Page 263 - Build Your Own Quadcopter_ Power Up Your Designs with the Parallax Elev-8

242 Bu il d Y o ur O w n Q u a d c o p t e r

The environment is either indoors or outdoors. I selected the outdoor environment,
since that is the area where I will usually operate the Elev-8. In addition, I will try to always
have the quadcopter in my line of sight, since that also maximizes the range.
The second factor is related to the specific WiFi protocol that is to be used. The common
protocols are IEEE 802.11a/b/g/n. The Hero 3 WiFi uses the Artheros AR6233 chip that
supports all the common a/b/g/n protocols. The Android tablet I chose for the test has a “b”
WiFi, which means that the maximum range is no more than 140 m (153.11 yd).
The last factor deals with the effective power radiated from the GoPro WiFi transmitter.
This is impossible to know unless you dissect a GoPro, which is exactly what somebody did.
Go to the website http://www.ifixit.com/Teardown/GoPro+Hero3+Teardown/12457/1
and see how the folks at iFixIt tore apart a Hero 3 Black Edition.
The actual test was very simple. I set the GoPro on a tripod in my back meadow and
established a WiFi connection with an Android tablet that was running the free GoPro app.
I clicked on real-time preview and saw myself on the tablet screen. I then moved away from
the camera until I lost contact. This happened at about 100 m (109.36 yd) from the camera
and tripod setup. This test was direct line of sight. I next walked back toward the setup to
reestablish the communications link, which occurred at 100 m (109.36 yd). I took a picture at
this point, which is shown in Figure 9.17.
I circled myself in the photo because it is very difficult to discern any details at that
distance. I then walked 50 m (54.68 yd) toward the setup and took another picture, which is
shown in Figure 9.18. This figure confirms both reliable communications at the maximum
distance that I will be flying the Elev-8 and the maximum detail I could expect to see on the
ground. Notice that I had to circle myself in the figure again, since it is still difficult to pick
out distinct objects.

Figure 9.17 The 100-m (109.36-yd) range check.