Here’s the results of the small 1/4-wave antenna we ordered from digikey (ANT-2.4-CW-RH-SMA-ND). We went with a power level 7 on channel 26. The antenna is about 1″ long (probably the dipole is coiled inside that area). For this test, it was pointed straight downward. The antenna looks like this:
The boxplot suggests that this won’t work for us.
The results look pretty good at the top height (.1m down from the transmitter), but are all over the place for the lower heights except for the last one. This pattern is consistent with a broadcast pattern that follows a narrow vertical angle of perhaps 30 degrees perpendicular to the main axis of the antenna.
That’s a shame, because it would have made a great solution for us, if it had worked.
[...] Quarter Wave Antenna, verticalVertical small antenna through SMA connector. Fully crossed 2 heights, 4 distances, 10 angles. Power level 7. Conclusion. Works well at the high heights, clear distinction. However, lower motes couldn’t get the signal. Probably the signal pattern cuts them out. [...]
Pingback by State of the Antenna Analysis « Hand Hygiene — October 22, 2009 @ 6:07 pm