HDTV OTA - Antenna placement

[tthurman]

While in the process of incorporating my new HTPC into my set up, I've decided to put my digital convertors into service for something other than temporary work. I took the coupon deal a few years ago to get a couple TIVAX ST-8's, which seem to work pretty good. The remote sucks though, and you have to be right at the box to get it to work, regardless, I'm curious as to others experience with this.

I live on one of the larger ridges in Knoxville, and aim at Sharp's Ridge where the antenna farm is. I'm fairly certain that Sharp's Ridge is higher than where our house is located, which is nine miles away. We are three houses down from the highest point of our road, and surrounded by sixty feet plus trees. To aim towards Sharp's Ridge I have to aim up hill, so I am pointing at these trees, and my neighbors house at ground level.

I'm using a Antennas Direct DB2, and pickup anywhere between 16 - 20 channels with the antenna out in the driveway. I've started playing with placement last night in the house, and still get several channels with the thing just sitting atop my equipment rack. Problem is that I'm missing some of the big ones like NBC, CBS, and I REALLY want to bring in college football.

[cburbs]

You need to try and get the antenna on the roof or in the attic.

[tthurman]

Yep, was hoping to avoid the attic, roof mounting is a no go in our neighborhood. I figure I'll get a J mount, and position it on one of the rafter cross members in hopes to get it as high as possible, which will still be slightly below my neighbors roof line.

After doing a lot of reading it's amazing the massive swing in results people get with various setups.

[Bass Addiction]

In the attic for me and I live on a hilltop but located in a decent depression causing me to aim uphill and towards the trees. I am pretty sure that I am about 9 to 10 miles away from the main antennas. I get 40 channels at the moment...

[sandtrap]

Your HOA or municipality cannot outlaw roof mount

http://www.fcc.gov/guides/over-air-reception-devices-rule

Basically, You can mount on any property you own where you can get a signal and nobody can stop you.

If you don't want to try that is your choice, but they can't stop you.

[Mike4AU]

Try the attic. Hook up a TV in the attic to determine the best position for the antenna. If that does not give you good results, the HOA cannot stop you from placing an outside antenna on your property. That said, wifey may stop you from placing it outside.

[tthurman]

Hmmm, that's good to know about the antenna.

Well, I guess this will be a fall project, no way I'm getting in an East Tennessee attic this time of the year. :whew:

I have been playing around with placement inside the house though, and after picking up around 19 channels on the first floor with the TIVAX, I was surprised to have moved up a floor, on the same side of the house and everything, and only get 10 on my Samsung. Perhaps the Sammy turner isn't as good, as I would think the added elevation would do nothing but help, 15-18 more feet, and I'll be where it's going to be in the attic.

[HopefulFred]

I'm no kind of expert, but I feel like for a little bit of time and effort, you could probably do a lot better. Primarily, isn't that tuner analog output (SD) only? That's up to you, but why not put a tuner card in the HTPC and feed it the raw antenna signal? Then you can record the Vols all season long in HD.

The gamble, and the parts I have mixed experience with is antenna placement and selection. My situation is slightly different in that I am generally closer to the antennas here in Atlanta, and they are not so tightly spaced geographically. If I am interpreting your situation correctly, you've got a number of fairly strong broadcast signals coming from within a few degrees (say 10-15, maybe less) of the same direction, but you have significant interference at your end of the transmission line. It's my understanding that multipath rejection should be of primary concern for you, and maybe the DB2 isn't your best choice. There's probably plenty of signal strength, but the reflected signals and scattered garbage coming through the trees and off your neighbors' houses makes it tough for the tuner to lock onto the signal (because of all the noise from reflections). I think a yagi in your attic will be a simple and cheap way to really dial it in. http://www.dtvusaforum.com/dtv-hdtv-...ses-cures.html

Would you be using cables already installed in your walls? That really can simplify the whole process if you can tap into cable runs already in place. That's what I've done by using the mast the previous owner of my house had installed on the roof for the satellite service they had. I just pulled down the dish they left and clamped my new antenna onto the mast, then switched the splitter connections to the fittings designed (impedance?) for terrestrial broadcast (again, already tacked on the the outside of my house).

Like I said, I'm no expert; but if you've got the infrastructure already in place (the wiring) trying a few options would be totally worthwhile.

Fred

[ben9732]

Fred has some good advice. I'd also mention that what is in-wall and used as an exterior wall or roof covering may also affect your signal grabbing ability.

OTA can be weird. I've got an antenna from England that was rated to be very good about a decade ago. It did very well and I had to adjust it within a few degrees to get it perfect. Two years ago we were forecast to have a hurricane so I went up on the roof and took down the array leaving only the receiving wings up there with the wire wound around the pole and the wings at the shingle level at no particular direction. Damn thing works fine and I've not put the array back up.

[tthurman]

I think the tuner is SD, but I figured I'd try it before investing more into this venture. If it works, I'll for sure be getting a card for the HTPC.

Then you can record the Vols all season long in HD.

It would be nice to think this could be a bearable situation.

I never thought about multi-pathing, but it makes since, all the channels I really want are within 5 degrees, and all at 8.6 to 9.0 miles out. I've worked with DirecTV guys dealing with the same problem downtown less than a mile from the towers, but figured that was more or less created by signals bouncing off the steal structures, never proximity of the towers being so tightly bunched. Now that you mention it, it certainly makes sense as they addressed this issue with individual specific bandwidth antennas that are highly directional.

Unfortunately I'll have to run new cable, but fortunately I've got a pretty good path. I'll hook the antenna up and drop a cable to the upstairs TV to test prior to doing anything permanent. Never thought of the DB2 pulling in to much signal, I'll check into some other options. Looks like the U-75R has been discontinued at Radio Shack. I have a feeling the trees are a big problem here, I made a make shift mast out of a piece of unistrut and stuck it out in the driveway, and get in excess of 24 channels, all good and clean.

In the attic I would be going through 3/4 plywood and asphalt shingles. Siding and OSB for signals coming through the exterior walls. Gives me some stuff to play with for sure, thanks for the suggestions guys!

[paw]

AVS has forums for OTA. There's probably one for Knoxville. The Denver one is very laid back, friendly, helpful, troll and drama free. Unlike some other AVS forums. :peeping:

[HopefulFred]

I have a feeling the trees are a big problem here

This is probably true. Trees near my house are at least 20 feet higher than my antenna and cover pretty much the entire arc between me and all the towers - nearly 40 degrees in my case. I tried to (perhaps not very successfully) chose an antenna with good multipath rejection, but those antennae are highly directional - a problem in my case but not in yours. I notice more frequent problems in the spring and summer (after the trees have grown leaves) than in the winter. Also, as a storm blows in, the wind in the trees alone can cause a break-up of the signal.

[tthurman]

I did check out the AVS OTA forums, thanks for pointing that out!

Fred, I've been reading that site you linked quite a bit, and found one of those RS antennas, but after some more antenna moving, I'm getting all but one of our major networks with the DB2 on my one foot tall unistrut stand on the floor of our second floor bonus room. Basically I took a big foot door stop, and used it to tilt the antenna upwards in hopes it would resolve signals bouncing off trees and my neighbors house. To my amazement, it worked, and I'm getting everything but the VHF one. Before I commit to the attic I'm going to try a Terk HDTVi (doesn't appear I need amplification offered with the "a" version) since it is more directional and rejects multipath better, all my channels are in the same general area so it seems plausible that it may work especially considering it has VHF rabbit ears too.

[HopefulFred]

You never know what will work until you try.

:cool:

[tthurman]

Well, didn't turn out to be the be all to end all answer, BUT it does pick up VHF, which in our area is the NBC affiliate.

I've got it tuned in to pick up the Olympics,and pretty much don't care about anything else right now. I called my wife upstairs to see it as I switched between Ant A and B, with both tuned to NBC, the difference in HDTV OTA is breathtaking compared to the Comcast feed.

As soon as the weather allows, I see the antenna going in the attic and a SiliconDust HDHomeRun Dual being installed.