Digital TV

[wb1aij]

Just connected my mother-in-laws TV up to an A/D converter so she could get the local channels ( her satellite TV does not offer local channels)& got a nice surprise. She used to only get a few channels from Hartford,Ct. & one from New Haven because she is using a rabbit ears antenna.. Now she gets ch 3-1, 3-2, 3-3, 24-1, 24-2, 24-3, 30-1, 30-2, 30-3 & they come in much clearer than when she was receiving analog. Seems each transmitter has a few digital channels in the same bandwidth as their old analog bandwidth.

[K9ACT]

After using ours for a few months, I have one remaining complaint and it seems to belie one of the basic claims for DTV.

That claim being that much less power is required at the transmitter.  If this is true, it seems to just be a red hearing because they are not getting as much signal into my receiver as the analog stations do/did.

Many of the channels I could get on analog have no signal at all and the ones I do get require very careful pointing of the antenna.  No one direction fits all with digital.

So, it might require less power to get the same signal to my antenna but they are not using the equivalent power level to maintain the same signal strength.  They are just using less power and we have to take what we get.

Having said all that, being 50 miles or so from any stations and no access to cable, it is nice to be able to see clear pictures for a change.  The ones that come in are incredibly clear.

It is obviously a good idea but with many issues we could argue all day about like, why do taxpayers have to get involved in making sure everyone has one and wouldn't you like to have access to the lobbying group that got that contract for whoever is making the converters?

js

[KA1ZGC]

After using ours for a few months, I have one remaining complaint and it seems to belie one of the basic claims for DTV.

That claim being that much less power is required at the transmitter.  If this is true, it seems to just be a red hearing because they are not getting as much signal into my receiver as the analog stations do/did.

Not all of them are running their digital transmitters at full licensed power. You won't really know for another four days. It will then change again with allocation and equipment changes over the next year or so.

We're still not even to the halfway point of the transition. Once the NTSC transmitters go dark, then the ATSC transmitters can be put to full power. It costs too much money to run both at full strap at all times (with not one penny reimbursed).

We won't know how the transition went until it's actually happened. This long, agonizing limbo we've been stuck in is about to end. Good riddance, too.

At this point in the game, it's still too early to draw conclusions.

[KA1ZGC]

Just connected my mother-in-laws TV up to an A/D converter so she could get the local channels ( her satellite TV does not offer local channels)

They're required to by law. Someone should follow up on that.

[Tom WA3KLR]

Does anyone know the actual law on the switchover time? 

I hear "on the 12th", "by the 12th", "after the 12th...no more analog".  Is anytime during the 12th o.k.?  Or is it supposed to be 12:00:01 a.m. or 12:59:59 p.m. of the 12th?

[KA1ZGC]

I'll bet anyone still paying the electric bill on an analog transmitter currently has their finger poised over the "PLATE OFF" button. The only ones still broadcasting analog are doing it so they can honestly say they kept the analog going right up to the very end.

If the time is specified somewhere, they'll all drop off the face of the dial at once. If not, they'll all drop in groups over the course of the day on June 12th and the FCC probably won't care as long as they're all off on June 13th.

You'll notice I didn't care enough to research that very far, either. 

[W1RKW]

Bob,
Does your MIL live in CT?  If so, Dish Network and Direct TV offer the local channels on their sats.  Unfortunately, one has to subscribe to receive them.

[Pete, WA2CWA]

From the DTV web site:
The digital transition is underway. Prepare now! On Feb. 17, some full-power broadcast television stations in the United States may stop broadcasting on analog airwaves and begin broadcasting only in digital. The remaining stations may stop broadcasting analog sometime between April 16 and June 12. June 12 is the final deadline for terminating analog broadcasts under legislation passed by Congress.

Want to learn more, then go here:
http://www.dtv.gov/whatisdtv.html

[kb3ouk]

I guess that since the deadline is the 12th you can assume that all stations have to be off by midnight june 12th. the number of subchannels varies some have one channel while there a a few stations(out in LA) that have 8.

[KB2WIG]

 " I guess that since the deadline is the 12th you can assume that all stations have to be off by midnight june 12th. "

  or be cited for treason
.. ._. _...

klc

[KA1ZGC]

Bob,
Does your MIL live in CT?  If so, Dish Network and Direct TV offer the local channels on their sats.  Unfortunately, one has to subscribe to receive them.

It doesn't matter where she lives. Like I said before, all cable and sattelite TV service providers are required by law to provide their subscribers with the local stations serving the Designated Market Area in which they live.

The only waivers to that requirement are those few remaining instances where no uplink yet exists for a given station. Those waivers are not permanent.

If her sattelite carrier doesn't offer the channels serving the DMA she's in, they're either operating under waiver or violating the regs. Failing to offer local channels is not an option for sattelite or cable providers.

[Tom WA3KLR]

The DTV transmissions from what I've seen on the FCC page below, the coverage is the same or a little better than the NTSC was.  ERPs vary but are generally about 1/10th of what the NTSC transmitter was.  This is not short-changing us as far as signals, its just that the digital modulation with the sound included is more efficient than NTSC; greener broadcasting. 

The DTV signal is essentially vestigial digital AM and like the old NTSC cut the bandwidth in half, but there is only one carrier now and it is much reduced in amplitude, close in level to the digital modulation.

On the FCC page below, plug in your address and you will get the list of stations you should receive.  Click on a station call letters, then click on the Gain/Loss Map link and you will get a map of coverage that compares the old NTSC signal versus the new DTV signal; ERPs are stated for the two systems.

http://www.fcc.gov/mb/engineering/maps/

[Tom WA3KLR]

There are frequency changes and final power levels to come yet.  Statistically about 1/3 of the DTV stations in your area will change frequency.

Channel 12 here in Philadelphia, one of the main stations has a terrible signal on 12-1 DTV on UHF.  After the switchover they will be back onto Channel 12 with the good old antenna and probably more power to boot. 

You have to wait until after the 12th to see what the final reception levels are. 

[W2VW]

The operative word is rescan.

Certain analog transmitters will remain lit after June 12. They will carry an informative, brilliantly produced information loop. Several #1 DMA analogs will be on for two weeks or one month after the 12th.

One large #2 DMA broadcaster will be going dark at 11:30 PM Friday.

Rescan Friday evening.

Certain broadcasters will be making changes for the next few weeks.

Rescan at least once weekly to take advantage of those changes.

Blurb comparing new stuff to old standard from 1952
http://dtvrules.com/DTV_vs.html

[AJ1G]

Don't know what algorithm antennaweb.org uses for DTV service prediction, but it's pretty poor.  Says my QTH should not get any DTV service, yet Channel 69 about 10 miles away in Hopkinton RI pegs the "S meter" on DTV receivers with only a short piece of wire on the antenna input!

For our Charlestown RI cottage, I am going to put in a new UHF antenna along with new high quality twin lead feed and hope for the best. 

On Dish Network here at home.  Only gripe is that we can get only local CT stations on dish, even though we are closer, and more in the market of the RI stations.  Across the river in Westerly, RI, the opposite is true.  Cox Cable, AFAIK, only carries RI stations and no CT stations.

[KA1ZGC]

On Dish Network here at home.  Only gripe is that we can get only local CT stations on dish, even though we are closer, and more in the market of the RI stations.  Across the river in Westerly, RI, the opposite is true.  Cox Cable, AFAIK, only carries RI stations and no CT stations.

The requirement is to feed stations that have a legal claim to your designated market area. Since cable and sattelite carriers are competing with those same broadcasters for advertising dollars in those DMAs, you can guarantee they won't go one step beyond that requirement.

Who decides what DMA your town is in? A monkey on crack, for all I know.

[Tom WA3KLR]

Dave, thanks for the technical paper reference. 

DTV signal - you got it or you don't. 

NTSC - analog signal - it's still there and locked - how much snow can you stand?

Chris,

It seems to me that there was an adverse change in the antennaweb.org site.  A few months ago the calculated reception results became much less reasonable than it had been.  As you say a local strong signal for you is missing from the report.  The new FCC page I referenced above is much more realistic.

[W2VW]

Dave, thanks for the technical paper reference. 

One of the interesting points is the method of power measurement of DTV verses NTSC. DTV isn't as PW as it seems.

[KA1ZGC]

That's quite the writeup. It's also the first one I've seen that tries to explain that ATSC transmit contours must satisfy a 90:50 threshold vs. 50:50 for NTSC and FM broadcast we're accustomed to.

Anyone who just read that paragraph who is asking themselves "what the hell is that supposed to mean?" should follow the link Dave posted.

[W3RSW]

So far only four DTV stations received here in the middle of the outer Hebrides, three networks and PBS, but I must say, all four are perfect whereas the analog suffered from ghosts, excessive snow and horizontal skewing,  

(...well, would you believe on an old tube archival set?  Makes you wonder what some of the modern analog tuners, synchro horiz. lock/ phase lock loop circuits, etc. would have done with 1950 signals received by local cables or aficionados from the hilltops. Remember those mile long ladder line runs, boosters at the tower, ice, deer, vandelism, and power outages, etc.? )  

Seriously, the DTV from the nearsest local station is perfect in that the old analog station/signal was so close, hills so numerous, etc. that any dipole or 'unipole' had to be aligned by magic to eliminate horrendous ghosting. Most of the time, I just gave up and hoped the ghosts didn't obliterate too much of the 'smaller print.'

The DTV signal from the farthest local (25 miles or so) is still 'perfect'  on a folded diplole taped to the window. Amazing.  Almost makes one want to put up an array on the hill behind the house to get all the Pittsburgh stations, 90 to 100 miles away, just like in the old days.

[W1GFH]

Set up a DTV box with rabbit ears on the TV in the spare bedroom of a friend's mothers apt. on Central Park West in Manhattan. Got all the local channels -- except WNBC (local analog 4, digital 28 I think) was "no signal". Odd because the xmtr ant. is on the Empire State Bldg with the others, so it should come roaring in. I switched back to analog and it was there, piss weak. But no digital sig. Must be some weird "shearing" of the sigs among the buildings.

[KA1ZGC]

My money's on multipath cancellation.

[W4EWH]

Does anyone know the actual law on the switchover time? 

I hope they take cameras to the transmitter sites and show the event. Very few viewers have seen an actual tv transmitter, so it's certainly a newsworthy story. I wouldn't be surprised to see a few old techs get teary-eyed.

73,

Bill W1AC

[KA1ZGC]

There's nothing to see. The average TV transmitter looks like any other cabinet with a couple of buttons and some meters. There's no "ooh" nor "aah" factor to them these days. They look about as exciting as the side of a cereal box.

In this day and age, most people just aren't impressed by that sort of thing anymore.

[W2VW]

should come roaring in. I switched back to analog and it was there, piss weak. But no digital sig. Must be some weird "shearing" of the sigs among the buildings.

If it isn't raining try checking again between 1AM and 4:30 AM. Empire is doing building work and many signals will switch to backup sticks. That will change your multipath situation. This work will last for at least the next month. Don't try it this Friday or Saturday as they might cancel work due to the switchover.

Changing polarity on the receive antenna is one tool to try in that area of the city.