I have just installed my new Panny projector and ran a 35' Monoprice HDMI cable from my H10 DTV sat receiver. I have to reboot (unplug) the H10 in order for the Panny to get a signal. Everytime that I turn off either the projector or sat receiver, I have to repeat this step.

Now, this works for a short er 6' cable, and I tested it before installing the cable without issue (as far as I can recall).

Why is this? Any advice?

Well, the problem is easy----Your cable is too long. You could probably have got away with a 28ft-30ft---But at 35ft you are pushing it. You can buy an extender (amp) booster.---like this one

http://www.ramelectronics.net/html/EXT-HDMI-141SB.htm

I have to disagree with Jeff... 35' of HDMI should not be a limiting factor, given good quality cable.

I currently run 2 50' HDMI cables back to my PT-AE1000U with no problems whatsoever.

Both cables are from bluejeanscable. One runs back from a Psyclone4:1 HDMI switch, the other from Denon AVR-887.

I'm running a Monoprice 22AWG cable... I actually ran 2 HDMI cables and both have the same challenge. I'm curious if one of the components is having trouble retaining the handshake?

you may want a switcher because that will take care of the problem if it is handshake, or if the signal is too weak the switcher will probably amplify the signal

Plugged in my new Oppo 821 via the same HDMI cable... No issues with the HDMI connection. The Panny picked it up right way. Looks to be the DTV receiver. I'm going to call DTV to see if I can get a new receiver.

I have a very similar problem connecting the projector to my computer. I have to reboot the computer to get the screen to display onto the projector (or, alternatively, while the proj. is connected to the computer, scan for hardware changes in device manager and then enter standby mode and return - not so easy if can't see your screen).

I isolated to problem to being with my video card. When the video card is connected to the DVI monitor, it is set up for that. Even if the screen resolutions are the same (1920x1080, 24-bit color, 24 Hz refresh rate), for some reason the monitor and projector use different horizontal scanning frequencies.

Long story short - the HDMI interface uses the same computer DVI plug and play interface. When you connect your projector, the projector sends information to the device about what modes it supports and refresh rates, etc. The proj. and my monitor do not support any of the same horizontal refresh rates. My video card will not adjust between the modes without a restart.

Your receiver may be doing the same thing - once it is powered on, it will not change modes to support what is plugged in. This sound like a stupid way to do things especially for a sattelite receiver, but it might just be a software upgrade to the receiver or something. Or maybe the Panny uses a non-standard mode, and most devices use a standard mode, so just plugging the cable in does the trick.

One question though - you say every time you turn off your sat. receiver, the problem comes back. I thought that was how you fixed the problem, not how it occurred.

I meant when I turn both of them off, the problem returns. The only way that I can fix it, is to turn on the projector, and then reboot the sat receiver. Once I'm done watching, and turn both the sat receiver and projector off, the problem returns.

So the only way to get it to work is to turn on the sat receiver while the projector is on and plugged in? That is what it is like with my computer.

What happens if:
1) The receiver is on and working with the projector, you're watching tv, and you just unplug and replug the projector (leaving the reciever on the whole time)?
2) The receiver is on and working with the projector, you're watching tv, and you power-off and back on the projector (leaving the projector on the whole time)?

With my computer, both 1 and 2 work. My projector is being returned right now, but as soon as I get it back, I'll check into what exactly the signals are that it requires, and all the sync frequencies. Hopefully I'll be able to find out if these values are abnormal for most display devices.