Chart of HDTV freqs?
 

In article ,
John Smith wrote:

Really? Something is quite wrong there!

Digital signals should require much less power to deliver the same
"quality" signal.

JS-

Why do you say that?

You can't have a less-than perfect digital TV signal. There is no snow
because a weak digital signal's picture freezes or goes away. Therefore
there is no way to compare quality levels of less-than perfect pictures.

Most of the time my simple antenna picks up good HDTV. However there
are times when reception is poor, and I have to switch to the Analog
tuner. I'd rather have a little snow than no picture at all!

Fred

Chart of HDTV freqs?
 

Look at the spectra of the signals an compare the levels. More amplitude in
the sync pulse and average video than the ATSC pilot across the board from
what I'm seeing. Perhaps they are trying to get away with less. Perhaps
fooling around with tower work and dropping the power. Hard to tell with
the GUI meter and never had the service monitor up at the time. One is DTV
VHF HI that is a new one with no Analog so I lose it completely and 2 are
UHF that are fading on me from time to time where I have to punch to the
Analog broadcast, one of which is VHF. Generally more power is needed on
UHF to come up with comparable range.

"Fred McKenzie" wrote in message
...
In article ,
John Smith wrote:

Really? Something is quite wrong there!

Digital signals should require much less power to deliver the same
"quality" signal.

JS-

Why do you say that?

You can't have a less-than perfect digital TV signal. There is no snow
because a weak digital signal's picture freezes or goes away. Therefore
there is no way to compare quality levels of less-than perfect pictures.

Most of the time my simple antenna picks up good HDTV. However there
are times when reception is poor, and I have to switch to the Analog
tuner. I'd rather have a little snow than no picture at all!

Fred

Chart of HDTV freqs?
 

Fred McKenzie wrote:

...
Why do you say that?


Easy, with digital you are simply determining whether a signal is
present--or on (a binary one), on not--and off (a binary zero) ... an
analog signal contains much more data which can "screw up."

You can't have a less-than perfect digital TV signal. There is no snow
because a weak digital signal's picture freezes or goes away. Therefore
there is no way to compare quality levels of less-than perfect pictures.


Oh, yes you can, indeed, ever hear of "lossy data compaction?" It is
used for audio and video where not every bit/byte of data need to be
perfect--attempt that with an executable file and it fails ... the
program itself can "deduce" if the data is just "degraded" or is beyond
use and pass it along to the video/audio device or toss it as decided ...

Most of the time my simple antenna picks up good HDTV. However there
are times when reception is poor, and I have to switch to the Analog
tuner. I'd rather have a little snow than no picture at all!

As I say, something is wrong, and it may not be "all on your end", and
broadcast HDTV may need some upgrades to the software handling the
coding/decoding of the signals ... widespread usage, in the future, and
"fixes" along the way should provide a much improved system.

I have not had a chance to "experience" broadcast HDTV yet ... however,
the cable HDTV is much improved over old analog ...


Fred

Chart of HDTV freqs?
 

John Smith wrote:

Fred McKenzie wrote:

Most of the time my simple antenna picks up good HDTV. However there
are times when reception is poor, and I have to switch to the Analog
tuner. I'd rather have a little snow than no picture at all!

As I say, something is wrong, and it may not be "all on your end", and
broadcast HDTV may need some upgrades to the software handling the
coding/decoding of the signals ... widespread usage, in the future, and
"fixes" along the way should provide a much improved system.

I experience the same phenomenon. My antenna is a UHF indoor bow tie dipole.
(All my HD channels are currently on UHF.) I am about 30 miles from the TV
tower which is at 1200'. My HDTV set can show signal bars like a cell phone.
Without moving the antenna or other surrounding objects, the signal will
sometimes slowly vary by one or two bars. If it goes down too far the
picture breaks up and quits. At other times the same station will give a
solid 3 or 4 bars.This happens on all channels. Perhaps atmospheric
movement? Lots of dust here in the desert. Any other ideas?

I have not had a chance to "experience" broadcast HDTV yet ...
however, the cable HDTV is much improved over old analog ...

I have cable HDTV on my other set in the family room. Surprisingly (to me)
the broadcast HDTV picture is superior in quality to the cable HDTV picture.
Perhaps Cox is using more compression to squeeze more channels in the line.

Chart of HDTV freqs?
 

AJ Lake wrote:

...
I experience the same phenomenon. My antenna is a UHF indoor bow tie dipole.
(All my HD channels are currently on UHF.) I am about 30 miles from the TV
tower which is at 1200'. My HDTV set can show signal bars like a cell phone.
Without moving the antenna or other surrounding objects, the signal will
sometimes slowly vary by one or two bars. If it goes down too far the
picture breaks up and quits. At other times the same station will give a
solid 3 or 4 bars.This happens on all channels. Perhaps atmospheric
movement? Lots of dust here in the desert. Any other ideas?


Yes, ducting and "ghosting" of the signal(s) due to reflections, etc.--I
can see these as being a REAL problem. From your description(s), sounds
like "they" just took the exact-same
technology/encoding/decoding-schemes and implemented them onto broadcast
.... what works well with cable (a relatively "stable" signal NOT prone
to the effects stated above ...) may not work all that well with
broadcast ... sounds like some "upgrades" are already in order.

I have just assumed, up to this point, that the digital HDTV signal is
"packeted" ... however, unlike our broadband modems and satelite
internet, you cannot request for a corrupt packet to be "resent" to your
TV ... however, I am wondering if corrupt packets (or, seriously
degraded ones) are just being "tossed" rather than passed along to the
video/audio circuitry? Perhaps the software should assume that no
matter how degraded (or, at least seriously degraded packets) should be
passed on and the viewer be allowed to determine if it is of enough
worth, or not? It almost sounds like this would be preferable to
no-signal-at-all. But then your description of "the bars" beginning to
degrade would soon reach a point of "un-viewable signal" anyway?; so,
at this point, perhaps no-signal-at-all is preferable ... hmmm, I wonder?

I have not had a chance to "experience" broadcast HDTV yet ...
however, the cable HDTV is much improved over old analog ...

I have cable HDTV on my other set in the family room. Surprisingly (to me)
the broadcast HDTV picture is superior in quality to the cable HDTV picture.
Perhaps Cox is using more compression to squeeze more channels in the line.

Hmmmm, you have me all the more anxious to have HDTV implemented in my
area ... LOL!

Regards,
JS

Chart of HDTV freqs?
 

"J. Mc Laughlin" wrote in message
.. .
... and some stations will be transmitting DTV on a third channel (not the
present analog nor the present DTV channel)

I have also found that a number of stations have applied for changes (so
far
they seem to be ERP changes) to what is contained in the eighth FCC report
of March 2008. One needs to go to the FCC site and enter call sign of
each
station to find the present information.

A surprise to me is that the coverage contour for analog TV is 64 dBu and
for DTV is 41 dBu - a difference of 23 db. However, the reductions of ERP
do not seem to be that large. Stations that are now a bit weak may be
unusable after Feb. 2009.

73, Mac N8TT

The DTV RF signal needs to be about 17 dB out of the noise to work and
produce a nice, clean picture. Analog TV RF signal needs to be about 40 dB
out of the noise for a snow-free picture on screen. Holy crap, that's 23
dB! Coincidence? I think not.

In my case, I get generally horrible analog performance from Los Angeles
stations, 124 miles away. However, I usually have a half-dozen digital
pictures from there and they are, of course, perfect whenever they come in.

By the way, the original question -- as if anybody really remembered it --
is answered he

http://rabbitears.info/market.php

That site has a grunch of data. See the links at the top. This guy is
working his butt off.

73,
"Sal" KD6VKW

Chart of HDTV freqs?
 

Sal M. Onella wrote:


That site has a grunch [bunch] of data. See the links at the top. This guy is
working his butt off.

73,
"Sal" KD6VKW



Sal:

Excellent URL, well worth my looking over ... thanks, I will certainly
bookmark this one!

Regards,
JS

Chart of HDTV freqs?
 

"Fred McKenzie" wrote in message
...
In article ,
John Smith wrote:

Really? Something is quite wrong there!

Digital signals should require much less power to deliver the same
"quality" signal.

JS-

Why do you say that?

You can't have a less-than perfect digital TV signal. There is no snow
because a weak digital signal's picture freezes or goes away. Therefore
there is no way to compare quality levels of less-than perfect pictures.

Well, there is, sorta. You do need much more analog signal to get a noise
free picture, compared to the level of digital signal you need for a good
"lock."

By the old TASO standards, you need over 40 dB s/n to get a nice picture,
which requires a lot more peak RF power. By comparison, the digital signal
needs only about 17 dB s/n.

Chart of HDTV freqs?
 

John Smith wrote:
Easy, with digital you are simply determining whether a signal is
present--or on (a binary one), on not--and off (a binary zero) ... an
analog signal contains much more data which can "screw up."

OTOH, when the digital signal is neither a one nor a zero,
or the CRC doesn't check, it fails completely while the
analog signal is slowly fading away.

During Hurricane Ike, all the digital signals here failed
while the analog signals were still (noisily) providing
useful information.

I hear digital voice used on HF amateur radio has the
same problem.
--
73, Cecil http://www.w5dxp.com

Chart of HDTV freqs?
 

Dear Sal:
Thank you. I should have taken the trouble to think about the
difference.
Thinking back to the extensive tests of (analog) TV performance that
were performed in the 50s, makes the 64 dBu understandable. At that time,
the noise-figures of TV sets were, by modern standards, poor. It was also
found - without surprise - that people would tolerate a poor picture is the
sound was OK, thus followed the preferred ratio of video to sound carrier.

As noise figures fell, many of us became accustomed to satisfactory
performance using simple, indoor antennas. That is another way of saying
that the ERP standards of the 50s were overkill in the 21st century. With
the advent of DTV, outside antennas will once again become the norm.

What seems to be missing - at least until competitive pressure catches
up - is an effective way to compare NF of TV sets or converter boxes. One
needs a box that presents a small-signal DTV signal.

Again, thanks. 73, Mac N8TT
--
J. McLaughlin; Michigan, USA
Home:
"Sal M. Onella" wrote in message
...

"J. Mc Laughlin" wrote in message
.. .
... and some stations will be transmitting DTV on a third channel (not
the
present analog nor the present DTV channel)

I have also found that a number of stations have applied for changes (so
far
they seem to be ERP changes) to what is contained in the eighth FCC
report
of March 2008. One needs to go to the FCC site and enter call sign of
each
station to find the present information.

A surprise to me is that the coverage contour for analog TV is 64 dBu and
for DTV is 41 dBu - a difference of 23 db. However, the reductions of
ERP
do not seem to be that large. Stations that are now a bit weak may be
unusable after Feb. 2009.

73, Mac N8TT

The DTV RF signal needs to be about 17 dB out of the noise to work and
produce a nice, clean picture. Analog TV RF signal needs to be about 40
dB
out of the noise for a snow-free picture on screen. Holy crap, that's 23
dB! Coincidence? I think not.

In my case, I get generally horrible analog performance from Los Angeles
stations, 124 miles away. However, I usually have a half-dozen digital
pictures from there and they are, of course, perfect whenever they come
in.

By the way, the original question -- as if anybody really remembered it --
is answered he

http://rabbitears.info/market.php

That site has a grunch of data. See the links at the top. This guy is
working his butt off.

73,
"Sal" KD6VKW