A gremlin indeed. While you will invariable receive loads of ideas, I will start by throwing out the first one that came to my mind. Do with it what you will. Confirm you have a set of conditions that are repeatable every single time. Turn off AC power circuits in your home, except the circuit needed to perform your tests. Confirm if the symptom persists. It it does not persist, something powered by one the circuits you turned off is contributing. Power up one circuit at time until you find a circuit that results in the symptom occurring again. Then troubleshoot further by removing power (unplugging/removing) items from that circuit. Once you find the culprit, then we talk solutions. If turning off circuits except the one needed for your tests does not yield results, then troubleshoot further by removing power (unplugging/removing) items from that circuit. Do this one at time until you find the culprit. Once you find the culprit, then we talk solutions. If removing items from test circuit does not yield results and the only thing left connected is the offending radio, then starting powering down all battery operated devices in your home, including any device powered by a UPS. This includes cell phones, iPads, laptops etc... Blasts of GSM noise from a phone has been a common source of interface in the past and can be suspect. You could have other items in your home that contribute interference in a similar way. I am one that most generally likes to remove all variables and build back up until the problem occurs. In this case I am taking a hybrid solution. Hope there is a nugget of help in there for you. Michael WHRS965 KE8PLM Sent from my iPad using Tapatalk