What would be a middle of the road antennal upgrade for the 915 mhz 3D robotics telemetry? I ordered a 21 cm [ larger ] pole antenna for the plane. If I got this http://www.ebay.com/itm/Ramsey-LPY9-Logi-Log-Periodic-PCB-Antenna-915-MHz-/360283780191?pt=US_Networking_Boosters_Extenders_Antennas&hash=item53e296345f for the ground end would it loose all signal if I flew behind it even if I was still within 1000 feet? I primarily always want to fly long range the same direction, so I could aim it that direction, but I just don't understand just how directional these antennas are. Does 30-40 degrees mean all is lost out of that range even within site say 1000 feet? Thanks
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This log periodic antenna has a least a 6 db front to back ratio. Each 3 db gain or loss is equal to doubling or halving the effective signal. This is what gives it directionality which may be a good thing if your turning the antenna to always point home from the drone or at the drone from home. Using like antennas in terms of polarity is always good. A beam width of 30 to 40 degress is ok if you're only flying in one direction, you have a few 1000 feet wide beam at a mile away. If you're not turning the antenna from the home station and the drone is on the backside of the antenna and in a bank turn this creates not only the loss from the front to back ratio but a loss from loss of polarity (vertical-horizontal) becuase the drones attitude has changed. Simple dipole antennas in the same polarization for each end either vertical or horizontal would work well. Consider a dipole on each end and a 1 watt 915 data radio like the RFD 900 on each end, you'll have many miles of worry free omni-directional performance.
Geoffrey
Did this work well for extending range? My stock antenna is losing signal out at around 300 ft if I am lucky... Any other recommendations on ready made antennas for 3dr telelmetry 915 mhz? http://www.ebay.com/itm/Ramsey-LPY9-Logi-Log-Periodic-PCB-Antenna-9...