I was not able to get your model number to work so you might want to recheck it is correct per the one listed on the overhead opener motor unit. But if your wall switch works normally and you tried new batteries in all the remotes with no change to any of them then you have some form of signal interference.
There is an antenna in the overhead opener as you noted. The remotes send out a signal in a specific frequency and an antenna is used for reception, similar to your radio. And just like your favorite radio station the signal can sometimes get lost in static if another station or power source interferes with it. When you stand right under the opener, it is like moving your radio to higher ground, the opener has an easier time tuning in and activating the door.
Sources of interference I have dealt with are old remotes in a drawer somewhere with something bumping a button, televisions, satellite systems, a change in local phone or power lines, airports, military bases, sprinkler timers, refrigerators in the garage, radios, and a host of others.
Try to look for any pattern that might help lead you there. For example, does it happen on certain days only, or, at certain times of the day? Did the problem start when you had a new appliance installed, or your neighbor changed his garage door opener?
Sometimes turning off the power breakers for different rooms of the house can help pin-point the source. If turning off the power to your living room allows the remotes to suddenly work, for example, it could be that new TV is the problem. Many service professionals have meters that can help track the signals as well.
If no source can be found, or it is found but nothing can be done to eliminate it, some garage door openers have accessory antennas available that can help with reception. Some experimenting, just like you do with your radio antenna, might locate a spot that works more consistently.