The Official AVS 'Smart Antenna' topic - AVS Forum
Forum Jump: 
Reply
 
Thread Tools
post #1 of 167 Old 03-05-2007, 12:17 PM - Thread Starter
AVS Special Member
 
holl_ands's Avatar
 
Join Date: Jun 2004
Location: San Diego, CA
Posts: 3,612
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 26 Post(s)
Liked: 54
I always found it curious that the DTB-H260F (as marked on the circuit board),
actually contained the ATI Xilleon 240H chip:
http://www.avsforum.com/avs-vb/showt...ni#post8837172

Maybe they originally planned to use the ATI Xilleon 260, but, since 260 was not ready,
decided to use the Xilleon 240H for production:
http://ir.ati.com/phoenix.zhtml?c=10...887&highlight=
http://ati.amd.com/products/xilleon240sh/index.html

I would speculate that the DTB-H261F would finally use the ATI Xilleon 260 series chip.
The Xilleon 260, announced Sep2006, would presumably allow Samsung
to design one STB for World-wide markets, thereby reducing production costs:
http://ir.ati.com/phoenix.zhtml?c=10...1139&highlight
http://ati.amd.com/products/xilleon260/index.html
holl_ands is offline  
Sponsored Links
Advertisement
 
post #2 of 167 Old 03-05-2007, 03:09 PM
Senior Member
 
WillieAntenna's Avatar
 
Join Date: Jan 2007
Location: Southern, WI
Posts: 395
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by holl_ands View Post

I always found it curious that the DTB-H260F (as marked on the circuit board),
actually contained the ATI Xilleon 240H chip:
http://www.avsforum.com/avs-vb/showt...ni#post8837172

Maybe they originally planned to use the ATI Xilleon 260, but, since 260 was not ready,
decided to use the Xilleon 240H for production:
http://ir.ati.com/phoenix.zhtml?c=10...887&highlight=
http://ati.amd.com/products/xilleon240sh/index.html

I would speculate that the DTB-H261F would finally use the ATI Xilleon 260 series chip.
The Xilleon 260, announced Sep2006, would presumably allow Samsung
to design one STB for World-wide markets, thereby reducing production costs:
http://ir.ati.com/phoenix.zhtml?c=10...1139&highlight
http://ati.amd.com/products/xilleon260/index.html

Interesting to see that the 240 had a control for the smart antenna. I have heard the term but never understood what it was all about and I just look it up and it very interesting feature to have up to 4 antenna and it automacticly click on and off each antenna and control the gain. When that going to come out ?

So is the ATI-260 is consdier as 6th gen chip ?


-Willie
WillieAntenna is offline  
post #3 of 167 Old 03-05-2007, 05:35 PM - Thread Starter
AVS Special Member
 
holl_ands's Avatar
 
Join Date: Jun 2004
Location: San Diego, CA
Posts: 3,612
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 26 Post(s)
Liked: 54
Quote:
Originally Posted by WillieAntenna View Post

Interesting to see that the 240 had a control for the smart antenna. I have heard the term but never understood what it was all about and I just look it up and it very interesting feature to have up to 4 antenna and it automacticly click on and off each antenna and control the gain. When that going to come out ?

So is the ATI-260 is consdier as 6th gen chip ?


-Willie

ATI Xilleon and Theater would probably be called "5th Gen"....like other recent chips.
Where "5th Gen" means they 1) "meet" ATSC A/74 Receiver Performance Guidelines,
2) accommodate +/- 35 usec (or even better +/- 50 usec) multipath capability and
3) successfully decode (most??) of the "Field Test Ensembles".....which were
captured from problematic locations, but apparently have problems in some of the
captures and may never be fully successful.

The "3rd Gen" chips could not handle pre-echo, where the direct path signal is
greatly reduced (e.g. going through a building) and the delayed signal bouncing
in from the side is stronger.
PS: The "Generation" names came from successive Zenith chips....

But it's tough to compare performance cuz no one is testing production units
where they name the manufacturer.
I posted some named and unnamed test results in the 5th Gen thread:
http://www.avsforum.com/avs-vb/showt...RA#post7024579
http://www.avsforum.com/avs-vb/showt...RA#post6384680

Note that Samsung's Prototype Receiver, with so-called "Gemini" chip (ATI Theater? Xilleon?)
and Alps tuner far outperformed LG/Zenith's 5th Gen Prototype Receiver (2 years earlier),
esp wrt short delay, nearly equal strength multipath.
(Strange, cuz pre-5th Gen LG and ATI chips claimed zero delay multipath performance.)

However, we never saw CRC type tests for production units from any manufacturer.

================================
In that same thread, I also posted the (one and only) on-air test report for the
(one and only) Smart Antenna, as controlled by the (one and only) OTA STB,
with 3rd Gen ATI NXT2004 and an EIA/CEA-909 Smart Antenna Interface:
http://www.avsforum.com/avs-vb/showt...ia#post5979741

BTW: The ATSC Decoder chip only provides info re quality of the signal,
it's still up to the STB to actually control the Smart Antenna.

Many (non-LG) ATSC Decoder chips claim they "support" EIA/CEA-909.
When I talked to LG rep at CES2007, he was very negative wrt to how many
people would use (or "need") a Smart Antenna....so I bent his ear for awhile....
For what it's worth, Smart Antenna Interface is still optional for the SD-only STB
under the Dec2008 NTIA coupon program.

Here is more info re Smart Antennas:
http://www.avsforum.com/avs-vb/showt...00#post5826625
http://www.avsforum.com/avs-vb/showt...io#post5842783
http://hdtv.forsandiego.com/messages...html#POST27838
If you read up from the last post, you'll find discussion re FM Diversity Combiners.

===============================
Right now, the DTA-5000 is limited to sub-urban environments, performing about
as well as a 4-Bay, and since it has built-in, variable gain Preamps may (or may not)
have desensitization/overload problems with very nearby transmitters.

I would like to see a Smart Antenna Combiner that would work with EXTERNAL antennas,
so the user could point them to receive stations from different directions (like San Diego!!!),
or could use an array of two to four hi-gain outdoor antennas, pointed as necessary
to optimize performance for the local situation.
holl_ands is offline  
post #4 of 167 Old 02-21-2008, 09:05 AM
AVS Addicted Member
 
Ken H's Avatar
 
Join Date: Nov 1999
Location: Metro Detroit
Posts: 45,876
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 12
Split off from main HDTV STB Topic.

'Better Living Through Modern, Expensive, Electronic Devices'

Ken H is offline  
post #5 of 167 Old 03-01-2008, 12:41 PM
AVS Special Member
 
bdfox18doe's Avatar
 
Join Date: Oct 2000
Location: Charlotte, NC
Posts: 6,441
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 60 Post(s)
Liked: 68
I have one of the DTA-5000 Smart Antennas with the RJ-Tech RJ-900ATSC
receiver. Just got it up and running, so far works well, except the VHF performance of this antenna doesn't seem to be very good. It's having trouble picking up WTVI-DT on Ch-11 only 8 miles away. But, I get excellent,
solid reception on WNSC-DT on Ch-15 @ 29 miles.

Have found a few quirks with this combo, more later. Attached is my TVFool search results.
LL

Bob

The views expressed here are my own and do not necessarily represent those of the FOX,ABC,CBS,or CW Networks,MeTv, my employer or its parent company. Nor my wife for that matter!
bdfox18doe is offline  
post #6 of 167 Old 03-18-2008, 08:22 AM
Member
 
peepoop's Avatar
 
Join Date: Jul 2004
Posts: 36
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Is the DTA-5000 really the only commercially available smart antenna?
http://www.summitsource.com/dx-anten...acturers_id=54

Summit Source is the only place I could find that even sells it.

Are there any other models? Any other retailers selling smart antennas? I spent a good long while googling around and couldn't find anything. Best Buy doesn't even carry one.

I thought SAs were supposed to be THE FUTURE! What's up?
peepoop is offline  
post #7 of 167 Old 03-18-2008, 09:00 AM
AVS Special Member
 
m_vanmeter's Avatar
 
Join Date: Feb 2006
Location: Georgetown, KY
Posts: 5,433
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 21
they work fine for near distance urban type reception (note they are green zone). Phased dipole antennas are unity gain, and for near-fringe or fringe antennas they will not work. They claim you can "extend" the range with a pre-amp, but the best preamp can't amplify a signal that is not there. Yagi and stacked bow-tie antennas are the current standard for a reason...they provide a lot of gain and are directional, too things critical to receiving VHF or UHF signals at any real distance.
m_vanmeter is offline  
post #8 of 167 Old 03-19-2008, 03:12 PM
Newbie
 
blacksburg98's Avatar
 
Join Date: Dec 2007
Posts: 14
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
There are only a couple of concrete announcements.
http://www.audiovox.com/pressrelease...200801075.html
RCA ANT2000
Terk HDS01 Smart Antenna
Terk HDS02 Smart Antenna

DX5000 seems to be the only one available on the market.
GE also has its own smart antenna, but its compatibility with the other brands is still unknown.
http://www.jascoproducts.com/hdtv/GE...al-Antenna.asp
blacksburg98 is offline  
post #9 of 167 Old 03-22-2008, 06:05 AM
Member
 
PeterTheGeek's Avatar
 
Join Date: Feb 2008
Location: Minnesota
Posts: 199
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 12
I found this information on another new smart antenna.

"Also, Antennas Direct will announce a partnership with the NAB to develop a new CEA909A compliant Indoor Smart Antenna."

I found a few listing on this press release. Here is one copy of the press release I found at Business Wire:
http://www.businesswire.com/portal/s...20080319005637

The CEA909A was just published in December 2007. I looked but couldn't find a reference for it. What I know of it, and that isn't much, it takes the little interface box between the tuner and the antenna into the tuner. The short answer is that there is only one coax cable going from the tuner to the antenna. No separate connector to control the antenna is used.

Broadcom and GE/Jasco both have antennas that work in this fashion. But I have no idea if they are following the CEA909A standard, it would have been off a draft version, or not.

I am hoping that computer tuners will start using the CEA909A standard. No additional connector is a big help for PCI tuner cards and tuner dongles. There isn't room for them anyway.
PeterTheGeek is offline  
post #10 of 167 Old 03-22-2008, 09:55 PM
Advanced Member
 
jackmay's Avatar
 
Join Date: May 2000
Location: Foster City, Ca.
Posts: 571
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by m_vanmeter View Post

they work fine for near distance urban type reception (note they are green zone). Phased dipole antennas are unity gain, and for near-fringe or fringe antennas they will not work. They claim you can "extend" the range with a pre-amp, but the best preamp can't amplify a signal that is not there. Yagi and stacked bow-tie antennas are the current standard for a reason...they provide a lot of gain and are directional, too things critical to receiving VHF or UHF signals at any real distance.

And a slowly varying phase for the simple antenna which is important for the 20 Mbps digital HDTV signal to prevent waveform degradation. A Yagi will have more rapid phase variation but I have never heard if they degrade the signal in practice.
jackmay is offline  
post #11 of 167 Old 03-22-2008, 11:14 PM
AVS Special Member
 
milehighmike's Avatar
 
Join Date: Jan 2005
Location: Highlands Ranch, CO
Posts: 1,259
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
My neighbor installed a rotor a couple of years ago for his outdoor antenna. I believe it's a CM. I recollect it has a remote that allows tuning the channels on the TV and rotating the antenna concurrently. So if channel 4 is pushed on the rotor's remote, the TV changes channels to channel 4 and the rotor moves the antenna to receive channel 4. I realize this isn't a setup for indoors, but it is a "smart" antenna.
milehighmike is offline  
post #12 of 167 Old 03-23-2008, 05:47 AM
Member
 
PeterTheGeek's Avatar
 
Join Date: Feb 2008
Location: Minnesota
Posts: 199
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 12
Quote:
Originally Posted by milehighmike View Post

I realize this isn't a setup for indoors, but it is a "smart" antenna.

Technically, a auto-rotor like your neighbors is not a smart antenna. Smart antenna that are CEA909 have four antenna's in them and it adds the phases from the four to get a direction. From someone else's posting, holl_ands posting, the DTA5000 switches in inductors to do the summing. More advanced units can use high speed summing amplifiers to get finer control of the beam direction.

Now to why I said technically, it looks like many of the tuner set-top boxes firmware treats the smart antenna like a glorified rotor. The plus is when it does a scan it looks for the best setup at that time. Then that is loaded into a lookup table that gets retrieved every time that channel is selected. There is a rumor that the MaxMedia unit will do continuous updates for the smart antenna. The first units are shipping and I hope to hear something about that later.
PeterTheGeek is offline  
post #13 of 167 Old 03-23-2008, 01:16 PM
AVS Special Member
 
TalkingRat's Avatar
 
Join Date: Mar 2008
Posts: 2,176
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked: 21
Thanks for that link about Antennas Direct, Peter!! I'm looking forward to more detail after the NAB exhibit in April.
TalkingRat is offline  
post #14 of 167 Old 03-28-2008, 01:43 AM - Thread Starter
AVS Special Member
 
holl_ands's Avatar
 
Join Date: Jun 2004
Location: San Diego, CA
Posts: 3,612
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 26 Post(s)
Liked: 54
Quote:
Originally Posted by PeterTheGeek View Post

Technically, a auto-rotor like your neighbors is not a smart antenna. Smart antenna that are CEA909 have four antenna's in them and it adds the phases from the four to get a direction. From someone else's posting, holl_ands posting, the DTA5000 switches in inductors to do the summing. More advanced units can use high speed summing amplifiers to get finer control of the beam direction.

Now to why I said technically, it looks like many of the tuner set-top boxes firmware treats the smart antenna like a glorified rotor. The plus is when it does a scan it looks for the best setup at that time. Then that is loaded into a lookup table that gets retrieved every time that channel is selected. There is a rumor that the MaxMedia unit will do continuous updates for the smart antenna. The first units are shipping and I hope to hear something about that later.

Minor clarification: Inductors are used with individual antenna elements to
make them electrically "longer" and to work over a wider freq. range.
Each of the multiple antennas is terminated in a variable gain preamp,
which is then summed. Direction is controlled by the gain settings.
holl_ands is offline  
post #15 of 167 Old 03-28-2008, 05:50 AM
Member
 
PeterTheGeek's Avatar
 
Join Date: Feb 2008
Location: Minnesota
Posts: 199
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 12
Thanks for the clarification holl_ands.

This does look like the year where some real digital TV smart antenna's get rolled out. Just wonder if anyone seen anything on the RCA ANT2000? It was to be out this spring according to Audiovox's press release. I have been looking with Google but no luck yet. I was hoping to get the ANT2000 for my new tuner box.
PeterTheGeek is offline  
post #16 of 167 Old 03-28-2008, 07:15 AM
Senior Member
 
pkeegan's Avatar
 
Join Date: Aug 2005
Location: Centennial, CO
Posts: 490
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 14
Smart antennas might be good where you want a single tuner matched to a single antenna. What about when you want to hook up several digital tuners to a single antenna? You might be better off with just a good regular VHF/UHF antenna.
Please correct me if I am wrong.
pkeegan is offline  
post #17 of 167 Old 03-28-2008, 10:28 AM
Member
 
KE0MI's Avatar
 
Join Date: Oct 2001
Location: Columbia, Missouri
Posts: 87
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by pkeegan View Post

Smart antennas might be good where you want a single tuner matched to a single antenna. What about when you want to hook up several digital tuners to a single antenna? You might be better off with just a good regular VHF/UHF antenna.
Please correct me if I am wrong.

As long as the multiple receivers are all tuned to the same RF channel, the primary receiver should optimize on that ATSC stream, meaning that you could watch subchannels of the main stream, but possibly not different carriers on the other sets (depending largely on direction and multipath echoes). Ideally, each receiver would have its' own antenna.
KE0MI is offline  
post #18 of 167 Old 03-28-2008, 02:43 PM
Member
 
PeterTheGeek's Avatar
 
Join Date: Feb 2008
Location: Minnesota
Posts: 199
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 12
Quote:
Originally Posted by KE0MI View Post

As long as the multiple receivers are all tuned to the same RF channel, the primary receiver should optimize on that ATSC stream, meaning that you could watch subchannels of the main stream, but possibly not different carriers on the other sets (depending largely on direction and multipath echoes). Ideally, each receiver would have its' own antenna.

Yes, there should be one antenna per tuner as a general rule. I am planning on doing something like what KE0MI was saying. I have a 2004 30" HDTV Samsung TV that is really bad with multi-path. And I have plenty of multi-path in my area to be bad with. So I am thinking of getting a converter box with a smart antenna interface. Split the RF off to the TV just before the tuner box and let the tuner box control the antenna. I also will be able to record on my nice JVC VHS/DVD standard definition from the tuner box.

We will see how well this experiment works.
PeterTheGeek is offline  
post #19 of 167 Old 03-31-2008, 04:49 AM
Member
 
PeterTheGeek's Avatar
 
Join Date: Feb 2008
Location: Minnesota
Posts: 199
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 12
I found another press release on the Direct Antenna's new products. The non-smart antenna units look interesting as well. But the press release contains more information on all the antennas including the smart antenna.
Press release Link

No pictures on the smart antenna, it hasn't been designed yet, but there is pictures for the other two.
New Antenna Pictures
PeterTheGeek is offline  
post #20 of 167 Old 03-31-2008, 03:29 PM
Newbie
 
RockerChick's Avatar
 
Join Date: Mar 2008
Posts: 2
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
I just purchased a RCA DTA800 Digital TV Converter Box and when I installed it all I got was a black screen that said the signal is too weak. So I looked in the directions and it said it recommends a Smart Antenna. I was just wondering if anyone can tell me what a Smart Antenna is and where would I get one? I've tried looking online but the few sites I can find use all these technical terms that are way over my head! I have a rabbit-ear antenna, and the regular tv stations are fuzzy or don't come in at all. I do live near some mountains which I was told is why the regular tv stations don't come in well. So would a Smart Antenna even work for me? Thank you!
RockerChick is offline  
post #21 of 167 Old 04-14-2008, 05:55 AM
AVS Special Member
 
seatacboy's Avatar
 
Join Date: Jan 2008
Posts: 1,055
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
Liked: 17
Quote:
Originally Posted by peepoop View Post

I thought SAs were supposed to be THE FUTURE! What's up?

Engadget story about new CEA smart antenna standards
seatacboy is offline  
post #22 of 167 Old 04-14-2008, 06:23 AM
AVS Special Member
 
dagger666's Avatar
 
Join Date: Jan 2006
Posts: 1,109
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
is the jury still out on these antennas effectiveness
dagger666 is offline  
post #23 of 167 Old 04-14-2008, 06:36 AM
AVS Special Member
 
seatacboy's Avatar
 
Join Date: Jan 2008
Posts: 1,055
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
Liked: 17
Quote:
Originally Posted by dagger666 View Post

Is the jury still out on these antennas effectiveness?

Yes. Very few Smart Antennas are for sale, very few early-adopter reports or reviews, not much info.

In theory, a "Smart Antenna" will provide a simplified means for non-tech-oriented users to obtain adequate performance in some difficult reception environments. We don't know yet whether "Smart Antenna" devices actually provide measurably better results in real-world situations, or if the "Smart Antenna" concept is just an overpriced, overmarketed product.
seatacboy is offline  
post #24 of 167 Old 04-14-2008, 10:50 AM - Thread Starter
AVS Special Member
 
holl_ands's Avatar
 
Join Date: Jun 2004
Location: San Diego, CA
Posts: 3,612
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 26 Post(s)
Liked: 54
Here's a picture of a Smart Antenna I haven't seen yet:
http://broadcastengineering.com/hdtv/smart_antennas/

Aldo Cugnini works for AGC Systems LLC, who helped get Magnavox/Philco boxes certified:
http://www.agc.embarqspace.com/
Before that he worked for Philips, et. al. in the development of the
original "Grand Alliance" prototype ATSC Receiver:
http://www.agc.embarqspace.com/#/ourfounder/4526274775

Well, I'm off to NAB to see some from Antennas Direct, Terk and others....
holl_ands is offline  
post #25 of 167 Old 05-28-2008, 03:50 PM
Advanced Member
 
tamahome02000's Avatar
 
Join Date: May 2008
Posts: 525
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Smart antennas sound like a cool idea. What if you already have an hdtv with a tuner? Would you have to buy another tuner to use the smart antenna?
tamahome02000 is offline  
post #26 of 167 Old 05-28-2008, 08:10 PM
AVS Special Member
 
IDRick's Avatar
 
Join Date: Feb 2006
Location: Eastern Idaho
Posts: 1,033
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 24
Quote:
Originally Posted by tamahome02000 View Post

Smart antennas sound like a cool idea. What if you already have an hdtv with a tuner? Would you have to buy another tuner to use the smart antenna?

Hmmm, I could find a link that talked about smart antennas:

http://broadcastengineering.com/hdtv...nnas/?cid=top1


But, who actually sells a smart antenna? Sounds like a concept phase item. Can you provide a link?
IDRick is offline  
post #27 of 167 Old 05-28-2008, 08:40 PM
Advanced Member
 
tamahome02000's Avatar
 
Join Date: May 2008
Posts: 525
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
There's plenty of threads here about it:

http://www.google.com/search?q=%22sm...3Aavsforum.com

But I think there's only one outdoor antenna that supports it and a handful of converter boxes.
tamahome02000 is offline  
post #28 of 167 Old 05-29-2008, 11:33 AM
AVS Special Member
 
IDRick's Avatar
 
Join Date: Feb 2006
Location: Eastern Idaho
Posts: 1,033
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 24
Quote:
Originally Posted by tamahome02000 View Post

Smart antennas sound like a cool idea. What if you already have an hdtv with a tuner? Would you have to buy another tuner to use the smart antenna?

Interesting system. From what I can track down, it appears that the smart antenna requires a smart antenna enabled receiver that outputs directly to the tv or a recording device (VCR/DVD recorder). It is doubtful that a tuner on a HDTV has the capability of driving the smart antenna.
IDRick is offline  
post #29 of 167 Old 06-05-2008, 07:32 AM
AVS Special Member
 
hphase's Avatar
 
Join Date: Mar 2001
Location: New York
Posts: 2,999
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Has anyone seen a NON-CECB STB that has a CEA-909 "Smart Antenna" interface? If they don't have to be CECB-compliant, these boxes may actually have HD video outputs and DD digital audio outputs.

Anyone know about any?
hphase is offline  
post #30 of 167 Old 06-17-2008, 11:12 AM
AVS Addicted Member
 
Ken H's Avatar
 
Join Date: Nov 1999
Location: Metro Detroit
Posts: 45,876
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 12
From Broadcast Engineering

Smart antennas, by ALDO CUGNINI

The analog cutoff is now less than one year away, and with that change will come new reception issues for terrestrial broadcast viewers. Although the FCC has sought to replicate analog service in its digital channel allocation plan, most broadcasters will have a digital channel assignment different from their analog one. Inherently, this means that the RF field conditions at the viewer's location will be considerably different from those of the analog service. Smart antennas offer a convenient way to minimize the impact on the viewer.

Because terrestrial television receivers must potentially receive signals from various locations, a fixed antenna cannot provide optimum reception across the available channels. In addition, community antennas using the same transmitting site may cause receivers to experience different multipath reception conditions across different channels. While indoor antenna re-aiming may not affect an analog viewer — or the viewer simply tolerated a lower SNR on some channels — re-aiming an antenna for optimum digital service could be quite burdensome.

Electronically steerable smart antennas that automatically optimize the preferred signal direction for each particular broadcast emission were developed years ago for military applications and are increasingly being used in cellular telephone base stations. This optimization can take into account various signal quality factors, such as signal strength, multipath energy and BER.

Digital signal reception varies widely
Terrestrial television reception is subject to many transmission path impairments, including multipath interference, where delayed echos of the transmitted signal can arrive at the antenna because of reflections off large objects in the receiving space. Moderate to severe multipath can lead to an increase in BER, which could compromise video and audio or, in the worst case, result in no reception at all.

While this situation can often be remedied by physically re-aiming the receiving antenna, this adjustment may not be ideal for all received stations because of their different transmission powers, frequencies and locations.

These difficulties are compounded because of the cliff effect,wherein the BER increases catastrophically below a certain C/N ratio or D/U interference ratio. As such, antenna adjustment can be problematic under many reception conditions. The situation is equally inconvenient with outdoor antennas (requiring a rotator) or indoor ones (requiring frequent trips to the television).

It is now practical to use this same technology for consumer digital television reception. By providing an automatic mechanism to adjust the antenna, the direction and gain (amplification) of the antenna can be electronically changed, with no need for user intervention or physical adjustment of the antenna. This type of antenna functions by changing the relative gain and phase (delay) of the internal elements. While offering a high degree of optimization for both signal capture and interference rejection, this kind of adaptive antenna is somewhat complex and hence expensive to implement.

Practical smart antennas
An alternate type of smart antenna is the so-called switched beam antenna system. In this system, multiple fixed elements within the antenna are selectively used so that a primary receiving direction is favored. At the same time, strong sources of multipath can be negated. An optimization algorithm can perform a trade-off between the two factors. The user simply plugs the antenna in to a suitably equipped DTV receiver or converter box, and the receiver automatically adjusts the antenna for optimal reception of each DTV station.

The optimization algorithm is typically executed by the CPU in the receiving device and is done once during initial setup. In addition to selecting different azimuth directions, units can operate with different levels of RF amplification. This is useful in areas of high signal strength to avoid overload of the receiver front end, which could otherwise result in high intermodulation distortion.

Selecting an antenna direction and gain setting for optimum signal reception involves assessing the signal quality over the operating extent of the antenna. Various parameters of the received signal can be evaluated and weighed, including signal strength, mean squared error of the channel equalizer, spectral flatness and unwanted interference.

Depending on the system architecture, this optimization process can be tightly integrated with the demodulator or implemented separately. The combination of direction and gain can also be used in a more sophisticated algorithm that anticipates third-order intermodulation interference from strong UHF taboo channels, or from the n ± 1, two-channel pairs where tuner RF selectivity may be minimal.

A standardized smart antenna interface
While a smart antenna can be an option to the consumer, it will only function if the appropriate interface is available at the receiver. Such an interface has been developed and standardized by the Consumer Electronics Association, and is known as CEA-909A, “Antenna Control Interface.”

This standard describes how a compliant receiver can operate with any compliant antenna, regardless of manufacturer. The standard also specifies the data format used, the connection standards and other requirements.

The antenna configuration is neither specified nor implied, leaving specific design considerations to the manufacturer. As such, an elaborate system can even be designed using a full-blown antenna farm. The more practical design allows for the realization of an affordable, attractive antenna with a small form factor.

The CEA R4-WG4 working group has also defined a control protocol that works over the antenna coax, resulting in two options for the CEA-909A standard: one that uses a separate connector for the control signal, and one that shares the RF signal connector/coax.

Proven utility
DTV smart antennas have been tested in a variety of field locations with promising results. The new antenna has demonstrated a considerable advantage over various indoor antennas, including the popular mini yagi, with no amplification, and the set-top UHF loop/VHF rod antenna combination with built-in amplification. The smart antenna performs at least as well as a hand-optimized yagi — but doesn't require user intervention. In a few locations, smart antennas may be unable to automatically optimize the signal. However, in those few cases, a yagi would require meticulous adjustment as well, especially when subjected to a high level of multipath.

Preliminary tests by the CEA R-5 Antenna Standards committee have shown impressive results, finding that a smart antenna can be most effective in ghosty areas and can increase DTV system performance by as much as 12dB. In addition, both the MSTV and the NAB have endorsed the technology, and the NTIA is allowing the interface on converter boxes certified in its DTV coupon program.

Various DTV converter box manufacturers now include the smart antenna interface on their products. Nonetheless, and despite the potential of the technology, the public knows little about it, and retail stores are of little help. With a bottom line mentality, the major store chains have been hurt in the past by poor antenna sales, so they don't want to carry a slow mover that won't come down in price unless millions are sold. Just imagine the confused customer who has reception difficulties and blames it on the DTV receiver or converter. As with the DTV transition itself, education is needed in order to fully appreciate the benefits of digital television.

'Better Living Through Modern, Expensive, Electronic Devices'

Ken H is offline  
Reply HDTV Technical

User Tag List

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off