NSA/MWR/C1 - Temperature Stabilization of Noise Diode Impaired

On 1/17 we had a big spike in the data and lost temperature stabilization. The instrument 
had problems maintaining the Noise Diode (ND) temperature since. At ambient temperatures 
under about -20 C the ND was not maintaining the set temperature of 30 C. This problem 
was reported in P010122.1.

Fred Solheim recommended on 1/22 that we powercycle the instrument as it looked like the 
instrument CPU had lost the temperature reference.

So we powercycled the instrument on 1/22 @ 20:30 and lost all comumnication to it; after a 
second powercycling the instrument came back on line and the temperature stabilized 
quickly (within a couple of minutes) to the set temperature (30 C)

Fred Solheim reported after the system was restored:
"I've never seen this behavior before. I don't think it was due to the RF deck physically 
hanging temperature, because the recorded temp dropped about 30 C in one observation 
cycle. If this happens again, send the MWR down along with data files for us to look at."

Data collected in the periode 1/17/2001 6:00 to 1/22/2001 21:45 are questionable since it 
is uncertain whether the temperature really was unstable and what really caused the 
problem.

• Mean 23.8 GHz sky brightness temperature(tbsky23)
• Blackbody kinetic temperature(tkbb)
• Temperature correction coefficient at 23.8 GHz(tc23)
• Temperature correction coefficient at 31.4 GHz(tc31)
• 31.4 GHz sky signal(sky31)
• 23.8 GHz Blackbody signal(bb23)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• Ambient temperature(tkair)
• Mean 31.4 GHz sky brightness temperature(tbsky31)
• 31.4 GHz blackbody(bb31)
• Averaged total liquid water along LOS path(liq)
• 23.8 GHz sky signal(sky23)
• IR Brightness Temperature(ir_temp)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• (tknd)
• 31.4 GHz blac2body+noise injection signal(bbn31)
• Total water vapor along LOS path(vap)
• Mixer kinetic (physical) temperature(tkxc)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)

• Number of data points averaged for 23tbsky, 31tbsky, vap & liq(num_obs)
• IR Brightness Temperature(ir_temp)
• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Standard deviation about the mean for the total water vapor amount(vap_sdev)
• Standard deviation about the mean for the total liquid water amount(liq_sdev)
• Mean 23.8 GHz sky brightness temperature(tbsky23)
• Total water vapor along LOS path(vap)
• Standard deviation about the mean for the IR brightness temperature(ir_temp_sdev)
• Number of points included in the ir_temp ensemble(num_obs_irt)
• Averaged total liquid water along LOS path(liq)
• Fraction of data in averaging interval with water on Teflon window(water_flag_fraction)
• Standard deviation about the mean for the 31.4 GHz sky brightness temperature(tbsky31_sdev)
• Standard deviation about the mean for the 23.8 GHz sky brightness temperature(tbsky23_sdev)

• Averaged total liquid water along LOS path(liq)
• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Total water vapor along LOS path(vap)
• Mean 23.8 GHz sky brightness temperature(tbsky23)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• IR Brightness Temperature(ir_temp)