Help with Digital TV/HDTV antennae

Factual Questions
1

I’ve recently taken the plunge and purchased an HDTV. I have an HD cable box now, and it allows me to get some cable-only HD channels (ESPN and the like), as well as 3 of the 6 local broadcast stations’ digital versions. But, I want to use an antenna for over-the-air viewing of the digital broadcasts. One reason is that I need it to get the 3 stations whose digital versions aren’t carried by Time Warner. The other reason is that, even for the 3 that are, the image quality is better when I capture it over the air. My TV has a built-in HDTV tuner, so it’s only a good antenna that I need. And all the local broadcast affiliates have their digital stations on UHF, so my antenna needs are fairly simple.

I purchased a little amplified loop antenna, and ripped off the rabbit ears because I think they were hurting UHF reception more than they were helping. So I had just the amplified UHF loop. It works to get all of the available stations, but not at the same time! I can get 3 or 4 of them in one position, and I have to reorient the antenna ever so slightly to get the other ones. The interesting thing is that all the stations I’m trying to receive are broadcast from the same place, a ridge about 8 miles away.

Well, I don’t want to get up to move the antenna every time I change the channel…that makes surfing very hard. And it’s obvious that my locaton is on the fuzzy edge of where this antenna is effective. So I need something better. I plan on putting an antenna up in the attic of my one-story brick ranch. I’ve run a length of coax from a wall jack up into the attic awaiting the eventual device. But I don’t know what to put up there. The UHF loop isn’t effective up there without power, and for obvious reasons I don’t want to leave a powered device up in my attic, even if I had a place to plug it in.

I see a lot of different high-gain designs that are supposedly more efficient than a UHF loop. But I have no sense for which is the best kind, because my antenna theory is somewhat shaky (that’s an understatement). There’s the grill-and-bowtie type, shown here and here. There’s the mini-multi-element type like this. And of course, there’s the classic roof-mount antenna. A UHF-only version would be small enough to mount in my attic, if that would even work. Roof mounting is not an option, because I hate ugly roof antennas. Then again, I’m starting to wish I hadn’t torn the big mast down when I moved into my house 3 years ago. I never would have guessed I could use it now.

I need nearly the full UHF range; the frequency assignments run from 18 to 53. Something directional is okay, and probably preferred given that all the stations I want are within 9 degrees of each other from my house. I don’t care how ugly it is, because it’s ideally going to be hidden. So…

Which of the above options are the best? Or can I just make one out of some rusty coat hanger and PVC pipe? :wink:

2

I’d suggest going to antennaweb.org and plugging in your zip code. It will tell you everything you need to know about your particular location and where the towers are in relation to you.

I’d go more into depth, but my boss is lurking and might jump into my office at any time.

3

Any chance you can mount a traditional TV antenna on the roof? I just got an HDTV, and I had basically nothing but headaches with indoor antennas. (I"m not saying all indoor antennas are bad, that was just my experience.) For about $50 I got a new antenna and put it up on top of my house, and now the signal strength from all the local HD channels is 125% of full strength, according to my HD receiver.

4

Ooops, missed the last part of your post. But a rooftop antenna works fabulous for me.

5

The Gemini antenna that you mentioned, also sold as the “Silver Sensor”, has received many excellent reviews. It’s supposed to be the best indoor antenna for HDTV. For outdoor antennas, there are many good UHF-only antennas.

Beware of feed-line loss. Keep it as short as possible. There’s no point in putting a good antenna on the roof, or in the attic, only to lose most of the signal to feed-line losses, which are significant at UHF.

6

Airblairxxx, I’ve already been there. That’s how I know what direction and what distance the towers are from me. As I mentioned in my OP, all the local digital towers are 7.5-8 miles from me, and range from 291-300 degrees.

I’m leaning heavily towards putting this guy in my attic. It’s a UHF Yagi with a corner reflector. It’s highly directional…which is good since I only need one direction. It seems to be a common choice for situations similar to mine, from what I can find with some cursory web searching.

But I’d still like the input of the Dopers who know this stuff.

7

mks57, how do you recommend minimizing this loss? I’ve got a 12-ft length of decent-quality coax running from my newly-installed wall jack up into the attic, awaiting a new antenna. It’s got to be 8 ft just to get above the ceiling. Is this short enough?

Of course, I’ll also need a transformer to connect the coax to the terminals of the antenna, if I go with the roof-mount-in-the-attic option. I’m guessing handing over the extra couple dollars for a gold-plated one is worth it?

8

That should be fine. People start having problems when they use long runs (more than 50 feet) of cheap coax that was installed twenty years ago. Coax does not improve with age.

Gold plating doesn’t buy you anything. Since it’s in the attic, you don’t have to worry about weatherproofing the connections, like you would for an outdoors antenna.

9

12 feet of RG-6 coax will be essentially negligible in terms of signal loss, as long as you don’t squash it in the installation or mess up the ends. Your roofing materials will cause greater signal loss than your short run of cable. The main concern is old places with 300-ohm twinlead or old RG-59 coax, either of which leak out (and in!) more signal than they carry.

As for spending extra for a gold-plated balun, not unless you’re looking to color-coordinate the attic. Just be sure it’s rated for carrying the full UHF band, which nowadays, is a non-issue.