AVS Forum banner
Status
Not open for further replies.
1 - 12 of 12 Posts

·
Registered
Joined
·
92 Posts
Discussion Starter · #1 ·
Moved into a house in the suburbs of Chicago. I am guessing that I am about 40 miles from the Sears Tower where I believe most stuff comes from. The attic has a very large antenna that the previous owner used to get OTA. I have no idea who makes it or basically anything about it.


My question is if I can get a decent analog picture now, will I be able to get a digital picture as well? I am about to buy a Dish 6000U and would like to know if I am going to need a new antenna.


I went through the antenna finder at antennaweb.org and it confused me. When I put in my address it brought up the yellow, green. light green, blue channel assignments. All the local-DT channels I want were in yellow and the analog locals that I am getting were in blue. Does this mean that since I get the blue channels I should receive the yellow ones as well. Maybe I'm looking at this the wrong way. Please help.
 

·
Registered
Joined
·
491 Posts
mukaman...first off, you typically need a UHF antenna to receive HDTV signals. so it wouldn't be surprising to see antennaweb.org list 2 different kinds for VHF and UHF. Antennaweb.org should tell you the distance to your transmitter(s), and based on that, you can make your decision. You may want to hook up a analog tv to your existing antenna to see if UHF channels come in strong, and ghost free. If they do, you may be able to use the one that's already there...
 

·
Registered
Joined
·
1,033 Posts
I agree, try the analog channels first. The big thing you need to be concerned about is whether or not there is any "ghosting" on the analog UHF channels. This is an indication of multipath, which is the bane of digital reception. It really doesn't mattr how "snowy" the analog picture is, even if you lose color, as long as there's not a lot of ghosting.


-- Gary
 

·
Registered
Joined
·
491 Posts
Gary, what's ghosting? jk
 

·
Premium Member
Joined
·
7,093 Posts
It shows up on analog broadcasts as a ghost image, like the main image but offset to one side and much weaker.
 

·
Registered
Joined
·
92 Posts
Discussion Starter · #7 ·
As always quick responses. Thanks!!!


I have already hooked up the antenna to my analog TV and get a decent picture on all channels. Some do look a little snowy but no ghosting. Sounds like I might be fine for the digital channels. It also does not look like I have an amplifier so any simple Radio Shack ideas. Will it even help or just make a snowy picture more snowy?


Still confused about antennaweb.org. Why would the digital channels only require a yellow antenna when the aalog channels require a blue. Both signal come from the same place, is the digital signal simply stronger thus allowing a 40 miles away house to get the signal with a simple yellow antenna.


Thanks again for the input.
 

·
Registered
Joined
·
32,172 Posts
The digital signal is far more forgiving. I have an antenna in my attic and when I try to watch analog channels they are all snowy. None are "watchable."


On the digital channels, broadcast from the same towers and at much lower power levels, I get a beautiful crystal clear picture. First of all, the tuner is able to distinguish between "signal" and "noise". Second of all, the signal has some level of built-in error correction (I believe) to allow for it to be "fixed on the fly.


It's wonderful how easy it is -- relative to analog -- to get a pristine digital picture.


You probably won't need an amp for digital. It might help for analog, but only if you have a good amp and then still only maybe.


Mark
 

·
Registered
Joined
·
3,594 Posts
Quote:
Second of all, the signal has some level of built-in

error correction (I believe) to allow for it to be "fixed

on the fly.
8vsb is fairly heavily coded. A 187/207 Reed-Soloman code

is used on top of a 2/3 rate Trellis code. The actual

channel rate is 32.28 Mbps, so 40% of the bits are

used for error correction.


Ron
 

·
Registered
Joined
·
92 Posts
Discussion Starter · #10 ·
Thanks rogo for the added input. It sounds like I should be fine for the digital signal. Time to buy a 6000U.


dr1394...holy smokes. I am clueless on what you said. I need to order the 8VSB as well since I do not have a choice. Is what you said about the 8VSB good news for me or bad news.


I'm sorry to throw another question out when I'm sure there is an answer in antenna 101, but I do not recall reading it before. How do you know which way to point your antenna based on the degrees provided by antennaweb.org? Is there one end that should point in the direction of the tower and how do you determine which end.
 

·
Registered
Joined
·
386 Posts
Analog signal strength is not necessarily a good harbinger of one's ability to receive the simulcast digital signal. As of today, digital broadcast stations are not required to replicate their analog service area.

Because of the relatively small number of digital viewers, many stations are choosing to operate their digital facilities with reduced power and save on energy costs. Antennaweb does not consider the actual operating parameters when providing their rudimentary propagation analysis.


In my experience, 40 miles is quite a distance to receive a stable digital signal -- especially with an attic antenna. Hopefully, you have favorable terrain conditions between you and the transmitters.
 
1 - 12 of 12 Posts
Status
Not open for further replies.
Top