2/2009 OTA Ch. realignment question?

[HoTat2]

Hi folks;

Just curious about the new OTA channel realignment (channels 2-51) that will take place when the analog TV signal goes dark after 2/17/2009. I notice that almost none of the DMA markets will be using the VHF-Lo band channels 2-6. And I’m frankly surprised antenna manufacturers are not more rapidly phasing out most of those which are capable of receiving it.

But is the technical reason why these low band channels are going to be inappropriate for DTV broadcast, because they will not be used exclusively for TV broadcasting? And must be shared and accept any interference from other future non-broadcast services that will also be using these frequencies as I suspect?

Since I cannot believe that the FCC can allow such a large chunk of valuable radio spectrum (54-88 MHz) to go essentially unused this way.

[Kansas Zephyr]

No, it's still only for TV. (less 72-76Mhz...not new)

It's fear that multi-path, inherent to VHF-low, will be a problem with digital transmissions.

Early generation DTV tuners didn't handle multi-path very well (lots of signal...but no stable reception). So, a large number of broadcasters thought they would be better off keeping their new digital RF assignments.

Real-world use, however, has some now thinking that they fretted too much.

The chief engineer at KSNW-3 (digital 45), told me that he wished now they would have planned to go back to 3. But, it's too late to go back, since they planned well in advance, and paid lots of money to make channel 45 their new permanent home.

[jdspencer]

Of the four stations here, only the digital ch 4 will be going to its analog number (34). The others will be staying where they are, 7, 8 and 42. Interestingly, it's ch4 that is the most stable for me. ")

[rotomike]

Hi folks;

Just curious about the new OTA channel realignment (channels 2-51) that will take place when the analog TV signal goes dark after 2/17/2009. I notice that almost none of the DMA markets will be using the VHF-Lo band channels 2-6. And I’m frankly surprised antenna manufacturers are not more rapidly phasing out most of those which are capable of receiving it.

But is the technical reason why these low band channels are going to be inappropriate for DTV broadcast, because they will not be used exclusively for TV broadcasting? And must be shared and accept any interference from other future non-broadcast services that will also be using these frequencies as I suspect?

Since I cannot believe that the FCC can allow such a large chunk of valuable radio spectrum (54-88 MHz) to go essentially unused this way.

i thought they were doing away with vhf band for tv? All our digital channels went to UHF channels when they went digital but your saying they are keeping the vhf band for tv?

Mike

[Kansas Zephyr]

i thought they were doing away with vhf band for tv? All our digital channels went to UHF channels when they went digital but your saying they are keeping the vhf band for tv?

Mike
Yes.

There were no more VHF "slots" open in most markets (remember to include "safe' distances for adjacent markets' stations, too), so they had to put the additional digital signals in UHF, for most places.

This has led to the misconception that VHF is going "bye-bye".

In a few UHF analog markets, some stations actually got digital VHF assignments.

VHF analog stations have the option of moving their digital signal back to their "old" VHF RF channel, after the analog cut-off.

That's one of the reasons for PSIP, allowing stations to keep displaying their legacy, or final (their option), channel number on your HDTV, regardless of the RF channel used.

[rotomike]

so in our area lets say channel 5 vhf went to channel 19 UHF but shows up as channel 5-1 because that info gets sent to display that but your saying they can go back to regular channel 5 vhf after which would allow people with vhf antennas that currently get it to continue to get it with that vhf antenna. is this the stations desicion to choose to go back or not to go back?

mike

[cover]

so in our area lets say channel 5 vhf went to channel 19 UHF but shows up as channel 5-1 because that info gets sent to display that but your saying they can go back to regular channel 5 vhf after which would allow people with vhf antennas that currently get it to continue to get it with that vhf antenna. is this the stations desicion to choose to go back or not to go back?

mike

From what I've seen, in my market, the plan is that most of the VHF analog stations that are now using UHF for digital will go back to VHF for digital after the cut-off. I don't know whose decision it is or where I found the info, but I bet it wouldn't be too hard to Google it.

[Carl Spock]

Over the country, about 45 stations will go back to VHF Lo when it's all said and done. More are going to be using VHF Hi or UHF frequencies. VHF Lo has some noise/interference problems with digital signals.

This chart (http://hraunfoss.fcc.gov/edocs_public/attachmatch/DA-06-1082A2.pdf) will give you the final channel designations for most DTV stations. There has been a third round of assignments but this covers the vast majority of broadcasters.

[l8er]

From what I've seen, in my market, the plan is that most of the VHF analog stations that are now using UHF for digital will go back to VHF for digital after the cut-off. I'm relatively sure that's not correct. The RF spectrum that's getting freed up for the FCC to sell is the current analog spectrum. These broadcasters have all spent thousands of dollars for the new digital channel equipment - I seriously doubt all that equipment is going to be replaced with new digital equipment for their analog assignment after the cutoff. It's not physically nor financially feasible. The digital signal is an entirely different transmission path from transmitter to antenna (new transmitter, new feedlines, new antenna).

[Upstream]

Carl -- the list you linked is an old tentative list.

Here is the FINAL list of Channel Assignments --> http://fjallfoss.fcc.gov/edocs_public/attachmatch/FCC-07-138A2.pdf

The column labeled NTSC Chan is the old Analog channel number. The column labeled DTV Chan is the new Digital channel number for post-Feb-2009.




Rotomike -- notice that several Maine channels are moving back to VHF frequencies. Also, depending on where you live in Maine, you may want to check nearby New Hampshire or Massachusetts channels.

[Carl Spock]

Thanks for the update. That is a later list. Saved.

[harsh]

i thought they were doing away with vhf band for tv?You're not alone. There are thousands that bought into the digital=UHF hogwash.

As with many things where what you have will work but they want the revenue, you too were duped.

[HoTat2]

Over the country, about 45 stations will go back to VHF Lo when it's all said and done. More are going to be using VHF Hi or UHF frequencies. VHF Lo has some noise/interference problems with digital signals.

This chart (http://hraunfoss.fcc.gov/edocs_public/attachmatch/DA-06-1082A2.pdf) will give you the final channel designations for most DTV stations. There has been a third round of assignments but this covers the vast majority of broadcasters.

Well OK;

But unless it is just a case of the VHF-Lo band being undesirable for both forms of broadcasting due to N/and I, as I have had interference problems with the analog VHF-lo band channels for years. One would think that with the signal being digital and therefore inherently more immune to noise and interference, it would be much more suited to broadcasting on the low band than the analog was.

Or perhaps the issue was primarily caused by undue fears of multipath effects based on the poor performance of early DTV tuners as Kansas Zephyr states.

Whatever the case, it still seems like a awful waste of spectrum to have 55-88 MHz essentially lying empty this way with only some 45 DTV stations scheduled to occupy it nationwide after 2/17/2009. And I’d be very surprised if the FCC doesn’t simply decide to reclaim these channels for other purposes later on.

[HoTat2]

And given this situation, due to the strong winds we’ve been having in the L.A. area lately. I’ve noticed one of the VHF-Lo band elements on my rooftop antenna hanging loose. Therefore I’m going to have to replace it sooner than I wanted to, so as to get ready for the AM21’s release. But with no stations listed in the Los Angeles DMA for the post 2/17/2009 VHF-Lo band. Why bother with it? So I may purchase an outside aerial such as this one;

http://www.solidsignal.com/prod_display.asp?PROD=HD7697P&xzoom=Large#xview

And simply forget about the TV low band’s analog signals as its days are numbered anyway. I’ll just have one small standard TV in the kitchen to deal with that won’t be able to receive channels 2-6 until I can acquire one of the NTIA’s coupon subsidized DTV receivers for it.

[Carl Spock]

You're not alone. There are thousands that bought into the digital=UHF hogwash.

As with many things where what you have will work but they want the revenue, you too were duped.
Boy, now that's just, well, harsh.

I think this has evolved with time. There was a point in the FCC's plans when everybody was going to go to UHF. Every antenna company out there made a new line of antennas, UHF only, that were called HDTV antennae. So are you saying this is an evil plan by Channel Master, Winegard, Antenna Specialist and all antenna installers to get us to change our antennas unnecessarily? They were the only ones who would benefit from this.

For whatever reason, DTV's broadcast status has changed over the past few years. If anything was money driven, my bet would be by the broadcasters who didn't want to give up the reach of their VHF frequencies and had the rules changed. Greater reach means more viewers which means you can charge more for advertising. Now there is money.

It turns out that digital being only on UHF is hogwash but at one point I'm pretty sure that was the plan.

[raoul5788]

You're not alone. There are thousands that bought into the digital=UHF hogwash.


The only places I have read that uhf would be the only way to get ota digital are places like this where the wrong information sometimes gets spread around. Where did you hear otherwise?

[Carl Spock]

I thought HDTV would only be broadcast over UHF from conversations I had with the chief engineer of our local CBS affiliate back in 2002 when they turned onto HD.

I owned the local stereo store. The CBS station was the first local broadcaster to go HD. Both my customers and I had questions. The engineer was curious how well I could receive his signal at customer's houses around the area. We talked maybe half a dozen times when they fired up HDTV. I know the engineer confirmed what was the conventional wisdom back then, that for HDTV you'd only need a UHF antenna. Now his station is one of those which is going back to their VHF frequency next year. I may call him again to find out what changed.

[Upstream]

I think part of the confusion stems from two issues:

* Some stations are broadcasting digital on UHF until they are able to broadcast digital on VHF in Feb 2009. Some people may have thought the temporary UHF assignments were permanent.

* In some cities, all stations are moving to UHF. So in some places, you will only need a UHF antenna. But some people may have thought that since that was happening in some places, that it was happening in all places.