how to build your own set top Atsc and QAM tuner?

i am looking to build a set top ATSC/QAM stand alone tv tuner without the need for a pc interface

I assume that by tuner, you hope to attach an antenna to the input, and have an hdmi or component (rca yellow, white, red) output.

I would suggest an educational background including a Bachelor's Degree in Electrical Engineering or equivalent as a pre-requisite, if you plan to design, build, and troubleshoot.

Likely, the RF front end will require some surface mount soldering skills... I've yet to see a kit or hobbyist's design, despite my search.

You'll want an RF amp, a mixer, a local oscillator (likely a numerically controlled, phase - frequency locked loop), an intermediate frequency amp set to 44 MHz (as appears to be standard), some way to sync to the pilot, demodulate 8VSB (over the air) or 16VSB (cable tv) as applicable, an 8 level to 2 bit converter, to handle trelllis encoding and forward error control, de-interleaver, etc...

All of this, is necessary to convert a 6 MHz bandwidth, 8 level signal, into an MP4 stream, that can then be recorded to disk, or sent to a display.

You may be able to find some sort of downconverter, to shift the desired station to baseband, and then digitally sample the baseband, for demodulation by a 'software defined radio' approach.

A good place to start, is reading the following spec:

http://www.atsc.org/cms/index.php/standards/standards/50-atsc-a53-standard