I wanted to clarify the method of connection, without the Internet.

I wanted to clarify the method of connection, without the Internet.
Installation of the RTK Base with the radio module using the Mobile (bluetooth).
then receive corrections on the second RTK module with a radio module used a Bluetooth connection.
Is this possible?

If you’re asking if can use two Bluetooth serial module to send data from base to rover using 6-pin connector interface:

  1. Class 1 Bluetooth module has 100m working range
  2. Class 2 Bluetooth module has 10m working range

Alpha RTK receiver has Class 2 Bluetooth module inside. I’m not sure if using Bluetooth can have useful base/rover operating range, even if you use two class 1 Bluetooth modules via 6-pin connector port. You should be able to Google search “Bluetooth Module + Serial + Master + Slave” and find information on such Bluetooth module for short range use.

no. not this way.
I expect to use your kit in construction.
as a replacement for the standard powerful FMS.
with a distance of 1km to 4km. (Radiomodule)
I thought I’d use the phone as a terminal.

For RTK rover, there is no problem using Android phone as the GIS Data Collector terminal communicating with Alpha over Bluetooth and connecting to NTRIP Caster using Lefebure NTRIP Client.

The problem is with RTK base, there is no available NTRIP Server for Android that can fetch Alpha RTK base data over Bluetooth and sent to NTRIP Caster.

In our user guide, the Alpha RTK base connects to a laptop running NTRIP server to send data to NTRIP Caster.