Sometimes I get asked if there is a way to create a communications system that will function fully off grid. For homesteaders and those off-grid it is often nice to have an independent onsite means of communication and honestly it is not all that difficult to implement.
While there are many services out there like Tikl and so forth they all have the flaw of not being able to operate trully independantly from a grid or without some sort of connectivity to a grid whether that is via cellular data, grid-tied WiFi, a sattelite data connection or any number of other 'internet' connection types.
I am going to keep this very brief and just say that I have tested several means over the years to accomplish this goal but the best I have found is the Serval Project. I am not going to go into all the details of implementing it but there are several ways of using it and I will leave it up to the reader to explore them but for a very simple system (especially for simple on-site use) all you really need is their App, a smartphone that can run the App and optionally a wireless router that has no 'internet' connectivity.
It is worth noting that Serval has hardware available that enables very long range communication but in many places the use of such devices requires licensing or is not permitted at all so do your research if you pursue that line of implementation.
It is worth noting here about Serval that I did have some success running the App on Android-x86 as a virtual machine but did not tinker with it long enough to really explore it's potential in that regard. My idea at the time was to use a netbook to operate as a node for the mesh network because it had a significantly broader WiFi radius than any of my phones. Just an idea I thought to throw out there if anyone is pursuing this sort of thing for setting up an onsite communications system. You can find out more about Android-x86 here: http://www.android-x86.org/
You can find out more about the Serval Project here: http://www.servalproject.org/
As an honorable mention there is another App by the Briar Project but I have never tested it and it has much less functionality than Serval.
You can find out more about Briar here: https://briarproject.org/index.html
That is all. Good Luck!