Tv Converter Box Problem (1 Viewer)

Hello to all...this is my first post, however, given my (personal) AV equipment and my lack of understanding much of how it works, it's probably not my last!

My ladyfriend has two analog TVs for which we purchased a pair of Zenith convert boxes. She live in a high-rise condominium which has a hugh antenna serving the entire building. I hooked one of the boxes up, which went quite easily, however, of the channels she WAS receiving (8), four of them are now absent. I expected this after reading this and other forums about the issue...during which I also decided to purchase the Zenith (Insignia clone) with the LG chip...since many folks had noted loss of weaker stations.

BUT...one of the now-absent stations was one of, if not THE, strongest stations she'd been receiving. With the converter tied-in, it shows "No Signal". Initially I thought that particular unit was bad, so I pulled it off and put the other box on...same deal..."No Signal".

I don't get this one folks. We're in the Washington, D.C. area and I'm referring to Channel 4...one of the monster local channels...NBC!

Any ideas? Thanks in advance if you can 'splane this to me.....

Rhino

What type of antenna is serving the building a VHF, UHF or combo antenna? Have you checked your location at Antennaweb.org to see the frequencies that the digital channels are broadcasting on? Do they match up with the antenna type? How close are you to the antenna farm? Very close and you can actually overload the tuner and it won't work. Or the building can be boosting the signal and you the same will happen. If you are close enough, you can try a cheap indoor antenna.

-Robert

Robert_], Thanks for the input.

To be honest, I don't have any idea what type, size or even location of the antenna serving my gal's building. It's a ten-story condo building and I assume the antenna is on the roof. To the best of my knowledge all the units have coax connections to it (them?). I don't think the problem is signal over-boost from what I've seen...i.e. the channel never ghosted or clipped. I'm not 'radio savvy' enough Robert to identify frequency matching properties of the antenna. The transmitter antennae are about 17 miles distant. It seems your take on it is too much signal...I'll try the box on her other TV which has only rabbit ears (the coax isn't plumbed to her bedroom). THAT should identify if the box is overloaded. Thanks again.....

Rhino

First, as to the best converter box, go to ConsumerReports.org - DTV converter boxes ratings to check out the best boxes.

As to channel 4 lack of reception, I looked up Washington on antennapoint.com. All the stations are UHF except ABC and all on the same compose heading and as you said, all within 17 miles. Since you lost NBC (digital channel 48), your building antenna may be your problem. In metro areas like DC, with multiple buildings, you have to deal with Multi-path, Multi-path signals reaching the antenna out of phase can confuse the ATSC (Digital) chip set in your converter box (or digital TV tuner sets).

If the signal reaching the front of the antenna is not 2 to 3 times stronger than a bounced signal from the same station reaching the back of the antenna, the ATSC chip doesn’t know which signal to use, so it just keeps searching.

The answer, at the distance you are from the towers, is to buy a new indoor antenna tuned to receive digital signals and help reject Multi-path signals, working with the ATSC chipt set in your tuner.

Signals bounce off walls also in apartment also, so if you try an indoor antenna, move it around the room, to find the best location for it, aiming it in different directions as you watch the signal strength on channel 48. When it’s the strongest, check your other channels.

Buy your new antenna from someone who will refund your purchase price, no questions asked, until you find the right antenna.

Thanks a bunch for the reply Mike. Sounds very much like you're on to the problem...channel 4 is VERY strong where my gal is...which is why its absence stumped me to begin with. Since I posted the original question(s) a couple of other folks have mentioned they, too, are having problems with 4, and they are not in Patty's building. I really don't know much of anything about radio/TV waves...frequencies, 'multi-path', bandwidth, digital-analog or otherwise. There has been some discussion...which may (and probably is) be bogus rumor...about channel 4 changing is broadcasting paradigm as we get close to the mandatory Feb '09 date of change-over. I doubt that will have any effect, but I honestly don't know. Based on what you've offered, I intend to hook one of her boxes up to the rabbit ears she has in her bedroom. If bypassing the roof-top antenna results in channel 4 reception, the equation will be solved per your suspicions. Thanks again for your input.