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Interpretation of the NSMA Standard

This file contains an interpretation of the NSMA standard format for the electronic transfer of antenna patterns (see REP.WG16.89.003) by OETINFO an Engineer at the Federal Communications Commission.

Filenaming Convention:

The filename should be a case insensitive, unique, six digit ID code (see WG16.95.043) assigned by the manufacturer with the file extension of ".nsm". (e.g. 24032g.nsm)
1st digit: [0-9, 1 digit Frequency Code Number] +
2nd-5th digits: [0000-ZZZZ, 4 digit alpha-numeric unique Manufacturer ID Number assigned by manufacturer] +
6th digit: [A|C|G|M; 1 digit Manufacturer Code which is registered with the NSMA] +
Extension: [.nsm, a standarded file extension for this version (v1) of the NSMA standard]

File Structure:

[Antenna Manufacturer] + CRLF
[Antenna Model number] + CRLF
[Comment] + CRLF
[FCC ID number] + CRLF
[reverse pattern ID number] + CRLF
[date of data] + CRLF
[Manufacturer ID Number (see filenaming convention)] + CRLF
[frequency range] + CRLF
[mid-band gain] + CRLF
[Half-power beam width] + CRLF
[polarization (char 7) + chr$(32) + datacount (char 7)  + chr$(32) + CRLF]
[angle(1) (char 7) + chr$(32) + relative gain in dB(char 7) + chr$(32) + CRLF]
.
.
.
[angle(datacount) (char 7) + chr$(32) + relative gain in dB (char 7) + chr$(32) + CRLF]
.
.
.
[polarization (char 7) + chr$(32) + datacount (char 7)  + chr$(32) + CRLF]
[angle(1) (char 7) + chr$(32) + relative gain in dB(char 7) + chr$(32) + CRLF]
.
.
.
[angle(datacount) (char 7) + chr$(32) + relative gain in dB (char 7) + chr$(32) + CRLF]

The first ten lines must exist and end with both a carriage return and line feed.

Dates should be formatted (12/31/[19]96 or 31 DEC [19]96 or [19]96.12.31).

Mid-band Gain should be in dBi (relative to and isotropic radiator).

Frequency Range must be in Megahertz. (6525.0 - 6875.0)

Place "NONE" on any rows which otherwise would be blank.

All values should be left justified in their character fields.

Polarization must be in the set [HH|HV|VV|VH|ELHH|ELHV|ELVV|ELVH]

-180 deg < Angle(x) < 180 deg for [HH|HV|VV|VH]

-90 deg < Angle(x) < 90 deg for [ELHH|ELHV|ELVV|ELVH]

Angle(1) < Angle(2) < ... < Angle(datacount)

Relative Gain in dB < ~0 including sign
(Most values will be non positive. Exceptions may include antennas which have slightly depressed main lobes at 0 degrees. e.g. some panel antennas) (relative to the mid-band gain given on line 9 above)

Details from NSMA WG-16 publication

The following are detailed explanations of each of the data lines.

(Antenna Manufacturer)                       (30data)

This is the name under which the data was filed with the FCC. There will be no abbreviations.

(Full model number)                          (30data)

This is the full model number as used when the data was filed with the FCC. Modifiers to the model number such as dashes or exceptions are to be included.

(FCC ID number)                              (16data)

This is the ID number issued by the Common Carrier Branch of the FCC. For services which do not issue ID numbers, insert the word (none) in upper case.

(Reverse pattern ID number)                  (16data)

This lists the reverse pattern FCC ID number. The reverse pattern is generally obtained by inserting the feed in a opposite manner in order to reverse the pattern.

(date of data)                               (16data)

This date is the date referenced on the published pattern

(manufacturer ID number)                     (4data)

This is the reference number assigned by the antenna manufacturer. This 4 digit alpha-numeric should be included with all antennas models and should also be used to name the antenna pattern filename.

(frequency range)                            (16data)

This is to identify the full frequency range for which this pattern is valid and agrees with the range as specified in the printed pattern. The frequency is in Megahertz.

(mid-band gain)                              (16data)

This is the gain of the antenna at mid-band. The gain is in gain above an isotropic radiator (dBi).

(half power beam width)                      (16data)

This is the included angle centered on the main beam of the antenna and defines the angle where the antenna response falls -3 dB.

(polarization) (data count)   (7data,1space)      (7data,1space)

The data is preceded by an indication of the polarization the data. The commonly accepted polarization designators for linear polarization are to be used:

HH
Horizontal polarized port response to a horizontally polarized signal in the horizontal direction.
HV
Horizontal polarized port response to a vertically polarized signal in the horizontal direction.
VV
Vertical polarized port response to a vertically polarized signal in the horizontal direction
VH
Vertical polarized port response to a horizontally polarized signal in the horizontal direction
ELHH
Horizontal polarized port response to a horizontally polarized signal in the vertical direction
ELHV
Horizontal polarized port response to a vertically polarized signal in the vertical direction
ELVV
Vertical polarized port response to a vertically polarized signal in the vertical direction
ELVH
Vertical polarized port response to a horizontally polarized signal in the vertical direction

The data count will be the number of data points to follow.

All eight responses should be included. If different polarizations have identical responses, they are to be duplicated in order that a full set of data be listed.

(angle)        (response)     (7data,1space)      (7data,1space)

A full compliment of data will show the antenna response in the horizontal direction for a 'horizontal cut' and in the vertical direction for a 'vertical cut'.

The data is presented in two columns. The angle of observation is listed first followed by the antenna response.

For the horizontal direction, the angle of observation starts from -180 degrees (defined as the left side of the antenna) and decrease in angle to the main beam , 0 degrees, and then increase to +180 degrees. The full data will cover the 360 degrees of the antenna.

For the vertical direction, the angle of observation starts from -5 (-90) degrees (defined as the antenna response below the main beam) and decrease in angle to the main beam, 0 degrees, and then increase to +5 (+90) degrees. The full data will cover the 10 (180) degrees centered about the main beam.

The antenna response is listed as dB down from the main lobe response and is shown as negative.

As a minimum, the data points are the breakpoints. That is, those points which define a change in the slope of the data or an adequate number of points to define a non-linear line. It is acceptable to include periodical points (eg. every 1 degree or more) between the breakpoints.




Last Updated/Reviewed on: Thursday, January 13, 2000 


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