I've had my Access installed for 3-4 months without issue and in what is totally in my mind a coincidence, I ran across this thread a couple of weeks ago looking for some other information about the Acurite Access and a few days later, I started losing signal between the Access and my 5-in-1.
I have two Temp/Humidity sensors installed in my garage attic and the second floor attic. The second floor attic sensor is maybe 20-25 feet from the eve where the 5-in-1 is installed. The Temp/Humidity sensors have not lost connection to the Access, but now I'm losing connection with the 5-in-1 almost every day. First thing I did was change the batteries in the 5-in-1 but it still loses connection... Aside from it happening once overnight, for the most part the only (mostly) common thread I've found is that the sun comes up. But no, I don't think the Sun is causing the problem. So far, it seems to come back on its own, but I did have to force it once or twice by powering off the access and removing the batteries. My firmware version on the Access is 47. To top things off, I've emailed Chaney instruments support twice and still haven't gotten a response after more than a week since I sent the first email.
At this point, I'm about to go back to my SmartHub and sniff the traffic with a Raspberry Pi and the scripts I found from nincehelser a couple of years ago (THANKS by the way! I had great fun building that pi and playing with the configs, scripts, etc.) I'd be happy to keep using the Access but I don't know that its "there yet". And just when I was getting over what felt like forced obsolescence of the SmartHub...