Each line represents the direction from which I perceive a radio collar signal to be coming from. I've taken them at different points in the study area, represented on this map by the numbered squares. Supposedly, these lines should intersect, because the radio signals should be coming from the same place, but they don't. At all. Radio-tracking is hard here. Unlike Yellowstone, which was mostly open valley with a couple annoying hills, Turtle Island is just mountains and ravines. Radio signals bend and bounce around and off mountain walls, reflect off water, and do all sorts of weird stuff that physics tells them to do.
I have to try to figure out where the signal is coming from, if there is one. I do this by pointing an antenna and listening to a speaker playing the signal that the antenna picks up. The signal strength is evident in the volume of the beeps from the speaker. So I wave the antenna around, trying to figure out when I hear the loudest beep. This isn't easy. In addition to multiple peaks in volume from signal reflection off things, the signals here don't seem to be consistent and fade in and out, so sometimes I can't tell if I'm moving through a loud area, or the signal is just getting louder. I feel pretty hopeless right now. I didn't think I was very good at radio-tracking in Yellowstone. Even less so right here. At least the scenery is nice.
don't lose hope! i'm sure they understand the ravines and mtns throw everything out of whack.
ReplyDeletedo you know the rate at which the transimitting collar pulses out a radio signal? you should be able to refine your perception of where the signal is coming from if you can compare that with the rates of the various signals you recieve (in addition to signal strength of course). a difference in time might indicate reflection off of various structures like mountains, etc. (im basically saying use frequency in addition to amplitude.)
ReplyDeletethis is a pretty interesting problem. if you could fill me in on the details i'd be willing to do what i can to help you come up with some sort of methodology.
lol lol oh god i hate line intersections!
ReplyDeleteAh Kevin I have no doubt you were more than adequate tracking radio signals at yellowstone.
ReplyDeleteAt the very least you keep a really great blog out at turtle island, and that is worth something to us all!
good luck triangulating those big bats!
加油！！