| Author |
Message |
Jeff Rife
Guest
|
 Posted:
Thu Mar 31, 2005 8:28 am Post subject:
Re: DTV reception is much more difficult than analog |
|
|
Charles Tomaras (tomaras@tomaras.com) wrote in alt.tv.tech.hdtv:
| Quote: | Well now in my market the ABC affiliate uses their -2 sub channel for a
duplicate of -1 which I can't figure out why?
|
Without examining the transport stream, it's hard to tell.
Locally, the WB station had four subchannels for a while: 50-1, 50-2, 75-1,
and 75-2, but there was only one video stream and two audio streams. All
four sub-channels used the single video stream and the audio stream went
with the subchannel number, so they could provide alternate audio services
easily.
So, there is no telling what your ABC station is really doing for sure.
| Quote: | The NBC affiliate has a
weather channel on their -2 sub. Auto scan also picks up the NTSC versions
of these stations as well. It's just really confusing for the average person
to deal with all of this plus the aspect ratio issues. I don't have an
answer save for...I have a hard time recommending it to someone who isn't
pretty much up to date with their technology abilities.
|
Blaming the STB and ATSC for the brain dead behavior of some broadcasters
hardly seems fair.
--
Jeff Rife |
| http://www.nabs.net/Cartoons/FoxTrot/GutterBall.gif
|
|
| Back to top |
|
 |
Drewdawg
Guest
|
| Posted:
Thu Mar 31, 2005 8:28 am Post subject:
Re: DTV reception is much more difficult than analog |
|
|
Jeff Rife wrote:
| Quote: | Drewdawg (nope@not.here) wrote in alt.tv.tech.hdtv:
Bob's chance is coming this summer when Crown Castle starts its
"nationwide" DVB-H service offering mobile TV & Radio in the L-Band.
Bob has been on about COFDM SFN for years now and it appears it's
finally coming to America.
As far as the proof being in the pudding it appears to be dinner
time. :-)
And I predict it's Bob who will be eating it. ;-) lol
Actually, an SFN probably will work OK. But, it can only deliver the
same programming across the SFN, not thousands of different signals,
and that's what makes it unsuitable for OTA TV in the US.
|
Agreed, but I'm thinking there will be areas of the US without SFN
reception. Crown Castle has a tall order to fill if they expect to offer
*everyone* this service. I'd like to see their "Coverage" map when it comes
out.
When it comes to the boonies (like Dover, DE), big sticks work! ;-) |
|
| Back to top |
|
|
Jeff Rife
Guest
|
| Posted:
Thu Mar 31, 2005 4:47 pm Post subject:
Re: DTV reception is much more difficult than analog |
|
|
Drewdawg (nope@not.here) wrote in alt.tv.tech.hdtv:
| Quote: | Agreed, but I'm thinking there will be areas of the US without SFN
reception. Crown Castle has a tall order to fill if they expect to offer
*everyone* this service. I'd like to see their "Coverage" map when it comes
out.
|
Oh, yeah, agreed. I'm sure it will look a *lot* like cell phone coverage
maps. The only advantage it will have over cell phone is that the number
of users shouldn't affect it, since it is transmit-only at the towers.
--
Jeff Rife |
| http://www.nabs.net/Cartoons/OverTheHedge/Macarena.gif |
|
| Back to top |
|
|
none
Guest
|
| Posted:
Thu Mar 31, 2005 5:54 pm Post subject:
Re: DTV reception is much more difficult than analog |
|
|
Mark Crispin <mrc@CAC.Washington.EDU> wrote:
<snip>
| Quote: | I don't have much of a problem with the tuners. They output 1080i
so the TV's aspect ratio is locked. The tuners also lock their
aspect ratio on HD or widescreen SD programming.
|
AR is not locked on *all* TVs and STBs.
It depends on the brand/model of equipment. |
|
| Back to top |
|
|
Bob Miller
Guest
|
| Posted:
Thu Mar 31, 2005 7:06 pm Post subject:
Re: DTV reception is much more difficult than analog |
|
|
Jeff Rife wrote:
| Quote: | Drewdawg (nope@not.here) wrote in alt.tv.tech.hdtv:
Agreed, but I'm thinking there will be areas of the US without SFN
reception. Crown Castle has a tall order to fill if they expect to offer
*everyone* this service. I'd like to see their "Coverage" map when it comes
out.
Oh, yeah, agreed. I'm sure it will look a *lot* like cell phone coverage
maps. The only advantage it will have over cell phone is that the number
of users shouldn't affect it, since it is transmit-only at the towers.
Today's pocket cell phones are in the 100 milliwatt area. One milliwatt |
is one-thousandth of a watt. So cell phones operate at 1/10th of a Watt.
This determines the size of the cell they can operate in. The cell
towers themselves operate at around 10 Watts.
I don't know what the limit is for Crown Castle whose spectrum is in the
1.5 GHz area but Qualcomm in the 700 MHz spectrum they will use is
limited to 50,000 Watts. The Qualcomm power level is therefore as much
as 500,000 times greater than a cell towers power level.
I believe that would suggest a slightly bigger coverage map per transmit
site and over all better coverage.
For example at 1000 Watts of ERP we were able to receive mobile with
COFDM at 20 miles. With only 1/10th of a watt of power a cell phone must
have a cell tower within a mile or so. Makes for radically different
coverage maps. The Crown Castle and Qualcomm networks target cell phone
users so initially they will have similar coverage maps but far fewer
cells. However when they are fully deployed they will cover virtually
the entire country. Your cell phone will receive DTV in a far greater
coverage area than you can make a call in.
Bob Miller |
|
| Back to top |
|
|
Charles Tomaras
Guest
|
| Posted:
Thu Mar 31, 2005 10:54 pm Post subject:
Re: DTV reception is much more difficult than analog |
|
|
"Jeff Rife" <wevsr@nabs.net> wrote in message
news:MPG.1cb540eed6fd8074989c47@news.nabs.net...
| Quote: | Charles Tomaras (tomaras@tomaras.com) wrote in alt.tv.tech.hdtv:
Well now in my market the ABC affiliate uses their -2 sub channel for a
duplicate of -1 which I can't figure out why?
Without examining the transport stream, it's hard to tell.
Locally, the WB station had four subchannels for a while: 50-1, 50-2,
75-1,
and 75-2, but there was only one video stream and two audio streams. All
four sub-channels used the single video stream and the audio stream went
with the subchannel number, so they could provide alternate audio services
easily.
So, there is no telling what your ABC station is really doing for sure.
The NBC affiliate has a
weather channel on their -2 sub. Auto scan also picks up the NTSC
versions
of these stations as well. It's just really confusing for the average
person
to deal with all of this plus the aspect ratio issues. I don't have an
answer save for...I have a hard time recommending it to someone who isn't
pretty much up to date with their technology abilities.
Blaming the STB and ATSC for the brain dead behavior of some broadcasters
hardly seems fair.
|
No blame here..I'm just giving the realities of HDTV in Seattle. I can deal
with it and I'm very pleased with my setup. I cannot however recommend it to
techologically average friends because I don't want to be thier tech support
person. |
|
| Back to top |
|
|
inkyblacks@yahoo.com
Guest
|
| Posted:
Thu Mar 31, 2005 11:55 pm Post subject:
Re: DTV reception is much more difficult than analog |
|
|
Yesterday I tried one more position for my indoor antenna and found
that by raising it by just one more foot, I was for the first time able
to get all local digital channels in the middle of the day without
moving the position of the antenna. Who could imagine that one lousy
foot would make such a big difference! So it has taken me 10 months to
find the sweet spot in my apartment for my antenna, and I have to use a
specific indoor antenna (Silver Sensor) with an antenna amp (Zenith
indoor amp) to get the system to work.
How are old ladies going to deal with over-the-air digital TV? The
other thing I don't like is the labeling of channels like 9.1 and 9.2.
This scheme is too complex for most people. Unless you are technically
inclined and have patience, or are lucky enough to be able to have a
good outdoor antenna, I think OTA digital is too much work and
complexity for the elderly and for women.
Better receiver chips would help.
IB |
|
| Back to top |
|
|
Alan
Guest
|
| Posted:
Fri Apr 01, 2005 1:49 am Post subject:
Re: DTV reception is much more difficult than analog |
|
|
In article <1112295350.890069.113640@l41g2000cwc.googlegroups.com> "inkyblacks@yahoo.com" <inkyblacks@yahoo.com> writes:
| Quote: | Yesterday I tried one more position for my indoor antenna and found
that by raising it by just one more foot, I was for the first time able
to get all local digital channels in the middle of the day without
moving the position of the antenna. Who could imagine that one lousy
foot would make such a big difference!
|
Anyone who has ever looked at the issues of indoor TV antennas.
| Quote: | So it has taken me 10 months to
find the sweet spot in my apartment for my antenna, and I have to use a
specific indoor antenna (Silver Sensor) with an antenna amp (Zenith
indoor amp) to get the system to work.
|
Or, an outdoor antenna. As many of us have explained, there are reflections
of the signals indoors, blockages by metal in the walls, diffraction around the
edges (such as through windows).
There will be dead spots.
The dead spots will vary as people move around in the room
| Quote: | How are old ladies going to deal with over-the-air digital TV?
|
By putting the antenna outside, where it belongs.
| Quote: | The
other thing I don't like is the labeling of channels like 9.1 and 9.2.
This scheme is too complex for most people. Unless you are technically
inclined and have patience, or are lucky enough to be able to have a
good outdoor antenna, I think OTA digital is too much work and
complexity for the elderly and for women.
|
Oh, you think the elderly and women are incapable? What a snot you
are!
| Quote: | Better receiver chips would help.
|
No, they wouldn't. If the signal is not present in a spot, it does't
matter what receiver you use.
Alan |
|
| Back to top |
|
|
Jeff Rife
Guest
|
| Posted:
Fri Apr 01, 2005 1:51 am Post subject:
Re: DTV reception is much more difficult than analog |
|
|
inkyblacks@yahoo.com (inkyblacks@yahoo.com) wrote in alt.tv.tech.hdtv:
| Quote: | How are old ladies going to deal with over-the-air digital TV?
|
Easily, *if* they are dealing with OTA analog TV right now.
Many people are re-discovering the lost art of OTA TV reception because
digital TV has features that make it worthwhile to try. People that
don't care about those features today and who don't use OTA for their
local analog stations will keep doing what they have been doing: get the
digital locals from their cable or satellite provider.
--
Jeff Rife | Coach: What's the story, Norm?
|
| Norm: Thirsty guy walks into a bar. You
| finish it. |
|
| Back to top |
|
|
Mark Crispin
Guest
|
| Posted:
Fri Apr 01, 2005 2:23 am Post subject:
Re: DTV reception is much more difficult than analog |
|
|
On Thu, 31 Mar 2005, inkyblacks@yahoo.com wrote:
| Quote: | How are old ladies going to deal with over-the-air digital TV?
|
The same way they dealt with over-the-air analog TV. Either they have a
professional set up the antenna, they "assume FOX viewing positions", or
they decide for simplicity and go with cable or satellite.
-- Mark --
http://staff.washington.edu/mrc
Science does not emerge from voting, party politics, or public debate.
Si vis pacem, para bellum. |
|
| Back to top |
|
|
Alan
Guest
|
| Posted:
Fri Apr 01, 2005 5:30 am Post subject:
Re: DTV reception is much more difficult than analog |
|
|
In article <GM33e.77$N13.66@newsread3.news.pas.earthlink.net> Bob Miller <robmx@earthlink.net> writes:
| Quote: | Alan wrote:
No, they wouldn't. If the signal is not present in a spot, it does't
matter what receiver you use.
Dead spots in the room are rare with COFDM. Maybe because with COFDM in
a room you would use an omni antenna where with 8-VSB to avoid the
multipath problem with to many signals bouncing around that room you
would use a directional antenna.
|
No, this is nonsense. The symbol rate of 8vsb is not that high. Multipath
within the room will not be an issue for intersymbol interference.
| Quote: | The omni with COFDM welcomes the multipath signal no matter where it is
bouncing from and is capable of adding these signals together for a
stronger signal whereas the directional with 8-VSB is trying to
specifically avoid these other signals and just concentrate on the main
or strongest signal.
|
The problem, twit, is that the signals also CANCEL when they combine with
the strong reflections indoors. When the signals CANCEL, it doesn't matter
if you are using 8VSB, COFDM, NTSC, or something else. No signal is no signal.
| Quote: | So don't blame to much on dead spots, it may be the directional antenna
that is not aimed at all the signals at once.
|
As for indoor aerials (antennas) with the U.K. Freeview system:
http://www.freeview.co.uk/faqs/aerialsandreception.html
I quote from there:
A small number of households may be able to use a set top aerial.
This only applies if you live in a coverage area close to a
transmitter, but reception would still be unreliable and so we
strongly recommend that you use a roof or loft aerial for good
reception.
So, the folks who use COFDM say it doesn't have this magical ability
to work with indoor antennas.
Alan |
|
| Back to top |
|
|
Randy Sweeney
Guest
|
| Posted:
Fri Apr 01, 2005 7:11 am Post subject:
Re: DTV reception is much more difficult than analog |
|
|
<inkyblacks@yahoo.com> wrote in message
news:1112295350.890069.113640@l41g2000cwc.googlegroups.com...
| Quote: | Yesterday I tried one more position for my indoor antenna and found
that by raising it by just one more foot, I was for the first time able
to get all local digital channels in the middle of the day without
moving the position of the antenna. Who could imagine that one lousy
foot would make such a big difference!
|
Makes perfect sense... you have to remember how short UHF waves are...
namely between 1-2 feet long.
so moving your antenna 1 foot was enough to completely change the Rayleigh
multipath interference pattern and take you from a null to peak
the fact that UHF signals are the same size as human sized stuff accentuates
the multipath effects... this is a particular issue for RFID where gain
margins are ridiculously low and multipath is killer. |
|
| Back to top |
|
|
inkyblacks@yahoo.com
Guest
|
| Posted:
Fri Apr 01, 2005 8:13 am Post subject:
Re: DTV reception is much more difficult than analog |
|
|
Alan,
It is often not a black and white issue of signal or no signal. The LG
5th chip receiver claims to be able to display signals at one fourth
the signal strength of previous designs. In the apartment where it was
tested, they picked up stations that they could not pick up before and
picked up all signals detected with a scope. There may be situations
where even the best receiver will not help, but certainly if reports
from Bob Miller and Sinclair are true about the LG design, it is a big
boost to indoor reception in America.
IB |
|
| Back to top |
|
|
Bob Miller
Guest
|
| Posted:
Fri Apr 01, 2005 8:28 am Post subject:
Re: DTV reception is much more difficult than analog |
|
|
Alan wrote:
| Quote: | In article <1112295350.890069.113640@l41g2000cwc.googlegroups.com> "inkyblacks@yahoo.com" <inkyblacks@yahoo.com> writes:
Yesterday I tried one more position for my indoor antenna and found
that by raising it by just one more foot, I was for the first time able
to get all local digital channels in the middle of the day without
moving the position of the antenna. Who could imagine that one lousy
foot would make such a big difference!
Anyone who has ever looked at the issues of indoor TV antennas.
So it has taken me 10 months to
find the sweet spot in my apartment for my antenna, and I have to use a
specific indoor antenna (Silver Sensor) with an antenna amp (Zenith
indoor amp) to get the system to work.
Or, an outdoor antenna. As many of us have explained, there are reflections
of the signals indoors, blockages by metal in the walls, diffraction around the
edges (such as through windows).
There will be dead spots.
The dead spots will vary as people move around in the room
How are old ladies going to deal with over-the-air digital TV?
By putting the antenna outside, where it belongs.
The
other thing I don't like is the labeling of channels like 9.1 and 9.2.
This scheme is too complex for most people. Unless you are technically
inclined and have patience, or are lucky enough to be able to have a
good outdoor antenna, I think OTA digital is too much work and
complexity for the elderly and for women.
Oh, you think the elderly and women are incapable? What a snot you
are!
Better receiver chips would help.
No, they wouldn't. If the signal is not present in a spot, it does't
matter what receiver you use.
Alan
|
Dead spots in the room are rare with COFDM. Maybe because with COFDM in
a room you would use an omni antenna where with 8-VSB to avoid the
multipath problem with to many signals bouncing around that room you
would use a directional antenna.
The omni with COFDM welcomes the multipath signal no matter where it is
bouncing from and is capable of adding these signals together for a
stronger signal whereas the directional with 8-VSB is trying to
specifically avoid these other signals and just concentrate on the main
or strongest signal.
So don't blame to much on dead spots, it may be the directional antenna
that is not aimed at all the signals at once.
Bob Miller |
|
| Back to top |
|
|
Bob Miller
Guest
|
| Posted:
Fri Apr 01, 2005 8:28 am Post subject:
Re: DTV reception is much more difficult than analog |
|
|
inkyblacks@yahoo.com wrote:
| Quote: | Alan,
It is often not a black and white issue of signal or no signal. The LG 5th chip receiver claims to be able to display signals at one fourth
the signal strength of previous designs. In the apartment where it was tested, they picked up stations that they could not pick up before and
picked up all signals detected with a scope. There may be situations where even the best receiver will not help, but certainly if reports
from Bob Miller and Sinclair are true about the LG design, it is a big boost to indoor reception in America.
IB
|
Yes and as we stood there with the designers of the 5th gen chip from LG
they gave due credit to COFDM as the source of their inspiration.
Photos of Korean engineers here.
http://public.fotki.com/robmx/5th_generation_test/
Bob Miller |
|
| Back to top |
|
|
|
|
|
|
FAQ
Memberlist
Register
Profile
Log in to check your private messages
Log in