OE1IFM

This weekend I designed another building block of the BeaconTNG project. The Navsync CW25-TIM GPS module will be the
GPS receiver for timing, location information and frequency synchronization of the new system and it will be integrated
right into the beacon enclosure. The CW25-TIM can be programmed through command extensions to the NMEA protocol via
RS232. It has an integrated synthesizer that works up to 30MHz. This fits perfectly as 30MHz is the desired master clock for
the AD9851 DDS chip I use.

So BeaconTNG will have an SMA connector to attach an external active GPS antenna. This connector will also deliver 3.3V
for the antenna. The CW25-TIM will be connected to the MCU’s UART for programming the desired synthesizer frequency
and to deliver date/time and location information to the MCU. Digital I/O connections will be there for 1pps signal, status
lines and reset. The 30MHz signal is feed through a 30MHz bandpass to clean harmonics and noise from the synthesizer.
The 10MHz base frequency of the synthesizer is very loud as well. Only 15dB lower than the 30MHz signal. After the
bandpass a driver/buffer stage is implemented, which I just breadboarded today for the first test. I removed the 30MHz
Xtal from my lab unit and fed in the GPSDO signal from the breadboard.

First TX was at 19:04 on 7.040.055!