P4 and USB WiFi Extender Question.

[Wolfvaine]

Hi All,

I was wondering if it is possible to use a wifi extender powered by a USB power pack as a portable boost for the drone? I here of some people being able to get them setup and using the them on other DJI drone models other than the P4 series. If the question was asked already or answered already sorry new to the site and thought I would ask for some assistance as I do have the gold dishes that go over the antenna but do nothing more than look like crap and a waste of $20. Just keep imagining some Chinese guy laughing in a room somewhere in China saying "Sucker born every minute!"

Thanks for any help or direction of where to look and proceed to. I know heard tells that the opensource for the drone can be modified and also that the controller can have its wifi chip replaced or upgraded to buit that all voids warranty for the newer drones but since my has passed the manufacture warranty this is no longer a concern for me to modify the controller.

Thank again for the assist.

 

[wa5tef]

Well Wolfvaine, it seems that you are wanting to boast the signal beyond legal power limits as allowed by the FCC! Also, you are probably using the "gold dishes" wrong because they do work very well. in fact, with my Phantom 4, I can nearly double the range and foliage penetration with compared to the stock antennas. To be clear, you must point the reflected signal towards the drone and the reflectors must be mounted properly, as in the correct distance from the stock antennas and aligned straight! I believe if you try them again, using these directions, you will notice quite a bit of difference!

Good luck,
Jim
WA5TEF.

 

[Wolfvaine]

Well Wolfvaine, it seems that you are wanting to boast the signal beyond legal power limits as allowed by the FCC! Also, you are probably using the "gold dishes" wrong because they do work very well. in fact, with my Phantom 4, I can nearly double the range and foliage penetration with compared to the stock antennas. To be clear, you must point the reflected signal towards the drone and the reflectors must be mounted properly, as in the correct distance from the stock antennas and aligned straight! I believe if you try them again, using these directions, you will notice quite a bit of difference!

Good luck,
Jim
WA5TEF.

Hi Jim
Yea have purchased them from Best Buy. There is a slotted hole which slides on first to the antennas and the dish is open to the top of the antenna. Modified this cause they would flop around on the antenna so took a paper clip and put it through the top pin hole to the top of the antenna to stabilize the antennas to the center and upright. The WiFi boost doesn’t violate any of the FCC regulations for signal boost in the ISN under the 2.4ghz or the 5.0ghz bands . The extender would not work to reach their claimed 5 mile desert range. It would only work in urban areas where the area has heavy interference from other WiFi units / routers. Made sure to stay compliant on the FCC rules because of who the neighbors are . LOL

 

[wa5tef]

OK, that paper clip could be your problem. At these frequencies, a short piece of metal such as that, assuming it is metal, can act as a sort of antenna, that might either increase or decrease the Effective Radiated Power. Mine that I got from Amazon 18 months ago, have two holes, one exactly fits the slightly rounded bottom of the antenna and the top fits closely to the slot of the top of the stock antenna. These two holes keeps the reflectors properly aligned. I flew my Phantom 5 out to 7,500 feet at 390 feet altitude and with the reflectors pointed at the drone, had a full 100% signal on both telemetry an video, using Litchi. When I hovered the drone and kept its orientation fixed, I moved the reflector direction left and right of center and at any point other than directly on, the signal dropped dramatically. When pointed away, it promptly disconnected with 11% video and 0% data. Then with the reflectors removed and using only the stock antennas, properly spaced and positioned, the signal dropped to around 60% on telemetry and about 45% on video. I promptly replaced the reflectors and flew it home, satisfied how well they worked for me.

Also, you mentioned WIFI interference. I currently run a wireless internet business from my ham shack, using my 110 foot ham radio antenna to receive 5.8 GHz feed of the internet signal and three 2.4 GHz sector antennas to broadcast the signal to my area customers. These signals are fairly directional at about a 60 degree beam path so stronger than your standard WIFI signal from a router. I have experienced no interference what so ever from either the 2.4 or 5.8 GHz transmitters. I frequently fly the Phantom right in front of the antennas either inspecting my ham antennas or even hanging a parachute cord with which is used to pull up heavier wire antennas. I even made such a flight yesterday and the Phantom, with its frequency hopping technology did not notice any external signals! The first few flights several months ago were scary as I expected the worst possible outcome but nothing happened. One of these flights can be seen at this link:

Anyway, keep trying those reflectors as they do work, very well also!

Good luck,
Jim
WA5TEF

 

[WetDog]

What you can do is to remove the standard antennas, replace them with SMA connectors and then attach those to one of many 2.4 GHz after market directional antennas. You gain signal at the expense of beam width so pointing the antenna carefully is very important and this can be annoying / difficult in many situations. You can even attach 2.4 GHz 'wifi' antenna amps to the antenna.

It takes some bit of DIY skill and is technically NOT legal unless you are a licensed amateur radio operator - and then only on Channel 13 (IIRC). It is unlikely that the FCC attack drones would ever find you but if Something Happened during a flight with a non standard rig, there might be consequences.

Being an amateur radio operator and someone who likes to play around with wires, I, of course, did this. Works like a treat. Except I hardly use the rig. It's clumsy and big and doesn't give all that much more capability than the 'windsurfer' (gold foil / semi parabolic reflectors) that you can pick up for $20. Yes you can fly out to the netherlands and back, but then what do you do? Fly right back? I like to loiter and take video so full on distance is less of an issue. I do find it useful to blast through trees since these large columns of water tend to absorb microwaves.

If your gold foil antenna didn't help, perhaps try another one. Although the ones I've seen all look pretty much the same, it doesn't take much misalignment to make them essentially useless.

All and all the DJI antennas are a nice compromise between power and ease of use. All antennas are compromises so you have to pick what's important to you.

 

[wa5tef]

Wet dog, can you be more specific? How are Hams able to legally modify the WiFi equipment to exceed the one watt ERP limit? I’m not familiar with it.
Thanks
Jim
WA5TEF.

 

[WetDog]

Channel 13 (IIRC, too lazy to look it up, but it's a single channel in the 2.4 GHz band) is a secondary authorization for amateur use. So, as long as you stay within EIRP for the band - which might be as high as 100W since some of the satellite comms are here) and you follow the usual good behavior rules of a secondary user, you are free to use different antenna / amplifier combos - again, following all of the other FCC radiation limits and assorted rules.

Primary users on that band are industrial microwave so I don't think the little drones are in danger of creating much havoc, radio wise.

The technical details are around here in various threads. Basically, you pull apart the RC, remove the antennas, switch to SMA connectors (there are, or were, kits to do this with the correct connectors, they're industry standard but when you start looking around there are approximately six dozen tiny little GHz connectors available). Create or buy a patch or helical antenna (for extra points use the formulas in the ARRL Antenna book), optionally use some bog-standard (and bog-illegal for most everyone) WiFi amplifiers (Sunhaus or similar), hook everything up and go.

For even more fun and practice soldering tiny little GHz connectors, put some SMC connectors back on the original DJI antennas so you can have it both ways.

The patch antennas work incredibly well. Of course, what you gain in dB you lose in dispersion pattern and the 15 dB antenna that is pretty common has a pretty narrow beam width. That may or may not be a big deal depending on just exactly how you are flying.

Like I've said before, I have this complex patch antenna / amplifier that I built - mostly because I could - but don't use it all that much because it's a clunk to set up. The 'Windsurfer' antennas get you about 70% there for almost non of the hassle. Of course, they aren't strictly legal either.

To everyone else:

You are not supposed to modify antennas / amplifiers / anything to do with the radio communications (hear that folks?). Doing so makes all that hard work that DJI did to get FCC certification moot.

Of course, the FCC can't chase down everybody with a modded drone (or Wifi) antenna. Even your basic cantenna violates FCC rules. However, if Something Were To Happen that involved the drone and the authorities notified the FCC and the FCC could be bothered to come out and do something, you might get a stern letter or something. Do something spectacular and they might try to make an example of you. Typically FCC violations are treated by fines and loss of frequency privileges. And lawyer fees, of course.

73
KL1SA