Moon Surface Temperature 2'77cm Wavelength by Christian Monstein

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Moon Surface Temperature _at_2.77cm Wavelengthby
Christian Monstein
Bild NASA Apollo-11
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80cm offsetdish mounted on 5m-dish at Bleien
observatory
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Receiving equipment

• Software tools on pisces
• Windows 98
• AR5000-control
• FLUKE45-control capture
• VNC remote software
• Fictional Daemon ftp-server
• Humidity-sensor
• Temperature sensor
• Apache www-server

Moon
Offset dish 80cm beam switching- mode 6 x
90sec 10,7...12,75GHz
AR5000
RS-232C
Power supply 15V via bias-T
Pentium 66MHz
IF1950...2150MHz 75?
Logarithmic detector AD8307
IF210,7 MHz BW220KHz 50?
RS-232C
25mV/dB
FLUKE45
Ethernet
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Collecting data and overview
Moon set
Moon rise
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Drift evaluation by 4th order- polynom
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Drift compensation
½(TskyTsysTmoon) dB
½Tmoon dB
-½(TskyTsys) dB
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Histogramm creation
?dB
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Exception handling

• Geostationary satellites between Moon and Earth
• Sun within tracking path during new moon phase
• Terrestrial man made noise
• High noise temperature below 15 elevation
• Rainfall increases atmospheric attenuation
  drastically
• System failures (timing, pointing and other Bill
  Gates-effects)
• Imperfect operator...
• Radio-refraction not yet corrected (only optical)!

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Analysis disc temperature

• Antenna temperature Ta Tref10(?dB/10)-1,
  where Tref94K
• Compensation LNC-dustcover loss ?c0.1dB
• Compensation atmospheric loss a00.2dB...0.24dB..
  .1.5dB (rain)
• Compensation elevation effect ?aa0sin(??/180)
  -1
• Evaluation proper antenna temperature. TpTa ?c
  ?a
• Evaluation antenna directivity with a sun transit
  measurement -gt D
• Evaluation antenna beam solid angle ?a(4 ?)/D
  ²
• Evaluation moon disc area (solid angle) ?m
  ?(?/2)²
• Evaluation moon brightness temperature TmTp
  ?a/ ?m
• Filtering with smoothed mean method by 9 hours
  observation time
• Data approximation by a 6th order polynom

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Estimation of Tref
1. Theoretical, due to noise figure (preamp)
ohmic losses(cover)
2. Solar radio noise (LEAR) as a reference
3. Cold sky/horizon
Average
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Estimation of antenna directivity by a transit
meridian scan of the sun
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Final result
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Observation parameter

• Observationtime 7.1.2001-8.3.2001 276 hours
  248657 samples
• Sample rate 5digit/4sec
• Observationmode beam-switching (6 resp. 8) x
  90
• 1 ? (antenna temperature raw data) 0.5 Kelvin
• 1 ? (moon disk temperature raw data) 22 Kelvin
• 1 ? (moon disk temperature integrated data) 22
  K/?9 lt 10 K (4)
• Mean disk temperature 213 Kelvin
• SNR signal to noise ratio typically 8.6 dB
• Estimation of temperature lag ?t 5 days
• Observing frequency 10.83 GHz 2.77 cm
  wavelength
• Observing bandwidth 220 KHz
• Integration time pre0.2sec, post9h

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Finito
Christian Monstein HB9SCT Wiesenstrasse
13 CH-8807 Freienbach Private cmonstein_at_swissonl
ine.ch http//www.monstein.de/ Business monstein
_at_astro.phys.ethz.ch http//www.astro.phys.ethz.ch/
rapp/