JSON object max size?

Using jquery, I'm able to send json objects from client to server using ajax like this:

var strJSON = '{"event":[{
    "dates":[
        "2009-10-14","2009-10-15"],
   "teams":[
        {"id":"0","country":"USA","state":"CA","name":"California Polytechnic State University","subteam":""},
        {"id":"1","country":"USA","state":"CA","name":"California State University, Bakersfield","subteam":""},
        {"id":"2","country":"USA","state":"CA","name":"California State University, Fresno","subteam":""},
        {"id":"3","country":"USA","state":"CA","name":"California State University, Fullerton","subteam":""}]
}]}';

$.ajax({
    url: '../ajax/save_event',
    type: 'POST',
    data: { data : strJSON },
    dataType: 'json',
    timeout: 8000,
    cache: false
});

It works well. But if the JSON string gets much bigger (not sure the exact size, but somewhere around 5x bigger), the $_POST data received by the server is empty. Anybody know why?

I'm using Apache/PHP/jquery. It happens from both IE and Firefox. Is there a config setting somewhere I need to adjust?

Here's an example of a string that fails to make it through:

{"events":[{"dates":["2009-10-10","2009-10-11","2009-10-12"],"divisions":[{"level":"Collegiate","name":"Varsity","subdivision":"Division I","rounds":[],"teams":[{"id":"0","country":"USA","state":"CA","name":"California Polytechnic State University","subteam":""},{"id":"1","country":"USA","state":"CA","name":"California State University, Bakersfield","subteam":""},{"id":"2","country":"USA","state":"CA","name":"California State University, Fresno","subteam":""},{"id":"3","country":"USA","state":"CA","name":"California State University, Fullerton","subteam":""},{"id":"4","country":"USA","state":"CA","name":"Stanford University","subteam":""},{"id":"5","country":"USA","state":"CA","name":"University of California, Davis","subteam":""},{"id":"6","country":"USA","state":"CA","name":"San F