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Channel 7 now six times worse
By adamg on Tue, 11/10/2009 - 12:02pm
Rob Sama is one of those outliers who still relies on a traditional antenna to pull in TV. So he was surprised to discover that Channel 7 is moving to Channel 42:
... None of this bothered me terribly, except for the fact that I now had to reprogram my DVR to record off of 42 instead of 7. But it also seems as if at the same time they made this announcement, they turned down the signal strength on channel 42, so that now it doesn't come in smoothly like it used to, but cuts out periodically, making NBC basically unwatchable. ...
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Comments
I rescanned my TV and found
I rescanned my TV and found channel 42, but it won't select when I use the UP button on my remote - I have to punch in "4" + "2" for some reason.
It might be deleted. Check
It might be deleted. Check your menu for channel options to see if you can undelete it.
Delete first?
On mine, I deleted 7.1 first, then rescanned. It found the new 7.1 (channel 42) and I can page up & down channels. It treats it as 7.1, not 42.
Double Rescanning
The FCC recommends that with all the hopping around that the stations are doing right now, you should occasionally do a “double rescan”.
On most digital converter boxes you can add channels by rescanning, but it’s very difficult to get rid of them once you have them programmed in, and the boxes get confused. You need to wipe your box by disconnecting the antenna and rescanning, then power cycle it, then hook the antenna back up and do a second rescan.
As for why they're having problems with Ch. 7, it seems the FCC has throttled back their power. This is a response I got from WHDH in regards to the poor reception on 7:
“WHDH is experiencing signal difficulties following the transition that took place on June 12.
The signal difficulties we are experiencing are a result of post-transition power allocation assigned by the FCC that is not sufficient to maintain the signal strength that we had prior to the transition. We are petitioning the FCC to adjust the technical parameters so that we will be able to improve reception. In the meantime, we will continue to simulcast on Channel 42 (our pre-transition digital channel) so that viewers will be able to receive our signal. We appreciate your patience as we resolve this matter.
Thanks”
Why the Changes - well...
I was engaged in a closed loop mail list of viewers with some of the engineers at CH 7 some months ago. I won't get into the techie stuff - boring.
When WHDH started using digital signals they were allocated Ch 42 (UHF-Digital-DTV) and started using that and were simulcasting on both for a long time. The game plan was that after the transition they would change their existing CH 7 to digital and switch everything back to that and abandoning CH 42.
However after CH 7 was switched to digital in June it had problems. A combination of the quirks of digital signals, FCC power restrictions, geography (hills and buildings matter it seems) and nearby businesses with their own radio signals simply limited the CH7 signal.
I live just 5-6 miles from the transmitter tower and was having problems. Imagine what other people were experiencing at a distance.
They sent techs into the field to check on signal strength in various communities and determined that a boost in transmitter power would fix the problem. Keep in mind that they were sending thousands of watts on their analog signal but under digital the FCC has limits.
In any event, the FCC denied the request to increase the power to the digital signal on CH 7. The only solution was for them to abandon CH 7 and go back to CH 42.
Ch 42 was only off for a few weeks after the June transition and when the problem arose they switched it back on and have been simulcasting since on both. I found that I was doing better with Ch 42 myself.
Antenna placement and style is also a factor here. Attic or rooftop antennas are now recommended but if you have a decent amplified antenna you may be OK. If your TV is in an interior room you may have problems. You will need to move the antenna to an exterior wall, preferrably the side of the house that faces Needham where the transmitter is. In my case I had to re-arrange the furniture in an interior room amd move the set and antenna to that very wall. On the other side of the house (the wrong-facing side) I had to drop $40 on an amplified antenna (I rent and external antennas are not an option.)
When you scan your box you may still pick up a dead carrier for CH 7. Also these boxes - depending on model - may read CH 42 but register it as "virtual 7." In my case on one box I actually call up Ch 42. On the other I have 4 channel 7s. The two dead ones and the two operating on Ch 42.
For what its worth, CH 7 in Boston is not the only station that has had this problem. Quite a few across the country have experienced similar problems.
Why are they giving up Channel 7?
Seems like a prime channel assignment -- I don't understand why they'd give it up in favor of 42, and go through an expensive rebranding campaign to tell everyone where to find them now. Won't they need all new logos now, too?
I don't think any of the HD
I don't think any of the HD channels have the same channel number they had when they were broadcasting in analog. But, they're all re-mapped by your HDTV so you don't notice the difference (channel information is included in the digital signal). Once you re-scan the channels I think channel 42 will be mapped back to channel 7 so it will appear the same as before.
It's just like a web-site's IP address changing, but in the case you have to manually update the mapping between URL and IP address instead of having it happen automatically.
7 -> 42
I read somewhere that a lot of VHF stations around the country have been having difficulty delivering a reliable DTV signal and have applied for FCC permission to move to UHF.
Almost ALL The Stations Are Doing This
Almost EVERY broadcast TV station in the nation, when they switched from analog to digital, moved to the UHF band, even if they had been broadcasting on low- or high-numbered VHF channels. Then, they continued to give their old channel numbers because digital TVs and digital-to-analog boxes would scan for imbedded channel numbers from prior operations. Weird. And newspapers that still offer TV listings do so by the now-mostly-abandoned channel numbers.
Digital conversion eliminated analog channels 2-6 and 52-69
When the FCC had all channels convert from analog to digital, they mapped to the digital UHF band. Hence, analog channel 7 will now map to digital UHF channel 42. However, if you have a digital tuner, you will still be able to "tune into" channel 7 on your TV set. More about that here: http://en.wikipedia.org/wiki/Virtual_channel
The FCC also grabbed Channels 2-6 and 52-69 (they had already gotten Channels 70-83 back in the late 80's - early 90's) and converted them for other uses, hence the real channel span is from 7 to 51, with several subchannels. Only exception: Channel 37 is not used in North America.
I could be wrong on this; corrections or updates cheerfully accepted.
So if the FCC didn't grab channel 7 ...
... why couldn't WHDH-TV keep it when they went all-digital?
Digital VHF problems
WHDH did have digital Channel 7, but there were so many problems receiving it that WHDH had to simulcast it both on Channel 7 and 42. Once WHDH got the approval, they moved to Channel 42 permanently.
WHDH (Channel 7) history.
DTV transition
The FCC did not "take back" the Lo-VHF band (Ch.2-6), only the high end of the UHF end (Ch.52-69) were repurposed and auctioned off.
You are correct about the channel mapping - a singularly confusing concept that preserves the branding of TV stations that often have invested a lot of time and effort in marketing themselves as "NBC10" or "FOX25" or something like that. Problem is, because VHF channels were around long before UHF were, most of the major network affiliations ended up in the VHF band. But the ATSC scheme of DTV in the USA does not work as well on VHF frequencies, which have noticeably different signal propagation characteristics and require a different antenna to properly receive. So most of them moved to UHF frequencies. Channel mapping preserves the branding...even though a station that WAS on Channel 7 (VHF) might now actually be transmitting on Channel 42 (UHF), the DTV receivers are all set up to scan the dial, find the station on 42, recognize a flag that says "show me as being on channel 7", and display it as Channel 7. But it's not Channel 7 - it's Channel 42, different frequency, different signal characteristics, and - because of the higher frequency - different transmitter powers.
So you end up with thousands of perplexed viewers who say "I have the exact same antenna setup...why can't I get Channel 7 like I used to?" And they don't realize it's because they're probably using the wrong antenna for the job. Or it's because UHF signals, being higher in frequency, are more "line of sight" and thus more easily blocked by hills, trees and skyscrapers. Or it's because what was an "acceptable" signal for viewing was actually pretty poor...too poor a signal for a DTV receiver to show anything but a blank screen.
bemused
> one of those outliers who still relies on a traditional antenna to pull in TV.
I'm more than a little bemused by folks who feel the need to pay for TV when you can get twenty channels with a little wire loop on the back of your set.
> But it also seems as if at the same time they made this announcement, they turned down the signal strength on channel 42
This I don't get. Had the author gotten a signal on 42 before and it was better? Or was he comparing the signal on 7 vs. the signal on 42?
It's possible if there's some distance between him and the transmitters in Needham, especially distance over tree-covered hills, the VHF would have given him a better signal.
> Digital conversion eliminated analog channels 2-6 and 52-69
Did they really eliminate 2-6? I understand eliminating the higher channels because there's been some proposals for new devices. Such as Google's "white spaces", a proposed national public safety radio network, and yet more cellphones.
But the lower frequencies, requiring large whip antennas, don't work well with mobile devices. I'd wonder who would want those frequencies.
> they had already gotten Channels 70-83 back in the late 80's - early 90's
Late 70s/early 80s. It became home to some police radio systems, cellular phones, and Nextels.
I knew it was one of those date spans...
I thought Channels 70-83 lasted until 1990 or so, but you are correct - they are now part of the cellphone and radio system network.
As for Channels 2-6, some stations still operate these stations, but in much smaller markets, so my previous statement was incorrect. The reason for this is that the frequencies on Channels 2-6 cause a lot of interference with the radio stations, hence when the digital transmission occured it was easier to transmit outside of that...and I can bet more cell phone companies will want those frequencies.
I don't think 70-83 were
I don't think 70-83 were ever widely deployed. At one time the idea was that they would be used for "translators" to repeat TV signals down into rural valleys. Sometime in the late 1970s those frequencies got reassigned to other services, but a few stations in remote areas might have been able to hold out while cellular phones and trunked two-way radio were in their early years.
They continued to make TVs that would tune up to 83 until the late 80s, so that's probably what you're seeing.
Sorry I misspoke about Google's "white spaces"; they wanted wireless data on unused channels -within- the now-much-smaller UHF tv band, not on the upper channels that are being lost.
Also didn't Channel 7 make this switch a month or two ago? I remember having to rescan for 7 about that time, not today.
But it's pretty unlikely that Channels 2-6 would end up as part of a cellular system, not unless you want phones with a big whip antenna you'd have to pull out. Some groups have proposed taking 5 and 6 for radio broadcasting, perhaps an extended FM band with more community stations, or digital broadcasting.
I think they're still available for TV, but for a variety of reasons ( vulnerability to electrical noise, interference from distant stations, trouble penetrating built-up areas, requiring big antennas, digital TVs not optimized for these frequencies ) only a few dozen stations asked to remain there. They may have an advantage for distance in rural areas though.
Channel 6 can be used for FM
Channel 6 can be used for FM radio. Pulse 87 (87.7 FM) in NYC is actually TV channel 6
> Channel 6 can be used for
> Channel 6 can be used for FM radio. Pulse 87 (87.7 FM) in NYC is actually TV channel 6
That's the audio part of analog channel 6 sort-of lining up to 87.7 on your stereo.
But if you got all of Channel 6 for FM audio, including the space used for video signals, you'd get 82-88, or 30 more spots on your FM dial.
Channel 6 TV heard on the radio
All analog TV used an FM signal to transmit their audio carrier. Albeit with a different stereo scheme and different pre-emphasis, but it was pretty much just regular FM. If you had an FM tuner that could be tuned to the right frequencies, you'd hear the audio of the TV broadcast.
With TV6, the aural carrier transmits on 87.75MHz, and the bandwidth is wide enough to overlap 87.8-88.0 (centered on 87.9) which is "Channel 200" in the FM band, which as you said, is only used in very limited circumstances by grandfathered 10 watt Class D FM educational stations and FM translators (currently in the US, there's one of each and that's it). All FM radios can tune to 87.9, and most will tune to 87.7 and thus hear the aural carrier on TV6.
With DTV, there is no separate aural carrier - it's all just digital. Tune a radio to a TV6 running ATSC/DTV and you'll just hear white noise. There are no full-power TV stations still running any analog signal anymore, of course. Although WRGB TV6 in Albany, NY tried to run both a digital signal and an analog signal via cross-polarization. Worked (sort of) for a month or so until the FCC yelled at them to stop doing it.
Low Power TV stations were exempt from the DTV migration of 2009, so there's still some analog stations out there, like WNYZ-LPTV6 in New York. But their days are numbered. Many already have a DTV migration schedule, and a deadline...while not announced...is inevitable. And probably not long in coming, the rumors I'm hearing are as soon as 2011. Currently the FCC is in the midst of a "filing window" for new LPTV stations and the FCC will not allow any of them to transmit in analog - they all have to be DTV from day 1.
Technically, 87.9 is also
Technically, 87.9 is also part of channel 6 (82-88). It's basically in a "guard band" at the very end of the channel, and is kind of a "zeroth" pseudo-slot in the FM band. 87.9 can't be assigned in markets where there's a channel 6.
There's still a few Spanish LPTV analog stations in Boston. Hopefully they will be able to make the conversion.
Wire Loop Doesn't do it.
Something like that will work if you live relatively close to the transmitter. Otherwise, Amazon.com sells power-assisted antennae, which work to some extent. Or, you can go back to the old-style antenna on the roof. Unless you had very good reception to begin with, chances are you will not have the same selection of channels with(H)DTV.
I'm using something like a
I'm using something like a double-bowtie over a metal grate that sits on a shelf next to the TV set, and this pulls in almost everything. They used to sell these at Radio Shack, but you can order more elaborate ones from Channel Master.
I don't know if amplified set-top antennas would help in the city, where you might just be amplifying interfering signals, but maybe if you're out on 495 somewhere.
But an attic or rooftop antenna that you can aim, which can also be amplified, is the best for those far away.
Yes, I got 42 better before
Hence my belief that they turned the signal strength down.
I can report back to you now that it's working better, though not perfectly as it once was.
Moving to Channel 42
So happy to found this information. Couldn't figure out why my Tivo wasn't recording anything on my season pass manager. If I delete all the current channel 7 shows and reselect them do you think that is all that needs to be do?
Channel 5 signal?
Is anyone else having trouble with channel 5's over-the-air signal? It's been dropping lately, and last night it was off more than on.
I wasn't able to watch the senate debate because I kept getting "No signal." Anyone know if there's some change in their signal strength or something?
Around 6pm the signal seems
Around 6pm the signal seems to dim a bit.