This is a GPS receiver with NEO 7 module programmed to extract 10 MHz reference (or any frequency up to 10 MHz)..It can be powered from an external 12V power source via a LP2950 regulator or from the USB interface with CP2102 (Ensure that you use 3.3V USB to RS232 adapter !!!). The power source is determined with an ON-OFF-ON switch. To avoid using the USB interface as a mouse from PC, connect the USB interface first without powering the NEO7, run the GPS software select the proper COM port and then power up the GPS. To use an external GPS active antenna I share a 75 ohm TV coax used for a discone using 2 diplexerers for satellite usage (high-low pass filter for 900 MHz). The low pass under 900 MHz is used for the discone and the high pass that also permits DC power passing is used for the GPS active antenna. The received signals of about 15 satellites, are -40 dBm using 50 m of TV coax. To adapt the connectors I use SMA to F adapters. Two led are used one for power and one for received signal reference to quickly identify if it generates 1 PPS instead of 10 MHz. The produced signal has a lot of jitter.