But as I said, most 43C* aircraft don't transmit their position, so no alerting system will ever be able to alert you to all 43C* aircraft within your six mile radius, since Radarbox doesn't know where the aircraft is. In fact, in MyLog, only ONE 43C* aircraft has ever transmitted it's position - 43C1C0 (ZD949). So you will never be able to get the alerts you want.
Although when Radarbox can do multilateration (June?), all that will change. Or you could download Planeplotter, subscribe to multilateration, setup an alert zone, and get alerts for non-ADS/B aircraft within a six mile area of your location.
For example, this Boeing E-3A Sentry: