[BC] FCC rule question

[Alan Gearing]

Jeff:

If you are referring to antenna pattern calculations the following applies:

    47 CFR §73.150 Directional Antenna Systems.

    (b)(6) The values used in specifying the parameters which describe
    the array must be specified to no greater precision than can be
    achieved with available monitoring equipment. Use of greater
    precision raises a rebuttable presumption of instability of the
    array. Following are acceptable values of precision; greater
    precision may be used only upon showing that the monitoring
    equipment to be installed gives accurate readings with the specified
    precision.

    (b)(6)(i) Field Ratio: 3 significant figures.

    (b)(6)(ii) Phasing: to the nearest 0.1 degree.

    (b)(6)(iii) Orientation (with respect to a common point in the
    array, or with respect to another tower): to the nearest 0.1 degree.

    (b)(6)(iv) Spacing (with respect to a common point in the array, or
    with respect to another tower): to the nearest 0.1 degree.

    (b)(6)(v) Electrical Height (for all parameters listed in Section
    73.160): to the nearest 0.1 degree.

    (b)(6)(vi) Theoretical RMS (to determine pattern size): 4
    significant figures.

    (b)(6)(vii) Additional requirements relating to modified standard
    patterns appear in §73.152(c)(3) and (c)(4).

There are also "standards" for specifying things like:

distances (nearest 0.1 km), physical tower heights (nearest 0.1 m), 
tower coordinates (to 0.1 second of latitude/longitude), there may be 
others.  Some of these may be in the Rules (can't recall exactly where 
at the moment), others may be restrictions on how precise a value is 
allowed to be entered into the Commission's online e-forms.

The staff typically calculates/plots coverage/allocation contours in 
1-degree increments.

If I think of anything else, I'll let you know.

Al Gearing

Jeff Glass wrote:
> Hello:
>
> Is there an FCC rule that specifies the required precision/accuraccy for AM
> Broadcast engineering calculations?
>
> Thanks,
>
> Jeff Glass</HTML>
>
>    

-- 

####################
Alan E. Gearing, PE
Mullaney Engineering, Inc.
PH: 301-921-0115
FX: 301-590-9757
email: AEGearing at TZSawyer.com