Trident topside unit wifi channel & using multiple Tridents in one location

I’m hoping to gain some insight into a problem I’m having using multiple Tridents in one location. I do marine education outreach programs and we would like to have two Tridents set up at one table to show the live feeds on two monitors. I have attempted this and I believe that both wifi topside units are using the same frequency to transmit the live feed. Only one of the Tridents will connect fully (showing the 3 green lights) and show the live feed. The Trident that will not connect shows only 2 green lights. If I have the Tridents setup about 150 feet apart along the dock I do not experience this issue at all.

Do you all have any solutions in mind? I was thinking maybe the wifi could be set to different frequencies somehow.

After getting some info from my friend Bill, I’ve learned that it seems like his Trident stays on channel 1 no matter what even after forcing his home WIFI to channel 1. His impression of the way most WiFi APs would behave is to try to use a channel not being used, or with signals with a
small signal strength. This is why we find it surprising that the Trident wifi signal is not changing to a clear frequency band.

Info from Bill:

"I’m not aware of a way to specify the WiFi channel that the TSAP uses.
Mine came up on channel 1. Maybe someone on the forum would know, but
I don’t recall it being mentioned.

I forced my LAN WiFi AP to channel 1, and the TSAP still used channel

  1. There were no signals on the other channels. I thought most WiFi
    APs would try to use a channel not being used, or with signals with a
    small signal strength.

I use the Wifi Analyzer Android app from farproc (with ads) to see
what channels are being used. The WiFi Analyzer app by olgor.com has
better reviews.

The recommended channels to use on 2.4 Ghz are Channel 1, 6 & 11 since
these channels do not overlap into each other."

Does anyone on the forum know of a way to change wifi channels on the Trident so I can use two units at the same table?

Thank you very much.

Matt

Unfortunately, it is absolutely impossible to control two Trident from one tablet. It is impossible for many reasons at the same time, and the WiFi channel is not the main thing. It is possible to connect multiple tablets to one Trident, but that’s not a good idea either (low channel speed from Trident to Topside Buoy).

Thank you for that information. I don’t think I was that clear on my post. I would have both Tridents connected to their own individual control tablets while in the same location.

I do have some new information to report after testing at the dive location yesterday. One of the Tridents is connecting at the 2.4Ghz band and the other is connecting on 5Ghz. The one on 5Ghz seems to be impacted by other wifi networks in the vicinity. My inclination is that it is outside interference causing my issues. That being said, if there is a way to change wifi channels on the topside unit it would be very useful to get on a more clear channel in any given location.

Just wanted to throw in some additional information here. While there might be WiFi interference, the symptoms you are mentioning also sounds like Homeplug interference. The OpenROV kits + Trident all use the Homeplug standard (and many other vehicle manufacturers also adopted it). One issue that exists with cross-talk between tethers. Here is an older post that describes it in a little bit of detail.

This was something we ran into issues with for the Trident production line (since we had many vehicles on and in close proximity to one another). In order to solve this we had to mux together the signals at the Homeplug (the tether) level and then have a router that assigned all the IP addresses for connected vehicles. That said, because of the power travelling up the tether to power the topeside, we had to make custom boards to do the breakout to make sure that the DC power was not coupled together between the vehicles.

The simplest solution, and the most reliable one that I have found to work for multiple vehicles, is to have each tether and topside about 5m apart. As long as you keep the vehicles+tethers+topsides separate then having the tablets on the same table should be fine. For the vehicles and tethers underwater, they can be closer, but if you have the tethers get tangled/cross underwater, you will probably see the same issue again.

You can try setting up a different WiFi channel on the Topside buoy.

To access Topside Buoy interface we need to reset the password.
Download the archive https://orov.jfrog.io/artifactory/orov-deb-public/pool/main/topside-openwrt-image_18.06.2-8_all.deb.
Then extract the file upgrade-topside.sh from it.
Inside this file you will find an ssh key which will give us access to root:
ssh -oStrictHostKeyChecking=no -i key root@10.1.1.1.
Then set a new password with the passwd command.
After rebooting Topside buoy, you will be able to access the Topside buoy web interface at http://10.1.1.1

Thank you for this great info! I will give all these ideas a try and report back soon.