title: The sample code for admob on iPhone is not showing an ad
body: <p>My goal is to create an AdMob banner in my iPhone app.  As a starting point, all I want to do is sucessfully run the example code provided by Google.  I registered for an adMob account and got a publisher id.  I download the sample code provided by Google at <a href="http://code.google.com/mobile/ads/docs/ios/fundamentals.html" rel="nofollow">http://code.google.com/mobile/ads/docs/ios/fundamentals.html</a>.</p>
  
  <p>I added the following to the top of my BannerExampleViewController.m:</p>
  
  <pre><code>#define MY_BANNER_UNIT_ID @"xxxxxxxxxxxxx3dc2"
  </code></pre>
  
  <p>The code runs without errors or warnings.  I don't see any messages on the console.  However, when I run in the Simulator (4.2) I get just a grey screen without the ad as shown in Google's screen shot.  The documentation advises that you have to wait 2 minutes the first time but I have waited longer than that and no joy.</p>
  
  <p>Any hints would be much appreciated.</p>
  
  <p>Thanks,</p>
  
  <p>Dessie.</p>