A cal diode was installed on the 430 dipole of mathew's on the ch. Calixto reported that the cal at 430Mhz was 42.1 K. The system temperature was measured using the cal. The setup was:

• The telescope was parked at az=275(dome side) ch=8.8 degrees (this is an lst around 13 Hr).
• The cal was toggled on 1 sec, off 1 sec. This continued for 960 seconds.
• 1 Mhz around 430 was detected with at 2 millisecond time constant and sampled at 1 khz.
• The median value for each 1 second was then used for the cal on, off

• Fig 1 top: Total power vs time for the cal on. These are the 1 second medians. The units are linear in power (A/D counts). The spikes are caused by lightning.
• Fig 1 middle: Total power vs time for the cal off.
• Fig 1 bottom: (CalOn-calOff)/(median(calOn-calOff). This shows the fractional change in the ratio vs time. Looking at the individual  calOn, calOffs you see that the variation is not present when the cal is off. The ripple is coming from the cal.
• Fig 2 Top: Tsys vs time using 42.1 for the cal Temperature. The avgerage value is 151.8 K.
• Fig 2 bottom: A sine wave was fit to Tsys vs time. The Amplitude is 3.3K and the period is 219.7 seconds. The amplitude does not match with the fraction of cal from page 1.  3% of 42.1K=1.2K not 3.3 K. So maybe some of the oscillation is in the cal off too??

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