With longer antennae and more power to the transmitter, this 433 MHz transmitter/receiver pair was able to trigger the cameras on my IR/visible KAP rig from more than 500 feet away. I have not flown the rig to test this remote control system yet, just tested it on the ground in big fields. I set up the camera rig on a tripod and walked away from it pressing the button on the transmitter to signal the receiver to send a pulse to the USB ports of both cameras. In a couple of tests, the radio reception is not completely reliable past about 450 feet. I guess it could be more reliable when the receiver is aloft in the open air. So it is useful for low elevation mapping flights and pole aerial photography, but maybe not for general purpose triggering of aerial cameras unless you have only 400 feet of kite or balloon line.

I modified the antenna on both the transmitter and receiver without having any actual understanding of how antennas work or can be modified. So it might be possible for a person with real knowledge to get better results. I learned that the wavelength of a 433 MHz signal is 70 cm, and that a half-wavelength antenna should work well. I think my homemade 35 cm antennae worked better than the 11 cm antenna the transmitter came with and the tiny coil antenna on the receiver PCB. I also don’t know whether increasing the battery power to the transmitter made any difference or would be expected to.

The transmitter/receiver pair was purchased on ebay for $9.80 including shipping. Links to more information are in this previous note. A few extra photos are in the set at Flickr: https://www.flickr.com/photos/chrisfastie/sets/72157629805448178/