Angular: How to use ngRepeat and set a default radio button option?

I checked this question, but it wasn't very helpful because they're using ng-repeat differently.

This is also not helpful.

I have a form:

<label ng-repeat="option in options">
  <input type="radio" ng-model="myObject.value" ng-value="option.key">
</label>

My angular controller:

options = {
  key: 'Option 1'
  val: 'Value 1'
}
$scope.myObject = { value: 'default option' }

I would like this to set a default radio option. What's happening is that the last option in list is set as the default no matter what I try. I'm sure I don't understand why that is, so here I am.

How do I set a default radio option and what's wrong with my current configuration? Thanks for your help.