At the beginning of the development we wondered which technology was more appropriate for data transmission: the one based on the cellular phone networks (GSM and later derivatives) or satellite.
Satellite transmission has the obvious advantage of global coverage, enabling the use even in the middle of the ocean. The disadvantage, however, is the high costs of both the satellite module and the subscription to data connection services. The cost of a satellite based SHARKNET would have been four times as much and the subscription no less than $25/month (and more, depending by the usage).
Since the above costs would have made SHARKNET a tool suitable only for professional use, we opted for the cellular technology, that nowadays has very affordable costs and a very wide world coverage.
Specifically, the service contracts of all major cellular providers grant a coverage that at sea extends up to 14 nautical miles from the coast. This coverage would be more than enough to fulfill the needs of most freedivers, scuba divers and others practicing sports at sea. All of us however know very well that the actual coverage (bot at sea and ashore) is not total and, most of the times, it varies from operator to operator.
In order to increase as much as possible the phone coverage, we selected for all SHARKNET devices a connection plan dedicated to communications among machines, that is agnostic with respect to the connection provider and allows devices to always lock to the cell with the highest power. In other words, even if the SIM is provided by a given connection provider (for example, AT&T) and a given area is covered by Verizon only or any other domestic or foreign provider, the device will always connect to the net that works the best.
This solution guarantees the highest service availability and, at the same time, keeps the cost of the device and the monthly subscription fee very reasonable.
It is not in fact the classic, expensive and never end tariff plans! Sharknet allows you to spend a few euros a month and above all to activate the credit only the months of real use of the device. Find the credit association process in the APP SETTINGS >> CHARGING MY MY SHARKNET section. First of all, you will need to load the credit in your App: just add the amount you prefer (eg € 20) through your PayPal account.
And then associate the amount you prefer for the period in which you want to activate Sharknet (eg € 18 for 30 days). If you are a diving center, you can use the same procedure for all the Sharknets in your possession and activate and deactivate the credit for each device according to your needs.
