Hi people,

I'm new here, and I have a bit special requirement:
I have a DJI drone and I'm using another drone (ArDrone v1) electronics to have live video while flying. I want to improve the range as much as possible, so I bought a TP-Link WR841ND v9.1 because it's DD-WRT and OpenWRT compatible, and because I can change antennas if needed (and also comes with two 5dBi). The idea is to use this router in the field, powered by a battery pack, as a repeater to improve the range. I've done already 3 things with the router:

I used the stock firmware, and it wasn't bad, but I had stability problems, specially to reconnect when the signal is lost and I return home (it should reconnect by itself).

I used DD-WRT, and it was relatively easy to setup, but it works flawlessly. The problem here is the range: it's worse.

I also tried with OpenWRT. It looks nice, and some people in the DD-WRT forum say that OpenWRT has better range, but it's really difficult to me to understand and setup. I didn't manage to configure it properly to get it working. I'm using the web browser to try to set it up following the tabs and menus, but it doesn't work. I've tried to follow the instructions I found in the wiki, but they are meant for the command line, and seem to be difficult to understand/follow. Am I missing anything? Is there somewhere else where I can get help to get this working with OpenWRT?

I've also bought one 8dBi antenna and a small panel antenna, and I've tried all combinations (2x5dBi, 1x5dBi+1x8dBi, 1x5dBi+panel, 1x8dBi+panel), all with similar results, whichs seems to me that the antennas are being underused or not enough powered (maybe some energy saving feature). Any tips?

Thanks in advance

I don't have any direct help to your questions...

But have you thought about using a RaspberryPI with a good USB wireless adapter (and a good and BIG detachable antenna)?

There is also an Arduino with a MIPS processor capable of running OpenWRT...

I'm still going to put my hands on an Arduino, it's the easiest thing to program and project things.

I don't know if you are a programmer or are just trying to acomplish a simple thing with some urgency...

Sorry for my bad english

Does your drone have 2 antennas? I don't think so.
Both antennas should be identical, there are 2 different streams coming from them and both streams are required.
Play with diversity, you can disable diversity and disable an antennae.
Put that BIG ASS antennae to your drone, the communication is bidirectional, WiFi 1.0.1.

(Last edited by Nilfred on 1 Mar 2015, 06:16)

Hi,

Thanks both for your answers. In the drone side, I'm using the mainboard from the ArDrone, which includes the antennas printed on the board. That makes it very difficult to upgrade that side.

So my only way is to improve the ground side as much as I can . I tried with DDWRT to change the antenna mode from 1+2 to 1, for each antenna, and the results where even worse. Now I installed again OpenWRT to give it another chance, and see if this time I could manage to make it work. No luck . I don't consider right now the Raspberry option because it complexity right now. I'll only take that way if I see no other solution, but I would like to be able to use OpenWRT at least one time

The ArDrone is on 192.168.1.1, and it acts as an AP, without password, with DHCP server, so it assigns a dynamic IP to the clients that connect to it.
I usually set the repeater router using Lucy as:

IP 192.168.1.2
subnet 255.255.255.0
Router: 192.168.1.1
DNS: 192.168.1.1

Then, I go to Network -> Interfaces, and delete the two WAN interfaces, just to minimize chances of weird things, but I've also tried letting them there.

Then, I go to Network -> WIFI, and there, I use Scan button, and I join the ArDrone network, so it automatically replaces the setup with the drone's one, as client. When I go to the setup screen, it's also called (wlan0) in the title.

Then, I create a second WIFI network as master called Ardrone_EXTENDER, so I'm sure that my phone connects through the router, and not directly to the drone. This one is called (wlan0-1) inside the setup menu title.

As OpenWRT creates a second Network interface called WWAN, I check the boxes in the setup screen for both WIFI networks, to be part of WWAN interface. I've tried also checking LAN, without success.

Then, back to Network -> Interfaces, I edit LAN, and check 'Disable DHCP for this interface.', because if it works, I have a double DHCP server, and is not the Ardrone who assigns it.

Also, in the same window, in the Physical settings tab, within Interfaces, I check the boxes for Ethernet Adapter: "eth0" (lan) and the two WIFI Networks, so they can see each other, right?

And for Firewall, I set everything in LAN firewall-zone, so that minimized the chances of the firewall blocking communications.

Am I missing anything?