I’m following the instructions here and here to try and make a Stratum-1 NTP server using GPS and a Raspberry Pi 2. If this works, I should have a very accurate NTP server for a very reasonable amount of money.
I ordered the Raspberry Pi 2 from Amazon, and the other parts from HAB Supplies in the UK. The total cost (prices include tax) was:
|Raspberry Pi 2||£29.99|
|GPS expansion board||£35.99|
|Antenna and cable||£41.99|
Edit: I already had a spare 32GB SD card and power supply. If you don’t have those already, you’d need to buy them too.