Excellent information - I agree.
Thought I'd add these points as well:
I purchased and returned a couple amplifiers the other day - one
amp for the antenna end (before any splitters), and another with four
outputs (a "DA" or "Distribution Amplifier") for
the entertainment center: the TV, a couple tuners on the Myth box, and
my stereo receiver.
I brought them home and found that the rated bandwidth on the
amps cuts off before they get far into the OTA UHF band. They were
apparently designed to amplify US-Cable only, and not OTA antenna
signals.
They went back and I shopped at the local Fry's and found a
couple nicer amps that go up to 900MHz. The Vanco amp that will go at
the antenna end also has a switchable "FM Trap" designed to
remove interfering FM radio signals (which are plunked down in the
middle of the US VHF TV band, near channel 6 - can't remember if
they're below or above). The FM trap switch will stay off on my amp
'cause I want to use the signal for my radio receiver as well. The
Vanco has a pot to adjust gain, maxed on mine.
If you are trying to get a US over-the-air signal and you
want to get UHF channels, you need to check the amp you're buying to
make sure it is rated for up to 900MHz. I was surprised that they were
selling amps that wouldn't do UHF in the US, but they look at me funny
these days when I try to buy stuff for an OTA antenna setup too,
so...
I currently have the amp that will eventually go up on the
antenna end (lazy/busy right now) inline at the MythTV input, and it
makes a significant improvement to the quality of the picture. Most
UHF channels went from unusable/crashable to noisy-watchable. The
channel I wanted most (30 - PBS) got the most improvement in the UHF
band, which is a great thing. Channel 69, the top of our local band
never did come in (and again, since that one is UPN, that might just
be a great thing too! ;). I expect further improvement when this amp
goes to the head-end and I add some more gain with the DA at the
MythTV end. I'll fine-tune the antenna location and orientation as
well (it's an inside-the-attic mount, and is fighting with ductwork,
pipes and wiring for a clear shot at Atlanta's antenna
district).
I haven't gotten around to installing the DA just yet, but wanted
to make a point about that amp as well. Typically, a consumer-level
1-in, 4-out DA does not have an individual output stage for each of
the four outputs. Instead, it's just an amplifier inline with a
four-way splitter. This means f.e., that if you're using only three of
the four outputs, you should terminate the unused output. You can use
a commercial terminator, or solder up your own out of a small 75-ohm
resistor and an F-connector.
My setup when finished will look like this (ASCII art - use
monospaced font):
/// ______
|
_______________ | |-- PVR-350
|--| antenna amp |--S----/ long cable /----| DA |-- PVR-250
(soon)
---------------
|
| |-- VHS deck, TV
|
| |-- FM Stereo
Bedroom
TV ------
Regarding the quality of the picture from Tuner 47, prior to
amplification, the channels that came in best were VHF 2 and 5. They
looked very good indeed, and wouldn't have required any amplification
if that was all I wanted to look at. Interestingly, the best channels
are at the low end, and channel 69 won't come in at all - maybe we're
watching Tuner 47's performance roll off as frequency
increases...
Finally, Thanks Michael for maintaining the definitions on my
tuner, and thanks everyone else working on ivtv!
DC
"Michael T. Dean" wrote:
>David Cain wrote:
>
>> ... I've now accomplished what I set out to do and have UHF channels
>> (albeit not channel 69, but since that's UPN here it's no great
>
>> ... I've now accomplished what I set out to do and have UHF channels
>> (albeit not channel 69, but since that's UPN here it's no great
>> loss... ;)
>> ...
>> OK, I'm going to go to bed and dream of amplifiers for my poor OTA TV
>> signal...
>
>Just thought I'd chime in here with some info I've been meaning to
>post. A lot of people--especially those using the LG TAPE (type 47) and
>TCL 2002N (type 50) tuners for which I provided the tuner
>definitions--have complained of poor picture quality when using the
>> ...
>> OK, I'm going to go to bed and dream of amplifiers for my poor OTA TV
>> signal...
>
>Just thought I'd chime in here with some info I've been meaning to
>post. A lot of people--especially those using the LG TAPE (type 47) and
>TCL 2002N (type 50) tuners for which I provided the tuner
>definitions--have complained of poor picture quality when using the
>tuner.
--
--
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|
| "Grease is great,
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|
| - Bruce Gibson
| http://www.jimmiedave.com/
|
| "Grease is great,
| grease is good,
| let us have some
| on our fo-od"
|
| - Bruce Gibson
