Test background

The comrades at the Zhenjiang Monitoring Station monitored the broadcast frequency and found that the broadcast content of the 91.13MHz frequency was false and vulgar, filled with a large number of illegal advertisements such as drug promotion and pornography, which easily deceived the masses. , there is a "black broadcast" property.   

Shanghai Linpu Company assisted Zhenjiang Radio Monitoring Station to use Narda portable monitoring direction finding receiver + 10MHz-8GHz ADFA2 wideband automatic direction finding antenna + 20MHz-250MHz directional antenna provided by Shanghai Linpu for investigation work.   

Test process one: 

The comrade at the monitoring station gave us the signal position and time of 91.13Mhz, so we installed the ADFA broadband automatic direction finding antenna in the car in less than 5 minutes, and matched it with the Auto DF direction finding software equipped with the Narda portable monitoring direction finding receiver. . At about 19:30, the black broadcast signal was received at No. 7 Dongchang Middle Road, Jurong City, and the harsh content of "guaranteed for three years, etc." was demodulated, and the signal strength was about -97dBm.  

Test process two: 

As the monitoring vehicle continues to drive on the road, the collected data is calculated on the heat map, and it is found that the direction of the incoming wave of the black broadcast may be in the northwest direction. Near Juzhuo Road.

Test process three: 

Switching the portable antenna, the signal is the strongest when pointing to the top of the 6 buildings, so I went directly to the top of the building and found that the "black broadcast" was an umbrella antenna. (less than 30 minutes)

More "black broadcast" search cases are as follows. If you need to know about relevant cases, please contact our sales, thank you.

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"Black Broadcast" finds -Wenzhou "92.6M" finds