TAILIEUCHUNG - EMISSION CONTROL (EMCON)

When EMCON is imposed, RF emissions must not exceed -110 dBm/meter2 at one nautical mile. It is best if systems meet EMCON when in either the Standby or Receive mode versus just the Standby mode (or OFF). | EMISSION CONTROL EMCON When EMCON is imposed RF emissions must not exceed -110 dBm meter2 at one nautical mile. It is best if systems meet EMCON when in either the Standby or Receive mode versus just the Standby mode or OFF . If one assumes antenna gain equals line loss then emissions measured at the port of a system must not exceed -34 dBm . the stated requirement at one nautical mile is converted to a measurement at the antenna of a point source - see Figure 1 . If antenna gain is greater than line loss . gain 6 dB line loss 3 dB then the -34 dBm value would be lowered by the difference and would be -37 dBm for the example. The opposite would be true if antenna gain is less. MIL-STD-461B C RE-02 or Seam or MIL-STD-461D RE-102 Connector 70 dBpV m for externally mounted systems Leakage RF System 1 1 Meter Maximum EMCON Emissions 1 Nautical mile -34 dBm at RF port For Line Loss Antenna Gain P t G -110 dBm m 2 4bR 2 Figure 1. EMCON Field Intensity Power Density Measurements To compute the strength of emissions at the antenna port in Figure 1 we use the power density equation see Section 4-2 PG p - 1 or rearranging PtGt Pd 4bR2 2 D 4bR 2 Given that Pd -110 dBm m2 10 -11 mW m2 and R 1 NM 1852 meters. PtGt Pd 4BR2 10-11mW m2 4B 1852m 2 10 -4 mW . -34 dBm at the RF system antenna as given. or the equation can be rewritten in Log form and each term multiplied by 10 10log Pt 10logGt 10logPD 10log 4bR2 3 Since the m2 terms on the right side of equation 3 cancel then 10log Pt 10logGt -110 dBm dB dBm . -34 dBm as given in Figure 1. If MIL-STD-461B C RE02 or MIL-STD-461D RE-102 measurements see Figure 2 are made on seam connector leakage of a system emissions below 70 dByV meter which are measured at one meter will meet the EMCON requirement. Note that the airframe provides attenuation so portions of systems mounted inside an aircraft that measure 90 dByV meter will still meet EMCON if the airframe provides 20 dB of shielding note that the .

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