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#138844 - 07/07/08 01:31 AM Re: Television Digital Cutover & Communications [Re: haertig]
MartinFocazio Offline

Pooh-Bah

Registered: 01/21/03
Posts: 2203
Loc: Bucks County PA
Originally Posted By: haertig

(2) You have the wrong type of antenna (A VHF model when you may need a UHF one). You may also need an amplifier today if your stations are broadcasting at low power.

I have (had) a massive, just massive UHF/VHF antenna, it was a zillion elements and about a football field long. The UHF section was a huge corner reflector thing hanging way off the front. I know the difference between UHF and VHF, I have a ham radio license, I'm familiar with the basic concepts of antenna construction, I've built a few myself.

Originally Posted By: haertig

(3) Your digital tuners - both in the the PC card and the digital converter box - are not very good. Many of the digital converter boxes are indeed junk. Rushed to market at cheap prices. You might look at the "DTVPal" made by Echostar/DishNework. It is brand new and getting very good reviews.

I'm not looking at anything anymore. When a free television virtually pulled from the trash works better than the whizzy new tech that's supposed to replace it - well, I'm reticent to invest anything it it.

Originally Posted By: haertig

You are evidently running into what is commonly called "the digital cliff". Either you have a great picture, or you don't have any picture. There is a very small window right near that cutoff where you will see pixelation, noise, and things cutting in and out. If your stations are broadcasting their digital signals at low power, the cliff may be closer to you than you'd like. But this will probably change at the analog-digital changeover date. Many stations are using temporary digital transmitters and small antennas today, and are ramping up their higher power transmitters and better antennas for the changeover date.

I miss analog hills.

Originally Posted By: haertig

It's not the signal that disappeared (except if the transmitter broke - unlikely). It's your tuners ability to lock onto the signal. A very small deviation in the signal may throw your tuner over the cliff where it can't lock the signal.

Ummm....and this is different (in terms of my experience) how?

Originally Posted By: haertig

You are confusing HDTV (high definition TV) and DTV (digital TV). These are two separate things. There is no mandate for stations to go HD, only for them to go digital. There is still tons and tons of standard definition programming being broadcast digitally. This will continue after the analog cutoff date.


No, I'm not. I know that the DTV system (ATSC) can carry HD but does not have to. My point is that I can't recall ever being at a party where people were griping about the picture quality on their TV. I, like many other folks, didn't really have a problem with the NTSC system, it was, like AM radio, "good enough" for the job and a technology that was mature, cheap and effective.

Originally Posted By: haertig

If your comment on "most people don't care for how the signal looks" is supposed to go along with your second comment about stretching a 4:3 aspect ratio to a 16:9 one (I can't tell from your working), for the most part this distortion is caused by people who are ignorant of how to work their TVs. But not always. There are some TV stations that are notorious for actually broadcasting stuff in "stretch-o-vision". They do this because to many ignorant people, "short, fat characters" on the screen equal high definition. Not at all. It only means "distorted aspect ratio". I certainly don't set my TV to intentionally distort the picture, and if I run across a show that is actually being broadcast in stretch-o-vision, I move on to a different channel.


My point exactly. Most people don't see the difference. If you can't tall fat-o-vision from HD, that means there's really no point (for most folks) to having HD at all.
To be honest, until recently, I didn't really see a major difference for HD vs. SD, in terms of picture quality. The gamma still is horrid, the compression artifacts are really annoying. I have been checking out uncompressed 1080i via digital downloads, and it's really not all that wonderful (at least to me). Certainly it's not going to be enough for me to go out and buy any new gear, ever.

Originally Posted By: haertig

Quote:
Did I mention ATSC does not work when mobile? Yeah, that's not in the spec.

This has to do with the need for the receiver to sample the digital signal at specific intervals. If the receiver is moving quickly, this is difficult. Think of a car honking the horn while it first drives towards you, then past you - the frequency that the horn is broadcasting does not change, but it appears to get lower in frequency to your ear as you are passed because of the Doppler Effect. New broadcast specs, which are backwards compatible with existing tuners, are starting to overcome this limitation.


Yeah, I know all about doppler shifts - I compensated for them when I used to work AO-SAT for field day and such when I was more active in Ham Radio. It's amazing to me that the slight movement of a car, relatively speaking, can kill an ATSC signal, whereas I can stream video with no problem via my Verizon mobile card.

I've hammered on this one long enough. I think this is a poor technology, one that is unnecessarily complex and expensive, and is solving a problem nobody has. It was imposed by fiat by a government that was supposed to re-allocate spectrum to the public good. The "D" block is a fiasco, the balance of the 700 Mhz auction was hardly a huge success, and here we are, a few months away, and the last thing I'll ever watch OTA is going to be the Olympics via an ancient - but working - Analog NTSC tower in Philadelphia.

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#138846 - 07/07/08 01:38 AM Re: Television Digital Cutover & Communications [Re: MartinFocazio]
Am_Fear_Liath_Mor Offline
Carpal Tunnel

Registered: 08/03/07
Posts: 3078
Hi martinfocazio

Have you tried a HDTV E-PHEMT mast LNA such as the one you can find here at http://www.researchcomms.com/hdtv.html, which can give around 20dB Gain and only 0.4 dB Noise figure. That should help considerably with your UHF signal problems.



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#138849 - 07/07/08 02:13 AM Re: Television Digital Cutover & Communications [Re: MartinFocazio]
haertig Offline
Pooh-Bah

Registered: 03/13/05
Posts: 2322
Loc: Colorado
Sounds like you know about antennas and radio. You didn't say that before. I was just trying to help, that's all. Most folks these days have never even seen a TV antenna up close, let alone know VHF vs. UHF or how to aim one. Cable and satellite are the norm now (in urban and suburban settings at least).

I do disagree with you about digital vs. analog one being superior to the other. But that's OK. We can agree to disagree. It surely depends on our circumstances. Digital reception just trounces analog reception in my area. Even with low power transmitters for the digital and high power transmitters for the analog. I do agree that good upconverted DVDs are fine. Yes, I can clearly tell the difference between BR (or HDDVD) and upconverted DVD, but it really doesn't change the movie watching experience. It's most impressive for those who like to closely observe the nose hairs in the actors though. But anyone who puts up with stretch-o-vision broadcast or adjusts the aspect ratio to "fill their screen" by distorting things is pretty ignorant IMHO.

SD broadcast TV viewed on my 65" HDTV looks pretty lousy (partly because of the horrible compression that Dish adds). That is typical for HDTVs, but some are better than others at displaying marginal SD programming. However, if I use my OTA antenna, ATSC still beats NTSC by a good margin, and HD really shines. Your areas is just different I guess.

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#138859 - 07/07/08 06:48 AM Re: Television Digital Cutover & Communications [Re: haertig]
KG2V Offline

Veteran

Registered: 08/19/03
Posts: 1371
Loc: Queens, New York City
Originally Posted By: haertig
Sounds like you know about antennas and radio. You didn't say that before. I was just trying to help, that's all. Most folks these days have never even seen a TV antenna up close, let alone know VHF vs. UHF or how to aim one. Cable and satellite are the norm now (in urban and suburban settings at least).

snip


The problem with Digital (and having chatted with Marty more than once I know some of his experiences) - picture you are "deep fringe" - with analog (and in this case AM is even better than FM) you might get a static filled signal - in TV, we'll call it "seeing raster", but the human mind can pull signal from the noise. In digital, you drop ONE bit, you have no reception. It's wonderful when it works, and you can get every bit in each digital packet - but with analog, if you lose the same amount of data, you don't lose signal, you just get a noisy signal
_________________________
73 de KG2V
You are what you do when it counts - The Masso
Homepage: http://www.thegallos.com
Blog: http://kg2v.blogspot.com

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#138860 - 07/07/08 10:19 AM Re: Television Digital Cutover & Communications [Re: KG2V]
MartinFocazio Offline

Pooh-Bah

Registered: 01/21/03
Posts: 2203
Loc: Bucks County PA
Originally Posted By: kc2ixe
In digital, you drop ONE bit, you have no reception. It's wonderful when it works, and you can get every bit in each digital packet - but with analog, if you lose the same amount of data, you don't lose signal, you just get a noisy signal


And this is the main flaw in the whole DTV scheme - it's not fault-tolerant like TCP/IP.

This is the main issue with DTV - there's no good way to deal with packet loss in the same way you do with TCP/IP, which can not only re-send lost packets, it can send packets via multiple paths and even network connections and you can put them all in order and store up enough for a decent stream as they pass through the local buffer. I've read up on the ATSC standard (and QAM and all the rest of the jargon associated with DTV) and I am astonished that a specification as poorly engineered as this ever was adopted as a standard. From a data-delivery standpoint, and in looking at real-world situations like multi-path reflections and intermittent signal reduction due to leaf coverage, weather patterns and so forth, it's no wonder I'm at - and off - the edge of the "digital cliff".
This is now the second time I've seen how a digital "upgrade" from analog is in fact a downgrade for end users. Many of the same issues I face as a firefighter with our APCO-25 Digital Radios are similar to the ATSC issues (random, unexplained outages, does not work where the old analog system did). At least in the fire service, we've been given the ability (in fact a MANDATE) to NOT use the digital system for Fireground Communications (it's deemed to unreliable for on-scene life safety). With television broadcasts, I won't have that option.

I wonder what hurricane season 2009 will be like when the cable TV wires go down and people try to get local information on TV and they find that the old TV in the garage that worked last year does not work anymore.

My bet: You'll see a hasty "temporary reactivation" of the NTSC Analog facilities before 2009 is out.

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#138864 - 07/07/08 01:04 PM Re: Television Digital Cutover & Communications [Re: KG2V]
OldBaldGuy Offline
Geezer

Registered: 09/30/01
Posts: 5695
Loc: Former AFB in CA, recouping fr...
"...In digital, you drop ONE bit, you have no reception..."

Yeah, you get a black screen, with the little words "No Signal" up in the corner. And in our limited experience, it comes and goes with a very irritating frequency. Hopefully when they go all digital it will get better. If not, we will be hitting the $5 DVD bucket at WallyWorld a lot more...
_________________________
OBG

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#138959 - 07/08/08 11:11 AM Re: Television Digital Cutover & Communications [Re: MartinFocazio]
Eugene Offline
Carpal Tunnel

Registered: 12/26/02
Posts: 2995
Originally Posted By: martinfocazio
and I've not tested it in an emergency situation when the cell sites are saturates, but as a way of getting online when the power is out and the wires are down it works.


A lot of times the data cards run ona separate "channel" so voice calls don't saturate the data calls and vice versa.

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#138960 - 07/08/08 11:19 AM Re: Television Digital Cutover & Communications [Re: OldBaldGuy]
Eugene Offline
Carpal Tunnel

Registered: 12/26/02
Posts: 2995
Originally Posted By: OldBaldGuy
"...In digital, you drop ONE bit, you have no reception..."

Yeah, you get a black screen, with the little words "No Signal" up in the corner. And in our limited experience, it comes and goes with a very irritating frequency. Hopefully when they go all digital it will get better. If not, we will be hitting the $5 DVD bucket at WallyWorld a lot more...


Its not that bad, all your broadcast digital video like this uses a lossy compression so your loosing a few bits there and there anyway. When you do drop some bits is when you see the blocky look on the screen as whole packets get dropped then you start to drop too many and the display get blanked.

Its the same as the little satalite dishes when they get covered with snow, your signal startes to get blocky then goes away.
The real annoying thing is when your aying for cable tv and it gets blocky so you can tell they are just forwarding a signal from a little dish, might as well just get the dish.


Edited by Eugene (07/08/08 11:20 AM)

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#138963 - 07/08/08 12:52 PM Re: Television Digital Cutover & Communications [Re: Eugene]
Nishnabotna Offline
Icon of Sin
Addict

Registered: 12/31/07
Posts: 512
Loc: Nebraska
I'm undecided as to whether I even need to continue getting TV signals. The effort it takes to uncover anything worthwhile in the midst of the crap is tiring.

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#138967 - 07/08/08 01:11 PM Re: Television Digital Cutover & Communications [Re: MartinFocazio]
OldBaldGuy Offline
Geezer

Registered: 09/30/01
Posts: 5695
Loc: Former AFB in CA, recouping fr...
I'm not trying to hijack this thread at all, and this question may have already been answered here, but I have lost track with all the high tech acronyms, etc, so here goes. Is there something, maybe like an aircard, that you can stick in a laptop and receive TV signals? Digital signals? That would be perfect for us ramblin' folks who don't want to mess with a sat dish...
_________________________
OBG

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