Shulou(Shulou.com)06/02 Report--

Frequency interval 350kHz harmonic interference case office building PAE transmitter F0=*.2MHz emission (common system: through the cavity combiner to the antenna feed), air traffic control building RS XU4200 reception (low noise; does not connect the cavity), ambient noise RSSI=-112dBm. The distance between the transceiver antenna and the transmitter antenna is 100m, path attenuation = 32.5 + 20 Log F + 20 Log DVDs 32.5mm 41.5-20=54dB. The transmission level of the cavity combiner cable attenuation is estimated to be 47 dBm for 6 dB,F0=*.200 MHz, so when the level of the receiving antenna to the air traffic control building is 47 dBm-54dB-6 dB=-13 dBm and the cable attenuation 3dB is, the RSSI level of the receiver should be-16 dBm, which is consistent with the measured value in the table. Here, the harmonic output is taken as-36dBm, and the total cable attenuation of the cavity combiner is estimated that the harmonic level of 7dB MHz is-36dBm, so the level of the receiving antenna to the air traffic control building is-36dBm-54dB-7 dB=-97dBm, and the RSSI level of the receiver should be-97dBm. This interference level can not be avoided unless the antenna distance is increased. In the table below, the harmonic level of 50kHz and its multiples is higher, and the harmonic level is higher, reaching about-20dBm (need to check the transmitter to confirm). When the deviation from the carrier 500kHz is above, the harmonic level is-46dBm, then-46dBm-54dB-7 dB=-107dBm, the interference can be effectively avoided. And in the actual measurement, if the receiving frequency is not set according to the 25kHz frequency interval, if it is set to * .280 dBm, the value of Harmonics in the parameters will be significantly reduced (- 102RSSI), indicating that the Harmonics in the parameters refers to the harmonics of 25kHz and its multiples, and the value should be-36dBm, not 25kHz and its multiple frequency and the frequency above deviating from the carrier 500kHz is Spurios, that is, stray radiation, the value should be-46dBm.

XU4200 Frequency (MHz)

RSSI level value (dBm)

Annotation

* .200 (F0)

-16 colors, 20.

* .225 (F0+25kHz)

-92mm / m / m / 97.

* .250 (F0+50kHz)

-80,000,000,84.

Higher harmonic level of 50kHz and its multiples

* .275 (F0+75kHz)

-93mm Musi 98

* .300 (F0+100kHz)

-84mm Mui 87

Higher harmonic level of 50kHz and its multiples

* .325 (F0+125kHz)

-91mm Musi 93

* .350 (F0+150kHz)

-83mm Mui 86

Higher harmonic level of 50kHz and its multiples

* .375 (F0+175kHz)

-92mm / m / m / 97.

* .400 (F0+200kHz)

-84mm Mui 87

Higher harmonic level of 50kHz and its multiples

* .425 (F0+225kHz)

-92mm Mustang 95

* .450 (F0+250kHz)

-85 years Mustang 87

Higher harmonic level of 50kHz and its multiples

* .475 (F0+275kHz)

-94mm Musi 98

* .500 (F0+300kHz)

-91mm Musi 97

Higher harmonic level of 50kHz and its multiples

* .525 (F0+325kHz)

-96mm Mutual 99

* .550 (F0+350kHz)

-92mm Musi 99

* .575 (F0+375kHz)

-95 years Mustang 97

* .600 (F0+400kHz)

* .625 (F0+425kHz)

* .650 (F0+450kHz)

-106

* .675 (F0+475kHz)

-105

* .700 (F0+500kHz)

-105

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