 Jul 2007
22.23 A LCP 5.0 91 0.9 110 30 1.8 47 36.5 Jul 2008
22.23 B RCP 5.0 88 0.9 105 30 1.8 47 36.5 Jul 2008
23.05 A LCP 3.4 83 0.9 97 30 1.8 48 36 Jul 2008
23.05 B RCP 3.7 70 0.9 91 30 1.8 47 36 Jul 2008
normalized Gain curve (G = A0 + A1·Elv + A2·Elv2) Observed in confirmed
A0 = 0.95282A1 = 3.6092E-3A2 = -6.8913E-5 Mar 2003
A0 = 0.91119A1 = 4.7557E-3A2 = -6.2902E-5 Feb 2007

Comments:

  • Note that the system temperature at this frequency depends strongly on weather conditions!
  • The new gain curve (Feb 2007) was corrected for opacity. Because of the previous point it is always recommended to correct data at 1.3cm for opacity.
  • Zenith tau values can range from 0.05 to 0.2.

Version description for OBSINP

RX Name Wavelength [cm] Frequency (center) [GHz] Nr. of Horns
S13mm Multifrequency RX 1.3 21.7-24.4 (23.05) 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] -593.0,55.4

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
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

Spectroscopy modes and resolution

BW nchan nu Df Dv dv
MHz MHz kHz km/s km/s
100 32768 22000 3.1 0.042 0.048
100 32768 23000 3.1 0.040 0.046
100 32768 24000 3.1 0.038 0.044
500 32768 22000 15.3 0.208 0.241
500 32768 23000 15.3 0.199 0.231
500 32768 24000 15.3 0.191 0.221

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 measurements

VLBI calibration was only performed for the lower part of the band. Frequencies above 22.8 GHz will follow.

 
information_for_astronomers/rx/s13mm.txt · Last modified: 2015/11/28 19:58 by akraus     Back to top