I searched and searched and searched the internet. Not a single site will simply outline the frequency spectrum from VHF channel 2 to DTV channel 60whatever.

How are you supposed to know if a standard UHF antenna will work? How are you supposed to know if a given preamp or postamp will work for the DTV frequencies. I've had it. Not a single site will do any better than explaining the old UHF 69 = 809 mhz (or something like that). Where on the spectrum is HDTV?

Can anyone enlighten me?

Digital broadcasts (which may or may not contain HD content, although the HD content % has definitely been going up) use the exact same spectrum as their analog ancestors. Most, but not all, of digital broadcasting occurs in the UHF portion of the spectrum. Here in Boston, all digital stations are in UHF.

For example, analog CBS broadcasts in Boston on VHF channel 4. Digital CBS broadcasts in Boston on UHF channel 30. When I enter channel 30, my STB reads some mapping data sent along with the video signal and "maps" it to channel 4. After it's in my STB, I can enter channel 4 for CBS (which people in this area will do quite naturally) and it pulls up digital CBS, which is actually broadcasting on UHF 30. The STB knows that when I request channel 4, I really want 30. This part was very confusing to me when I got started with HD.

Go to TitanTV.com and enter your address. It will tell you what digital channels are broadcasting in your area. The first number is the regular 'ole channel on which the station is actually being broadcast. The second number is the probably more recognizable corresponding analog channel.

As for an antenna, any VHF and/or UHF antenna will suffice, no matter how many decades you have had it. Many people find that they're able to receive the digital stations better than the analog stations (better in the sense of no dropouts, since there's no such thing as a snowy digital picture). If you've got an old junker on the roof, use that. If you're within 20 miles of the broadcast towers, a simple indoor antenna sitting on top of the TV will probably do. Some salespeople will try to sell overpriced "HD Antennas" but its 100% marketting. If you are only looking to pick up UHF signals, the single most highly recommended antenna is the Radio Shack double bowtie (model number 15-632), now selling for under $5, although you may have to call several Radio Shacks to find one that still has it in stock.

Sorry for the very rambling response, but you weren't exactly clear in what you were asking and I wanted to cover all the bases.

Joe

There is no spectrum specifically designated for DTV...its all just re-using existing defined channels in either the VHF or UHF bands.

All TV channels (VHF, UHF) are actually 6 MHz bands centered on a designated carrier frequency. The frequency of the carrier determines if the channel is VHF or UHF.

VHF: The VHF channels (2-13) are around 100-200MHz. By definition, VHF is anywhere in the band between 30 and 300MHz. They channels are actually broken up into several different areas within this band, but that's not overly important. This is where the networks have been for 50+ years. The VHF spectrum is shared with FM radio, marine radio, etc. Ranges are slightly beyond direct line-of-sight. This band is pretty crowded.

UHF: UHF channels (14 and up) are also 6MHz wide, and have carriers between 300-3000MHz by definition. Again, not continuous, they are clustered in several areas of the band. UHF is shared with military communications, and others, but there is a lot more room here. Range is a little shorter, but generally less susceptible to interference.

When the FCC mandated that all stations begin to transition to digital broadcasting, they "loaned" every broadcast station a second 6 MHz channel until 2008, or whenever the transition is supposed to be complete. There is more room in most cities in the UHF band, so most DTV simulcast stations are up there. There are few DTV stations that are in VHF, however. You need to check in your particular area.

So any DTV transmissions from "channel 11 WBAL Baltimore NBC" are actually on channel 59 UHF. The old analog signal is still sent out on channel 11 VHF. Some DTV decoders will list the digital signal they receive as 59, some as 11, some as 11-1, some as 11D, some as 59-1...there is no standardization on how to display the channel #.

Within the 6MHz DTV channel, a station has several options, all of which meet the FCC requirement: use it all up to send out HDTV, use a small portion to send a digitized SDTV (480i) signal, use some more to send out a 480p signal, send out 2 or 3 different SDTV signals, etc. As long as its digital and at least one portion has a TV program signal in it, the FCC doesn't care. So you will see "59-1" "59-2" "59-3" subchannels sometimes. In reality, most stations don't do this- too expensive to carry 2 programs at once.

Once the FCC determines that all stations are 100% simulcasting in digital, they will "take back" the loaner channel, the analog signal gets shut off, and the digital-only broadcast will shift to the "regular" channel.

We have the following VHF/UHF "old-fashioned" analog channels:

2 (CBS/WBBM)
5 (NBC/WMAQ)
7 (ABC/WLS)
9 (WGN/WGN)
11 (PBS/WTTW)
32 (FOX/WFLD)
etc.

The NEW channels as my Mitsu TV shows on channel search:

3 (2 from above)
31 (32 from above)

When I see that old channel VHF! 2 has a DT on channel 3, this isn't VHF channel 3, is it? IOW, is my UHF-only antenna preventing me from picking up channel 3?

I understand bandwith etc. It would be SO much easier is someone just produced a spetrum so I could see that, for example, channel 3 DTV is NOT a VHF but a UHF.

Again, how am I, the consumer, ever supposed to know what antenna to buy and/or why I can't pick up various stations withOUT someone providing a freq. spectrum for each channel. With this type of grief, HDTV has little chance of going mainstream.

Channels 2-13 are VHF, 14-69 UHF... It's that simple. Your CBS-DT station in Chicago is on channel 3, so it's in the VHF band. Digital has no band of its own, it's either VHF or UHF. Your UHF only antenna is keeping you from receiving channel 3.

Bobby C

Someone above stated:

So any DTV transmissions from "channel 11 WBAL Baltimore NBC" are actually on channel 59 UHF. The old analog signal is still sent out on channel 11 VHF. Some DTV decoders will list the digital signal they receive as 59, some as 11, some as 11-1, some as 11D, some as 59-1...there is no standardization on how to display the channel #.


They seem to be saying that CURRENT ANALOG channel 11 WBAL has a simulcast DTV signal called "channel 59 UHF". I'd rather think in UHF/VHF terminology. It seems that "HDTV CHANNEL EQUIVALENT 3" really means vanilla VHF channel 3, not some magical channel 3 DT that REALLY resides at UHF channel 44.

As I think about it, it seems the only channel I can not pick up is "HDTV CHANNEL 3" which seems to be the ONLY VHF-resident DTV signal in Chicago.

Don't get wrapped up in how your TV displays the channel #. The same poster you quote also mentioned there was no standardization in how the number is displayed. Go to TitanTV.com or call the station and ask them what channel they are broadcasting the digital signal on. It may very well be in the VHF band.

If its between 2-13, it needs a VHF antenna.
Higher than 13, its UHF. "59 UHF" is redundant, but certainly not misleading.

The reference to channel 11 and its DTV channel 59 is correct. You CBS channel, WBBM channel 2, has its digital feed WBBM-DT on channel 3. This is how it really is.

You'll find it on channel 3 when you get a VHF antenna. Your set top box may leave it at channel 3 or make a conversion to channel 2-1 with PSIP which tries to make it easier for folks who are more likely to think of channel 2 as CBS.

Bobby C

Here are the analog and DT station assignments for Chicago:

Station Call Sign Analog Channel DT Channel

CBS WBBM 2 3
WB WGN 9 19
NBC WMAQ 5 29
Fox WFLD 32 31
Pax WCPX 38 43
PBS WTTW 11 47
UPN WPWR 50 51
ABC WLS 7 32

Hope this helps.

Go to antennaweb.org

Put in the information and eventually you will get a listing of all DTV stations in your area and the real channel number to tune to. Once you have entered this channel into the STB the broadcaster has the ability to change what channel number is actually displayed on the screen using PSIP so it is possible to put in 21, receive a picture and see 36 on the screen instead. At this time then you could directly put in either channel number and the same picture will be on your screen.

As for spectrum I think everybody has said nothing has really changed except for what kind of signal is being transmitted.

Richard F. Fisher
Mastertech Repair Corporation, Lawrenceville, GA
770-513-3987 E-Mail - help@mastertechtv.com
Have you been calibrated? ISF and HAA Certified
Factory Authorized
Mitsubishi, Hitachi, Toshiba, Harman Kardon, Infinity, JBL, NAD

Well, I heard the hype about the double bow tie from the Shack, so I picked it up with my Samsung Sir-t150 and brought it back to my top floor condo unit in newton (about 5 miles from the broadcast towers). Expecting, at worst, some dropout on the fringe channels, instead I got absolutely nothing. Barely a flicker on the meter. What a disappointment. Now I'm stuck looking for an amplified antenna. What about outdoor antennas you say. Well, the reason I didn't get satellite is the same reason that I can't do outdoor antenna--condo association. Everything is common area.

Praying that the amplified antenna works a miracle ...

I would love any suggestions

Brian: 1. If you are on the wrong side of the building, you will have to do some experimentation to find a spot where the antenna works within your condo. 2. The double-bowtie is a superb antenna, but unfortunately it comes with a twinlead cable. If you can't keep the cable 2 inches away from all metal objects then you should probably replace the cable with a balun and some coax. Many people have done that.

I'm in Beacon Hill, with the State House blocking my view to the towers. I'm in a 2nd floor condo and obstructed by the solid 10 floor State House, but get every digital station in Boston very well with the Radio Shack double bowtie. I did do the conversion the previous poster mentioned as that long cord originally attached to the double bowtie is reported to create a lot of problems. You need to get the signal inside some shielded coax as soon as possible, or else your cord will actually be acting as an antenna, creating some unnecessary multipath issues.

Even without modifying the antenna, however, I can virtually guarantee that your problem is that you just haven't played around with positioning your antenna long enough. Seriously, if you get really frustrated let me know and I'll bet you $20 I can get it working inside your condo. It sounds weird, but on my system, a half inch movement or 2-3 degrees of rotation mean the difference between getting all available channels and getting absolutely nothing. You CANNOT just plug in the antenna and expect it to work. How you position the antenna can be very counter-intuitive (i.e. pointing it right at the towers might not be best). It could take hours, but that's part of the fun of it.

In Newton, you do not want an amplified antenna! The signal is more than strong enough where you are and you will almost certainly do more harm than good if you try to amplify it. If I amplify mine in Beacon Hill, I get nothing, and you're closer to the towers than me. Spend a few hours tonight systematically moving that antenna around and you'll be watching HDTV! Give it a few more nights of experimenting and you'll find that one perfect sweet spot where you can get all available channels from one position. Good luck.

Joe

checking the NTSC channels may also help you to localize the best reception.

Richard F. Fisher
Mastertech Repair Corporation, Lawrenceville, GA
770-513-3987 E-Mail - help@mastertechtv.com
Have you been calibrated? ISF and HAA Certified
Factory Authorized
Mitsubishi, Hitachi, Toshiba, Harman Kardon, Infinity, JBL, NAD

First, I want to thank everyone for their help. I think there is a great sense of community here.

Nevertheless, my problems persist. Perhaps my problem is the lack of a coax connection to the double bow tie, but I tried a few hours of moving it around last night and an hour today and got nothing on my samsung sir-t150 signal indicator--just an occasional blip indicating at most 5% strength. To be frank, this scared me. I would have been willing to invest more time in it if I saw any signal strength improvement, but there was nothing, not to mention a subtle growing feeling of dread that pushed me to use a different antenna. So I got the elusive (Roam Consultants approved) shack 15-1862 amplified antenna. Yes, I know I am supposed to live too close to the towers to amplify, but with this thing at least I was getting blips upto 15% on rare occassion for nearly all channels (still no picture) and a moderately stable picture for FXT-Dt (how bittersweet, it had to be fox). Now people appear to have the most trouble with fox out of the networks in boston, so this is a little odd. I think it lends some credibility to the multipath idea ... perhaps fox's signal is so weak that it doesn't succumb to multipath as easily. But i think a few questions remain. First, why doesn't my signal indicator show a higher signal (wouldn't multipath show a really high signal on the indicator)? Second, when I run the antennas analog, I don't get ghosting, rather, I get snow and even occassional audio distortion. That sounds like lack of signal rather than multipath right? Third, if multipath is the problem, why am I having more success with amplification rather than less? I'm really confused.

Also, is there anyplace that explains how to do the direct coax connection to the double bowtie? I haven't given up on it yet!

Stay up late one nite and put up the outdoor antenna and drop a line to your stb while everyone's sleeping . You may evenually have to toss a couple of bucks or do a favor for a neighbor or super that stumbles across it , but it'll all be worth it . The worst they can do is make you take it down .

Brian: Heartbreak Hill is between Newton and Needham, and I suspected it was shielding you from the towers. That you see snow on analog channels confirms this. Joe on Beacon hill has a much stronger signal despite being much farther away. The tops of the towers in Needham are visible from downtown Boston.

You need a high gain antenna, but your condo situation makes this tough. A 4-bay would be better than your double bow-tie but it is not a very pretty indoor antenna. You must continue to experiment using analog channels such as 44. When you get an excellent picture on 44, you are ready for a DTV channel.

There are two types of signal strength "meters": a conventional analog-to-digital circuit, and a software routine that examines the purity (squareness) of the demodulated digital data signal. That second type will give a low value in a strong multi-path situation. It is nice when a receiver has both types, but I know of only one such receiver (4DTV).