3mm Testing in July 2001

Tony Wong

ATNF Epping

CA Forum, 6 Sep

Bandpass at 90.56 GHz

3c279128 MHz64 chans

3c279128 MHz64 chans

Bandpass at 90.68 GHz

After bandpass

calibration applied

Bandpass at 90.68 GHz

Phase/amp stability at 90 GHz

RMS 10but

amplitude variations

much greater!

Phase/amp stability at 90 GHz

Phase cycles

every 20 minutes

Phase/amp stability at 22 GHz

Amps decreasing- worsening weather?

How often to calibrate?

5 min on 3c279:

10% amp fluctuation, RMS 15

System Temperatures

Tsys, corrected for atmospheric absorption, was determined using

the paddle while stepping in frequency from 84-87

GHz.Some of the frequency variation may be due to

varying atmosphere.

System Temperatures

Same observation for 87-91 GHz.

System Temperatures

Since the “psJy” scale is derived

assuming constant GTsys of 500 Jy, the

visibility amplitude in psJy is anticorrelated

with Tsys.

Sensitivity Estimate, 86 GHz

Assuming a flux of 8 Jy for Uranus, the observed amplitude and Tsys give the geometric mean Jy/K for the two antennas.

Sensitivity Estimate, 90 GHz

Note strong RFI at 88.160 GHz. Significant RFI is also found at 88.000 and 88.320 GHz, weaker at 88.240 GHz.

Some Science ResultsMolecules in IRC+10216

HCN

HNC

C3N

SiS

Some Science ResultsDense Gas in the LMC

HCN

HCO+

Thermal SiO in N6334

W 17.5”

center