Broadcast HDTV reception problems

February 15, 2006 9:28 AM

How can I fix my broadcast HDTV reception problems?

I just bought a used DirecTV set-top box that receives ATSC, or broadcast digital, signals. I found a deal on a Toshiba DST-3000[pdf]. I picked it because it was the cheapest I found that received DTV. I get through the setup fine, scan for channels, and it finds only a few of the 8 analog signals available and only one of the 6 digital signals available. When I tune to the signals it did detect, or look at the signal strength meter on the setup display, there's basically nothing except for one channel where I can almost make out that there's a picture.

I'm using standard, unpowered VHF/UHF rabbit ears which allow me to get every local analog channel when I connect it via coax to either the VCR or TV's tuner. I've chained the digital receiver to the VCR, to the TV via coax. I've also tried using RCA connectors all the way. Nothin'. Whether the digital receiver is turned off or on if it's in the chain and I try to use the VCR or TV tuner I can't get any of the channels that I normally get clearly with this set of rabbit ears. This is true of both VHF and UHF. The farthest broadcast tower is no more than 10 miles away. The rest are about 6 miles.

I bought this box because I read that even crappy reception rendered great pictures with DTV, plus I'd add some PBS channels. There's no DirecTV Dish attached. I don't want cable or sattelite. I don't want to spend $200 plus on a purpose built ATSC receiver when this $70 box should have the same functionality.

I've looked at this previous question.

posted by putzface_dickman to technology (12 comments total)

why not just buy a coax splitter, hook one input to the STB, one input to another antenna (or get a Silver Sensor and use the rabbit ears for analog on this input), and deal with the 2.5dB loss from the splitter - call it a day?
posted by kcm at 9:51 AM on February 15, 2006

My buddy had the same problem; he went to Radio Shack right before the Super Bowl, picked up the cheapy antenna for $20 (with a scoff from the employee) and added quite a few HD channels to his line-up. He has digital cable, and before only received the IN-HD and PBS channels. Now he gets all the regular broadcast channels and it looks amazing.

I'd recommend getting a booster antenna, but don't be distracted by the expensive ones. try out the cheapy!
posted by blastrid at 9:52 AM on February 15, 2006

Just to be a bit more explicit about what I'm asking:
I want to use this set top box to view digital broadcast television. So far I can't watch anything with it. Why doesn't it work now? What should I do to try to make it work? What are the odds of it working? Am I mistaken in believing this should work? Would a new or differently positioned antenna work better than an antenna that seems to work well enough in another similar application already? Why? Are there inavoidable additional costs or considerations? Proviso? Addenda? Caveats?
posted by putzface_dickman at 10:15 AM on February 15, 2006

okay... well one problem may be that sometimes these D* receivers wont do anything, even ATSC, without a subscription to D*.

also, this is a first generation receiver and as such it will have all kinds of problems with multipath, or may even have problems if the signal is too strong.

having said that, if you can see the analog channels with no snow and no ghosting, you don't have a problem with multipath.

keep in mind that the digital stations are (for now) mostly on UHF channels, so your antenna might need upgrading as blastrid says. i would start off with the "silver sensor" which can be bought very cheaply. its UHF only, but should do okay with some of the higher VHF channels.

another tip is to check antennaweb.org to find out what digital stations are on what channel, and which way to point your antenna.

finally, you might have more luck finding someone who is using the same receiver over at avsforum.com.
posted by joeblough at 10:25 AM on February 15, 2006

First make sure the 'TV/VCR" switch is on TV, so it's RF (Channel 3/4) output is not stomping on the downstream signal.

If that doesn't clear things up, I would take things to the cleanest possible level and remove variables:

Antenna-(coax)->HD Receiver -(rca)-> TV

Does "all local channels" include UHF stations (> 13)? Your typical rabbit-ears-only antenna is strictly VHF -- UHF will usually have some sort of loop.
posted by SpookyFish at 12:52 PM on February 15, 2006

There is a UHF loop. 28,34,&53 are fox, pbs, upn in my market. I receive all 3 well w/o the set top box.
posted by putzface_dickman at 1:19 PM on February 15, 2006

Also, the menu displays from the set top box look great. It's just that there's no broadcast reception.
posted by putzface_dickman at 1:20 PM on February 15, 2006

Just to verify:

Antenna is connected directly to "IN FROM ANT"
Installation, 'Dish Setup -> Dish Type' = None
Installation, 'Local Area -> Local In 1' = Antenna
Installation, 'Local Area -> Local In 2' = None

Beyond that, I'm out of suggestions. Take it to a friends with a known good connection perhaps?
posted by SpookyFish at 4:28 PM on February 15, 2006

Go to avsforums, specifically their forum entitled HDTV Reception Hardware. Read the "sticky" posts up top first, then search for your issue, then post queries if needed, in that order. There's a pretty good signal-to-noise ratio over there.

Don't get dismayed if you find out that everyone there says that your MegaCorp GeeWhiz 2000 receiver is a piece of crap. There's always someone who says that and you're stuck with it now, so make the best of it.
posted by intermod at 8:01 PM on February 15, 2006

Here are the things I've learned:

Broadcast HDTV reception is fundamentally a bitch. That stuff about how it's so much clearer, how you get a perfect image is only true under certain conditions. See the linked article for details.

If you're buying equipment to receive broadcast digital, factor in the cost of a new antenna. The one that's adequate for your analog setup is probably not going to cut it for digital. Best results with outdoor antennas. The higher in the house the better with indoor.

Basically every DTV channel is broadcast in the UHF band. Those DTV channels with numbers lower than 13: They're spoofing to a higher channel. Antennaweb.org will tell you what the actual frequency is, the distance of the transmitter and how gnarly your antenna set up needs to be.

That antenna you see labelled as an HDTV antenna: that's a UHF antenna.

AVSForum is good.

The Hughes and Mitsubishi set top boxes that are as old as the one I bought, I'm told, are the same box.

These following things are true in my situation. YMMV.

A digital set top box needs way more antenna than a run-of-the-mill VCR, even for analog.

DTV channels will only display if the box can "lock" on the signal. Too little signal strength for a lock? No show. Not even snow.

I was able to get 1 DTV channel, and no analog channels through my set top box with a similar, but amplified, antenna in the same location as the antenna I already had. Luckily I just borrowed this second antenna. Now I know that the thing works. I don't know if my antenna problems are just par for the course, or a deficiency for this model of receiver, or a deficiency of my particular receiver. I am now set to begin an antenna arms race. I'll post back with whether elevation, amplification, or size makes the most difference.

Thanks all.
posted by putzface_dickman at 6:11 AM on February 16, 2006

So I monkeyed around on the weekend with an indoor antenna and learned some things I want to share.

First, all of the channels I want to get are to the east, ranging from 36 degrees to 108 degrees. The lone exception is at 189 degrees.

So it seems that it is pretty important to have the antenna on the right side of the house to get the best signal. First floor, indoor, east side worked better (2 channels) than 2nd floor, indoors west side (0 channels) and better than outdoor, west side, ground level (1 channel).

The house itself seems to offer serious interference. The more house between the antenna and the signal, the more trouble.

Since east side, indoor, first floor worked best I moved outdoors on the east side of the house. Even though I basically was only removing a single wall's worth of interference, I got a 3rd channel by moving outdoors.

Since outdoor seemed to be the way to go I bought an outdoor antenna. I picked the Radio Shack $25 UHF only antenna and needed the 300 ohm to 70 ohm transformer -this basically converts from twin lead to coax - ($5), Mast ($5), Wall mounting brackets ($15). I already had 100ft coax cable.

It looks like Lowes carries a $35 antenna that might be a better value, but it wasn't in stock anywhere in town.

With an outdoor antenna, initially mounted on the back deck 6 feet from the house, I was able to get all 6 HDTV channels with it pointed toward around 20 degrees. This took experimentation. The one HDTV station that was at 189 degrees came in intermittently. I think it worked because my antenna was pointed directly away from it, that must work too. Oddly, one of the two channels that are broadcast from the same broadcast antenna worked perfectly, while the other only intermittently.

On Monday I mounted my antenna at the roof line on the north east corner of the house. I got every channel to work, but the one to the SW seems strongly affected by the weather & time of day.

The DirecTV set top box still does not display analog channels at all. They are nearly perfect on the VCR's tuner which I connected to the new UHF antenna with a splitter like kcm suggested. That UHF antenna produces good images on the VHF channels too, but those towers are close by and high powered.

The guy at Radio Shack also suspected that most set top boxes must have a high signal threshold for broadcast DTV reception. Our ABC affiliate won't let the cable company show their HDTV broadcasts so a lot of other people have bought outdoor UHF antennas recently to pick up that one channel.
posted by putzface_dickman at 11:15 AM on February 22, 2006

Eight months later & I have come to some conclusions and discoveries that I should share.

1. The 2 eight story water towers 200 yards north of my house are notorious for causing multipath interference. Many of the houses on my street have enormous antennas to overcome the problem. My difficulties with reception were extreme because of the specifics of my situation. The neighbor who has lived in her house for 50 years confirms that the street included many early adopters of cable because of this.

2. Reuse a DTV set top box for broadcast HDTV only if you have it lying around, or can get it very cheaply. I added 4 channels without any antenna changes by upgrading to a purpose-built Samsung SIR T451, currently available on ebay for around $120.

3. A friend who lives 8 miles farther from the major broadcast towers than I do, but doesn't have a nearby structure to disrupt signals, was able to get every channel I do with unpowered rabbit ears with the SIR T451.

4. Amplifying the signal from your outdoor antenna should be the last thing you try. Height, direction, and size all make more of a difference than amplification.

5. Choosing a fixed Direction for your roof mounted antenna is all about compromise. Height should always be the maximum height you can manage. Use antennaweb to determine the size of your antenna.

6. You current TV will look pretty good with broadcast HDTV.
posted by putzface_dickman at 1:30 PM on October 2, 2006