For a racing frame, the best antenna mount is usually the one that protects the antenna first and keeps it clear of the props and carbon second. In practice, that often means a TPU rear mount or a flexible side mount, not a hard plastic piece bolted rigidly to the frame. Rigid mounts look tidy, but they transfer crash energy straight into the antenna and the VTX connector, which is how you end up with broken pigtails, torn u.FL plugs, or a snapped antenna after a few packs.
If you are running a long RHCP or LHCP antenna on analog, a rear TPU mount is usually the safest all-around choice. It keeps the antenna out of the prop wash, leaves the top plate cleaner, and tends to survive cartwheels better because TPU bends instead of cracking. On a true race frame, though, you want to pay attention to how far the antenna sticks out. A mount that places it too high can catch gates, branches, or the ground in a crash. A low-profile rear mount that angles the antenna back slightly is often the sweet spot.
Side mounts can also work well, especially on narrow frames where the rear gets crowded by a battery strap or electronics stack. The downside is that one side can get clipped more often in tight turns or during rollovers, depending on your flying style. If you go with a side mount, make sure it does not sit directly behind a prop arc and that the antenna has enough flex to fold away on impact. I have seen a lot of pilots use a short TPU tube or brace to keep the antenna upright without making it stiff.
Top mounts are less common for racing because they can get in the way of the battery and increase the chance of the antenna being ripped off in a front-first crash. They are not automatically bad, but they usually make more sense on freestyle builds than on a hard-used race quad. The main goal is to avoid transferring impact force into the VTX. A cheap antenna is easier to replace than a damaged video transmitter.
If you want the short version: use a flexible TPU rear mount if your frame allows it, keep the antenna as low and protected as you can, and make sure it is not near the props or battery leads. Also, route the coax so it has a little slack and is not pulled tight, because a lot of failures start there rather than at the antenna itself. If your frame is especially compact, a side mount with a soft holder may be the next best option.
