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EA:  EM_PROPAGATION_CONDITION

Status: STD 2005/06/07
Code: 337
Concept definition: The type of condition causing variation in the propagation path of electromagnetic energy due to interaction of the emitted energy with the vertical density gradient of the <ATMOSPHERE>.
 
Attribute value type: ENUMERATION
Reference type: IR
Reference: [BATT]
Supplemental references:  
Enumerants (presented in a natural order)
Status Attribute label Enumerant label ▾ Concept definition Code Ref type Reference Supplemental references
STD
2005/06/07		 EM_PROPAGATION_CONDITION RADIO_DUCT The propagation of radio energy under conditions in the <ATMOSPHERE> of the <EARTH> in which the refractive index (<<REFRACTION_INDEX_REAL_PART>>) decreases with <<ALTITUDE_MSL>> at a rate greater than 157 x 10-6 per kilometre; radio duct. The unit of measure equation is defined by N = (n-1) x 106 where n is the <<REFRACTION_INDEX_REAL_PART>> and is known as an "N-unit". Radio energy that originates within a duct and leaves the <AERIAL> at angles near the horizontal may be trapped within the duct. 1 IR [GMET, "radio duct"]  
STD
2005/06/07		 EM_PROPAGATION_CONDITION STANDARD The propagation of radio energy under conditions of standard refraction in the <ATMOSPHERE> of the <EARTH>, that is, an <ATMOSPHERE> or section of the <ATMOSPHERE> in which the refractive index (<<REFRACTION_INDEX_REAL_PART>>) decreases uniformly with <<ALTITUDE_MSL>> at a rate of approximately 40 x 10-6 per kilometre. The unit of measure equation is defined by N = (n-1) x 106 where n is the <<REFRACTION_INDEX_REAL_PART>> and is known as an "N-unit". 2 IR [GMET, "standard propagation"]  
STD
2005/06/07		 EM_PROPAGATION_CONDITION SUBSTANDARD The propagation of radio energy under conditions of substandard refraction in the <ATMOSPHERE> of the <EARTH>, that is, an <ATMOSPHERE> or section of the <ATMOSPHERE> in which the refractive index (<<REFRACTION_INDEX_REAL_PART>>) decreases with <<ALTITUDE_MSL>> at a rate of less than 40 x 10-6 per kilometre. The unit of measure equation is defined by N = (n-1) x 106 where n is the <<REFRACTION_INDEX_REAL_PART>> and is known as an "N-unit". 3 IR [GMET, "substandard propagation"]  
STD
2005/06/07		 EM_PROPAGATION_CONDITION SUPERSTANDARD The propagation of radio energy under conditions of superstandard refraction in the <ATMOSPHERE> of the <EARTH>, that is, an <ATMOSPHERE> or section of the <ATMOSPHERE> in which the refractive index (<<REFRACTION_INDEX_REAL_PART>>) decreases with <<ALTITUDE_MSL>> at a rate of greater than 40 x 10-6 per kilometre. The unit of measure equation is defined by N = (n-1) x 106 where n is the <<REFRACTION_INDEX_REAL_PART>> and is known as an "N-unit". 4 IR [GMET, "superstandard propagation"]  
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