Stratum 1 NTP server with Raspberry Pi

Using the GPS board I recently mentioned, and a Raspberry Pi, I built a stratum 1 NTP server. I'm working on a writeup of the process, in the meantime, here's a photo of the setup.

The red wire is used to bring the pulse-per-second signal to the Raspberry Pi GPIO connector (in this case, GPIO 18, but you can use a different line if that is already in use). The GPS is powered by the Raspberry Pi via USB, this also provides a ground return path for the PPS signal. At the same time, the GPS boards appears as /dev/ttyUSB0 to the operating system on the Pi.

GPS board

I got a GPS board in the mail, with PPS output, as well as NMEA output over USB, RS232 and Bluetooth. The plan is to build a basic NTP stratum 1 server to use at home.

Someone wrote a detailed review of this board.

A couple of photos of it on my workbench:

You can view the NMEA data on the terminal window, in this case it was being read over Bluetooth, the USB cable was just providing power.

AX.25 dissector for Wireshark

I learned today that Wireshark has an AX.25 dissector.

IRLP on the Raspberry Pi

Good writeup by VE7LTD on getting IRLP installed on the Raspberry Pi.

Hacking the UV3R HT

Cool project! How to hack the UV3R radio.

TNCPi with I2C

Here are some instructions on how to use the TNCPi with I2C, by G8BPQ.

SDR kit inventory

Inventory complete... looks like everything is here, I can't put this project off any longer...