An amplifier will not help you with locals

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Conjuror

SatelliteGuys Pro
Original poster
May 4, 2004
250
8
Just to crash a myth. When you receive a digital signal, you receive a stream of zeros and ones. If the stream is never broken, you'll always get perfect picture, no matter how far TV towers are. If the stream is broken sporadically, you cannot get the picture at all or you have a lot of droppings. An amplifier CANNOT boost broken digital signal.

Good: picture is always the best possible if you can get the signal.
Bad: If the signal is really weak, you cannot get even a "snowy" picture as you can get with analog signal.
It is simple, isn't it?
 
Here in Colorado Springs...my local signal strength from my stealth antenna without the amp is 20-28, and nothing will display. With amp plugged in, all locals are in the range of 71-87 and come in fine.
 
ya this is of intrest tome ,because my upgraded antena is going to be installed june 7th.the installer said he plans on putting $100 amp on a $125 antena, and a $75 rotor system.he thinks voom will cover up to $250 of the charge.if im gonna put $50-$75 of my money down i do not want a $100 part that is not needed.i see it helped shadow keeper.i do understand the fact that there is no good/bad picture with digital.it's either good or nothing.could you explain why shadow keeper boosted his signal strength with the amp.thanks
 
Do you actually think little 1's and 0's are flying through the air? I hope not, but from your post it seems that way.

The 8VSB digital data is still RF-modulated. It's an analog carrier. This means that a properly installed preamp at the antenna can strengthen the analog carrier enough to improve the SNR to allow the bitstream to be received with less error.

An amplifier that isn't at the antenna (such as a preamp) will only help in situations such as multiple splits, etc. where the preamped signal from the antenna may weaken. The preamp amplifies mostly "good" signal since it's closest to the source. A drop/distribution amp will amplify the analog carrier AND any noise present on the line (including noise that is actually induced by the drop amplifier). If noise is low and signal is weak, a drop/distribution amp in concert with a good antenna can make the difference between picture and no picture (although rare and unlikely).

The same situation is in play with cable. If signals are low to a cable modem, for instance, you can always add a drop amp. Assuming the signal is far enough above the noise floor, you'll get a sync whereas you may have not gotten sync otherwise. Why? Because these technologies still use analog carriers (QAM in the cable modem's case). The difference is the carriers contain a bitstream that must be demodulated and decoded.
 
Yes my amp (that is needed of course) plugs in the wall and hooks straight into the OTA line after it comes out of the diplexer and then goes in to my TV (HD Tuner). Without the amp, I can't get anything..but that's normal for people in the mountains.
 
And the little amp is just the basic one that comes with the Stealth that you use inside the house.

If someone knows for sure there is an upgraded amp that actually works with this model that will tune in Denver stations (70 miles away) I would really love to know. Denver broadcasts all of their locals mostly in HD, where here in the Springs, CBS is the only one.
 
conjuror,

I don't know where you got your information, but its just plain wrong.
 
Conjuror said:
Just to crash a myth. When you receive a digital signal, you receive a stream of zeros and ones.
...
It is simple, isn't it?

Yeah... just a little too simple.. but thanks for the chuckle! :D
 
cameron119 said:
Do you actually think little 1's and 0's are flying through the air?

The 0's are often mistaken for UFOs..... :p

The funny part is I once say a product brochure for some digital cordless phone that showed a showed a stream of 0's and 1's flying through the air to demostrate the superiority of digital over analog....
 
Conjuror said:
Just to crash a myth. When you receive a digital signal, you receive a stream of zeros and ones. If the stream is never broken, you'll always get perfect picture, no matter how far TV towers are. If the stream is broken sporadically, you cannot get the picture at all or you have a lot of droppings. An amplifier CANNOT boost broken digital signal.

Good: picture is always the best possible if you can get the signal.
Bad: If the signal is really weak, you cannot get even a "snowy" picture as you can get with analog signal.
It is simple, isn't it?

Conjuror....

You have a basic understanding of how it works, but are making a critical mistake. There is no such thing as a digital transmission. Everything, and I mean everthing, that travels over the airwaves is analog. Digital information is encoded in the transmission by modifying the analog radio waves.

If the radio transmission is too weak to decode the digital information embedded in it, then like you mentioned, you get no picture. And, if enough info is there, you get perfect picture. However, you most certainly can boost or amplifiy the radio transmission, so that is is strong enough to be able to properly decode the digital information embedded in it.

If it helps, think of it the way a modem connects over the internet. Computers speak to each other in Digital. But phone lines are only designed to carry analog information. You need a modem to convert the bits to analog for transmission over the phone line. At the other end, the analog information is then demodulated back to digital.

It is much the same with OTA digital channels, except the transmission medium is RF radio instead of a copper wire.

[Technical folks.. yes, I know, it's not exactly the same, but it serves to illustrate the concept]
 
Conjuror said:
Just to crash a myth. When you receive a digital signal, you receive a stream of zeros and ones. If the stream is never broken, you'll always get perfect picture, no matter how far TV towers are. If the stream is broken sporadically, you cannot get the picture at all or you have a lot of droppings. An amplifier CANNOT boost broken digital signal.

Good: picture is always the best possible if you can get the signal.
Bad: If the signal is really weak, you cannot get even a "snowy" picture as you can get with analog signal.
It is simple, isn't it?
Unbelieveable......... go over to AVS Forum "Local HDTV Info and Reception" there are literally 100's of antenna stories and much valuable information regarding using pre-amps to help out with OTA reception. Please don't misinform the readers of this forum.
 
The normal Stealth amplifier is actually INSIDE the plastic base of the Stealth. The unit inside your house is an inline phantom power supply that provides power back up to the amp.
 
One other thing to check in your area, if your digital channels are running at full power yet. I am in the Dallas area and , luckily, we have 16 OTA channels and most of them are at their full licensed power, except CH27 here. This link shows that they are "approved" for their full power of 1000kw but are still running on the temporary authority at 11kw. http://www.fcc.gov/fcc-bin/tvq?list=0&facid=17037
Check your city and see what your OTAs are running at. If they are at lower power, might have to wait until full power instead of spending much money on amps and antennas. If you already are at full power, then get the biggest sucker as tall as you can stand it!!!!
 
Whoa...
Looks that some folks here need to get some education first about "ones and zeros". I do not intend to go into too much technical details about this issue but if you are willing to spend your dollars on amplifiers to get digital channels, you are more than welcome. It is your money and I don't care how you gonna spend it but it will not help you. I am 60 miles from most transmitters and I am not using any amplifiers but I can still get all digital channels.
For those who wish to learn very basics about difference between analog and digital transmission, follow this link:
http://hometheater.about.com/cs/beforeyoubuy/a/aahdarcfaq1a.htm
 
nothing in that article telling me that an amp will not work. Conjuror, do you have another article to describe in detail what you are talkinga bout?
 
Conjuror said:
Whoa...
Looks that some folks here need to get some education first about "ones and zeros". I do not intend to go into too much technical details about this issue but if you are willing to spend your dollars on amplifiers to get digital channels, you are more than welcome. It is your money and I don't care how you gonna spend it but it will not help you. I am 60 miles from most transmitters and I am not using any amplifiers but I can still get all digital channels.
For those who wish to learn very basics about difference between analog and digital transmission, follow this link:
http://hometheater.about.com/cs/beforeyoubuy/a/aahdarcfaq1a.htm

I'm sorry... but that is a "DTV for dummies" type discussion about the format of the data being transmitted... if you really want to know how it works, read this paper on 8-VSB.

http://www.broadcastpapers.com/tvtran/Harris8VSB11.htm

But, I can summarize it for you here. Digital TV is carried over a standard Amplitude Modulated Radio Signal. You can most definately amplify the signal.

It will not get you a better picture, but it can certainly increase the range of the signal.

Do some reseach on 8-VSB. It is the piece of the picture you are missing. It describes how the MPEGII digital information is converted to analog for carriage on radio frequencies.

Here is a block diagram of the basic steps
Harris8VSB-image01.GIF


Notice the last step is "analog upcoversion"
 
This is not a personal attack so don't take it that way, but I would take what conjurer is saying about this with a grain of salt 'cause its way offbase.
I will, however, say that you will get a better signal by going to a larger antenna than an antenna w/an amp. If you are having trouble pulling things in then try the largest antenna that is reasonable for your situation before placing an amp in the setup.
 

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