Tuning clear-QAM TV over long coax

[bnh]

Hoping this wise community can suggest some options for me... My problem is my basement HDTV can no longer tune some clear-QAM channels. All the local HD digitals are very blocky, but some, including WGN-HD come in just fine. The standard def, digitals, also come in fine. It seems like two QAM frequencies are not getting a high signal (<50%), and those freqs have the local HD channels on them. Everything was working fine until i put a new Sage client PC on the basement HDTV.

I have Comcast basic cable. The Sage server digital tuners have no problem tuning these channels, so i assume it's not a Comcast problem.

The cable run to the basement TV is rather long (prolly >50 feet), and at least one link is not RG6. I've had an amplifier at the beginning of any splits since i started all this. I have one more spare amp, but i think it's an analog amplifier, Channel Master 3044, and i'm not confident it would be of any use.

My fear is that while i was installing the Sage client PC, i kept shifting the TV around, and while plugging/unplugging cords to connect everything up, i possibly messed up the coax input jack on the TV. Is that a reasonable fear? I don't know how else to test it without physically moving the TV to a known working cable feed (which is not a simple deal. it's a 65" DLP rear-projection unit.)

I would settle for using Sage to deliver HD content on my basement TV, but my basement client needs a hardwire ethernet...the Wireless-N it's using now is fine for SD and DVD content, but definitely not for broadcast HD. Getting wired ethernet into the basement area will be a significant investment in time and equipment.

Any thoughts? Are there test devices available to check if there is signal loss on the coax cable? Why would some QAM channels be fine, and others horrible, and yet the Sage tuners have no problem?

TIA

[Mitch G]

Some thoughts, suggestions, ideas:

1) From research I've done in the past, there really isn't consumer equipment for measuring signal strength, noise, etc on coax. So, you just have to work in the blind a bit.
2) Be sure all you coax connections - including any coax-splitter or coax-coax connections - are tight. Not just hand tightened but pliers/wrench tightened.
3) Maybe I'm wrong, but I don't think from an amplifier's point of view it matters if you are watching analog or digital programming. So, go ahead and try your spare amp to see if that helps.
4) I don't think you broke anything. I've seen cases where just rearranging coax cable behind a TV without disconnecting it can result in signal quality changes. Coax is funny stuff and if there's even a small RF leak you can have all sorts of problems.
5) I've had success using Nim-100 ethernet over coax adapters i bought on e-bay (~$70 for a pair) to connect an HD100 on the second floor to my server in the basement. That said, I do have a solid QAM signal there. But, to be honest, the Nim-100s might be fine even if the viewing signal quality is spotty. Using these devices would avoid having to run ethernet cables and thus solve your root problem related to using the HD200 to watch HD on the TV.


Hope some of this helps, at least,


Mitch

[bnh]

thanks for the reply. I will try the amplifier and prolly ditch the remaining non-RG6 cable...that way i think all the connectors would be factory installed.

i hadn't heard much of ethernet-over-coax devices. Obviously the PC end would have one device, but where does the other go? Anywhere on the coax network, or should it be on a separate port on the router?

[Mitch G]

The ethernet over coax stuff basically works like this:

cable feed/splitter/amp/whatever --*coax*-- NIM #1 --*coax*--NIM #2--*coax*-- TV

Sage server/router --*ethernet*-- NIM #1

NIM #2--*ethernet*--HD100/200

[bnh]

i finally got around to ruling some things out during this week. I replaced all coax with RG6 and factory connectors, and swapped in the spare amplifier. No change.

I then hooked up a Samsung QAM/ATSC tuner from the upstairs bedroom, and was pleased to see a beautiful HD QAM signal. Then after much grunting, i managed to fish some cat5e ethernet down into the basement from my router, and can get nearly watchable HD livetv playback on the Sage client (the client is a little underpowered: Pentium4 class).

So it appears i did something to the TV's tuner somehow, since it was working just fine until i moved it around a bunch to install the Sage client box... maybe i crimped the input jack somehow? I don't really want to go through the hassle of seeing if it can be repaired, so getting the ethernet cable hooked up, at least affords me the possibility of upgrading the client to something more HD capable and using Sage to view livetv. I guess i won't be experimenting with the ethernet-over-coax devices after all.

it could still be something else i'm overlooking, but i would recommend exercising caution when shifting a TV around. This is a Toshiba 65" DLP, got it from Circuit City (RIP). The analog signal is fine...just most (not all) of the QAM channels are goofy.

thx