Hi Mates!
I was replacing the shell of my Phantom 3 advanced and accidentally tore up one of the 4 antenna receivers (near the compass) from the Quadcopter.  Notice it was Antenna Number 4 (check picture attached).  What ids the main function of this?  Will it be safe to fly?  I was waiting for my order but it may arrive sometime May here in the Philippines.    Your inputs are highly welcome.  Thank you!

I assume you are telling us the cable broke at the point with the red circle.

My understanding is that two of those antennas are for control and two are for FPV.  The two for control would be receiving antennas.  The two for FPV would be bi-directional, that is, transmitting and receiving antennas.  I don't know which are which though.  If we assume your broken cable is for the antenna that is bi-directional, there is somewhat of a risk of burning out the FPV transmitter.  The RF energy will move down the cable, and since there is no antenna, it will behave as if the cable is the antenna.  The problem is the cable won't be the correct length for a 2.4 ghz wave, so the RF energy won't leave the cable efficiently.  Some of it will emit from the cable, and the rest will go back up the cable to the transmitter which would cause it to heat up.  If it gets hot enough, it could burn out.   Or it might not.  

If it's a receiving antenna, it won't hurt anything other than you'll have a seemingly weaker control signal.  

MHO

Hi Mark,

Thanks for the inputs.  It is a receiver antenna location on the landing skid of the Phantom 3.  I was about to do a test flight tomorrow but am afraid it might give me weak signal and cause a disconnection.  Anyway let's hear it from the other experts out there!.

Thanks!

Dehner

dehner Posted at 2017-4-1 06:38
Hi Mark,

Thanks for the inputs.  It is a receiver antenna location on the landing skid of the Phantom 3.  I was about to do a test flight tomorrow but am afraid it might give me weak signal and cause a disconnection.  Anyway let's hear it from the other experts out there!.

If you have your Home Point set properly, it should switch to RTH mode and come back even with a disconnected transmitter (you can turn your RC off and it will come home, but I don't recommend this). If research doesn't provide an answer as to which kind of antenna it is, flying it might be the best way to tell. Of course you can send it in....

Good luck!    Barney

If it were me, I would replace the antenna. It wouldn't be worth having the potential range issue.

As you're not sure of the actual service this antenna performs it would be wise not to fly the aircraft until its back to a serviceable condition. An antenna at the wrong length for its intended band affects its swr( standing wave ratio), not so critical for receiving, but transmitting through this broken antenna like as already been stated, could cause feed back into the circuits and cause more problems than you've already got. Flying with a known fault is bad practice my friend and can only end in tears. Be patient, make a sound repair and enjoy your flying .

Well stated Johnnyrebel! Safety First! Ken

Thanks for the inputs! I did test it the P3 (on a vast field) with Max range of 2km and it worked flawlessly.  It was a risk but hands down to DJI for the quality since it flew pretty well with one less antenna.  But now that I have the antenna replacement  I'm more confident in flying this quadcopter.    Will install it soon.