@Component({
  selector: 'page-schedule',
  templateUrl: 'list.html'
})
export class SchedulePage {
  itemsCollection: AngularFirestoreCollection<Schedule>;
  items: Observable<Schedule[]>;
  constructor(
    public db: AngularFirestore) {
  }
  ionViewDidLoad() {
    let loader = this.loadingCtrl.create({
      content: "Loading..."
    });

    loader.present().then(() => {
      this.itemsCollection = this.db.collection('userschedules');
      this.items = this.itemsCollection.valueChanges();
      loader.dismiss();
    });
  }
}

<ion-item class="text" *ngFor="let item of items | async">
    ...
</ion-item>