Mode A has always been weaker than Mode B, but with a decent 10-meter antenna it is quite usable. Many operators access Mode B with a 2-meter beam of some sort, then try to hear Mode A with a dipole or ground-mounted vertical , then complain that they cannot hear it.
There is no substitute for a good 10-meter beam. A tri-bander usually works too, but check the tuning to see that the SWR isn't too high at 29.5 MHz. If it is, you may have to re-tune it or even shorten the elements slightly. If you absolutely cannot put up a beam, your second choice can be a 10-meter ground plane, elevated so it is mounted in the clear. It has no forward gain of course, but it will give you a low radiation angle, which will help in hearing AO-7 when it is at low elevation which it is most of the time.
With Field Day coming up, a little attention now to your 10-meter antenna will show up in your results later.
73 Ray W2RS