[accesscomp] Re: Fw: Digital Ready TV Radio Alternatives

  • From: "Gene" <gsasner@xxxxxxxxx>
  • To: <accesscomp@xxxxxxxxxxxxx>
  • Date: Sat, 18 Jul 2009 10:18:00 -0600

I made a typographical error in my previous message. I intended to say that it appears the method of digitization is very different between radio and television stations and that the frequencies used by digital radio stations and television stations are mostly very different.


Gene
----- Original Message ----- From: "Gene" <gsasner@xxxxxxxxx>
To: <accesscomp@xxxxxxxxxxxxx>
Sent: Saturday, July 18, 2009 10:11 AM
Subject: [accesscomp] Re: Fw: Digital Ready TV Radio Alternatives


Regarding your comments, Mike and Scott, looking at the following Wikipedia article is instructive and lends strong support to the argument I was making yesterday about problems when the radio is moving and reception problems in fringe areas. There is also a brief reference to reception problems in rural areas as well. You will see some of the material in the following quote. Scott, you appear to be arguing by analogy between the digital radio service and digital television service. It appears that the method of digitization is different and the frequences os most stations are very different. I don't claim to have the technical knowledge to do more than rely on good sources of information and on my inferences from what I've observed myself since using a digital converter box. I remain very skeptical that a portable radio will receive digital television adequately when the radio is moving. Here is the link to the Wikipedia article and a quote from the text:

Before presenting the quote, I'll make one comment about the channel 6 radio reception question. There is an interesting bit of information in this article that indicates that one station in New York State is considering operating a transmitter for audio on the channel 6 frequency so those listening during drive time can still receive the station. It appears that in areas where channel 6 was available, many people used this service. I would expect this number to be much greater than those using TV radios to receive television audio. There is, evidently, a means to transmit an audio signal that won't interfere with the digital uses of the frequency.

Gene

http://en.wikipedia.org/wiki/DTV_transition_in_the_United_States#Loss_of_service

A major concern is that the broadcast technology used to transmit ATSC signals
called
8VSB
has problems receiving signal inside buildings and in urban areas, largely
due to
multipath
reception issues which cause
ghosting
and
fading
on analog images, but can lead to intermittent signal or no reception at all
on ATSC programs.
[28]
DTV broadcasts exhibit a
digital cliff
effect, by which viewers will receive either a perfect signal or no signal
at all with little or no middle ground. Digital transmissions do contain
additional data bits to provide
error correction
for a finite number of
bit errors
; once signal quality degrades beyond that point, recovery of the original
digital signal becomes impossible, and the image on the screen freezes, or
blinks back and forth to totally blank black.

The maximum power for
DTV broadcast classes
is also substantially lower; one-fifth of the legal limits for the former
full-power analog services. This is because there are only eight different
states in which an 8VSB signal can be in at any one moment, thus like all
digital transmissions, very little signal is required at the receiver in
order to decode it. Nonetheless, this limit is often too low for many stations to reach many rural areas, which was an alleged benefit in the FCC's choice
of ATSC and 8VSB over worldwide-standard
DVB-T
and its
COFDM
modulation.
Additionally, without the
hierarchical modulation
of DVB, signal loss is complete, and there is no switch to a lower resolution before this occurs. Even if power limits were increased, it would not solve
the multipath issue however.
----- Original Message ----- From: "Mike Pietruk" <pietruk@xxxxxxxxx>
To: <accesscomp@xxxxxxxxxxxxx>
Sent: Friday, July 17, 2009 3:51 PM
Subject: [accesscomp] Re: Fw: Digital Ready TV Radio Alternatives


Gene

The rural situation seems to be a mixed bag.  An article, a couple of
weeks back, in the Peoria Star Journal presented letters from readers of
rural locations who reported a significant increase in channels received
as well as markets picked up.  Apparently, proper antenna placement is a
significant factor in this reception so, whether it is skill or random
luck, some folks who feared the worst consider themselves blessed and
wished the whole thing had happened years ago.

Change is a painful thing.  I have no way of personally reporting on this
digital thing as we are cable customers who saw no impact one way or
another.  What I am waiting for next is the complaint from cable
subscribers complaining that they are not getting the new hd 2nd and 3rd
channnels.


What I did notice is that some analog channels continued on the air past
June 12 carrying a program explaining how to do the conversion.  It is in
English and Spanish and repeated over and over and over.
Channel 6 in the Quad Cities ran this for 2 or so weeks; and I noticed one
channel in Northern Florida was running this as late as a couple of weeks
ago.

Bob Crane has indicated that a portable receiver is in the works; but
indicated that it is still in development.  If I had to guess, Sangean, a
regular development partner of Crane, is probably who is involved; and if
it is Sangean, and one actually makes it into production, you can expect
it to be a quality product.

Time will tell.





How we use the name of God reveals more clearly than any creed we ever confess our deepest attitudes towards
the God of the sacred name.
R. C. Sproul



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