When trying to place down my spawn radio it doesn't always work, it will beep but not place it on the ground.
Are there certain conditions that need to be met to place the spawn radio?
A lot of the placeable equipment in battlefield 3 is kind of picky about where you can place it. In general you need a flat section of ground without any random debris on it. I've also found that it's much, much harder to place things if you're prone. The color of the the item should change as well when it's in a placeable area. If it's not placeable it will appear with a dark red tint, when it's placeable it will become kind of yellowish.
Also, sometimes it's just a little glitchy.
It's a bit choosy about its placement spot.
The surface must be level, and it must not be covered by foliage. Also, the radio beacon is larger than its icon (the thing you are holding before placing it), mostly due to its antenna, so, it requires more space than it would seem to need.
This is especially the case when you are trying to deploy it in a corner. You have to back away from the walls a bit for it to turn green, which signals for deployable.