I just received my Blackout edition GoTenna Mesh a couple weeks ago. I got 4 with plans to take them into the Cave where I work as the Facilities Manager and guide. I lead kayak trips on a river 200 feet underground. We’ve been fortunate so far that we’ve had no severe injuries requiring a rescue callout. Though myself and others here are perfectly capable of handling the situation, we would have to leave the group and ascend 200 vertical feet to reach the surface. Then run more than half a mile to the Visitors Center/ Gift Shop to report the injury and call out for the rescue.
Last week I successfully made contact from the bottom of the first 100 foot climb (inside the cave)to the Gift Shop using 1 device at the bottom of the shaft and 1 at the Gift Shop with 2 relay nodes strategically placed in between.
I’ve also been playing around with them along the family tour route. Unfortunately having only 4 I can’t get much further than I can with our 2-way radios. I’d really like to put these to the test while mapping the cave. I’m afraid I’ll need a whole lot more than I can ever afford to make them useful in the cave environment.
(I am open to product testing and have an influential reputation in the Caving Community, nationally and globally, as well as the National Show Cave Association. Maybe we can work something out that could benefit everyone involved)
That’s awesome!
We’ve heard from public safety using them in different underground transit systems in similar ways — leaving units near corners or obstacles so they can mesh messages that can’t get through point-to-point.
Did you take photos? 
When the firmware update expands the number of hoppable nodes between end point users (very much looking forward to that here), its going to greatly facilitate the goTenna Mesh’s usefulness in such cases.
Another big plus for this sort of goTenna use is the ~24 hour battery life (extendable with outboard backups, but no solar here 
). A tour operator could simply have guides carry in and replace the goTenna at each designated relay site each day, while picking up the depleted unit to be charged and swapped back in the next day.
GPS will probably not work, but there’s only so many places to go in a cave IF you stay with the group.
In a man made environment such as sewers and subways I could see these reaching great distances with fewer turns and curves than a natural cave. The section of cave where I lead the kayak trip is big and not too sinuous. I could probably reach the kayaks and beyond with an 8 pack. With so many commercial/show caves that offer wild cave trips I could see this as a great market for GoTenna. But like my boss, all of the National Show Cave Owners are gonna want to know that they will work in our unique environment. I did not get any photos this time but will be sure to take my camera on my next trip
The key point you made was potentially using multiple GoTennas in an emergency situation in a rather unique location. While I LOVE GoTenna, I would not want to rely upon it in a critical situation as you have described, especially if you might need to rely upon relay units which could run out of power – too many moving parts. A two-way radio might be the best in this situation. You said you tried one, but if you used a standard store bought one, their power has been limited to a mere 0.5w (now authorized to 2w) and use FRS (Family Radio Service). Many of these also have GMRS (General Mobile Radio Service), but most people don’t know/care they must be licensed (pay a fee / no test required) with the FCC to operate and is for personal use. GMRS can transmit up to 50w of power. In an emergency situation (life/death/severe injury), the FCC makes some exceptions who can operate the radio. There a vehicle mountable GMRS radios which can transmit up to 50w. You need to check legality on the use of this, but in a strictly emergency situation, you might be able to get away with its use. This operates in the 460MHz range so coverage could be adversely affected traveling through hundreds of feet of earth.
If you want to get a ball-park idea if this might work, get a couple of amateur radio operators to check reception while they operate in the 70cm band — 440MHz. All amateur radio operators are licensed to transmit in this frequency. One can be stationed in the gift shop and the other can take a ride down the river and check in with each other at different points. I bet you’d get some volunteers! Not sure if you could technically pay them for their service.
I hope my ideas might spawn other thoughts for you to check out. Please double check to ensure what I suggest is legal as it has been several years since I took my amateur radio exam.
GoTenna moderator: Thank you for allowing me to suggest something other than GoTenna for this scenario.
Here’s my take on the radio vs goTenna. The OP noted that the goTenna’s meshing extended further into the cave than than their current handhelds allow. They would have to (possibly) upgrade the radios (more power, different antennas or freqs) to exceed the coverage that the goTenna provides out of the box. Plus goTenna gives confirmation that a message was received, while all you might get from a radio is silence.
But my advice would be they really could use both. Redundancy is almost as important as capability with communications that must be depended on in an emergency. Having been listening to 11175 upper sideband shortwave on 9/11, I can confirm that but it’s a very long story…
Perhaps the best solution would be a radio system that uses a “leaky” coax to carry a signal throughout the cave, but environmental or historical considerations might preclude stringing coax through the cave. It may be a case where you make up for the potential pitfalls by running both systems.
Forget the Gotenna for a second that sounds amazing! Where are the pictures @danielagotenna asked for? I’m going to be looking this up since I have never heard of anything like it.
In a situation like a cave, one thing that Gotenna Mesh brings to the table is the easy implementation of repeaters. This is certainly also possible with voice communication systems (like GMRS). But it is neither as simple nor as cheap. Let’s face it. Basically ANYBODY can set up Gotenna nodes, and this is a BIG part of the beauty of the Mesh. Not to mention that they are small, inconspicuous, and inexpensive compared to, say, GMRS repeaters. And any Gotenna nodes could also be used by visitors to keep in contact with one another (since cell service will be nonexistent).
Another potential advantage of something like Gotenna is silence. This can be particularly important if giving tours of a cave - many people might not appreciate hearing a squawking walkie talkie as it echoes up and down the passageways of a cave.
Needless to say, I DO agree that carrying more than one communication system in a cave is a good idea. A two way radio system (whether it be GMRS, MURS, HAM, CB, or anything else) would be a smart idea in addition to Gotenna. A wired intercom system as mentioned might ultimately be the most reliable system in a cave. But as the poster here said, running cables could certainly spoil the natural ambiance.
I haven’t been back in through the Deep Darkness entrance since I made my original post. So I haven’t been able to get any photos of the GoTenna Mesh being used. But I’d be happy to share some photos/video of the trip we offer. Or you can follow our Deep Darkness Facebook page which you can find by searching @exploreindianacaverns
Thanks for sharing! How well do people with mild claustrophobia (like me) do on these excursions?
My pleasure. I apologize for the low quality of some of the photos. Cave photography is pretty tricky.
Claustrophobia, I’ve found, is a case by case condition. Every individual handles the environment in his/her own way. If your claustrophobia is “mild” as you say, it shouldn’t be an issue. The ceiling does get low for a bit and we have to retire our paddle and use our hands instead on the ceiling to navigate section of the river. The hardest part of the trip is the climb back to the surface
Big advantage to our normal canoe trips. Chance of rain is pretty low in a cave. I’ve been canoeing for years but kayaking became my new favorite activity last year.
True, but water flows downhill, then underground… They do vary in terms of the threat this poses, so having a pro caving guide is a good thing if you’re not familiar with local conditions. Hey, and it’s back home in Indiana. Too bad I’m not ten years or so younger.
I have a co-worker who is looking for caving. I told I know we have caves back home, across the state line, and I’ve even been in a few, but it’s been years. I’ll have to let him know about this.
My only experience is the Mammoth caves and I would not compare that to this.
If we could see the GID of the first fixed relay node, reasonable area from where the transmission originated within the cave could be determined based on the range from the first repeater.
Tom
I know it’s been a while but things get pretty busy around here. Today I finally got to play around a little bit in the cave. 
Great pics! That must be quite an experience. 
Gives me the chills thinking about it, because it has to be way cooler in there than above ground in southern Indiana right now.
When you get your goTenna Meshes updated, you’ll have to let us know the results. The extra hops should be a real advantage in linear network mesh systems.
It’s actually not too bad. It stays a constant 54°-56° year round. So it’s a great way to escape the summer heat or the winter cold.
Once I’ve gotten them updated I’ll try again to go even further. My furthest point of communication was 544.5 feet into the cave. Going down the first 200 feet were easy to achieve communication. Once I was in the sinuous walking river passage with all the breakdown (boulders) I had to place the nodes at nearly every bend
I was thinking of chills in the best of ways, but I think - having worked in refrigerated facilities - I like the mid-50s much better for anything other than a brief stay. It’s surprising how universal that tends to be with caves, with certain exceptions due to unique circumstances.
I think you’ll be happy with how the extra hops facilitates expanding coverage. This comment from earlier now sums up my experience. Lots of capability, little cost, and virtually zero hassle.
I took that to heart and things have worked pretty well from the beginning, even at 3 hops. I haven’t yet figured out how to do the solar power part of this in deep caves, though. 
To tell you the truth, I’m not entirely sure I figured out how to do it in the depths of winter above ground around here, but I was getting close by the time it got hot. I’ll get another chance at that soon enough.
The pics are great!