Finally I’ve had some free time to play with my new GPS receiver, a NEO M8N.
This nice and cheap object arrived to me over a little PCB where other components are positioned for an easier and fast utilization. The rx-tx serial data are 3.3 V level, so a converter is needed for a correct work. I’ve used a USB converter that provides the 5 Volt DC for the 3.3 Volt board regulator.
To configure the NEO M8N I’ve used U-Center, the software is freely available at U-Blox website.
At first start the power LED was on and after a while also the TimePulse LED began to blink.
Despite I used it in an indoor ambient has been quickly possible to receive a lot of satellites.
This GPS receiver will be used to discipline my VLF to MF receivers thanks to the possibility to change the TimePulse period configuring it by U-Center software. I’ve tried to change the frequency measuring it by an oscilloscope. Here follows some images of the test.
A first test at 136 kHz with a low duty cycle. I’ve tried it at the maximum frequency of 10 MHz and the result seems to be good looking also to its linearity.
Lately other tests with 50% duty cycle at some interesting frequency:
To set a decimal frequency we need to change the frequency setup to period setup, so it will be possible to write a very sharp frequency till to nHz’s. For example I’ve tried to set 8270.005 Hz, whose period is 120.918911 us (microSeconds). Minimum frequency reached is 0.01 Hz with a possible accuracy of 0.1 nHz (nanoHz)!