Discuss: Cheap FM RDF Tracker for locating downed bird

[CapnBob]

Going back to my early days in FM, we used to play around with these.
It seems to me it should be eminently doable to put together a basic RDF system that doesn't need GPS or Cell Signals.
It wouldn't be long range, but might be useful within that "last" 1/4 to 1/2 mile.

Using a small, self-powered FM transmitter, a simple wire antenna could be run around the landing struts on the bird.



Then, a T.D.O.A. (Time-Difference-Of-Arrival) detector. like the "HANDI-Finder" connected to an FM receiver could be used to home in on the FM carrier.



The HANDI-Finder Kit is $28, and the Transmitter could probably be built for half that.



Transmitter Instructable: http://www.instructables.com/id/The-Ult ... ansmitter/

HANDI-Finder page: http://www.handi-finder.com/


Thoughts?

 

[CapnBob]

Re: Discussion: Cheap FM RDF for locating downed bird

...Or this

http://www.instructables.com/id/433-MHz ... io-beacon/

 

[happydays]

Re: Discussion: Cheap FM RDF for locating downed bird

Would it have to use a 9v battery? I'm no electronics expert, but surely things have advanced and a system like this could be powered by lower voltage and therefore have lighter batteries? Then again, maybe not.

 

[CapnBob]

No doubt, Connor.
This is just the inception of the concept, and attempting to getting a discussion started. I'm sure with some digging, we could refine it quite a bit.
My original thought process was the limitations of GPS (upside-down crash= no sats), and areas where there is no cell service.
This requires neither.

 

[happydays]

Well then, I'm all in favour!