@Eriequiet
Those Verifone MX915 are a real pain. I figured them out though. Here’s some good positioning options:
It helps to basically put the tag against the screen slightly in from the edge, then slowly move it outward keeping it parallel with the screen edge. It helps to have a diagnostic card handy the first few times to figure out exactly when the field is on, because if you get a misread from fumbling around the clerk often has to back out a step in the POS and re-initiate the payment. Also the field shuts off automatically after about 30 seconds so if you’re trying too long you’re wasting your time.
I really need to put that montage video up of all the reads I’ve done over the last few months. Of all the readers I’ve tried that Verifone model is the second worst (first being ingenico) and they’re ubiquitous around here. I’m going to buy a second hand one and take it apart and examine the antenna. May even be able to trick the controller into trying to read without an expensive base station so I can test the field shape.
I also sometimes get an error that says to only present one card, which I thought was due to my flexDF but now I’m not so sure. Payment terminals are really dumb devices considering how important they are for our day to day operations.