Testing the Receiver and Monitor
I resurrected an old 10mW 5.8GHz transmitter with clover-leaf antenna and mini camera to provide a relatively weak signal that could be easily blocked to simulate a longer range. Also a second receiver and monitor to sit nearby just to keep an eye on the transmitter and as a comparison.
The RC-832 receiver seems to be fine. The receiver was compared against an older RC-305 and there was no noticeable difference in sensitivity or image quality.
The other receiver-monitor would indicate interference and noise but would not loose the image completely.
As a second comparison I connected two monitors to the RC-832 receiver; it has two AV outputs. The suspect monitor and another monitor that looks identical but is just from a different seller. The suspect monitor was cutting out while the other was displaying a noisy image. To be sure it wasn’t the AV output, the monitors were swapped over; the problem remained. So it is definitely a problem with the suspect monitor.