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Choke Ring Antenna Calibrations

Choke Ring Antenna Calibrations

Pictured above from left to right are antennas from Ashtech, Trimble, and Allen Osborne & Associates. With an increase in the number of companies offering a choke ring antenna, it is important that any differences is the dimensions from one antenna to another are noted. UNAVCO measured the dimensions of the Trimble Navigation, Ashtech, Allen Osborne & Associates, and Leika choke ring antennae.

This is a diagram of a generic choke ring antenna, defining the various standard dimensions (which are noted in the table below). Also noted in the table is the Difference in mm from the IGS reported values for those dimensions.

For more information on GPS Antenna Testing and Calibration, please see the The NGS/NOAA Antenna Calibration Page. Inside the table below, the NGS/NOAA test results for each specific antenna model are linked directly to the model number when available. Select the link to see the results.

Also of interest is the SCIGN (Southern California Integrated GPS Network) Website.

Dimensions of Manufactured Choke Ring Antennae

 

AOA Trimble Leica Ashtech "D" Ashtech "E" Ashtech "B"
Model 7490582-2 29659-00 10839 700936 700936-02 701945-02
DMC Element C 146-6-1 S/N 2243 C 146-6-1 S/N 1993 C 146-10-1 S/N 2839 C 146-10-1 S/N 2821-10 C 146-10-1 S/N 1306 unk
SCIGN NO NO YES YES YES YES
Units Inches mm Diff IGS Inches mm Diff IGS Inches mm Diff IGS Inches mm Diff IGS Inches mm Diff IGS Inches mm Diff IGS
"A" 3.988 101.3 0.70 4 101.6 0.40 3.984 101.2 0.81 3.97 100.8 1.16 3.992 101.4 0.60 3.972 100.9 1.11
"B" 1.584 40.2 -2.23 1.497 38.0 -0.02 1.487 37.8 0.23 1.489 37.8 0.18 1.51 38.4 -0.35 1.594 40.5 -2.49
"C" 5.482 139.2   5.508 139.9   5.475 139.1   5.453 138.5   5.475 139.1        
"D" 1.37 34.8 0.20 1.375 34.9 0.08 1.359 34.5 0.48 1.365 34.7 0.33 1.38 35.1 -0.05 1.37 34.8 0.20
"E" 0.12 3.0 -0.05 0.12 3.0 -0.05 0.125 3.2 -0.18 0.119 3.0 -0.02 0.14 3.6 -0.56 0.122 3.1 -0.10
"F" 14.9375 379.4 1.59 15.01 381.3 -0.25 14.9375 379.4 1.59 14.9375 379.4 1.59 14.9375 379.4 1.59      
"G1" 0.139 3.5   0.125 3.2   0.135 3.4   0.13 3.3   0.145 3.7   0.129 3.3  
"G2" 0.139 3.5   0.125 3.2   0.132 3.4   0.13 3.3   0.145 3.7   0.129 3.3  
"G3" 0.137 3.5   0.125 3.2   0.132 3.4   0.13 3.3   0.143 3.6   0.129 3.3  
"G4" 0.137 3.5   0.125 3.2   0.132 3.4   0.13 3.3   0.143 3.6   0.129 3.3  
"H1" 0.999 25.4   0.998 25.3   0.99 25.1   0.994 25.2   0.99 25.1   1.0 25.4  
"H2" 0.981 24.9   1.002 25.5   1 25.4   0.998 25.3   0.988 25.1   1.0 25.4  
"H3" 0.99 25.1   1 25.4   1 25.4   0.998 25.3   0.99 25.1   1.0 25.4  
"H4" 0.994 25.2   1 25.4   0.99 25.1   0.998 25.3   0.99 25.1   1.0 25.4  
"I" 14.1675 359.9   14.173 360.0         14.134 359.0              
"J1" 2.505 63.6   2.500 63.5   2.000 50.8   2.475 62.9   2.490 63.2   2.475 62.9  
"J2" 2.505 63.6   2.500 63.5   2.000 50.8   2.478 62.9   2.491 63.2   2.477 62.9  
"J3" 2.505 63.6   2.500 63.5   2.000 50.8   2.478 62.9   2.491 63.3   2.476 62.9  
"J4" 2.501 63.5   2.500 63.5   2.000 50.8   2.478 62.9   2.491 63.3   2.479 63.0  
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Last modified: Monday, 12-May-2014 00:18:29 UTC