Makes sense.. yes.. but why always at the same time??
It can be a number of things from the a/c or heat turning on, (can cause a spike or other odd issue, especially in older home/building etc), if you are in a multi-unit (condo, townhouse, apt etc) sometimes other people's electronics can "cross talk" in older buildings or in buildings that used to be single dwelling and have been split up into more rental units (may have electrical outlets that aren't 100% separate etc.
Because the Sonic Alert (and all "plug in and go" visual alert systems that use wall outlets) aren't hard wired into your home independent of the electrical outlets occasionally situations will occur that will cause funny power spikes or interference (so not a "spike" , just "line noise" - sort of like electrical static or tinnitus lol) which can trigger the receivers.
I actually spent a lot of time figuring out what the problem was when it happened to me - including speaking with a number of electrical technicians.
I worked in a repair department and one of our techs specialized in all types of electronic equipment - and was able to help figure out what the problem was. We were able to test it - and then actaully reproduce the problem by causing 2 types of interference 1) power spike 2) noise aka "dirty signal".
Once we figured out what was going on, I simply got a very good surge protecting power bar that also had a "filter" on it ... this filter (also called a "conditioner" is found on good surge protectors) makes sure that the electrical current is "clean" not with any thing that may cause issues with electronics. Since I've had it connected with the surge protecting power bar I have not even once had a "false trigger" ... it's now been 3years, and prior to the surge protector I was getting 1 trigger anywhere between every 48hours and every 3hours - so I'm absolutely sure that fixed the "problem". Nothing else was changed other than added the surge protector.
I also contacted Sonic Alert and they confirmed my finding and recommended (especially for multi-unit dwellings (apts, homes with rented rooms, older condos/townhouses etc) that receivers be plugged into a high quality surge protectors with the filter/conditioner ($20-50 depending on style # of outlets etc) to prevent any sort of "talking" or false triggering of the units.
I'd like to point out that this isn't a "Sonic Alert problem" it's an issue that exists for ALL visual or tactile signallers that work using the home/apts electrical outlets as the circuit (ie are plugged into the wall and send signals to other units that are also plugged into the wall). It is a more common issue in older places with older electric or that have been split up from a one family dwelling into a multifamily dwelling (a house made into 2 or 3 "units", an apt with very large 4bedroom units renovated so they are made into 2, 2bedrooms etc). Also - sometimes the issue is also the connections outside the building (how the individual units connect to the main transformer etc)
Hope that helps
