Originally Posted by thrang
Yes, have a 35 or 40 foot Redmere to my 1100 from the Pro and its rock solid
What is odd for Rich is it seems the Radiance and his previous JVC worked fine with his same cable.
The HDMI connection is a "system" encompassing the HDMI output chip, HDMI PCB transmission line design in the source, the HDMI output connector, the HDMI cable (plug, cable, plug all have an effect), the HDMI input connector, the HDMI transmission lines on the receiver PCB, and the HDMI receiver chip.
Changing the HDMI input connector, HDMI transmission lines on the receiver PCB, and/or HDMI receiver chip can easily affect the connection. We have seen that some projectors and TVs do not have as good an input layout as desired to do well as the end point of a long HDMI cable. This is why an active cable can help a lot. It effectively gives the projector/TV only a few inch connection to deal with.
When I design an HDMI input I try my best to keep the PCB traces very short and as close to the specified differential, and single-ended, impedance as possible. For example the input traces in the Radiance Pro 444X units are 7 mm long (about 1/4 inch), including the input ESD device. I have seen 3 or 4 inch long traces on what appears to be a general purpose FR4 PCB in some projectors/TVs, and in my opinion this is too long. It puts a discontinuity (the connector and its pads) 4 inches from the receiver chip instead of right at the receiver chip as desired. In addition commonly used FR4 PCB material does not have ideal impedance control, and the differential and single-ended impedance can actually vary some from unit to unit with longer traces.
Of course having some trace length is unavoidable if an HDMI input chip has multiple inputs. Even then I try to keep trace length to about an inch. I think much longer than this is asking to have long HDMI cable issues.
Not sure how I ended up on my soap-box about HDMI input design, but I will get off it now.