====== 1.3-cm primary focus receiver (17900-26240 MHz) ====== This receiver was build for spectroscopic observations. It has a linearly polarized feed. ==== 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 ^ |18.5 |A+B |linear |3.5 |63 |1.1 |57 |39 |1.7 |65 |45.9 |May 2009| |19.0 |A+B |linear |3.3 |60 |1.06 |52 |37 |1.6 |65 |45.5 |Sep 2009| |20.0 |A+B |linear |2.9 |68 |0.94 |72 |33 |1.6 |59 |43.8 |Feb 2008| |22.0 |A+B |linear |2.2 |63 |0.9 |69 |32 |1.5 |61 |42.7 |Dec 2009| |23.7 |A+B |linear |1.6 |65 |0.8 |76 |29 |1.4 |58 |42.2 |Jan 2008| ^ normalized Gain curve (G = A0 + A1·Elv + A2·Elv2)^^^ Observed in ^ confirmed ^ |A0 = 0.88196|A1 = 6.6278E-3|A2 = -9.2334E-5|Feb 2007| | **Comments:** * Both, the horizontal and vertical linear polariztions are measured. Channel A contains the horizontal direction and channel B the vertical. Decoupling between both axes is larger than 32dB. * For continuum observations both channels were added to avoid artificial variations of linearly polarized sources caused by the linearly polarized channels of the receiver. * Note that the system temperature at this frequency strongly depends on weather conditions! * Spectroscopic observations of sources with significant continuum emission at frequencies >23 GHz might suffer from instable baselines. This could cause problems when measuring weak, broad lines. Possible solution: the new control system allows to drive the focus on a cosine wave with a given amplitude (e.g. lambda/8) and frequency during the measurements. This largely suppresses the appearance of standing waves and therewith improves the baseline stability. ==== Version description for OBSINP ==== ^ RX Name ^ Wavelength [cm] ^ Frequency (center) [GHz] ^ Nr. of Horns ^ | **P13mm (17,9-26,5 GHz) ** | 1.3 | 17.9-26.5 | 1 | | **Version:** | **Comment** ||| |1. Cont./Line(LSB): 17,9-22,5 GHz (BW: 500 MHz) | Continuum and spectroscopy 1st freq. range ||| |2. Cont./Line(USB): 22,5-26,5 GHz (BW: 500 MHz) | Continuum and spectroscopy 2nd freq. range ||| | **Horn offsets** [arcsec]| 0.0, 0.0 ||| ==== 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 ^ 1.3cm PFK ^^^^ ^ Channel ^ IF ^ Pol. ^ Comment ^ | 1 | BB | linear | TP A | | 2 | BB | linear | TP B | | 3 | VLBA | linear | TP A | | 4 | VLBA | linear | TP B | | 5 | VLBA | cross | cos AB | | 6 | VLBA | cross | sin AB | ==== Spectroscopy modes and resolution ==== ^ BW ^ nchan ^ nu ^ Df ^ Dv ^ dv ^ ^ MHz ^ ^ MHz ^ kHz ^ km/s ^ km/s ^ | 100 | 32768 | 18000 | 3.1 | 0.051 | 0.059 | | 100 | 32768 | 20000 | 3.1 | 0.046 | 0.053 | | 100 | 32768 | 22000 | 3.1 | 0.042 | 0.048 | | 100 | 32768 | 24000 | 3.1 | 0.038 | 0.044 | | 100 | 32768 | 26000 | 3.1 | 0.035 | 0.041 | | 500 | 32768 | 18000 | 15.3 | 0.254 | 0.295 | | 500 | 32768 | 20000 | 15.3 | 0.229 | 0.265 | | 500 | 32768 | 22000 | 15.3 | 0.208 | 0.241 | | 500 | 32768 | 24000 | 15.3 | 0.191 | 0.221 | | 500 | 32768 | 26000 | 15.3 | 0.176 | 0.204 | | 2000 | 32768 | 18000 | 61.0 | 1.017 | 1.179 | | 2000 | 32768 | 20000 | 61.0 | 0.915 | 1.061 | | 2000 | 32768 | 22000 | 61.0 | 0.832 | 0.965 | | 2000 | 32768 | 24000 | 61.0 | 0.762 | 0.884 | | 2000 | 32768 | 26000 | 61.0 | 0.704 | 0.816 | 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 ==== === December 2013 === == Tcal and Tsys == {{:information_for_astronomers:rx:p13mm_dec13_ngc7027_tcal_from_specpointing_using_tau_spec.png?365 |}} {{:information_for_astronomers:rx:p13mm_dec13_ngc7027_tsys0_from_specpointing_using_tau_spec.png?365 |}} == Opacity and beam width == {{:information_for_astronomers:rx:p13mm_dec13_ngc7027_tau_from_specpointing_using_tau_spec.png?365 |}} {{:information_for_astronomers:rx:p13mm_dec13_ngc7027_hpbw_from_specpointing.png?365 |}} == Tcal and Tsys == {{:information_for_astronomers:rx:p13mm_dec13_3c48_tcal_from_specpointing_using_tau_spec.png?365 |}} {{:information_for_astronomers:rx:p13mm_dec13_3c48_tsys0_from_specpointing_using_tau_spec.png?365 |}} == Opacity and beam width == {{:information_for_astronomers:rx:p13mm_dec13_3c48_tau_from_specpointing_using_tau_spec.png?365 |}} {{:information_for_astronomers:rx:p13mm_dec13_3c48_hpbw_from_specpointing.png?365 |}} === March 2013 === == Tcal and Tsys == {{:information_for_astronomers:rx:p13mm_tcal_from_specpointing_using_tau_spec.png?365 |}} {{:information_for_astronomers:rx:p13mm_tsys0_from_specpointing_using_tau_spec.png?365 |}} == Opacity and beam width == {{:information_for_astronomers:rx:p13mm_tau_from_specpointing_using_tau_spec.png?365 |}} {{:information_for_astronomers:rx:p13mm_hpbw_from_specpointing.png?365 |}}