The A7105 module is necessary to support the Flysky protocol (also used by WLToys V911, V9x9, and Xeida 99×8) and the Hubsan X4 protocol. It is possible to scavenge this module from a WLToys Flysky protocol transmitter, an Xeida 99×8 transmitter, or to purchase it standalone.
The XL7105-D03 is an A7105 transceiver with an integrated power-amp providing 17dBm of output power. It can be obtained from Ebay or Aliexpress. Typical search term: ‘A7105-500m’
I have run a range test comparing the XL7105-D03 and V911-Tx modules. In both cases I set the Tx on the ground, the antenna was inside the Tx and was bound to the V911. I then walked until the light on the V911 would flash intermittently. The path was line-of sight, but along the edge of the woods, so not exactly a wide open field.
Using the V911 Module: range = 600ft Using the aliexpress module: range = 650ft The XL7105-D03 is rated at 500M, but at least with my setup, I didn’t see any where near that distance.
The Xeida module is similar to the WLToys modules, except that it has an antenna on the board, instead of a small attached antenna. A range test similar to the XL7105-D03 and V911-Tx modules (different location, different V911, different Tx) gave a range of about 100 ft.
*4.0.1 and earlier: Connect 8→GND and 9→3.3V. Leave 6 and 7 floating
After 4.0.1, connect 6→9 and 7→8
Link: Similar to V911ModuleRemoval