My research group is continuing our setup of two servers with multiple N210s for a GNSS application. Each server will have 4 or 5 N210s recording RF data at frequencies of interest. All are to be locked to the 10MHz reference and 1 PPS output from a Septentrio PolaRxS. I have successfully tested our PPS arrangement using test_pps_input. However, test_dboard_coercion sometimes reports an unsuccessful lock to our external oscillator. The number of unsuccessful locks varies with the inputs to test_dboard_coercion:
Set1: "--rx --ref external" reports an unsuccessful ref lock at 1500MHz Set2: "--rx --ref external --no_rx_gain" reports an unsuccessful ref lock at 1500, 1550, 1700, 1750, 1800, 1850, 1900, 1950, and 2000MHz.
These unsuccessful locks are intermittent. The results for Set2 don't worry me so much: we're always running at high gain when recording. What is the cause and is there a good solution to this problem? Our plan is to have all N210s writing constantly to a ring buffer, but only writing to file when triggered by an external source. The reference lock is critical since we're studying GNSS signals. Any help is appreciated. I know this list usually hits it out of the park, so I'm looking forward to your responses!