Don't understand why some digital TV channels get high signals, but they get unclear pictures?

Hello,

I got an old coax splitter (made in Taiwan; looks like
http://i7.ebayimg.com/04/i/06/26/5e/17_2.JPG but silver color; probably
from the 80s or so) that I got from someone. I decided to hook up my DB2
HDTV bowtie antenna (30 miles;
http://www.antennasdirect.com/DB2_Indoor_antenna.html ) to my old VCR
(also tried the CRT TV [analog; not digital], but neither made
differences) and my Broadband Technologies Air2PC-ATSC-PCI HDTV tuner
card (r0.2; DVB). I wanted to share the same big antenna (replaced a
cheap rabbit ear set for my VCR and TV) together for my two TV devices.

I noticed some low number TV stations/channels have crappy picture
(dots, etc.) with analog. However with digital, I get high signals (no
problems). I compared and made a chart (use a fixed width font like
Courier):

Ch.# - TV Station - Digital Signal Strength = Analog Results (TV first in first row; then VCR in second row):
2.1 - KCBS-DT - 99% = Clear (way better than rabbit ears that gave me unclear picture and sometime B&W)
Almost clear, but not perfect.
4.1 - KNBC-LA - 80% - 83% = Lots of dots with a thick purple and green horizontal bands, but viewable.
Annoying because picture shakes a lot and lots of white flickering lines. Would rather watch above row.
5.1 - CW/KTLA-DT - 88% - 91% = Lots of dots; sometimes B&W colors!
= Almost clear, but not perfect. Better than above row.
7.1 - KABC-HD - 68% = Clear.
= Clear, but I'd rather watch without the VCR for better colors.
All the rest (higher numbers to 99%) are clear on analog and digital
feeds.

Without any antenna connected, channel 4 is actually a little clearer
(no thick horizontal color bands) than above tests for this channel. Not
sure what's up with that.

Is this normal? Is my antenna not strong enough even though
http://www.antennaweb.org/aw/welcome.aspx said I am less than 20 miles
(mostly 17 and 18) and 323 degrees (compass orientation) between my home
location and TV stations. I am on a hill and there's a large thin tree
(not pine tree type facing the San Gabriel mountains).
--
"We are anthill men upon an anthill world." --Ray Bradbury
/\___/\
/ /\ /\ \ Phillip (Ant) @ http://antfarm.ma.cx (Personal Web Site)
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wrote in message
et...
Hello,
snip
I noticed some low number TV stations/channels have crappy picture
(dots, etc.) with analog. However with digital, I get high signals (no
problems).
snip
Without any antenna connected, channel 4 is actually a little clearer
(no thick horizontal color bands) than above tests for this channel. Not
sure what's up with that.

I wonder if you're suffering from multipathing of a particularly
strong signal on channel 4.

Is this normal? Is my antenna not strong enough even though
http://www.antennaweb.org/aw/welcome.aspx said I am less than 20 miles
(mostly 17 and 18) and 323 degrees (compass orientation) between my home
location and TV stations. I am on a hill and there's a large thin tree
(not pine tree type facing the San Gabriel mountains).

Yes, it can be normal. Low number channels are VHF while digital
signals are generally UHF. It's possible the digital transmission
antennas are not located in the same place as the analog.

My best Fox station Fox 64 in Providence is mostly snow on the analog
channel but gives robust reception on digital. Before HDTV I could
not get ABC6 in New Bedford (42 miles distant). Now I can. My analog
channel 4 (CBS) was pretty crappy but CBS4-DT is great. I'm using an
indoor amplified UHF antenna.

--
Hilton Evans
----------------------------------------------------------------
Lat +42° 11' 07"
Lon -71° 04' 35"
----------------------------------------------------------------
http://www.chempensoftware.com
----------------------------------------------------------------
http://mysite.verizon.net/hiltonevan...troimaging.htm

Rick Evans wrote:
wrote in message
et...
Hello,
snip
I noticed some low number TV stations/channels have crappy picture
(dots, etc.) with analog. However with digital, I get high signals (no
problems).
snip
Without any antenna connected, channel 4 is actually a little clearer
(no thick horizontal color bands) than above tests for this channel. Not
sure what's up with that.

I wonder if you're suffering from multipathing of a particularly
strong signal on channel 4.

If it helps at all, here are two screen shots of KNBC4LA (Chanenel 4)
from my VCR: http://forums.worldofwar.net/showthread.php?t=380094 with
the bowtie antenna.


Is this normal? Is my antenna not strong enough even though
http://www.antennaweb.org/aw/welcome.aspx said I am less than 20 miles
(mostly 17 and 18) and 323 degrees (compass orientation) between my home
location and TV stations. I am on a hill and there's a large thin tree
(not pine tree type facing the San Gabriel mountains).

Yes, it can be normal. Low number channels are VHF while digital
signals are generally UHF. It's possible the digital transmission
antennas are not located in the same place as the analog.

My best Fox station Fox 64 in Providence is mostly snow on the analog
channel but gives robust reception on digital. Before HDTV I could
not get ABC6 in New Bedford (42 miles distant). Now I can. My analog
channel 4 (CBS) was pretty crappy but CBS4-DT is great. I'm using an
indoor amplified UHF antenna.

Interesting. I was expecting all my channels to be clear with this more
powerful antenna for analog feeds.
--
"We are anthill men upon an anthill world." --Ray Bradbury
/\___/\
/ /\ /\ \ Phillip (Ant) @ http://antfarm.ma.cx (Personal Web Site)
| |o o| | Ant's Quality Foraged Links (AQFL): http://aqfl.net
\ _ / Please remove ANT if replying by e-mail.
( )

wrote:

Hello,

I got an old coax splitter (made in Taiwan; looks like
http://i7.ebayimg.com/04/i/06/26/5e/17_2.JPG but silver color; probably
from the 80s or so) that I got from someone. I decided to hook up my DB2
HDTV bowtie antenna (30 miles;
http://www.antennasdirect.com/DB2_Indoor_antenna.html ) to my old VCR
(also tried the CRT TV [analog; not digital], but neither made
differences) and my Broadband Technologies Air2PC-ATSC-PCI HDTV tuner
card (r0.2; DVB). I wanted to share the same big antenna (replaced a
cheap rabbit ear set for my VCR and TV) together for my two TV devices.

I noticed some low number TV stations/channels have crappy picture
(dots, etc.) with analog. However with digital, I get high signals (no
problems). I compared and made a chart (use a fixed width font like
Courier):

Ch.# - TV Station - Digital Signal Strength = Analog Results (TV first in first row; then VCR in second row):
2.1 - KCBS-DT - 99% = Clear (way better than rabbit ears that gave me unclear picture and sometime B&W)
Almost clear, but not perfect.
4.1 - KNBC-LA - 80% - 83% = Lots of dots with a thick purple and green horizontal bands, but viewable.
Annoying because picture shakes a lot and lots of white flickering lines. Would rather watch above row.
5.1 - CW/KTLA-DT - 88% - 91% = Lots of dots; sometimes B&W colors!
= Almost clear, but not perfect. Better than above row.
7.1 - KABC-HD - 68% = Clear.
= Clear, but I'd rather watch without the VCR for better colors.
All the rest (higher numbers to 99%) are clear on analog and digital
feeds.

Without any antenna connected, channel 4 is actually a little clearer
(no thick horizontal color bands) than above tests for this channel. Not
sure what's up with that.

Is this normal? Is my antenna not strong enough even though
http://www.antennaweb.org/aw/welcome.aspx said I am less than 20 miles
(mostly 17 and 18) and 323 degrees (compass orientation) between my home
location and TV stations. I am on a hill and there's a large thin tree
(not pine tree type facing the San Gabriel mountains).


The DB-2 is a UHF antenna for channels 14 to 69 (472 to 800 MHz). It
should have ok pickup for closer stations in the upper VHF 7 to 13
channels (175 to 212 MHz), but terrible response for lower VHF 2 to 6
(54 to 84 MHz). I find your post is hard to follow. You need to lookup
the actual broadcast channel for the digital signal for the stations and
provide that to make your post somewhat more clear.

Alan F

Alan F writes:
[...]
but terrible response for lower VHF 2 to 6 (54 to 84 MHz).

Alan,

Slight correction: VHF 2 to 6 is 54 to 88 MHz. There is a 4 MHz whole
between channels 4 and 5.
--
% Randy Yates % "And all that I can do
%% Fuquay-Varina, NC % is say I'm sorry,
%%% 919-577-9882 % that's the way it goes..."
%%%% % Getting To The Point', *Balance of Power*, ELO
http://home.earthlink.net/~yatescr

Alan F writes:
[...]
7 to 13 channels (175 to 212 MHz),

Again a slight correction: 7 to 13 is 174 to 216 MHz.
--
% Randy Yates % "Maybe one day I'll feel her cold embrace,
%% Fuquay-Varina, NC % and kiss her interface,
%%% 919-577-9882 % til then, I'll leave her alone."
%%%% % 'Yours Truly, 2095', *Time*, ELO
http://home.earthlink.net/~yatescr

Alan F wrote:

The DB-2 is a UHF antenna for channels 14 to 69 (472 to 800 MHz). It
should have ok pickup for closer stations in the upper VHF 7 to 13
channels (175 to 212 MHz), but terrible response for lower VHF 2 to 6
(54 to 84 MHz). I find your post is hard to follow. You need to lookup
the actual broadcast channel for the digital signal for the stations and
provide that to make your post somewhat more clear.

I too found the OP's post confusing, but I gather that he has good
reception and no problems with his digital tuner (AirPC PCI card) but
fair-to-poor reception with his analog TV and VCR. He seems to think
that they're receiving the same digital channels; of course they're
not. All of the LA area digitals seem to be on UHF. Of the ones he
listed, the callsign, virtual channel and actual channel a

KCBS-DT 2.1 60
KNBC-DT 4.1 36
KTLA-DT 5.1 31
KABC-DT 7.1 53

It looks like just about all of the transmitters, analog and digital,
are on the same mountain. As you noted, his reception of low-VHF
channels with a UHF antenna *should* be poor. In fact, I'm surprised
it's as good as he says it is.

Del Mibbler

The DB-2 is a UHF antenna for channels 14 to 69 (472 to 800 MHz). It
should have ok pickup for closer stations in the upper VHF 7 to 13
channels (175 to 212 MHz), but terrible response for lower VHF 2 to 6
(54 to 84 MHz). I find your post is hard to follow. You need to lookup
the actual broadcast channel for the digital signal for the stations and
provide that to make your post somewhat more clear.

I too found the OP's post confusing, but I gather that he has good
reception and no problems with his digital tuner (AirPC PCI card) but

Yes, good signals on my digital TV tuner. I did post their signal
strengths (%) in the chart (sorry for the crappy format). I revised the
chart so it would fit nicely:

Ch.# - TV Station
Digital Signal Strength; Analog Results (TV first; then VCR):

2.1 - KCBS-DT
99%; Clear (way better than rabbit ears that gave me unclear picture and
sometime B&W); Almost clear, but not perfect.

4.1 - KNBC-LA
80%-83%; Lots of dots with a thick purple and green horizontal bands,
but viewable.; Annoying because picture shakes a lot and lots of white
flickering lines.

5.1 - CW/KTLA-DT
88%-91%; Lots of dots; sometimes B&W colors!; Almost clear, but not
perfect.

7.1 - KABC-HD
68%; Clear. Clear, but I'd rather watch without the VCR for better
colors.

All the rest (higher numbers to 99%) are clear on analog and digital
feeds.


fair-to-poor reception with his analog TV and VCR. He seems to think
that they're receiving the same digital channels; of course they're
not. All of the LA area digitals seem to be on UHF. Of the ones he
listed, the callsign, virtual channel and actual channel a

KCBS-DT 2.1 60
KNBC-DT 4.1 36
KTLA-DT 5.1 31
KABC-DT 7.1 53

Here's the whole list I made:
My Stations I Ca

Station and Channel
Analog Channel. = Category

KCBS 2 = 60
KNBC 4 = 36
KTLA 5 = 31
KABC 7 = 53
KCAL 9 = 43
KTTV 11 = 65
KCOP 13 = 66
KCET 28 = 59
KOCE 50 = 48
KLCS 58 = 41

--

Stations That I Don't Ca

Analog Ch. = Station = Ch. Category

18 = KSCI/LA18
/FUNIMAT
/IND = 61
22 = KWHY = 42
23 = KTBN/KVMD = 23
49
51
34 = KMEX = 35
30 = Christian = 38 (i, Pax, Worship, & Faith)
40 = KTBN = 23
44 = KXLA = 49
51
46 = KFTR = 29
52 = KVEA = 39
54 = KAZA = ??
56 = KDOC = 32
57 = KJLA = 49
62 = KCRA = 68


It looks like just about all of the transmitters, analog and digital,
are on the same mountain. As you noted, his reception of low-VHF

And same direction (323 degrees).


channels with a UHF antenna *should* be poor. In fact, I'm surprised
it's as good as he says it is.

What do I need to improve the lower channels for analog feeds?
Obviously, I won't need to worry about this in 2/2009 when analog part
is dropped according to FCC.
--
"We are anthill men upon an anthill world." --Ray Bradbury
/\___/\
/ /\ /\ \ Phillip (Ant) @ http://antfarm.ma.cx (Personal Web Site)
| |o o| | Ant's Quality Foraged Links (AQFL): http://aqfl.net
\ _ / Please remove ANT if replying by e-mail.
( )

wrote:
snip
It looks like just about all of the transmitters, analog and
digital,
are on the same mountain. As you noted, his reception of low-VHF

And same direction (323 degrees).


channels with a UHF antenna *should* be poor. In fact, I'm
surprised
it's as good as he says it is.

What do I need to improve the lower channels for analog feeds?
Obviously, I won't need to worry about this in 2/2009 when analog
part
is dropped according to FCC.

A few weeks ago I talked to an engineer at KABC-TV/DT and he told me
that at the analog cutoff date, KABC-DT will be on Ch 7 where the
analog currently is. I also read that KCAL-DT will be on 9, KCBS will
take over Ch 43 (presently KCAL-DT). I suspect that 11 and 13 will be
the DTs for KTTV and KCOP respectively. Bottom line is you will need at
least hi band VHF reception.

GG

It looks like just about all of the transmitters, analog and
digital,
are on the same mountain. As you noted, his reception of low-VHF

And same direction (323 degrees).


channels with a UHF antenna *should* be poor. In fact, I'm
surprised
it's as good as he says it is.

What do I need to improve the lower channels for analog feeds?
Obviously, I won't need to worry about this in 2/2009 when analog
part
is dropped according to FCC.

A few weeks ago I talked to an engineer at KABC-TV/DT and he told me
that at the analog cutoff date, KABC-DT will be on Ch 7 where the
analog currently is. I also read that KCAL-DT will be on 9, KCBS will
take over Ch 43 (presently KCAL-DT). I suspect that 11 and 13 will be
the DTs for KTTV and KCOP respectively. Bottom line is you will need at
least hi band VHF reception.

Interesting. Does that mean I have to buy a completely new antenna? I
guess I have less than three years to change it for the new setup.
--
"We are anthill men upon an anthill world." --Ray Bradbury
/\___/\
/ /\ /\ \ Phillip (Ant) @ http://antfarm.ma.cx (Personal Web Site)
| |o o| | Ant's Quality Foraged Links (AQFL): http://aqfl.net
\ _ / Please remove ANT if replying by e-mail.
( )