RF Detector?

Take a computer that is not connected to the internet and plug the NVR into the ethernet port of the computer. Make sure the computer and NVR are on the same IP subnet. Then open a web browser and type in the IP address of the NVR or open SmartPSSLite.
 
You shouldn't need to be proficient in networking to run some of these steps, especially this part:
In terms of router security:

If you are struggling to interpret the results, just post them here. What AV are you running on your PC (and what OS)?