RFI measurement in Tibet

Jianli Zhang 5/8/2014

Equipment

• 1 butterfly antenna • 4 amplifiers (60dB)• A li-battery for amplifiers (12V)• Spectrum analyser• Cables

Settings for spectrum analyser:

• Spectrum analyser with RBW = 30kHz, Attenuation=0dB.

• Frequency range = 100KHz-300MHz• Set sys-settings-input/output, 75ohm(In YBJ

50ohm)• For all measurement go to ’Averaging’ mode

on the Spectrum Analyser, with at least 10 measurements for 1 average track.

Four measurements for one site

•Amplifiers + SpectrumAnalyser (end of antenna output cable unplugged). All electronics OFF. •Amplifiers + SpectrumAnalyser (end of antenna output cable unplugged). All electronics ON. •Antenna+ Amplifiers + SpectrumAnalyser (antenna output cable plugged). All electronics ON. 1 measurement at Galactic minimum (~11:30am in summer in YangBajing China) with antenna oriented E-W, one with N-S.•Same as 3., but now at Galactic maximum (~23:30pm midnight in summer in Yangbajing China)

• Position:• 30°6'7.82“N• 90°31'25.92“E• With LNA#4 and #5• Spectrum analyser 50 Ohm• The distance from antenna to

Spectrum analyser 6m• There was a storm at

6pm(20140725)

YangBaJing

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Galactic max and min @YangBaJing

Dingri• Position:• 28°34'9.13" N• 86°51'21.95" E• With LNA#1 and #2• Spectrum analyser 75 Ohm• The distance from antenna to Spectrum

analyser about 6m• The height of the antenna is about 1.3m

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Galactic max and min @Dingri

With Li Jianbi’s equipment @Dingri

• With LNA#1• Desktype spectrum

analyser 50 Ohm

PuMaJiangTang• Position:• 28°34'16.43"N• 90°11'34.06"E• With LNA#1 and #2• Spectrum analyser 75 Ohm• 100 measurements for this track• The distance from antenna to Spectrum

analyser 6m• The height of the antenna is about

1.4m

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