Campbell Scientific RF400/RF410/RF415 Spread Spectrum Radio/Modem - Manual (Page 77)

Appendix K. RF400/RF410 Pass/Fail Tests
K-5
(b) Choose an open area free of large
2
metal objects within 10 feet of the
RF400/RF410s (can be indoors or outdoors).
(c) Attach a 1/4 wave omni antenna (Item # 14310) to base
RF400/RF410
(d) Set up remote RF400/RF410 with NO antenna
(e) Separate RF400/RF410s by 5 feet
(f) Type 8 groups of 5 characters on the terminal (aaaaabbbbbccccc etc.)
(g) You should receive 100% of the characters
(h) With bad or missing ¼ wave OMNI antenna you should get few to no
characters echoed back.
1 Be careful to not exceed maximum supply voltage of 18 VDC to RF400/RF410. Use
“quiet” power supply without noise or hum (a 12V lead-acid battery is fine, if no trickle
charger is attached during the tests).
2 Examples of “large metal objects”: a steel filing cabinet; steel trim on cubicle
dividers; or steel shelving. Especially avoid such metal objects facing the
RF400/RF410s broadside. The idea is to avoid significant reflected signals because
they can add to or subtract from the direct wave signal making test results vary a lot
according to exact location. A fully absorbent rf environment with no reflections would
be ideal.
(2) TESTING YAGI or COLLINEAR ANTENNA
(a) Connect 12V power to base RF400/RF410 and remote RF400/RF410.
We recommend AC adapter Item # 15966 or a Field Power Cable
Item # 14291 connected to a 12V battery pack or 12V power supply
(see footnote 1 above).
(b) Choose an open area to conduct the tests (see footnote
2
above).
(c) Attach the yagi or collinear antenna being tested to base
RF400/RF410
(i) A yagi can be mounted on a microphone stand or similar (metal,
wood or PVC ok). Orient antenna elements vertically as shown
in figure below and adjust height so the bottoms of the elements
are 20 inches above floor. Aim yagi at remote RF400/RF410.
FIGURE K-2. Vertically Polarized 9 dBd 900 MHz Yagi
(ii) A collinear antenna should be solidly mounted in a vertical
position so that its omnidirectional “pancake” pattern is
horizontal. A metal or wooden stand can be used.