More info for 40-50 GHz Observing may be found on Ron's Q-band Performance page.

More info on receiver performance and observation planning may be found at Ron's Observation Planning page.

March 28, 2002 (with FEM surface, no Zernikes)

March 28, 2002 (active surface enabled for the first time, no Zernikes) operator log

Note also text file attached at the bottom of the page.

The gain in Kelvin/Jy as a function of Zenith Distance = 90-Elevation (in degrees) is given by a polynomial of the form

The gain in Kelvin/Jy as a function of Zenith Distance = 90-Elevation (in degrees) is given by a polynomial of the form:

For computed theoretical efficiencies at frequencies > 20GHz based on the current surface model, see this PTCS page.

Click the link under "Date of Observations" for a reference to a memo.

Click the link under "Date of Observations" for more information.

-- FrankGhigo - 25 Jun 2004

-- FrankGhigo - 13 Dec 2007

The gain curve is corrected for atmospheric opacity for Q band.

The gain curve is corrected for atmospheric opacity for K band and Q band.

The difference in gain as well as opacity between the two polarization is up to 10%,

The difference in gain as well as opacity between the two polarizations is up to 10%,

Note that the L, X, Ku-band data are not fully analyzed, so their results should be regarded as preliminary. C band data will be updated soon as well by result from more recent measurements. The final values (coming soon) may differ by a few percent from what is given here.

K band data were collected on December 28, 2005, and should be reduced soon.

%META:FILEATTACHMENT{name="efficiency050411.2005SpringV1.txt" attr="" comment="efficiency data for 2005SpringV1 Surf. model (BJN)" date="1196374960" path="efficiency050411.2005SpringV1.txt" size="4907" user="ToddHunter" version="1.2"}%

%META:FILEATTACHMENT{name="efficiency050411.2005SpringV1.txt" attr="" comment="efficiency data for 2005SpringV1 Surf. model (BXN)" date="1196374960" path="efficiency050411.2005SpringV1.txt" size="4907" user="ToddHunter" version="1.2"}%

Condon's memo **

Condon's memo (PTCS project note 31) **

Nov 22, 2003

Nov 22, 2003 (FEM surface model)

We also list the efficiency (Eff) corresponding to Gmax: Eff = Gmax/2.845

in which airmass A = 1/sin(Elev), T0 is extrapolated noise temperature for airmass = 0 (sum of the receiver temperature, antenna and ground contribution, etc.), Tau is the atmospheric opacity.

in which airmass A = 1/sin(Elev), T0 is extrapolated noise temperature for airmass = 0 (sum of the receiver temperature, antenna and ground contribution, etc.), Tau is the atmospheric opacity at the zenith.

December 28, 2005

December 28, 2005 (with FEM surface, no Zernikes)

%META:FILEATTACHMENT{name="efficiency050411.2005SpringV1.txt" attr="" comment="efficiency data for 2005SpringV1 Surf. model (BJN)" date="1196374960" path="efficiency050411.2005SpringV1.txt" size="4907" user="ToddHunter" version="1.2"}%

(#) The marked Gmax values and polynomial coefficients have been corrected for atmospheric absorption. The rest is not.

(#) The marked Gmax values and polynomial coefficients have been corrected for atmospheric absorption. The others are not.

More info for 40-50 GHz Observing may be found on Ron's Q-band Performance page.

K band data were collected on December 28, 2005, and should be reduced soon.

-- YuriKovalev - 28 Dec 2005

-- YuriKovalev - 01 Dec 2005

Gain curve data is summarized here, and references to memos are given. Click the link under "Date of Observations" for a reference to a memo.

Gain curve data is summarized here, and references to memos are given. Click the link under "Date of Observations" for a reference to a memo.

A simple model for the atmosphere was fitted by least-squares to the data:

A simple model for the atmosphere was fitted by least-squares to the data:

The gain curve is not corrected for atmospheric opacity for L, S, C, X, Ku bands.
The gain curve is corrected for atmospheric opacity for Q band.

Note that the L,X,Ku-band data are not fully analyzed, so their results should be regarded as preliminary. The final values may differ by a few percent from what is given here.

The difference in gain as well as opacity between the two polarization is up to 10%, which is about the uncertainty in the noise calibration temperatures (Tcals), hence not significant.

Note that the L, X, Ku-band data are not fully analyzed, so their results should be regarded as preliminary. C band data will be updated soon as well by result from more recent measurements. The final values (coming soon) may differ by a few percent from what is given here.

The gain (Gmax) values marked with (#) have been corrected for atmospheric absorption.

(#) The marked Gmax values and polynomial coefficients have been corrected for atmospheric absorption. The rest is not.

-- YuriKovalev - 08 June 2005

-- YuriKovalev - 01 Dec 2005

Note that the L-band and X-band data are not fully analyzed, so their results

Note that the L,X,Ku-band data are not fully analyzed, so their results

-- YuriKovalev - 20 May 2005

-- YuriKovalev - 08 June 2005

-- YuriKovalev - 13 Jul 2004

-- YuriKovalev - 20 May 2005

Note that the L-band and X-band data are not fully analyzed, so their results should be regarded as preliminary. The final values may differ by a few percent from what is given here.

-- YuriKovalev - 23 Jun 2004

-- YuriKovalev - 13 Jul 2004

Note that at the higher frequencies (>10GHz) the model used to correct the active surface has a significant effect on the gain curves. When a change in the surface model happens, a new determination of the gain curve will need to be done.

-- FrankGhigo - 27 May 2004

-- FrankGhigo - 25 Jun 2004

-- YuriKovalev - 22 Jun 2004

-- YuriKovalev - 23 Jun 2004

-- YuriKovalev - 10 Jun 2004

-- YuriKovalev - 22 Jun 2004

-- YuriKovalev - 02 Jun 2004

-- YuriKovalev - 10 Jun 2004

Gain(ZD) = Gmax * (A0 + A1*ZD + A2*ZD**2 + ...)

Gain(ZD) = Gmax * (A0 + A1*ZD + A2*ZD^2 + ...)

-- YuriKovalev - 28 May 2004

-- YuriKovalev - 02 Jun 2004

The gain in Kelvin/Jy as a function of elevation (in degrees)

The gain in Kelvin/Jy as a function of Zenith Distance = 90-Elevation (in degrees)

Gain(Elev) = Gmax * (A0 + A1*Elev + A2*Elev**2 + ...)

Gain(ZD) = Gmax * (A0 + A1*ZD + A2*ZD**2 + ...)

The gain (Gmax) values marked with (#) have been corrected for atmospheric absorption.

The gain (Gmax) values marked with (#) have been corrected for atmospheric absorption.

-- YuriKovalev - 28 May 2004

Click the link under "Date of Observations" for a reference to a memo. The gain in Kelvin/Jy as a function of elevation (in degrees) is given by a polynomial of the form
Gain(Elev) = Gmax * (A0 + A1*Elev + A2*Elev**2 + ...)
in which the coefficients are listed in the table.

A simple model for the atmosphere was fitted by least-squares to the data:
Tsys = T0 + Tatm (1 - exp(-Tau*A)),
in which airmass A = 1/sin(Elev), T0 is extrapolated noise temperature for airmass = 0 (sum of the receiver temperature, antenna and ground contribution, etc.), Tau is the atmospheric opacity.
The gain (Gmax) values marked with (#) have been corrected for atmospheric absorption.

%META:TOPICINFO{author="FrankGhigo" date="1085673600" format="1.0" version="1.1"}%

GBT Gain Curves and Performance data.

Gain curve data is summarized here, and references to memos are given.

-- FrankGhigo - 27 May 2004