Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.naic.edu/~phil/rfi/miscdevice/uprmgpsstation/20150914_gps_station_uprm.pdf Дата изменения: Tue Sep 29 15:55:32 2015 Дата индексирования: Tue Apr 12 12:59:25 2016 Кодировка:

RFI Test - UPRM GPS Station Luis Quintero, Arecib o Observatory 18 Sep 2015
1 Intro duction RFI test info and results for the Geology. The test was performed probe (ETS 7405 No.904) from 0 Sep 2015. This test was requested Figure 3: Probe No. 904 Performance. 3 Test Pro cedure · We tested four components of the UPRM GPS Receiver, Fig. 1, GPS Receiver Unit (right), GPS Antenna (left), GPS Power Adapter (center); Fig. 2, GPS Battery Charger for Solar Panel (inside the case). · Agilent E4445A Spectrum Analyzer preheated for more than 30min, outside of the screen room. · Thirty (35) 100MHz bandwidth scans (12.207kHz per channel), from 0 to 3500MHz, electric field. · Ten (10) seconds "integration" time. · Screen/shielded room front door closed. Fluorescent lights ON. · A/C ON, eth. switch OFF, 10MHz buffer OFF, 10MHz ref. cable disconnected. · 430MHz and S-band transmitters OFF. 4 Figure 2: UPRM GPS Receiver Battery Charger Test Results · GPS Receiver Unit: receiver connected to GPS antenna and power adapter, separated around 1ft. No battery charger connected. E-field probe 904 in front of LCD display. See results in Table 1 and Fig. 4. · GPS Antenna: same setup of receiver unit, but Efield probe 904 on top of the GPS Antenna, centered. See results in Table 2 and Fig. 5. No noticeable emissions above 1.5GHz. · GPS Power Adapter: same setup of receiver unit, but E-field probe 904 on top of the GPS Power Adapter. See results in Table 3 and Fig. 6. No noticeable emissions above 1.5GHz. · GPS Battery Charger: receiver connected to GPS antenna, no power adapter, instead battery charger. E-field probe 904 on top of battery charger. See results in Table 4 and Fig. 7. No noticeable emissions above 1.5GHz. · Clear write trace in plots below, black line. Peaks in blue are RF emissions outside of our frequency coverage (327MHz receiver, 430MHz receiver, and more than 1150MHz). Red peaks for emissions probably causing interference at the radio-telescope.

This document shows UPRM GPS Station using an electric field to 3.5GHz on Tue, 15 by Angel Vazquez.

Figure 1: UPRM GPS Receiver Test Setup

2

Test Equipment

Agilent E4445A Spectrum Analyzer: · · · · · · · · Trace 1: Clear Write, Average ON, 20 spec. Trace 2: Max Hold. Trace 3: Min Hold. RBW & VBW 39kHz, sweep 100.5ms. 8192 points per spec. Internal Amplifier ON. 6dB Attenuation. SCPI Commands from Python.

ETS Model 7405[1] probe No.904: · · · · · Electric field. Res. Freq. >1.0GHz. H/E Rejection 30dB. Performance: Fig. 3. + 15ft coax cable


5

Discussion · The Received is the most noisy component, mostly at lower frequencies. 327MHz and 430MHz receiver could be affected. There is a strong L-band emission at 1389.99MHz, and few more above with less power. · The Antenna looks better, despite there is a 1247.705MHz emission. · The Power Adapter looks ok, just few emissions around 1.2GHz. · The Battery Charger shows one peak at 325MHz, and few more around 1.4GHz.

6

Recommendations · For the GPS station installed at the RFI hilltop monitor, it's recommended to install the Receiver and Power Adapter inside the RFI shack. No solar panel. · If GPS station at the helipad (Solar Panel and Battery Charger, no Power Adapter) is approved for installation, we have to looks carefully for interference in L-band and S-band with the radio-telescope.

References [1] ETS LINDGREN, ETS Near-Field Probe Set Model 7405.


Table 1: UPRM GPS - Receiver Emissions Frequency (MHz) Amplitude (dBm) 312.280 -99.64 -98.83 312.769 312.915 -98.66 -100.53 313.013 313.550 -100.88 -100.58 313.574 313.660 -96.13 313.806 -98.89 -99.59 314.868 314.941 -98.62 ... ... 330.652 -99.75 331.714 -96.96 332.373 -99.71 333.740 -100.10 333.850 -101.13 334.875 -100.53 335.022 -100.16 -100.52 335.767 335.938 -99.75 -101.23 339.075 422.205 -98.58 422.852 -99.03 423.486 -97.74 424.878 -99.06 425.525 -97.49 426.904 -99.21 429.565 -100.61 432.898 -100.53 436.304 -100.95 439.612 -100.86 1389.990 -81.62 -102.55 1412.988 1440.002 -99.40 1600.000 -100.95 1649.988 -102.00 2779.993 -101.33 2879.993 -100.35

Figure 4: UPRM GPS - Receiver, Red Peaks Only


Table 2: UPRM GPS - Antenna Emissions Frequency (MHz) Amplitude (dBm) 2.563 -85.69 2.686 -87.37 -98.95 30.884 107.251 -93.48 -102.30 917.139 1247.705 -97.29

Figure 5: UPRM GPS - Antenna Emissions


Table 3: UPRM GPS - Power Supply Emissions Frequency (MHz) Amplitude (dBm) 19.800 -90.90 20.068 -90.65 20.129 -91.40 20.166 -91.53 61.890 -92.15 107.288 -94.68 225.000 -97.18 275.000 -97.02 1224.634 -102.57 -97.31 1286.023 1286.108 -100.64 1286.206 -98.45 1286.377 -100.89

Figure 6: UPRM GPS - Power Supply Emissions


Table 4: UPRM GPS - Battery Charger Emissions Frequency (MHz) Amplitude (dBm) 10.132 -96.01 14.221 -97.12 -97.12 16.138 16.687 -97.45 -96.42 17.224 17.786 -96.67 107.288 -99.20 107.361 -99.13 125.000 -96.77 150.000 -99.00 174.988 -86.99 -99.26 200.000 225.000 -89.01 249.988 -98.38 275.000 -95.77 325.000 -93.81 349.988 -101.12 374.988 -89.64 475.000 -96.40 500.012 -86.52 525.000 -100.26 532.593 -93.11 699.988 -101.97 -101.84 700.024 750.000 -96.63 799.988 -101.63 850.000 -102.89 -102.34 1147.681 1389.990 -96.45 1439.978 -102.23 1440.002 -102.27 1472.913 -102.38

Figure 7: UPRM GPS - Battery Charger Emissions