850 

14 CFR Ch. I (1–1–19 Edition) 

§ 171.311 

(2) CW. The CW pulse transmissions 

and the CW angle transmissions as may 
be required in the signal format of any 
function must have characteristics 
such that the requirements of para-
graph (d) of this section are met. 

(d) 

Radio frequency signal spectrum. 

The transmitted signal must be such 
that during the transmission time, the 
mean power density above a height of 
600 meters (2000 feet) does not exceed 

¥

100.5 dBW/m

2

for angle guidance and 

¥

95.5 dBW/m

2

for data, as measured in 

a 150 KHz bandwidth centered at a fre-
quency of 840 KHz or more from the as-
signed frequency. 

(e) 

Synchronization. 

Synchronization 

between the azimuth and elevation 
components is required and, in split- 
site configurations, would normally be 
accomplished by landline interconnec-
tions. Synchronization monitoring 
must be provided to preclude function 
overlap. 

(f) 

Transmission rates. 

Angle guidance 

and data signals must be transmitted 
at the following average repetition 
rates: 

Function 

Average 

data rate 

(Hertz) 

Approach Azimuth .................................................

13 

±

0.5 

High Rate Approach Azimuth ................................

1

39 

±

1.5 

Approach Elevation ...............................................

39 

±

1.5 

Back Azimuth .........................................................

6.5 

±

0.25 

Basic Data .............................................................

(

2

) 

Auxiliary Data ........................................................

(

3

) 

1

The higher rate is recommended for azimuth scanning an-

tennas with beamwidths greater than two degrees. It should 
be noted that the time available in the signal format for addi-
tional functions is limited when the higher rate is used. 

2

Refer to Table 8a. 

3

Refer to Table 8c. 

(g) 

Transmission sequences. 

Sequences 

of angle transmissions which will gen-
erate the required repetition rates are 
shown in Figures 2 and 3. 

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