So I've seen various antenna range boosters online for the Phantom 3 Standard controller and wanted to get some feedback from people on that...are those things legitimate? My concern is that it could mess with the transmission signal/ cause the drone to go haywire. I'm not trying to fly 4 miles away or anything, but I'm curious if they actually boost the signal of the controller. Just wanna play it safe and double check before I consider buying one. Thanks

I too have a dji phantom 3 Std.  I made a very inexpensive reflector by using the template from Tom's Tech Time on You tube.  I made the reflective surface from a section cut out of a tall aluminum can and glued it to the template.  I can't honestly say it helped but I did run the quad out 1700 feet with out any loss of control or video signal. I was too chicken to run it out any further as I could barely see it at that distance.

If you don't feel like DYI-ing you can also get them readymade. These work pretty well but I'm sure all the other ones work just as well.

Thanks everyone for your input, this is all very helpful. Yeah I definitely don't wanna take mine out of LOS, but it's good just to have the extra range to prevent any loss of signal, etc.

If you were to remove the plastic shell from the stock antenna, what you would see would be a piece of coax cable that had the insulator and shield removed very close to the end,  leaving a tiny bit of the center conductor exposed.  That is what radiates the signal from the r/c.  Parabolic type range boosters work by taking this omnidirectional signal and reflecting it in more or less one direction.  The copper used in the reflectors  is mostly a gimmick.  In this application,  aluminum foil,  aluminumized mylar or similar would do just as well so long as it was wrinkle free.  The reflective qualities of aluminum and copper are quite similar in this respect.   Also,  there is no need to put the reflective surface on the face of the range booster.  It will work just as well if you attach it to the back,  or even embed it into the plastic.  The rf produced by the Phantoms r/c goes right through the plastic.  Otherwise,  the stock antennas plastic housing would prevent any signal from getting out.  For anyone interested in getting the maximum performance from any antenna system,  I recommend the ARRL antenna handbook.  It is THE definitive source of antenna theory,  design and information