HDMI maximum cable length?

If you are using a DirecTV box and set your box to either 1080i or 720p, 50' (assume that is what you meant not 50") of Standard Speed HDMI cable will work. Make sure you get good gauge cabling (24 AWG or better). Since DirecTV's source is always 1080i or 720p (unlike Blu-Ray discs), you aren't going to lose any picture quality by not going to 1080p.

You can try to set the DirecTV receiver to 1080p and that might work. If 1080p doesn't work, you'll know it by either sparkles or lines or screens of a single color or no picture at all. Just go back to 1080i/720p. The only reason for 1080p would be some of the PPV channels require it.

From an HDMI standpoint, what applies to projectors also applies to LCD TVs. Also remember that HDMI cables don't have to be expensive. For 50' you should be able to get a really good cable for less than $50.

With a good quality cable (like the Belden bonded cable) you can go 150ft up to 1080p 60Hz using a cable equalizer.

Is there a web site that has this advertised? I have a hard time believing that a cable equalizer can make a passive cable work at 150 feet in all instances, not just where everything just happens to balance out. However, I'd like to learn something new, so I thought I'd ask.

No, this is from testing with a pattern generator and an oscilloscope running eye diagram measurements. That length is definitely pushing it, but from what I've seen checking in different systems, probably 90% of transmitter/receiver combinations would work perfectly. There are a few poor transmitters out there, but those are mostly older generation units that you are unlikely to come across.