3mm Testing in July 2001 Tony Wong ATNF Epping CA Forum, 6 Sep

Bandpass at GHz 3c MHz 64 chans

3c MHz 64 chans Bandpass at GHz

After bandpass calibration applied Bandpass at GHz

Phase/amp stability at 90 GHz  RMS  10  but 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 T sys, corrected for atmospheric absorption, was determined using the paddle while stepping in frequency from GHz. Some of the frequency variation may be due to varying atmosphere.

System Temperatures Same observation for GHz.

System Temperatures Since the “psJy” scale is derived assuming constant GT sys of 500 Jy, the visibility amplitude in psJy is anticorrelated with T sys.

Sensitivity Estimate, 86 GHz Assuming a flux of 8 Jy for Uranus, the observed amplitude and T sys give the geometric mean Jy/K for the two antennas.

Sensitivity Estimate, 90 GHz Note strong RFI at GHz. Significant RFI is also found at and GHz, weaker at GHz.

Some Science Results Molecules in IRC HCN HNC C3NC3N SiS

Some Science Results Dense Gas in the LMC HCN HCO + Thermal SiO in N6334 W 17.5” center