QAM and OTA ASTC on an HVR-1600

[Ender]

I have an HVR-1600 in my system. Now Time Warner in my area only transmits the local channels in the clear on their QAM channels. The only thing is, CBS is not carried by Time warner in HD, only analog, or Digital.

Now due to antenna restraints, my family will not let me put an antenna outside. I only get PBS, and fortunately CBS, in a viewable fashon.

My question to anyone is this:

If I took a satellite diplexer, such as this one:
http://unicornelex.com/detail.php?itemno=28-2019&

it is a 5-2050 MHz output, with a dc pass on the sattlite end, the UHF in has a range of 5-800MHz, and the Sat in has 950-2050MHz.


Would I be able to hook up both my antenna, and the digital cable feed to my HVR-1600, and be able to watch all the locals in HD without switching the cables all the time?

I really do not want to have to go buy another tuner this year and thought this may be a suitable alternative.

[Humanzee]

I think QAM and ATSC work differently, but I could be wrong. If I recall correctly ATSC OTA was working in sage well before QAM, even though the signal has always been there. So they wouldn't be the same. You might be able to find an ATSC tuner for cheap anyway, granted maybe not for $8. I have a usb Fusion 5 tuner that I have used before. It won't do QAM in sage so I havn't used it since we moved. I can't get NBC to work reliably in QAM so I might be up on the roof soon myself.

[omega]

Humanzee is correct, the signals are different. OTA ATSC uses 8VSB modulation, whereas digital cable uses QAM (most likely either QAM256 or QAM64). While the 1600 has the hardware capability to tune both modulation types, you'd have to do some serious tweaking to get SageTV and the card to dynamically switch back and forth depending on the channel number, if that's even possible.

The other issue is combining the two sources. You may well find a frequency point that lies between your ATSC and QAM channels, but the diplexer you mentioned is not going to do the trick. The 950MHz low end on the Sat input is too high for digital cable. On my cable system, Comcast Minneapolis, all of the available QAM channels are in the 500-800 MHz range (roughly corresponding to physical channels 70-115, give or take). Your system may well be different, but in general, cable systems don't go over 1GHz.

[Ender]

Well thanks for the advice. I did some experimentation, and it seems it its impossible. Plus I cannot seem to get a single QAM channel in sage with the 1600. Well I do have a Leadtek HDTV Cinema around, I think I'll try that for QAM. Hopefully it's BDA drivers like Sage.

If not, when I get the cash together I will just go get an HDHR, or some USP tuner.