For normal operation of the probe, it is necessary to ensure a satisfactory Signal-to-Noise Ratio (SNR or CN0) for GNSS satellites. To ensure a good performance of spoofing/jamming detection algorithms, the average CN0 value should not be lower than 30 dB. But even with the worst CNO Average values the algorithms will behave well.
You can check the average CN0 value here:
1. GP-Cloud, charts --> CN0 Average:
2. GP-Cloud, Probe Config Popup-->Channel info:
3. Embedded Web Configuration Panel:
4. On the third page of the device screen:
Reason 1: The GNSS antenna's RF cable is too long, combined with a low-gain GNSS antenna preamplifier.
Solution 1: Use an antenna with a higher preamplifier gain.
Solution 2: Reduce the length of an RF cable.
Solution 3: Use low-loss RF cable. For example LMR400 instead of RG58.