First question: does anyone know of a forum dedicated to the Hauppauge products in the US?

2 (CBS), 7 (ABC), and 11 (FOX) have bad signal quality over the PVR-1600, the HDHomerun receives these channels just fine. In fact my Samsung DLP HDTV also has problems with these channels (although when we first got the TV it had no problems until we had to get the colorwheel replaced). I don't understand why the HDHR can get the signals in so strongly but neither the PVR nor the HDTV can't. :confused:

I have a YAGI antenna that runs to a Channel Vision 8PIA-II (http://www.channelvision.com/image/product/CVT/RF%20Amplifiers/CVT-2%208PIA%20II.jpg), and there are three 50' coax cables that go to the HDHR and the PVR-1600, so there's nothing else special going on with the HDHR compared with the PVR-1600.

When you say channels 2, 7, and 11 are you talking about analog channels using the the analog tuner in the 1600 and that when you are using the HDHome run are you talking about it receiving the digital channels for CBS, ABC and Fox.

I have the PVR-1600 set up for digital recording only -- I didn't set up the analog tuner. So all tuners are recording HD/Digital signals.

I see that you are in OC, so I'll also state that my YAGI is not quite pointed at Mt. Wilson (it's about 20-30 deg off), but since we used to get all the digital channels and that the HDHomerun has no problems getting the channels, I don't see that being much of an issue - though I do still plan on readjusting the antenna just the same.

I suggest that you first get your TV's ATSC tuner to get the digital channels without problems and when it is working fine then try the HDhomerh and the 1600 card again.
Your 1600 Card has 1 analog tuner and 1 digital tuner so I am confused by your statemnt "setting up all tuners for digital recording only.