Frequently asked questions

A cave communication system that carries short text messages and sensor data along a lightweight fibre line, with nodes along it that each open a small Wi-Fi pocket, so people underground can message the surface from an ordinary phone.

Cave radios push a signal through rock, which physics makes slow and short-ranged. LoCave goes around the problem instead: the signal runs along the passage on fibre, and radio is used only for the last few metres, where it works well.

The two are not really competitors. A team may well carry both.

No licence. Wi-Fi at 2.4 GHz and the node-to-node LoRa radio at 433 MHz both use licence-free ISM bands, and the fibre uses no spectrum at all. The exact rules for those bands are national, though, so we confirm the position for your country before a deployment rather than asking you to take a website’s word for it.

Short text messages in both directions, plus status and sensor data from the nodes themselves: link quality, which node hears which, how many Bluetooth devices are near each node, and temperature and humidity from Ruuvi beacons placed underground. A message sent from a phone shows a tick once the gateway has received it. A message sent from the surface into the cave does not yet carry a delivery receipt; that arrives with a firmware update.

It is not an internet connection and it does not carry voice. A phone on a node’s Wi-Fi opens a small chat page hosted on the node, and that page is the whole interface.

Yes, in two ways. The gateway can relay every message into a Telegram group, and messages written in that group go into the cave, marked so the team knows they came from outside. And the LoCave cloud dashboard: whenever the gateway has an internet connection it uploads everything, and the members of your organisation follow the deployment live from anywhere, send messages to all nodes or one, ping a node, see the line and the map, set alerts and export the record.

LoCave’s own comparison is around five times faster than conventional cabling. The honest answer for your cave depends on the passage. A walking-sized gallery and a series of squeezes are not the same job, and we would rather size it against your survey than quote you an average.

Far enough that the fibre is not usually the constraint. The passage is.

We deliberately do not publish a range figure, because a number on a marketing page gets read as a guarantee and then designed around. Send us the survey and we will give you a real answer for that cave.

It is built for cave conditions, and the line is designed to be repairable in the field rather than to be perfect. Tell us about the specific hazards in your system — a streamway, a known ropey squeeze, a sump bypass — and we will tell you how the line is routed around them.

Yes, and for a show cave or a site being worked repeatedly that is usually the right answer. For an expedition the line more often comes back out with the team. The system is the same either way.

The nodes on either side of the break switch to their radio link automatically. If they are within radio range of each other the line keeps working, at the lower speed radio allows; if they are not, everything beyond the break is cut off until the fibre is joined again, which the line is designed to allow underground.

Around ten phones at once on one node’s Wi-Fi. Messages are short, up to about 120 characters, and accented letters are sent as plain ones (č as c), which is part of what keeps them reliable over the radio hops. For a large team, deploy more nodes rather than more phones per node.

Yes. LoCave is available now. It is not a prototype and not a waiting list.

It is delivered as a project rather than off a shelf, so the first step is a conversation rather than a basket: tell us about the cave and what you need the link to do, and we will scope a deployment around it.

LoCave’s published comparison is roughly a tenth of the cost of an equivalent VHF installation. A real figure depends on the length of line, the number of nodes and what the surface end has to connect to, so it comes out of the conversation rather than a price list.

Yes. IRNAS Technologies works internationally. Tell us where you are and we will be straight with you about what support looks like at that distance before you commit to anything.

Ask. We would much rather show a system working than describe one.