Sign in with
Sign up | Sign in
Your question

Continuing saga of 3rd generation OTA reception

Last response: in Home Theatre
Share
Anonymous
September 20, 2004 7:43:44 PM

Archived from groups: alt.tv.tech.hdtv (More info?)

1) OTA (over the air) ch 54 mapped to ch 3 has sound dropouts at certain
times of the day due to either overdrive or adjacent channel interference.
Reducing the signal level with traps or reducing the antenna amp gain only
reduces the frequency of occurrence of the sound dropouts. The dropouts
occur more on ch 3.1 than 3.5. I installed a 24db trap for ch 50 and this
has improved the sound on
ch 54 (3) We receive here a ch 50 (strong +30db analog), ch 52 (digital),
ch 54 (digital), ch 59 (strong digital)

2) Also ch 52 mapped to 40 does not map on this tuner and is intermittently
not receivable. When using an older analog TV I noticed that there was a
very faint analog ch 52 on that TV. I installed and tuned a trap for 52 and
tuned it untill the analog ch diappeared into the snow. This allows me to
receive ch 52 (40) reliably. It still does not map.

3) If the signal level for ch 59 (44) was above 100% (on the menu) there is
a barely perceptible dropout in the sound

4) The set is very susceptible to ghosts. You get breakup and loss of
signal as the tuner tries to lock on the different (time) signals.

This is probably a worst-case antenna/location situation and I'd not bother
with it but for the fact that a slightly newer Samsung does not have these
problems. Analog pictures from the antenna farm for different frequencies
are very watch able with barely noticeable ghosts

I'm guessing that the software for the older tuner stressed sensitivity over
selectivity. And we have a worst-case situation here in this location. I'm
in contact with a customer who has a RCA DLP set built in 2003 with built-in
tuner and he cannot receive ch 52 (40) either.

Some things I've noticed about "third generation" HD tuners:
1) There must be more than 10db difference between the Origional and Ghost
signal for good lock.
2) There can be NO analog signal visable on older NTSC tv (more than -30 db)
or there will be no lock. That's 50 db of signal difference.
3) Strong analog signals will affect the sound of a digital ch up to 4
channels away. EX: 30 db analog on 50 affects sound on digital 54
4) Digital signals over +15 db will cause sound dropouts
5) Minimum signal for good lock -20db best is -10db The higher the signal
level the more chance of ghosts from wire pinches, improper termination etc,
again the 10 db rule applies.
6) Using older R59 single shield cable will compound problems with reception
on long runs.
7) The better the signal condition the faster the lock
Anonymous
September 21, 2004 9:47:19 AM

Archived from groups: alt.tv.tech.hdtv (More info?)

Interesting. What tuner are you referring to?
--
"Jeff Rigby" <jeffg212@comcast.net> wrote in message
news:uMSdnSyfFcl4r9LcRVn-jQ@comcast.com...
> Some things I've noticed about "third generation" HD tuners:
Anonymous
September 23, 2004 6:10:32 AM

Archived from groups: alt.tv.tech.hdtv (More info?)

Jeff Rigby (jeffg212@comcast.net) wrote in alt.tv.tech.hdtv:
> Some things I've noticed about "third generation" HD tuners:
> 1) There must be more than 10db difference between the Origional and Ghost
> signal for good lock.
> 3) Strong analog signals will affect the sound of a digital ch up to 4
> channels away. EX: 30 db analog on 50 affects sound on digital 54
> 4) Digital signals over +15 db will cause sound dropouts
> 5) Minimum signal for good lock -20db best is -10db The higher the signal
> level the more chance of ghosts from wire pinches, improper termination etc,
> again the 10 db rule applies.

Since *none* of these are true with a first generation receiver (the RCA
DTC-100), your generalization about "third generation receivers" is not
valid.

--
Jeff Rife |
SPAM bait: | http://www.nabs.net/Cartoons/CloseToHome/NamespacePollu...
AskDOJ@usdoj.gov |
spam@ftc.gov |
Anonymous
September 23, 2004 3:20:51 PM

Archived from groups: alt.tv.tech.hdtv (More info?)

"Jeff Rife" <wevsr@nabs.net> wrote in message
news:MPG.1bbc32e35c1bb4a98984c@news.nabs.net...
> Jeff Rigby (jeffg212@comcast.net) wrote in alt.tv.tech.hdtv:
> > Some things I've noticed about "third generation" HD tuners:
> > 1) There must be more than 10db difference between the Origional and
Ghost
> > signal for good lock.
> > 3) Strong analog signals will affect the sound of a digital ch up to 4
> > channels away. EX: 30 db analog on 50 affects sound on digital 54
> > 4) Digital signals over +15 db will cause sound dropouts
> > 5) Minimum signal for good lock -20db best is -10db The higher the
signal
> > level the more chance of ghosts from wire pinches, improper termination
etc,
> > again the 10 db rule applies.
>
When comparing the third generation tuner from Samsung to a 4th generation
tuner from Samsung
1) 5 db for 4th 10 db for 3rd
3) strong analog signal will not affect the sound on a 4th generation
4) strong digital signal will not affect the sound on a 4th
5) -20 db signal for a good lock even if signal strength changes quickly
with tower movement. Third generation can't stand quick signal level
changes.
6) Analog co-channel interference will cause 3rd generation to not lock, 4th
generation didn't have a problem with -30 db signal (barily visable)

> Since *none* of these are true with a first generation receiver (the RCA
> DTC-100), your generalization about "third generation receivers" is not
> valid.

Then what are the problems with the DTC-100, why hasn't it taken over the
market if it doesn't have any problems? Why are there second, third, fourth
and fifth generation receivers. Why has a new standard E-VSB been adopted.
|

What are the faults of the different generation tuners? Can anyone generate
a table or list by generation ?
Anonymous
September 23, 2004 7:25:58 PM

Archived from groups: alt.tv.tech.hdtv (More info?)

Jeff Rigby (jeffg212@comcast.net) wrote in alt.tv.tech.hdtv:
> Then what are the problems with the DTC-100,

1. The way ABC and ESPN create their streams, the audio sometimes has
locking problems on the DTC-100. Going into and out of the menu usually
(99%) solves this.

2. It seems to require a higher raw signal level than my newer receivers.
It works just fine if C/N is above 18dB or so, but it takes a bit more
(about 3dB) raw signal to achieve this with *some* signals.

3. The interface is not the best. My #1 complaint is that you can't get
PSIP guide information unless you turn on "virtual channels". It
also lacks the diagnostics of *any* kind that newer receivers have,
like detailed error data, detailed stream data, etc.

4. Simply because it is so old a design, it just doesn't have a lot of the
newer bells and whistles, including such things as DVI outputs.

Compared to my 4th generation receiver, there are no real reception
differences except for the need for more raw signal, which is solved by
a pre-amp in all cases.

> why hasn't it taken over the
> market if it doesn't have any problems?

It *did* take over the marketplace. It just isn't made anymore. I suspect
that it is the #1 installed ATSC receiver, since it was the only decent
one for about 4 years (it's still one of about 3 that can handle all closed
captions on digital broadcasts), *and* the RCA F38310 TV has it inside,
*and* some DirecTV combo units are based on it.

> Why are there second, third, fourth
> and fifth generation receivers.

First, these exist because people have chosen to give them these labels,
even though it has been a process of evolution, not a step-by-step change.
This is one of the many reasons a generalization about a "generation" of
ATSC receivers based on *one* comparison is laughable.

The primary reason that the receivers changed is that as new features (DVI,
etc.) came out, receiver manufacturers also tweaked the actual receiver
quality. In general, it wasn't required for most reception locations, and
sometimes the change was simply because newer chips were cheaper.

Also, some people *have* to have the "latest", and CE companies know this,
so they keep coming out with new units to sell to people that don't really
need them.

--
Jeff Rife |
SPAM bait: | http://www.nabs.net/Cartoons/ArloNJanis/CircularSaw.gif
AskDOJ@usdoj.gov |
spam@ftc.gov |
Anonymous
September 23, 2004 8:34:02 PM

Archived from groups: alt.tv.tech.hdtv (More info?)

"Jeff Rife" <wevsr@nabs.net> wrote in message
news:MPG.1bbced527f4943e598984f@news.nabs.net...
> Jeff Rigby (jeffg212@comcast.net) wrote in alt.tv.tech.hdtv:
> > Then what are the problems with the DTC-100,
>
> 1. The way ABC and ESPN create their streams, the audio sometimes has
> locking problems on the DTC-100. Going into and out of the menu
usually
> (99%) solves this.
>
> 2. It seems to require a higher raw signal level than my newer receivers.
> It works just fine if C/N is above 18dB or so, but it takes a bit more
> (about 3dB) raw signal to achieve this with *some* signals.
>
> 3. The interface is not the best. My #1 complaint is that you can't get
> PSIP guide information unless you turn on "virtual channels". It
> also lacks the diagnostics of *any* kind that newer receivers have,
> like detailed error data, detailed stream data, etc.
>
> 4. Simply because it is so old a design, it just doesn't have a lot of the
> newer bells and whistles, including such things as DVI outputs.
>
> Compared to my 4th generation receiver, there are no real reception
> differences except for the need for more raw signal, which is solved by
> a pre-amp in all cases.
>
> > why hasn't it taken over
the
> > market if it doesn't have any problems?
>
> It *did* take over the marketplace. It just isn't made anymore. I
suspect
> that it is the #1 installed ATSC receiver, since it was the only decent
> one for about 4 years (it's still one of about 3 that can handle all
closed
> captions on digital broadcasts), *and* the RCA F38310 TV has it inside,
> *and* some DirecTV combo units are based on it.
>
> > Why are there second, third,
fourth
> > and fifth generation receivers.
>
> First, these exist because people have chosen to give them these labels,
> even though it has been a process of evolution, not a step-by-step change.
> This is one of the many reasons a generalization about a "generation" of
> ATSC receivers based on *one* comparison is laughable.
>
> The primary reason that the receivers changed is that as new features
(DVI,
> etc.) came out, receiver manufacturers also tweaked the actual receiver
> quality. In general, it wasn't required for most reception locations, and
> sometimes the change was simply because newer chips were cheaper.
>
> Also, some people *have* to have the "latest", and CE companies know this,
> so they keep coming out with new units to sell to people that don't really
> need them.
>
So features which we all know are sales tools change from "generation" to
generation. But I was interested in
worst case fixes from model year to model year (generation). There is a
function called adaptive equalization that relies on pure processing power.
This function allows the receiver to lock "receive" signals that have ghosts
in them, to receive stations that have rapidly changing signal levels. The
algorithms (software) as well as the hardware have been changing to fix
worst case problems. . There have been small incremental changes in the
signal level required, as you mentioned but major changes otherwise.

I have a customer who has an RCA HD tv and it can't receive a worst case
station here in Sarasota, just as I can't receive it with my 2003 Samsung HD
tuner but a 2004 Samsung tuner can.

I realize that best case hasn't changed much except for add-ons but worst
case HAS. You might not notice the differences because you have a best case
situation. I'm blessed with a (I think) worst case. I'm in an industrial
area with lots of metal roofs, power lines between me and the antenna farm
and stations in three different directions (multiple antennas). So I have
ghosts, more ghosts and weak and STRONG stations as well as one channel that
has weak analog co-channel interference. I see a major differnce between
model years, read on here about "Generations" and use that term, maybe
mistakenly.
Anonymous
September 23, 2004 9:47:17 PM

Archived from groups: alt.tv.tech.hdtv (More info?)

Jeff Rigby wrote:
> "Jeff Rife" <wevsr@nabs.net> wrote in message
> news:MPG.1bbc32e35c1bb4a98984c@news.nabs.net...
>
>>Jeff Rigby (jeffg212@comcast.net) wrote in alt.tv.tech.hdtv:
>>
>>>Some things I've noticed about "third generation" HD tuners:
>>>1) There must be more than 10db difference between the Origional and
>
> Ghost
>
>>>signal for good lock.
>>>3) Strong analog signals will affect the sound of a digital ch up to 4
>>>channels away. EX: 30 db analog on 50 affects sound on digital 54
>>>4) Digital signals over +15 db will cause sound dropouts
>>>5) Minimum signal for good lock -20db best is -10db The higher the
>
> signal
>
>>>level the more chance of ghosts from wire pinches, improper termination
>
> etc,
>
>>>again the 10 db rule applies.
>>
> When comparing the third generation tuner from Samsung to a 4th generation
> tuner from Samsung
> 1) 5 db for 4th 10 db for 3rd
> 3) strong analog signal will not affect the sound on a 4th generation
> 4) strong digital signal will not affect the sound on a 4th
> 5) -20 db signal for a good lock even if signal strength changes quickly
> with tower movement. Third generation can't stand quick signal level
> changes.
> 6) Analog co-channel interference will cause 3rd generation to not lock, 4th
> generation didn't have a problem with -30 db signal (barily visable)
>
>
>>Since *none* of these are true with a first generation receiver (the RCA
>>DTC-100), your generalization about "third generation receivers" is not
>>valid.
>
>
> Then what are the problems with the DTC-100, why hasn't it taken over the
> market if it doesn't have any problems? Why are there second, third, fourth
> and fifth generation receivers. Why has a new standard E-VSB been adopted.
> |
>
> What are the faults of the different generation tuners? Can anyone generate
> a table or list by generation ?
>
>

From talks I have had with top engineers at Motorola, LG and last week
a cable company, there is not that much difference between 1st and 4th
generation receivers. The major break is with the 5th generation
receiver tech of LG. Night and day from our experience.

The cable company has gone through all available receivers and claims
they have the best luck with the DTC-100. They are still receiving and
transmitting snowy analog local channels because their customers are
happier with snow as apposed to drop-outs.

Wait for the 5th generation.
Anonymous
September 24, 2004 1:01:49 AM

Archived from groups: alt.tv.tech.hdtv (More info?)

Jeff Rigby (jeffg212@comcast.net) wrote in alt.tv.tech.hdtv:
> There is a
> function called adaptive equalization that relies on pure processing power.
> This function allows the receiver to lock "receive" signals that have ghosts
> in them, to receive stations that have rapidly changing signal levels. The
> algorithms (software) as well as the hardware have been changing to fix
> worst case problems.

I have found that most of these "problems" can be solved with changes to
the antenna...no new technology is needed. I can easily generate horrible
multipath by pointing my antenna in a specific direction, and it *will*
kill the signal. But, a simple swing of 20° or so and the multipath goes
away.

> I'm in an industrial
> area with lots of metal roofs, power lines between me and the antenna farm
> and stations in three different directions (multiple antennas). So I have
> ghosts, more ghosts and weak and STRONG stations as well as one channel that
> has weak analog co-channel interference.

Except for the metal roof problem, I'm pretty much the same, and antenna
selection and aiming solves all the problems. A rotator is almost a
"must-have" for some situations, but some people just don't want that, so
they will have to spend money on technology that can capture a much weaker
signal, even though a stronger signal from that same channel is available at
their location.

--
Jeff Rife |
SPAM bait: | http://www.nabs.net/Cartoons/FoxTrot/TransporterError.j...
AskDOJ@usdoj.gov |
spam@ftc.gov |
Anonymous
September 24, 2004 2:47:04 PM

Archived from groups: alt.tv.tech.hdtv (More info?)

"> I'm in an
industrial
> area with lots of metal roofs, power lines between me and the antenna farm
> and stations in three different directions (multiple antennas). So I have
> ghosts, more ghosts and weak and STRONG stations as well as one channel
that
> has weak analog co-channel interference.

Except for the metal roof problem, I'm pretty much the same, and antenna
selection and aiming solves all the problems. A rotator is almost a
"must-have" for some situations, but some people just don't want that, so
they will have to spend money on technology that can capture a much weaker
signal, even though a stronger signal from that same channel is available at
their location.

That pretty much describes me. Although to be fair to me I am feeding 2
apartments and one business (mine). With multiple people (tvs) it is hard
to use a rotor.

Also, as a servicer of HD TV I'm supposed to know about these issues. I'm
getting in late because CABLE dominates my service area. Since I am getting
in late I don't know what problems the first tuners had or the second
generation but the third generation I'm sadly familiar with. I had a 4th
generation in here for service so I can compare the two.

I've spent $270 in tuneable traps to get this 3rd "generation" tuner to
work. With the 4th "generation" tuner the traps were not necessary and one
channel comes in that I still can't get on the 3rd generation tuner.

I realize that you object to my use of "generation" but I can't without
knowing more about the various tuners pick out the feature that makes it a
next generation unit. I'm looking at worst case problems solved as the
feature that seperates the two. I did notice that between what I call a 3rd
and 4th generation Samsung tuner that the 4th had QAM support for
unscrambled HD cable channels. It may even be true that, between the two
Samsung tuners, the difference might be only software not hardware.
Anonymous
September 24, 2004 3:48:34 PM

Archived from groups: alt.tv.tech.hdtv (More info?)

Jeff Rigby (jeffg212@comcast.net) wrote in alt.tv.tech.hdtv:
> It may even be true that, between the two
> Samsung tuners, the difference might be only software not hardware.

That's quite likely. My ability to receive with my PCI HDTV card has
improved with new software releases. One of the best added features was
a system that re-builds the incoming stream on the fly so that a single
uncorrected error doesn't get the system out-of-sync for a long time...you
just get a glitch on one or two frames, and then everything is smooth again.

--
Jeff Rife | "If we give peas a chance, won't the lima
SPAM bait: | beans feel left out?"
AskDOJ@usdoj.gov |
spam@ftc.gov | -- Pinky
Anonymous
September 24, 2004 4:31:11 PM

Archived from groups: alt.tv.tech.hdtv (More info?)

Jeff Rigby wrote:
>
> 1) OTA (over the air) ch 54 mapped to ch 3 has sound dropouts at certain
> times of the day due to either overdrive or adjacent channel interference.
> Reducing the signal level with traps or reducing the antenna amp gain only
> reduces the frequency of occurrence of the sound dropouts. The dropouts
> occur more on ch 3.1 than 3.5. I installed a 24db trap for ch 50 and this
> has improved the sound on
> ch 54 (3) We receive here a ch 50 (strong +30db analog), ch 52 (digital),
> ch 54 (digital), ch 59 (strong digital)
>
> 2) Also ch 52 mapped to 40 does not map on this tuner and is intermittently
> not receivable. When using an older analog TV I noticed that there was a
> very faint analog ch 52 on that TV. I installed and tuned a trap for 52 and
> tuned it untill the analog ch diappeared into the snow. This allows me to
> receive ch 52 (40) reliably. It still does not map.
>
> 3) If the signal level for ch 59 (44) was above 100% (on the menu) there is
> a barely perceptible dropout in the sound
>
> 4) The set is very susceptible to ghosts. You get breakup and loss of
> signal as the tuner tries to lock on the different (time) signals.
>
> This is probably a worst-case antenna/location situation and I'd not bother
> with it but for the fact that a slightly newer Samsung does not have these
> problems. Analog pictures from the antenna farm for different frequencies
> are very watch able with barely noticeable ghosts
>
> I'm guessing that the software for the older tuner stressed sensitivity over
> selectivity. And we have a worst-case situation here in this location. I'm
> in contact with a customer who has a RCA DLP set built in 2003 with built-in
> tuner and he cannot receive ch 52 (40) either.
>
> Some things I've noticed about "third generation" HD tuners:
> 1) There must be more than 10db difference between the Origional and Ghost
> signal for good lock.
> 2) There can be NO analog signal visable on older NTSC tv (more than -30 db)
> or there will be no lock. That's 50 db of signal difference.
> 3) Strong analog signals will affect the sound of a digital ch up to 4
> channels away. EX: 30 db analog on 50 affects sound on digital 54
> 4) Digital signals over +15 db will cause sound dropouts
> 5) Minimum signal for good lock -20db best is -10db The higher the signal
> level the more chance of ghosts from wire pinches, improper termination etc,
> again the 10 db rule applies.
> 6) Using older R59 single shield cable will compound problems with reception
> on long runs.
> 7) The better the signal condition the faster the lock



Jeff R.:

I note a new OTA receiver on the Market by Samsung....

Does the new Model SIR-T451 feature any new 'improvements'

like?:

Digital front face readouts
Better internal hardware & software (what generation?)
Any new cable connection ports
a new $250 price......
I'm guessing on these features... options...
Anonymous
September 24, 2004 5:53:59 PM

Archived from groups: alt.tv.tech.hdtv (More info?)

> I note a new OTA receiver on the Market by Samsung....
>
> Does the new Model SIR-T451 feature any new 'improvements'
>
> like?:
>
> Digital front face readouts
> Better internal hardware & software (what generation?)
> Any new cable connection ports
> a new $250 price......
> I'm guessing on these features... options...

I'd guess a late 4th generation, more stable than the earlier SIR-T351 with
more features. Don't know anymore than I read here. It's hard to tell
anything from a schematic....the only thing I have access to that you don't.
September 27, 2004 3:00:16 PM

Archived from groups: alt.tv.tech.hdtv (More info?)

> Jeff R.:
>
> I note a new OTA receiver on the Market by Samsung....
>
> Does the new Model SIR-T451 feature any new 'improvements'


I just picked up a 'discontinued' SIR-T165, and I would like to
see if the SIRT-T451 is any better (Before my 30 day return offer
runs out). Unfortunately I can't find anyone who carries it.
I called Crutchfield. It's on their web site, but not yet available.
Only $249.99 They have some specs on their site - looks like the same
as the T165

Key Features:
- receives and decodes all over-the-air HDTV/SDTV formats
(when connected to an HD-compatible antenna)
- selectable output resolution (1080i/720p/480p/480i)
- Electronic Program Guide
- 1 set of A/V outputs (composite, S-video, and
1080i/720p/480p component video)
- DVI digital video output with HDCP copy protection
- RGB output — D-sub 15-pin connector
- one RF input (Antenna)
- optical and coaxial digital audio outputs for Dolby® Digital
- multibrand remote control (operates most TVs)
- 13-7/8"W x 2-3/4"H x 10-1/4"D
- warranty: 1 year parts & labor



Somewhere I saw it referred to as a 'fifth generation'

It's not on Samsung's web site.
Anyone have more info / release dates?
Anonymous
September 28, 2004 4:22:30 AM

Archived from groups: alt.tv.tech.hdtv (More info?)

"Bruce" <bcamp2@netzero.net> wrote in message
news:326445e3.0409271000.55404773@posting.google.com...
> > Jeff R.:
> >
> > I note a new OTA receiver on the Market by Samsung....
> >
> > Does the new Model SIR-T451 feature any new 'improvements'

It seems to leave off the Firewire IEE1394 connection that can be used for
DVHS digital recording.

> I just picked up a 'discontinued' SIR-T165, and I would like to
> see if the SIRT-T451 is any better (Before my 30 day return offer
> runs out). Unfortunately I can't find anyone who carries it.
> I called Crutchfield. It's on their web site, but not yet available.
> Only $249.99 They have some specs on their site - looks like the same
> as the T165
>
> Key Features:
> - receives and decodes all over-the-air HDTV/SDTV formats
> (when connected to an HD-compatible antenna)
> - selectable output resolution (1080i/720p/480p/480i)
> - Electronic Program Guide
> - 1 set of A/V outputs (composite, S-video, and
> 1080i/720p/480p component video)
> - DVI digital video output with HDCP copy protection
> - RGB output - D-sub 15-pin connector
> - one RF input (Antenna)
> - optical and coaxial digital audio outputs for Dolby® Digital
> - multibrand remote control (operates most TVs)
> - 13-7/8"W x 2-3/4"H x 10-1/4"D
> - warranty: 1 year parts & labor
>
>
>
> Somewhere I saw it referred to as a 'fifth generation'
>
> It's not on Samsung's web site.
> Anyone have more info / release dates?
October 5, 2004 6:24:58 PM

Archived from groups: alt.tv.tech.hdtv (More info?)

"no one" <no-one@nowhere.net> wrote in message news:<a926d.3711$Ga3.786@newssvr16.news.prodigy.com>...
> "Bruce" <bcamp2@netzero.net> wrote in message
> news:326445e3.0409271000.55404773@posting.google.com...

> > It's not on Samsung's web site.
> > Anyone have more info / release dates?


Samsung now has more info on their web site - and a PDF
of the manual. Here's the link:

http://www.samsungusa.com/cgi-bin/nabc/product/b2c_prod...

In addition to the missing firewire port, it also has a smaller
remote control than the SIR-T165.

It now shows up as 'in-stock' on Crutchfield's web site. $249.99
and free shipping!
October 5, 2004 7:18:52 PM

Archived from groups: alt.tv.tech.hdtv (More info?)

> "Bruce" <bcamp2@netzero.net> wrote in message
> news:326445e3.0409271000.55404773@posting.google.com...

> > Key Features:
> > - receives and decodes all over-the-air HDTV/SDTV formats
> > (when connected to an HD-compatible antenna)
> > - selectable output resolution (1080i/720p/480p/480i)
> > - Electronic Program Guide
> > - 1 set of A/V outputs (composite, S-video, and
> > 1080i/720p/480p component video)
> > - DVI digital video output with HDCP copy protection
> > - RGB output - D-sub 15-pin connector
> > - one RF input (Antenna)
> > - optical and coaxial digital audio outputs for Dolby® Digital
> > - multibrand remote control (operates most TVs)
> > - 13-7/8"W x 2-3/4"H x 10-1/4"D


Perusing the PDF manual a bit more and comparing to the SIR-T165.

- The '451' takes half the power - (20 watts versus 40 watts)
(The SIR-T165 gets very hot! - needs ventilation)
- It is about half the weight
- It's a bit smaller in all dimensions
- I'm not sure, but it may NOT be able to tune
Analog NTSC signals! The SIR-T165 definitely does, but
I can't find a clear mention of it in the SIR-T451 manual.
!