Time period from install to now?
One thing I found worked for me was rather than presenting and hoping to get a read was, going to a swiping, slicing motion.
I would place my implant to the middle of the reader(where there is no antenna) and I would “slice” downward “cutting” the antenna on the perimeter with my implant.
Works every time.
I can also present to the antenna and I can get a successful read more often than not now, it is not as reliable as the “slicing method” … For me anyway.
Something worth trying.