history

Recent system performance measurements

Daily monitoring of Tsys.

Dewar temperatures

Calibration measurements

Miscellaneous

cal values

History:

13feb04: shi receiver moved down .8 inches into focus, new cal diodes installed.

09may03: measured cal values using sky and absorber.

22mar02: receiver installed on telescope

Calibration measurements:

17jun11: sbh calibration used to measure 1az term of platform.

02jul09: Tsys vs freq and cal values over entire band.

Feb04-Jun04: sbh GAIN CURVES.

Feb04-Jun04: System performance of data used for gain curves.

may03-sep03: sbh GAIN CURVES.

may03-sep03: System performance of data used for gain curves.

08apr02,11apr02 calibration runs. Performance: gain,tsys,sefd,pnterr,etc..

23mar02: cal and Tsys versus frequency.

Miscellaneous:

- 191222: polB Tsys high.

- 17jun11: sbh calibration used to measure 1az term of platform.
- 02jul09: Tsys vs freq and cal values over entire band.
- Feb04-Jun04: sbh GAIN CURVES.
- Feb04-Jun04: System performance of data used for gain curves.
- 09may03: resonances in the sbh receiver.
- may03-sep03: sbh GAIN CURVES.
- may03-sep03: System performance of data used for gain curves.
- 08apr02,11apr02 calibration runs. Performance: gain,tsys,sefd,pnterr,etc..
- 23mar02: cal and Tsys versus frequency.

Feb04 to Jun04 fit GAIN CURVES to calib data. (top...)

Gain curves were fit to the sband high calibration gain data using 13Feb04 through 30jun04. The start of this epoch was after the als were replaced and the dewar was lower .8 inches to bring it into focus. The plots show the gain data (black) and the fits (red) for 3300, 3500, 3700, and 3825 Mhz. These gain equations were installed on 03Jul04 and back data to be valid starting on 13feb04.

- Fig 1 shows the az,za distribution for the data. The fit used a linear fit in za up to za=14. Above 14 degrees terms in (za-14)^2 and (za-14)^3 were included. The fit also included 1az, 2az, and 3az sin, cos terms.
- Fig 2 plots the gain data and the fit to za. The fit equation is plotted with the sigma for the fit (in K/Jy).
- Fig 3 plots the fit residuals (data-fit) vs za.

equations. The coefficients can be found in the ascii file data/gain.datR8 (this is provided in the AO idl

distribution for correlator routines). You can also find a copy of it at AO in /pkg/rsi/local/libao/phil/data/gain.datR8. processing: x101/sbh/mar04/dogainfit.pro

feb04 thru jun04 : System performance of data used to compute gain curves. (top...)

Heiles calibration scans done from
13feb04 (new cals, horn lowered) thru 30jun04 were used to measure
the

system performance. This data was then used to compute the gain
curves used after 12feb04.

The first set of plots show
the system performance with all frequencies overplotted. The
sources are identified

by symbol and the frequencies by color.

- Fig 1 shows the distributions on the dish of the measurements.
- Fig 2 has the Gain in Kelvins/Jansky. This relies on the cals and the source flux. Ths next plot is Tsys vs za in Kelvins followed by the SEFD (System Equivalent Flux density) in Janskies / Tsys. At the bottom is the average beam width in arc seconds.
- Fig 3 plots the coma parameter, first sidelobe height below the peak, the main beam efficiency, followed by the main beam + 1st sidelobe beam efficiency.
- Fig 4 has the pointing errors in az,za.

- Fig 1 3300 Mhz Gain,Tsys . 282 points
- Fig 2 3300 Mhz sidelobes,beam efficiencies
- Fig 3 3500 Mhz Gain,Tsys 282 points.
- Fig 4 3500 Mhz sidelobes,beam efficiencies.
- Fig 5 3700 Mhz Gain,Tsys 282 points.
- Fig 6 3700 Mhz sidelobes,beam efficiencies
- Fig 7 3825 Mhz Gain,Tsys 201 points.
- Fig 8 3825 Mhz sidelobes,beam efficiencies

May03 to Sep03 fit GAIN CURVES to calib data. (top...)

Gain curves were fit to the sband high gain data from 15may03 through 30sep03. The start of this epoch was after the shimmin g of the elevation rails in feb03. The end date was chosen so that the cal had not drifted too much (see warning below). The plots show the gain data (black) and the fits (red) for 3300, 3500, 3700, and 3900 Mhz. These gain equations were installed on 10mar04.

- Fig 1 shows the az,za distribution for the data. The fit used a linear fit in za up to za=14. Above 14 degrees terms in (za-14)^2 and (za-14)^3 were included. The fit also included 1az, 2az, and 3az sin, cos terms.
- Fig 2 plots the gain data and the fit to za. The fit equation is plotted with the sigma for the fit (in K/Jy).
- Fig 3 plots the fit residuals (data-fit) vs za.

**Warning**: The sbh cal was drifting in time (see tsys
plots). During this period it was relatively stable. Use
these curves outside this region with care. The cals were replaced
in feb04.

The routine gainget() or corhgainget() will
now return the sbh gain for data after 01mar03 from these

equations. The coefficients can be found in the ascii file
data/gain.datR8 (this is provided in the AO idl

distribution for correlator routines). You can also find a copy of
it at AO in /home/phil/idl/data/gain.datR8.

Heiles calibration scans done from
15may03 (after shimming) thru 30sep03 were used to measure the

system performance. This data was then used to compute the gain
curves used after 01mar03.

The first set of plots show
the system performance with all frequencies overplotted. The
sources are identified

by symbol and the frequencies by color.

- Fig 1 shows the distributions on the dish of the measurements.
- Fig 2 has the Gain in Kelvins/Jansky. This relies on the cals and the source flux. Ths next plot is Tsys vs za in Kelvins followed by the SEFD (System Equivalent Flux density) in Janskies / Tsys. At the bottom is the average beam width in arc seconds.
- Fig 3 plots the coma parameter, first sidelobe height below the peak, the main beam efficiency, followed by the main beam + 1st sidelobe beam efficiency.
- Fig 4 has the pointing errors in az,za.

- Fig 1 3300 Mhz Gain,Tsys . 295 points
- Fig 2 3300 Mhz sidelobes,beam efficiencies
- Fig 3 3500 Mhz Gain,Tsys 294 points.
- Fig 4 3500 Mhz sidelobes,beam efficiencies.
- Fig 5 3700 Mhz Gain,Tsys 293 points.
- Fig 6 3700 Mhz sidelobes,beam efficiencies
- Fig 7 3900 Mhz Gain,Tsys 294 points.
- Fig 8 3900 Mhz sidelobes,beam efficiencies

08apr02,11apr02: calibration runs. (top...)

- Figure 1 show the gain in K/Jy, Tsys in K, SEFD in Jy/Tsys, and the average beam width. Sources are plotted with different symbols. Color is used separate the 4 frequencies.
- Figure 2 plots the coma parameter, first sidelobe height relative to the peak in db's, main beam efficiency, and the main beam plus first sidelobe beam efficiency.
- Figure 3 plots the pointing error in za (versus za,az), pointing error in az (versus za, az), and the total pointing error (sqrt(azerr^2+zaerr^2) versus za, and az. At top is plotted the mean and rms for the zaerr, azerr, and total error.

23mar02: cal and tsys versus frequency. (top...)

The plots show cal value versus frequency and the system temperature versus frequency. It looks a bit strange that the shape of the high and low cal differ by so much for some of the cals (since they differ by a 10db coupler). processing: x101/020322/doitcals.pro