P3P Max distance - RC vs. Healthy Drones

WetDog · Nov 19, 2015

In my local terrain (125+ foot tall Spruce / Hemlock forest) I am getting roughly 1500 - 1700 feet of range before the RC starts to complain of poor video signal and, on occasion, poor RC signal. The screen video does break up, indicating to me that signal is indeed degrading.

This is on a stock P3P with the antennas parallel to each other and as perpendicular as possible to the drone.

Looking at the flights on healthydrones shows the 'minor signal errors' to increase to the 50's but staying in the 'green' region. There seems to be a disconnect from what the aircraft is seeing and what the website is reporting. Is that a typical pattern?

bobmyers · Nov 19, 2015

The stock signal strength is related to Line of Sight-- If you are flying from a clearing and your altitude is such that the LOS from the Controller to the P3 is unobstructed then the signal should be good.. If additional distance puts the tops of the trees in the LOS, the signal will degrade.

WetDog · Nov 19, 2015

True enough and that is what I expected. However, the healthy drones interpretation seems to say that the signal was 'good'.

Meta4 · Nov 19, 2015

WetDog said:
This is on a stock P3P with the antennas parallel to each other and as perpendicular as possible to the drone.

Not sure if it's what you're doing or you just didn't word it right.
You want to have the RC antennas as close as possible to parallel with the upright legs of your Phantom.
If you have them perpendicular, that is going to reduce signal strength.

III% Streve · Nov 19, 2015

And again... Healthydrones is really nothing but a novelty. Look at the logs! They are the only source for the real story! Your loosing video signal alone tells you that your signal obviously WASN"T "good"!!

RF Guy · Nov 19, 2015

2.4ghz RF is eaten by trees. (microwave radio signals as used by the Phantom) It's the water absorbing it.
Clear and un-obstructed signal path will yield excellent distance (maybe 5000 ft)....but please know that beyond eyeball distances, you are running the risk of loosing your quad. It's not a long-haul industrial drone. The skies are FULL of RF signals these days. Licensed / un-licensed ... just a thick soup of radio signals in all directions and frequencies. I work in this spectrum marmalade every day. I'm intimately familiar with signal propagation, antennas and microwaves. I personally will NEVER fly my Phantom out of eyesight range. I'm not that rich. What you can't see - can hurt you in this case.

ovyyus · Nov 19, 2015

RF Guy said:
I personally will NEVER fly my Phantom out of eyesight range...

I often fly my P3P out of eyesight range, but I always maintain a direct line of sight between bird and controller.

WetDog · Nov 21, 2015

Meta4 said:
Not sure if it's what you're doing or you just didn't word it right.
You want to have the RC antennas as close as possible to parallel with the upright legs of your Phantom.
If you have them perpendicular, that is going to reduce signal strength.

Yah, that's what I meant. SOME parts of the unit are perpendicular to some parts of the drone, but it wasn't worded quite right....

WetDog · Nov 21, 2015

III% Streve said:
And again... Healthydrones is really nothing but a novelty. Look at the logs! They are the only source for the real story! Your loosing video signal alone tells you that your signal obviously WASN"T "good"!!

I guess this is my point. You can actually see the signal go down in the logs and in the healthydrones graphic, but it stays 'green'. I just wanted to make sure I wasn't missing something obvious.

Shammyh · Nov 21, 2015

WetDog said:
I guess this is my point. You can actually see the signal go down in the logs and in the healthydrones graphic, but it stays 'green'. I just wanted to make sure I wasn't missing something obvious.

You are missing something subtle, so perhaps not obvious.

The "signal indicator" from the app/controller is not logged. Healthy drones instead uses a function of time, and sees how many packets are missing over a given fixed period of time. Aka, take the first minute. I (healthy drones) know I should receive 100 packets of data per minute, as this rate is predictable and fixed. I know I did actually only receive 90, therfore, I know my link quality is degraded by 10%.

So, for the signal quality to start "degrading" in terms of healthy drones reporting, you'll need to actually start losing packets from the UAS.

Its not super super precise, but it my own experience it is broadly accurate.

WetDog · Nov 21, 2015

Interesting, thanks. Still, the (questionably significant) matter of healthydrones reporting the loss as 'green' (OK) when the video drops out. Seems odd.

III% Streve · Nov 21, 2015

Stop looking at HealthyDrones. Its not anything special. As far as I know, it is looking at controller signal, and NOT video signal. So having a fullt controller signal will obviously have no bearing on your having a weak video signal!

steelrotors · Nov 21, 2015

Hey guys. I consistently get about 3000 meters or 9000 feet across open fields by tilting the antennas straight back and resting them on he back of my iPad air2. It seems like it acts as a reflector and I do have to fiddle with the angle of the controller/ipad to get the sweet spot. I've been 2km across on lakes chasing water skiing buddies and never even flickered.