I work with WiFi, so I have a lot of 2.4 GHz radio junk laying around. On a whim, I modded my Turnigy 9x to have an SMA connector where the antenna used to be, so that I could try out various external antennas. I really like the antenna being in that location, where it is away from my hands, the body of the radio, the metal carrying handle, and so forth. Frankly, if I ever end up getting a different module, I will probably run the coax cable out the back of the radio and put a connector on it so that I can screw it into the back of the module and keep the antenna up top. But anyway...
I put a 5 dBi dipole onto the radio. I figured that the few dB of extra range would probably be beneficial, and as long as I didn't fly with the antenna pointing directly at the plane, the reduction in coverage at the top and bottom of the elevation pattern would be moot.
I fly with the antenna sideways, to maintain polarization with the antenna in the model. I found that, at one corner of the pattern, I would consistently lose control of the model. It was a real test of my flying skills. I would be turning final and all of the sudden the model would roll like crazy. When I slammed the stick the other way, nothing would happen, and then suddenly the model would roll wildly the other way. The Bixler 2 doesn't have spectacular roll authority to begin with, and twice I had the presence of mind to use up elevator to pull out of a crazy inverted dive, instead of trying to roll out of it. No crashes were had.
At first, I thought it must be some kind of interference in that location, but then I realized that it was probably because I had my antenna pointing that direction, and that was the dead spot at the "top" of the pattern. I made a conscious effort to turn to face the plane at all times, and didn't have any more problems. When I got home, I swapped out for a 2 dBi dipole, and I hope not to have any more problems.
In the WiFi world, it's seldom the case that the orientation of a 2 or 5 dBi dipole has a significant effect on performance. This is in part because WiFi is usually indoors, and there is enough reflection that signals are not strongly directional or significantly polarized. Looks like that principle doesn't hold AT ALL for RC models. Lesson learned.
I put a 5 dBi dipole onto the radio. I figured that the few dB of extra range would probably be beneficial, and as long as I didn't fly with the antenna pointing directly at the plane, the reduction in coverage at the top and bottom of the elevation pattern would be moot.
I fly with the antenna sideways, to maintain polarization with the antenna in the model. I found that, at one corner of the pattern, I would consistently lose control of the model. It was a real test of my flying skills. I would be turning final and all of the sudden the model would roll like crazy. When I slammed the stick the other way, nothing would happen, and then suddenly the model would roll wildly the other way. The Bixler 2 doesn't have spectacular roll authority to begin with, and twice I had the presence of mind to use up elevator to pull out of a crazy inverted dive, instead of trying to roll out of it. No crashes were had.
At first, I thought it must be some kind of interference in that location, but then I realized that it was probably because I had my antenna pointing that direction, and that was the dead spot at the "top" of the pattern. I made a conscious effort to turn to face the plane at all times, and didn't have any more problems. When I got home, I swapped out for a 2 dBi dipole, and I hope not to have any more problems.
In the WiFi world, it's seldom the case that the orientation of a 2 or 5 dBi dipole has a significant effect on performance. This is in part because WiFi is usually indoors, and there is enough reflection that signals are not strongly directional or significantly polarized. Looks like that principle doesn't hold AT ALL for RC models. Lesson learned.
