Campbell Scientific RF400/RF410/RF415 Spread Spectrum Radio/Modem - Manual (Page 78)

Appendix K. RF400/RF410 Pass/Fail Tests
K-6
FIGURE K-3. 3 dBd 900 MHz Collinear Omni Antenna
(d) Set up remote RF400/RF410 with NO antenna and with antenna
connector 20 inches above floor.
(e) Arrange antenna distance apart according to following table.
TABLE K-1. 900 MHz Gain Antenna Test Distances
Antenna Gain
Over ¼ Wave
Power Ratio
vs. ¼ Wave
Distance Apart*
( Ratio Power ft. 5
× )
9 dBd 11.2 dB 13.18 18 ft.
6 dBd 8.2 dB 6.61 13 ft.
3 dBd 5.2 dB 3.31 9 ft.
-2.2 dBd 0 dB 1.0 5 ft.
* This assumes a signal strength vs. distance relationship of 1/d
2
(f) Type 8 groups of 5 characters on the terminal (aaaaabbbbbccccc etc.)
(g) 100% of characters should appear on screen with good yagi/collinear
antenna.
(h) Removing yagi/collinear antenna, you should get no echoed
characters.