Aboard a cruise ship

Nothing specific to that potential use I can cite, given we were talking about what was possible, not necessarily what happened given the lack of hard evidence in any specific direction; there have been reports of jamming under other circumstances aboard or near cruise ships or their ports. There have been reports of widespread use, whatever their legality, in theaters overseas after the idea being shot down in the US despite requests from the industry to allow it. And they are widely available. I would post a link, but don’t want to help their business. If curious, Google “jammer store” and if you want to jam it, they probably have it.

From a gov’t briefing on the issue in the US, with several instances of maritime use that certainly raises the possibility of jammer use, not necessarily by the ship itself: https://www.gps.gov/multimedia/presentations/2017/02/COPUOS/hamilton.txt

As that report noted, jammers tend to be dirty and indiscriminate, reason they are also illegal, so they don’t need to be oriented toward a specific band or service to cause problems for services like the goTenna supplies.

Another possibility is jammer use against drones: https://forum.dji.com/thread-35974-1-1.html

Speculative, too, but the comments about radar in that thread raise another possibility for the source. Lots of things like that on a ship. But they also run wifi and given the number of complaints about overcharging for such services, seem to wanna run their own game in providing cell connectivity at a price that they wouldn’t want to interfere with.

Yes, illegal many places, but also used where illegal for many reasons, including documented incidents of use by individuals who simply think people spend too much time yakking on their phones. But it could be any one among a lot of things, as my 3 decades of radio monitoring experience suggests to me. The one place where such use would be reliably legal actually would be in international waters, which could account for the lack of formal complaints there along with no relevant reporting or enforcement agency unlike in domestic waters.

I’ll take a better look at what you posted. Perhaps we can discuss this somewhere else like DM or in a separate thread later if you are interested.

I don’t want to completely hijack the topic.

Yeah, I don’t want to focus on this, but it’s worthwhile that people have a means to evaluate potential interference on something like a cruise ship, which spew RF all across the band plan. A more general thread about interference could be useful.

My experience with goTenna is pretty limited yet, so I’m not really in a position to assess how susceptible this mode is to potential interference. I suspect the mode chose and it’s efficient use of it tends to minimize ta itMaybe a thread on that could be useful, as there’s almost always a solution or time will fix it, so don’t get discouraged.

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@bbwr10coqsm goTenna Mesh does incorporate techniques such as listen before talk, to work around interference. These features work well with common interference sources such as 900 MHz walkie talkies, cordless phones etc.
I feel what you experienced in the theater is probably because of the ships construction. Cruise ships these days are made up pre-assembled metal boxes (think containers).

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Good hint about airplane mode and tower seeking sucking battery. It sure does.

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Sharing some other cruise ship related reports from elsewhere on Mesh Community:

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Yes that’s true and it’s a pretty amazing process.

Good diagram and thanks for the post to remind us that interference does happen, but it’s relatively rare and can usually be mitigated. These ships are all truly different, so does their potential to affect reception by the users of electronic devices.

Interference can also result from a maintenance problem or equipment failure. If there is a problem on one cruise, the next could be fine once something gets fixed.

This does bring up something not yet mentioned, but which may bring results better than any official complaint would. Mention your problem to the crew. They may know a solution. They’d usually welcome a tip about something that causes passenger dissatisfaction, even more so if it leads them to discover a problem with their equipment. And if jammers were actually in use, hearing complaints about the effects might lead to reconsideration of such a policy.

Particularly with UHF, small changes in location or radio orientation can make a big difference with both ordinary reception and interference and those are easy to adjust.

Another things that may work is to use an extra goTenna as a relay, placing it in the window if you have one will work even if you don’t have a balcony or other outside space. This unit will be much more likely to catch signals in a difficult environment, then can relay the signal to users within the cabin. Relays don’t have to cover large distances to be useful.

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Yep, as a professional sailor on large Navy and commercial ships I can attest to the sturdy construction of the ships hull. It blocks rf very well. I don’t think the theater was using a blocker?

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Odds are they weren’t, but it’s a possibility. It’s the fact that these are jammers are used overseas in theaters and that they had no problems other than there and within the staterooms (dense construction). But without knowing the construction of the theater, hard to say. They do tend to be all enclosed without windows, which certainly attenuates a radio signal within a ship’s hull.

What would tell the tale would be to have the appropriate scanners to search for any jamming signals, which should be present and obvious if it is present. The same thing applies whenever interference is actually the problem, rather than simply poor or nonexistent signal reception. This is triceier now that so much is digital, but a jammer tends to have a continuous signal in the case of all but the most sophisticated jammers.

I used them on a cruise ship in Alaska in the fall with my grandparents (ha!) and they worked great. Wasn’t a big ship so worked pretty much anywhere, any deck to any other deck, with the exception of inner cabins.

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Heading out on NCL Dawn in March. I have 8 units I will bring with me. Three will be dedicated stateroom relay units. (NCL likes to unplug your devices when they clean the rooms, so I will have to see what I can do about that). The other 5 will be on people out and about on the ship, and at the ports. I’ll do up a detailed post of the trip and my experiences when I return.

The three staterooms are spread out pretty good, but only one is a balcony. The other two are outside rooms, but with windows only. The balcony room is towards the front of the ship upper decks, and the other two are midway, and towards the back.

Any thoughts?

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The GTM will run for around 24 hours on its internal battery. the relay units can just be plugged back in when you return. They should stay on in the meantime so long as you leave them on when you leave.

I’d McGuyver a way to attach a relay to the balcony. Try to get it as far out as possible. For the rooms with only a window view, try to have them in the window or as close to it as possible. You could even tape them to the window. Try to place them upright as much as possible to keep the transmission wave polarity alike.

Happy cruising!

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OI had the same idea just last week and bought a two-pack fast shipped home that arrived just in time to take it with. I goat-roped my niece into testing out the mesh network with me and we were both impressed. On board the Carnival Sensation with two nodes we had a range of about one third of the ship if the signal had to travel between decks or all the way across if we were both outside our staterooms. Ship-to-shore comms were solid as long as we didn’t have too much obstruction. We did quite well with only two nodes and what problems we had we were able to chalk up to that fact. We just got back yesterday.

I told the rest of my family that even if they didn’t use the device, they could carry a relay with them just to help. We’re planning on using it again on our next cruise, but I have other applications to use it for as well.

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Two units went at least this far. :slight_smile:

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Awesome pic and darn fine performance, I’d say.

Just guessing, somewhere around 1/2 mile, maybe a little more? it’s a big ship! Was the ship unit on the shore side or on the away side?

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The ship unit was shoreside aft, somewhat canted away. It kept working until I went deeper ashore amid thick shrubs and trees and pavilions. A relay somewhere on the beach would have been helpful, but I was satisfied with the performance given where we were and the time we had.

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Awesome work! Thanks for sharing.

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I did a cruise on the Celebrity Infinity last week.

The gotennas would not work from our stateroom on the third floor to the restaurant on 10. If we were both out of the room, you could get better range.

There is a library and computer room on 7/8 midship that might be a good place for a relay GTM.

Something to try next time.

I got no responses to shouts, unfortunately.

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I used 2 units on a recent Carnival Cruise. Some dead spots on board but had good range when we were both on outer decks. I suspect that with more units on board the relay function will increase coverage. I have just purchased 2 more and will see if there is any improvement on my next cruise.

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