<s>
In	O
broadcasting	O
,	O
digital	B-Device
subchannels	I-Device
are	O
a	O
method	O
of	O
transmitting	O
more	O
than	O
one	O
independent	O
program	O
stream	O
simultaneously	O
from	O
the	O
same	O
digital	O
radio	O
or	O
television	B-Application
station	O
on	O
the	O
same	O
radio	O
frequency	O
channel	O
.	O
</s>
<s>
This	O
is	O
done	O
by	O
using	O
data	B-General_Concept
compression	I-General_Concept
techniques	O
to	O
reduce	O
the	O
size	O
of	O
each	O
individual	O
program	O
stream	O
,	O
and	O
multiplexing	B-Device
to	O
combine	O
them	O
into	O
a	O
single	O
signal	O
.	O
</s>
<s>
The	O
ATSC	B-Device
digital	I-Device
television	I-Device
standard	I-Device
used	O
in	O
the	O
United	O
States	O
supports	O
multiple	O
program	O
streams	O
over-the-air	O
,	O
allowing	O
television	B-Application
stations	O
to	O
transmit	O
one	O
or	O
more	O
subchannels	B-Device
over	O
a	O
single	O
digital	O
signal	O
.	O
</s>
<s>
A	O
virtual	B-Protocol
channel	I-Protocol
numbering	O
scheme	O
distinguishes	O
broadcast	O
subchannels	B-Device
by	O
appending	O
the	O
television	B-Application
channel	O
number	O
with	O
a	O
period	O
digit	O
(	O
"	O
.xx	O
"	O
)	O
.	O
</s>
<s>
Simultaneously	O
,	O
the	O
suffix	O
indicates	O
that	O
a	O
television	B-Application
station	O
offers	O
additional	O
programming	O
streams	O
.	O
</s>
<s>
The	O
most	O
of	O
any	O
large	O
broadcaster	O
in	O
the	O
United	O
States	O
,	O
Ion	O
Television	B-Application
stations	O
transmit	O
eight	O
channels	O
(	O
in	O
standard	B-Device
definition	I-Device
)	O
and	O
the	O
Katz	O
Broadcasting	O
subchannel	B-Device
services	O
Court	O
TV	O
,	O
Ion	O
Mystery	O
,	O
Bounce	O
TV	O
,	O
Laff	O
,	O
Grit	O
,	O
Defy	O
TV	O
,	O
and	O
Scripps	O
News	O
.	O
</s>
<s>
Among	O
smaller	O
stations	O
,	O
KAXT-CD	O
in	O
San	O
Francisco	O
is	O
believed	O
to	O
have	O
the	O
most	O
feeds	O
of	O
any	O
individual	O
over-the-air	O
broadcaster	O
,	O
offering	O
twelve	O
video	B-General_Concept
and	O
several	O
audio	O
feeds	O
(	O
all	O
transmitted	O
in	O
standard	B-Device
definition	I-Device
)	O
.	O
</s>
<s>
WANN-CD	O
in	O
Atlanta	O
,	O
Georgia	O
,	O
with	O
ten	O
video	B-General_Concept
and	O
ten	O
audio	O
feeds	O
,	O
comes	O
at	O
a	O
close	O
second	O
.	O
</s>
<s>
Several	O
cable-to-air	O
broadcasters	O
,	O
such	O
as	O
those	O
in	O
Willmar	O
,	O
Minnesota	O
and	O
Cortez	O
,	O
Colorado	O
,	O
have	O
multiplexed	O
more	O
than	O
five	O
separate	O
cable	O
television	B-Application
channels	O
into	O
subchannels	B-Device
of	O
one	O
signal	O
.	O
</s>
<s>
Operating	O
in	O
a	O
sector	O
traditionally	O
lacking	O
subchannels	B-Device
,	O
digital	B-Device
cable	I-Device
television	I-Device
provider	O
Music	O
Choice	O
packages	O
its	O
nearly	O
50	O
music	O
channels	O
(	O
including	O
Music	O
Choice	O
Play	O
)	O
as	O
digital	B-Device
subchannels	I-Device
of	O
one	O
channel	O
.	O
</s>
<s>
The	O
audio	O
feed	O
and	O
rotating	O
stills	O
occupy	O
significantly	O
less	O
bandwidth	O
than	O
video	B-General_Concept
feeds	O
,	O
leaving	O
space	O
for	O
more	O
multiplexed	O
content	O
.	O
</s>
<s>
A	O
broadcaster	O
saves	O
significant	O
costs	O
in	O
power	O
and	O
bandwidth	O
through	O
multiplexing	B-Device
in	O
comparison	O
to	O
the	O
cost	O
of	O
operating	O
additional	O
analog	O
television	B-Application
stations	O
to	O
accommodate	O
the	O
extra	O
programming	O
.	O
</s>
<s>
Most	O
ATSC	B-Device
tuners	I-Device
will	O
automatically	O
add	O
a	O
new	O
digital	B-Device
subchannel	I-Device
to	O
their	O
internal	O
channel	B-Device
map	I-Device
,	O
once	O
it	O
is	O
tuned	O
to	O
the	O
station	O
carrying	O
the	O
new	O
channel	O
.	O
</s>
<s>
Mobile	B-Application
DTV	I-Application
is	O
also	O
carried	O
on	O
ATSC	B-Device
stations	O
,	O
but	O
as	O
a	O
separate	O
service	O
,	O
according	O
to	O
the	O
ATSC-M/H	B-Device
standard	O
.	O
</s>
<s>
The	O
Federal	O
Communications	O
Commission	O
(	O
FCC	O
)	O
considers	O
all	O
subchannels	B-Device
carried	O
by	O
a	O
single	O
station	O
to	O
have	O
the	O
same	O
call	O
letters	O
for	O
legal	O
identification	O
purposes	O
.	O
</s>
<s>
However	O
,	O
within	O
the	O
broadcast	O
sales	O
industry	O
,	O
to	O
differentiate	O
subchannels	B-Device
,	O
the	O
initial	O
letter	O
of	O
a	O
call	O
sign	O
changes	O
per	O
subchannel	B-Device
.	O
</s>
<s>
Although	O
digital	O
television	B-Application
services	O
in	O
Canada	O
use	O
the	O
same	O
ATSC	B-Device
technology	O
as	O
the	O
United	O
States	O
,	O
none	O
of	O
the	O
stations	O
currently	O
broadcasting	O
a	O
digital	O
signal	O
transmit	O
any	O
subchannel	B-Device
other	O
than	O
a	O
possible	O
HD	O
service	O
or	O
a	O
standard	B-Device
definition	I-Device
simulcast	O
of	O
the	O
main	O
channel	O
.	O
</s>
<s>
Unlike	O
the	O
FCC	O
in	O
the	O
United	O
States	O
,	O
the	O
body	O
that	O
governs	O
Canadian	O
broadcasting	O
licenses	O
,	O
the	O
Canadian	O
Radio-television	O
and	O
Telecommunications	O
Commission	O
(	O
CRTC	O
)	O
,	O
requires	O
stations	O
to	O
file	O
license	O
amendments	O
in	O
order	O
to	O
be	O
considered	O
for	O
permission	O
to	O
carry	O
digital	B-Device
subchannels	I-Device
(	O
this	O
differs	O
from	O
the	O
Commission	O
's	O
rules	O
for	O
premium	O
cable	O
television	B-Application
services	O
,	O
which	O
allow	O
the	O
addition	O
of	O
multiplex	B-Device
channels	O
consistent	O
with	O
the	O
service	O
's	O
license	O
requirements	O
without	O
the	O
need	O
to	O
amend	O
the	O
license	O
)	O
.	O
</s>
<s>
On	O
August	O
17	O
,	O
2012	O
,	O
the	O
CRTC	O
gave	O
approval	O
to	O
Leamington	O
,	O
Ontario	O
community	O
station	O
CFTV-TV	O
to	O
broadcast	O
four	O
local	O
subchannels	B-Device
on	O
its	O
digital	O
signal	O
,	O
making	O
it	O
the	O
first	O
station	O
in	O
Canada	O
to	O
launch	O
original	O
content	O
on	O
its	O
multiplex	B-Device
channels	O
.	O
</s>
<s>
Some	O
Mexican	O
TV	O
stations	O
use	O
digital	B-Device
subchannels	I-Device
as	O
they	O
are	O
used	O
in	O
the	O
United	O
States	O
.	O
</s>
<s>
The	O
Sistema	O
Público	O
de	O
Radiodifusión	O
del	O
Estado	O
Mexicano	O
,	O
a	O
public	O
broadcaster	O
,	O
operates	O
26	O
multiplexed	O
transmitters	O
throughout	O
Mexico	O
carrying	O
five	O
to	O
six	O
public	O
television	B-Application
services	O
,	O
while	O
XHTRES-TDT	O
carries	O
Imagen	O
Radio	O
audio	O
on	O
a	O
subchannel	B-Device
.	O
</s>
<s>
One	O
notable	O
experiment	O
involving	O
digital	B-Device
subchannels	I-Device
in	O
Mexico	O
was	O
undertaken	O
by	O
TV	O
Azteca	O
,	O
which	O
used	O
its	O
three	O
muxes	O
in	O
the	O
Mexico	O
City	O
area	O
to	O
broadcast	O
a	O
service	O
called	O
Hi-TV	O
,	O
featuring	O
several	O
channels	O
encoded	O
in	O
H.264	B-Application
MPEG-4	B-Algorithm
encoding	O
,	O
which	O
while	O
available	O
in	O
the	O
ATSC	B-Device
standard	I-Device
is	O
not	O
common	O
on	O
TV	O
sets	O
.	O
</s>
<s>
This	O
use	O
of	O
subchannels	B-Device
as	O
pseudo-restricted	O
signals	O
within	O
non-restricted	O
channels	O
was	O
placed	O
under	O
investigation	O
and	O
litigation	O
with	O
authorities	O
at	O
COFETEL	O
(	O
the	O
Federal	O
Teleommunications	O
Commission	O
)	O
,	O
involving	O
a	O
fine	O
of	O
4,453,150	O
Mexican	O
pesos	O
.	O
</s>
<s>
HiTV	O
subchannels	B-Device
began	O
broadcasting	O
on	O
an	O
intermittent	O
basis	O
in	O
2013	O
and	O
were	O
almost	O
completely	O
deactivated	O
in	O
late	O
2014	O
.	O
</s>
<s>
Televisa	O
and	O
TV	O
Azteca	O
use	O
subchannels	B-Device
in	O
rural	O
areas	O
in	O
order	O
to	O
ensure	O
national	O
network	O
service	O
.	O
</s>
<s>
Additionally	O
,	O
TV	O
Azteca	O
has	O
two	O
national	O
services	O
that	O
are	O
broadcast	O
as	O
subchannels	B-Device
in	O
most	O
areas	O
,	O
a+	O
and	O
adn40	O
.	O
</s>
<s>
In	O
October	O
2016	O
,	O
the	O
IFT	O
put	O
into	O
effect	O
new	O
guidelines	O
for	O
the	O
numbering	O
of	O
virtual	B-Protocol
channels	I-Protocol
.	O
</s>
<s>
Prior	O
to	O
this	O
,	O
digital	O
television	B-Application
stations	O
usually	O
used	O
virtual	B-Protocol
channels	I-Protocol
corresponding	O
to	O
their	O
former	O
analog	O
positions	O
,	O
still	O
the	O
case	O
for	O
certain	O
local	O
stations	O
.	O
</s>
<s>
The	O
IFT	O
enforces	O
minimum	O
bitrates	O
for	O
digital	O
television	B-Application
channels	O
,	O
and	O
as	O
such	O
it	O
is	O
not	O
possible	O
for	O
a	O
station	O
to	O
broadcast	O
two	O
HD	O
feeds	O
in	O
MPEG-2	B-Algorithm
encoding	O
.	O
</s>
<s>
Most	O
HD	O
feeds	O
are	O
provided	O
in	O
1080i	O
with	O
all	O
subchannels	B-Device
in	O
480i	O
standard	B-Device
definition	I-Device
.	O
</s>
<s>
Australian	O
digital	B-Device
subchannels	I-Device
are	O
currently	O
divided	O
between	O
high	B-Device
definition	I-Device
(	O
HD	O
)	O
,	O
standard	B-Device
definition	I-Device
(	O
SD	O
)	O
and	O
radio	O
subchannels	B-Device
(	O
the	O
latter	O
type	O
is	O
only	O
carried	O
by	O
the	O
stations	O
of	O
non-commercial	O
networks	O
SBS	O
Television	B-Application
and	O
ABC	O
Television	B-Application
)	O
.	O
</s>
<s>
All	O
networks	O
use	O
their	O
HD	O
subchannel	B-Device
to	O
provide	O
a	O
simulcast	O
of	O
their	O
primary	O
channel	O
or	O
their	O
multichannels	O
.	O
</s>
<s>
Inclusive	O
of	O
their	O
primary	O
standard	B-Device
definition	I-Device
channels	O
(	O
ignoring	O
HD	O
)	O
:	O
</s>
<s>
SBS	O
Television	B-Application
offers	O
three	O
unique	O
SD	O
subchannels	B-Device
(	O
SBS	O
Food	O
,	O
NITV	O
and	O
SBS	O
WorldWatch	O
)	O
and	O
a	O
HD	O
simulcast	O
of	O
its	O
primary	O
channel	O
(	O
SBS	O
HD	O
)	O
;	O
as	O
well	O
as	O
it	O
’s	O
SBS	O
Viceland	O
and	O
SBS	O
World	O
Movies	O
channels	O
with	O
no	O
SD	O
simulcasts	O
.	O
</s>
<s>
ABC	O
Television	B-Application
offers	O
three	O
unique	O
SD	O
subchannels	B-Device
(	O
ABC	O
TV	O
Plus/ABC	O
Kids	O
,	O
ABC	O
Me	O
,	O
and	O
ABC	O
News	O
)	O
and	O
a	O
HD	O
simulcast	O
of	O
its	O
primary	O
channel	O
(	O
ABC	O
HD	O
)	O
.	O
</s>
<s>
The	O
Seven	O
Network	O
offers	O
three	O
unique	O
SD	O
subchannels	B-Device
(	O
7two	O
,	O
7mate	O
and	O
7flix	O
)	O
,	O
a	O
datacasting	O
channel	O
(	O
Racing.com	O
)	O
and	O
a	O
HD	O
simulcast	O
of	O
its	O
primary	O
channel	O
(	O
7HD	O
)	O
as	O
well	O
as	O
it	O
’s	O
7two	O
and	O
7mate	O
channels	O
.	O
</s>
<s>
The	O
Nine	O
Network	O
offers	O
four	O
unique	O
SD	O
subchannels	B-Device
(	O
9Go	O
!,	O
9Rush	O
,	O
9Gem	O
and	O
9Life	O
)	O
,	O
a	O
datacasting	O
channel	O
(	O
Extra	O
)	O
and	O
a	O
HD	O
simulcast	O
of	O
its	O
primary	O
channel	O
(	O
9HD	O
)	O
as	O
well	O
as	O
a	O
HD	O
simulcast	O
of	O
its	O
9Gem	O
channel	O
.	O
</s>
<s>
Network	O
10	O
offers	O
two	O
unique	O
SD	O
subchannels	B-Device
(	O
10	O
Peach	O
,	O
and	O
10	O
Shake	O
)	O
,	O
two	O
datacasting	O
channels	O
(	O
TVSN	O
and	O
Gecko	O
TV	O
)	O
and	O
a	O
HD	O
simulcast	O
of	O
its	O
primary	O
channel	O
(	O
10	O
HD	O
)	O
as	O
well	O
as	O
their	O
10	O
Bold	O
channel	O
with	O
no	O
SD	O
simulcast	O
.	O
</s>
<s>
Community	O
television	B-Application
stations	O
in	O
Melbourne	O
(	O
C31	O
)	O
and	O
Adelaide	O
(	O
C44	O
)	O
also	O
broadcast	O
digital	O
signals	O
,	O
however	O
they	O
typically	O
only	O
broadcast	O
a	O
single	O
SD	O
subchannel	B-Device
which	O
simulcasts	O
that	O
station	O
's	O
primary	O
channel	O
.	O
</s>
<s>
There	O
have	O
been	O
a	O
number	O
of	O
issues	O
surrounding	O
the	O
introduction	O
of	O
digital	B-Device
subchannels	I-Device
in	O
Australia	O
.	O
</s>
<s>
The	O
first	O
subchannels	B-Device
launched	O
by	O
the	O
ABC	O
–	O
ABC	O
Kids	O
and	O
Fly	O
TV	O
–	O
closed	O
after	O
less	O
than	O
two	O
years	O
in	O
operation	O
in	O
2003	O
as	O
a	O
reaction	O
to	O
budget	O
cuts	O
by	O
the	O
conservative	O
Howard	O
government	O
under	O
Communications	O
Minister	O
Alston	O
and	O
low	O
viewership	O
(	O
partly	O
due	O
to	O
the	O
limited	O
distribution	O
of	O
set-top	O
boxes	O
)	O
;	O
and	O
commercial	O
broadcasters	O
could	O
not	O
legally	O
air	O
a	O
digital	B-Device
subchannel	I-Device
other	O
than	O
a	O
single	O
high-definition	O
service	O
until	O
2009	O
.	O
</s>
<s>
As	O
most	O
digital	O
services	O
in	O
Europe	O
rely	O
on	O
more	O
complex	O
methods	O
of	O
multiplexing	B-Device
,	O
where	O
a	O
large	O
number	O
of	O
digital	O
channels	O
by	O
many	O
different	O
broadcasters	O
can	O
be	O
broadcast	O
on	O
one	O
single	O
frequency	O
,	O
the	O
concept	O
of	O
a	O
subchannel	B-Device
is	O
instead	O
applied	O
to	O
the	O
variety	O
of	O
channels	O
that	O
are	O
produced	O
by	O
a	O
single	O
company	O
.	O
</s>
<s>
This	O
can	O
vary	O
widely	O
depending	O
on	O
the	O
country	O
:	O
for	O
example	O
,	O
ITV	O
currently	O
has	O
four	O
of	O
its	O
digital	O
channels	O
(	O
ITV1	O
,	O
ITV2	O
,	O
ITV3	O
and	O
ITV4	O
)	O
broadcasting	O
on	O
one	O
multiplexed	O
service	O
,	O
while	O
two	O
others	O
(	O
ITV2	O
+1	O
and	O
CITV	O
)	O
are	O
each	O
broadcast	O
on	O
another	O
,	O
separate	O
multiplex	B-Device
.	O
</s>
<s>
In	O
Japan	O
and	O
Brazil	O
,	O
ISDB	B-Protocol
(	O
similar	O
to	O
the	O
DVB	B-Application
format	O
)	O
is	O
used	O
,	O
and	O
was	O
specifically	O
designed	O
with	O
physical	O
RF	O
segments	O
that	O
could	O
be	O
split	O
to	O
use	O
for	O
different	O
subchannels	B-Device
.	O
</s>
<s>
In	O
Brazil	O
,	O
a	O
digital	B-Device
subchannel	I-Device
is	O
only	O
allowed	O
to	O
the	O
public	O
and	O
educational	O
stations	O
.	O
</s>
<s>
As	O
the	O
amount	O
of	O
data	O
which	O
can	O
be	O
carried	O
on	O
one	O
digital	O
television	B-Application
channel	O
at	O
one	O
time	O
is	O
limited	O
,	O
the	O
addition	O
of	O
multiple	O
channels	O
of	O
programming	O
as	O
digital	B-Device
subchannels	I-Device
comes	O
at	O
the	O
expense	O
of	O
having	O
less	O
available	O
bandwidth	O
for	O
other	O
purposes	O
,	O
such	O
as	O
the	O
ability	O
to	O
transmit	O
high	B-Device
definition	I-Device
content	O
.	O
</s>
<s>
A	O
station	O
carrying	O
multiple	O
subchannels	B-Device
will	O
normally	O
limit	O
itself	O
to	O
one	O
high-definition	O
channel	O
(	O
or	O
in	O
some	O
cases	O
,	O
two	O
HD	O
channels	O
)	O
,	O
with	O
any	O
additional	O
channels	O
being	O
carried	O
in	O
standard	B-Device
definition	I-Device
.	O
</s>
<s>
Because	O
of	O
the	O
tradeoffs	O
,	O
stations	O
owned	O
by	O
CBS	O
Corporation	O
through	O
its	O
CBS	O
Television	B-Application
Stations	O
subsidiary	O
(	O
which	O
include	O
owned-and-operated	O
stations	O
of	O
CBS	O
and	O
The	O
CW	O
,	O
and	O
some	O
independent	O
stations	O
)	O
generally	O
opted	O
not	O
to	O
carry	O
digital	B-Device
subchannels	I-Device
and	O
transmitted	O
only	O
a	O
1080i	O
high	B-Device
definition	I-Device
main	O
feed	O
;	O
this	O
changed	O
in	O
2013	O
with	O
the	O
addition	O
of	O
dedicated	O
local	O
news	O
channels	O
on	O
CBS	O
O&Os	O
in	O
New	O
York	O
City	O
and	O
Philadelphia	O
(	O
the	O
company	O
later	O
announced	O
the	O
creation	O
of	O
Decades	O
,	O
a	O
multicast	O
network	O
part-owned	O
by	O
CBS	O
which	O
aired	O
on	O
all	O
CBS	O
and	O
CW	O
owned-and-operated	O
stations	O
from	O
2015	O
to	O
2018	O
)	O
.	O
</s>
<s>
It	O
is	O
possible	O
for	O
stations	O
to	O
carry	O
more	O
than	O
two	O
subchannel	B-Device
feeds	O
in	O
HD	O
,	O
at	O
least	O
nominally	O
.	O
</s>
<s>
Actual	O
picture	O
quality	O
may	O
be	O
comparable	O
to	O
DVD	O
video	B-General_Concept
.	O
</s>
<s>
Callsign	O
Market/city	O
of	O
license	O
Description	O
KBMT	O
Beaumont	O
,	O
Texas	O
In	O
addition	O
to	O
broadcasting	O
ABC	O
programming	O
on	O
its	O
main	O
channel	O
in	O
720p	O
,	O
KBMT	O
transmits	O
NBC	O
programming	O
on	O
its	O
second	O
subchannel	B-Device
and	O
Cozi	O
TV	O
on	O
its	O
third	O
subchannel	B-Device
(	O
all	O
three	O
channels	O
are	O
broadcast	O
in	O
16:9	O
widescreen	O
,	O
although	O
the	O
DT3	O
subchannel	B-Device
is	O
presented	O
in	O
480i	O
)	O
;	O
the	O
station	O
also	O
offers	O
Me-TV	O
programming	O
in	O
480i	O
4:3	O
SD	O
on	O
its	O
fourth	O
subchannel	B-Device
.	O
</s>
<s>
KXII	O
Sherman	O
,	O
Texas	O
KXII	O
carries	O
Fox	O
programming	O
in	O
HD	O
on	O
its	O
third	O
subchannel	B-Device
and	O
MyNetworkTV	O
programming	O
in	O
SD	O
on	O
its	O
second	O
subchannel	B-Device
,	O
in	O
addition	O
to	O
carrying	O
CBS	O
programming	O
in	O
HD	O
on	O
its	O
main	O
channel	O
.	O
</s>
<s>
KTEN	O
Ada	O
,	O
Oklahoma	O
In	O
addition	O
to	O
carrying	O
NBC	O
programming	O
in	O
HD	O
on	O
its	O
main	O
channel	O
in	O
1080i	O
,	O
KTEN	O
carries	O
CW	O
programming	O
in	O
720p	O
HD	O
on	O
its	O
second	O
subchannel	B-Device
and	O
ABC	O
programming	O
in	O
720p	O
HD	O
on	O
its	O
third	O
subchannel	B-Device
.	O
</s>
<s>
WGXA	O
Macon	O
,	O
Georgia	O
WGXA	O
began	O
carrying	O
ABC	O
programming	O
on	O
its	O
second	O
digital	B-Device
subchannel	I-Device
on	O
January	O
1	O
,	O
2010	O
,	O
after	O
WPGA-TV	O
disaffiliated	O
from	O
the	O
network	O
in	O
a	O
compensation	O
and	O
program	O
content	O
dispute	O
;	O
WGXA	O
transmits	O
its	O
Fox-affiliated	O
main	O
channel	O
and	O
its	O
ABC	O
subchannel	B-Device
in	O
720p	O
(	O
the	O
native	O
HD	O
resolution	O
format	O
for	O
both	O
networks	O
)	O
.	O
</s>
<s>
The	O
station	O
's	O
main	O
channel	O
is	O
branded	O
as	O
"	O
Fox	O
24	O
"	O
and	O
maps	O
via	O
PSIP	O
as	O
24.1	O
,	O
while	O
the	O
ABC	O
subchannel	B-Device
brands	O
as	O
"	O
ABC	O
16	O
,	O
"	O
in	O
reference	O
to	O
the	O
station	O
's	O
physical	O
digital	O
channel	O
16	O
(	O
but	O
maps	O
its	O
PSIP	O
virtual	B-Protocol
channel	I-Protocol
as	O
24.2	O
)	O
.	O
</s>
<s>
A	O
standard	B-Device
definition	I-Device
feed	O
of	O
Comet	O
was	O
launched	O
on	O
its	O
third	O
subchannel	B-Device
in	O
October	O
2015	O
.	O
</s>
<s>
WKBN-TV	O
Youngstown	O
,	O
Ohio	O
WKBN	O
carries	O
a	O
simulcast	O
of	O
Fox-affiliated	O
sister	O
station	O
WYFX-LD	O
on	O
its	O
second	O
digital	B-Device
subchannel	I-Device
in	O
order	O
to	O
make	O
its	O
programming	O
available	O
to	O
the	O
entire	O
market	O
(	O
WYFX	O
is	O
licensed	O
as	O
a	O
low-power	O
station	O
)	O
,	O
in	O
addition	O
to	O
transmitting	O
CBS	O
programming	O
on	O
its	O
main	O
channel	O
.	O
</s>
<s>
Until	O
a	O
later	O
multiplexer	B-Protocol
upgrade	O
,	O
both	O
subchannels	B-Device
transmitted	O
in	O
720p	O
HD	O
(	O
the	O
main	O
signal	O
now	O
transmits	O
CBS	O
's	O
preferred	O
1080i	O
HD	O
format	O
)	O
.	O
</s>
<s>
Comparatively	O
,	O
its	O
sister	O
station	O
,	O
ABC	O
affiliate	O
WYTV	O
transmitted	O
both	O
its	O
MyNetworkTV-affiliated	O
second	O
subchannel	B-Device
and	O
its	O
Bounce	O
TV-affiliated	O
third	O
subchannel	B-Device
in	O
standard	B-Device
definition	I-Device
(	O
since	O
ABC	O
and	O
MyNetworkTV	O
both	O
transmit	O
in	O
720p	O
,	O
the	O
33.2	O
subchannel	B-Device
could	O
be	O
reconfigured	O
to	O
high	B-Device
definition	I-Device
in	O
a	O
manner	O
that	O
creates	O
limited	O
issues	O
in	O
regards	O
to	O
bandwidth	O
for	O
the	O
33.3	O
subchannel	B-Device
)	O
.	O
</s>
<s>
In	O
2017	O
,	O
WKBN	O
sold	O
its	O
spectrum	O
for	O
$34	O
million	O
as	O
part	O
of	O
the	O
FCC	O
's	O
spectrum	B-Algorithm
reallocation	I-Algorithm
program	O
and	O
merged	O
their	O
programming	O
onto	O
WYTV	O
's	O
,	O
requiring	O
the	O
removal	O
of	O
the	O
33.3	O
signal	O
in	O
order	O
to	O
manage	O
the	O
high	B-Device
definition	I-Device
needs	O
of	O
three	O
720p	O
channels	O
and	O
one	O
in	O
1080i	O
(	O
two	O
former	O
WKBN	O
and	O
WYTV	O
subchannels	B-Device
moved	O
onto	O
WYFX-LD	O
'	O
s	O
spectrum	O
)	O
.	O
</s>
<s>
WTHI-TV	O
Terre	O
Haute	O
,	O
Indiana	O
In	O
addition	O
to	O
airing	O
its	O
main	O
CBS	O
program	O
feed	O
in	O
1080i	O
,	O
WTHI	O
transmits	O
Fox	O
programming	O
in	O
720p	O
HD	O
on	O
its	O
second	O
subchannel	B-Device
and	O
CW+	O
programming	O
in	O
720p	O
HD	O
on	O
its	O
third	O
subchannel	B-Device
,	O
in	O
addition	O
to	O
a	O
standard	B-Device
definition	I-Device
480i	O
widescreen	O
Ion	O
Television	B-Application
feed	O
on	O
its	O
fourth	O
subchannel	B-Device
.	O
</s>
<s>
WTRF-TV	O
Wheeling	O
,	O
West	O
Virginia	O
In	O
addition	O
to	O
carrying	O
CBS	O
programming	O
in	O
1080i	O
on	O
its	O
main	O
channel	O
,	O
WTRF-TV	O
carries	O
ABC	O
programming	O
in	O
720p	O
on	O
its	O
third	O
subchannel	B-Device
.	O
</s>
<s>
Until	O
the	O
network	O
moved	O
to	O
a	O
subchannel	B-Device
of	O
NBC	O
affiliate	O
WTOV-TV	O
in	O
September	O
2014	O
,	O
WTRF	O
carried	O
Fox	O
programming	O
in	O
720p	O
on	O
its	O
second	O
subchannel	B-Device
,	O
which	O
remains	O
affiliated	O
with	O
MyNetworkTV	O
.	O
</s>
<s>
WUVG-DT	O
Atlanta	O
,	O
Georgia	O
WUVG	O
,	O
which	O
operates	O
as	O
a	O
Univision	O
owned-and-operated	O
station	O
,	O
carries	O
UniMás	O
in	O
720p	O
HD	O
on	O
its	O
second	O
subchannel	B-Device
due	O
to	O
a	O
lack	O
of	O
a	O
sister	O
full-power	O
station	O
,	O
and	O
both	O
GetTV	O
and	O
Escape	O
in	O
480i	O
on	O
their	O
respective	O
third	O
and	O
fourth	O
subchannels	B-Device
in	O
addition	O
to	O
carrying	O
Univision	O
programming	O
on	O
its	O
main	O
channel	O
in	O
720p	O
HD	O
.	O
</s>
<s>
WATM-TV	O
Johnstown	O
,	O
Pennsylvania	O
In	O
addition	O
to	O
carrying	O
ABC	O
programming	O
in	O
720p	O
on	O
its	O
first	O
subchannel	B-Device
,	O
WATM-TV	O
transmits	O
Fox	O
programming	O
of	O
its	O
sister	O
station	O
,	O
WWCP-TV	O
,	O
in	O
720p	O
on	O
its	O
second	O
subchannel	B-Device
.	O
</s>
<s>
WATM-TV	O
further	O
transmits	O
This	O
TV	O
and	O
Antenna	O
TV	O
programming	O
in	O
480i	O
on	O
its	O
third	O
and	O
fourth	O
subchannels	B-Device
,	O
respectively	O
.	O
</s>
<s>
WKTV	O
Utica	O
,	O
New	O
York	O
WKTV	O
previously	O
carried	O
NBC	O
programming	O
in	O
1080i	O
on	O
its	O
first	O
subchannel	B-Device
,	O
CBS	O
programming	O
on	O
its	O
second	O
subchannel	B-Device
,	O
and	O
The	O
CW	O
on	O
its	O
third	O
subchannel	B-Device
,	O
both	O
in	O
720p	O
HD	O
(	O
in	O
the	O
case	O
of	O
WKTV-DT2	O
,	O
this	O
differs	O
from	O
CBS	O
's	O
preferred	O
1080i	O
HD	O
format	O
)	O
.	O
</s>
<s>
The	O
station	O
also	O
offers	O
MeTV	O
programming	O
in	O
480i	O
SD	O
on	O
its	O
fourth	O
subchannel	B-Device
.	O
</s>
<s>
WTVG	O
Toledo	O
,	O
Ohio	O
In	O
addition	O
to	O
carrying	O
ABC	O
programming	O
in	O
720p	O
on	O
its	O
first	O
subchannel	B-Device
,	O
WTVG-TV	O
transmits	O
The	O
CW	O
programming	O
in	O
720p	O
on	O
its	O
second	O
subchannel	B-Device
.	O
</s>
<s>
This	O
allows	O
Toledo	O
,	O
Findlay	O
,	O
and	O
surrounding	O
areas	O
to	O
receive	O
CW	O
programming	O
over-the-air	O
;	O
in	O
the	O
past	O
CW	O
and	O
WB	O
programming	O
was	O
exclusive	O
to	O
local	O
cable	O
viewers	O
through	O
Buckeye	O
CableSystem	O
via	O
their	O
cable-only	O
Toledo	O
5	O
channel	O
,	O
requiring	O
antenna	O
viewers	O
to	O
pull	O
in	O
WKBD-TV/Detroit	O
from	O
the	O
north	O
for	O
CW	O
programming	O
.	O
</s>
<s>
WTVG-TV	O
further	O
transmits	O
WeatherNation	O
TV	O
in	O
480i	O
on	O
its	O
third	O
subchannel	B-Device
.	O
</s>
<s>
WGEM-TV	O
Quincy	O
,	O
Illinois	O
The	O
station	O
broadcasts	O
four	O
subchannels	B-Device
in	O
total	O
,	O
all	O
in	O
HD	O
:	O
the	O
main	O
subchannel	B-Device
in	O
1080i	O
,	O
and	O
three	O
additional	O
subchannels	B-Device
–	O
respectively	O
affiliated	O
with	O
Fox	O
,	O
The	O
CW	O
and	O
MeTV	O
–	O
in	O
720p	O
.	O
</s>
<s>
For	O
example	O
,	O
in	O
France	O
,	O
there	O
are	O
only	O
five	O
HD	O
services	O
:	O
one	O
each	O
for	O
TF1	O
,	O
France	O
2	O
,	O
Canal+	O
,	O
M6	O
and	O
Arte	O
;	O
in	O
the	O
United	B-Device
Kingdom	I-Device
,	O
four	O
HD	O
services	O
are	O
currently	O
transmitted	O
over	O
terrestrial	O
frequencies	O
:	O
BBC	O
One	O
HD	O
,	O
BBC	O
Two	O
HD	O
,	O
ITV	O
HD	O
and	O
Channel	O
4	O
HD	O
(	O
S4C	O
Clirlun	O
is	O
broadcast	O
in	O
Wales	O
instead	O
of	O
Channel	O
4	O
HD	O
)	O
.	O
</s>
<s>
In	O
the	O
United	O
States	O
,	O
digital	B-Device
subchannels	I-Device
have	O
been	O
used	O
to	O
provide	O
programming	O
from	O
multiple	O
major	O
networks	O
on	O
a	O
single	O
television	B-Application
station	O
.	O
</s>
<s>
This	O
has	O
become	O
prevalent	O
since	O
the	O
late	O
2000s	O
in	O
smaller	O
markets	O
that	O
have	O
as	O
few	O
as	O
one	O
or	O
two	O
commercial	O
stations	O
,	O
which	O
during	O
the	O
era	O
of	O
analog	O
television	B-Application
,	O
would	O
not	O
have	O
been	O
able	O
to	O
carry	O
the	O
complete	O
programming	O
lineups	O
of	O
all	O
four	O
major	O
commercial	O
networks	O
(	O
CBS	O
,	O
NBC	O
,	O
ABC	O
and	O
Fox	O
)	O
because	O
of	O
the	O
station	O
's	O
own	O
local	O
and	O
syndicated	O
programming	O
commitments	O
,	O
and	O
overlapping	O
network	O
programs	O
that	O
would	O
be	O
tough	O
to	O
schedule	O
outside	O
of	O
regular	O
timeslots	O
.	O
</s>
<s>
However	O
,	O
the	O
advent	O
of	O
digital	O
television	B-Application
allowed	O
WTRF	O
to	O
launch	O
two	O
digital	O
channels	O
(	O
one	O
as	O
a	O
primary	O
Fox/secondary	O
MyNetworkTV	O
affiliate	O
,	O
the	O
other	O
affiliated	O
with	O
ABC	O
)	O
while	O
still	O
carrying	O
CBS	O
programming	O
in	O
full	O
on	O
its	O
main	O
signal	O
(	O
WTOV	O
later	O
took	O
the	O
Fox	O
affiliation	O
for	O
its	O
second	O
subchannel	B-Device
in	O
September	O
2014	O
)	O
.	O
</s>
<s>
Upon	O
their	O
launches	O
in	O
September	O
2006	O
,	O
The	O
CW	O
and	O
MyNetworkTV	O
were	O
among	O
the	O
first	O
conventional	O
networks	O
to	O
actively	O
utilize	O
subchannel-only	O
affiliations	O
in	O
markets	O
where	O
a	O
standalone	O
station	O
is	O
not	O
available	O
to	O
affiliate	O
with	O
;	O
this	O
is	O
particularly	O
true	O
of	O
The	O
CW	O
's	O
small-market	O
feed	O
,	O
The	O
CW	O
Plus	O
,	O
which	O
originally	O
consisted	O
mostly	O
of	O
cable-only	O
affiliations	O
(	O
by	O
way	O
of	O
inheriting	O
the	O
model	O
and	O
much	O
of	O
the	O
affiliate	O
body	O
of	O
predecessor	O
The	O
WB	O
100+	O
Station	O
Group	O
)	O
.	O
</s>
<s>
Since	O
its	O
launch	O
,	O
affiliates	O
of	O
other	O
major	O
networks	O
have	O
taken	O
over	O
the	O
operations	O
of	O
cable-only	O
CW	O
Plus	O
affiliates	O
(	O
or	O
even	O
outright	O
replacing	O
WB	O
100+	O
cable	O
channels	O
at	O
the	O
launch	O
of	O
The	O
CW	O
)	O
and	O
began	O
transmitting	O
the	O
service	O
over	O
subchannels	B-Device
to	O
reach	O
viewers	O
who	O
do	O
not	O
subscribe	O
to	O
a	O
pay	O
television	B-Application
service	O
.	O
</s>
<s>
Some	O
Spanish	O
language	O
networks	O
(	O
such	O
as	O
Estrella	O
TV	O
and	O
Telemundo	O
)	O
have	O
also	O
been	O
carried	O
on	O
digital	B-Device
subchannels	I-Device
,	O
either	O
as	O
subchannel-exclusive	O
services	O
or	O
to	O
provide	O
programming	O
to	O
markets	O
where	O
a	O
main	O
channel	O
affiliation	O
may	O
not	O
be	O
available	O
.	O
</s>
<s>
Other	O
stations	O
have	O
launched	O
subchannels	B-Device
with	O
an	O
independent	O
station	O
format	O
on	O
their	O
DT2	O
signals	O
(	O
such	O
as	O
WTTV	O
in	O
Indianapolis	O
,	O
Indiana	O
–	O
a	O
market	O
with	O
enough	O
commercial	O
stations	O
able	O
to	O
support	O
affiliations	O
with	O
all	O
six	O
networks	O
and	O
a	O
standalone	O
independent	O
,	O
although	O
the	O
seventh	O
(	O
WTTK	O
)	O
instead	O
acts	O
as	O
a	O
WTTV	O
satellite	O
–	O
which	O
converted	O
its	O
4.2	O
subchannel	B-Device
as	O
an	O
independent	O
station	O
in	O
January	O
2015	O
as	O
a	O
result	O
of	O
owner	O
Tribune	O
Media	O
selling	O
the	O
local	O
rights	O
to	O
the	O
CW	O
affiliation	O
that	O
was	O
to	O
move	O
from	O
its	O
main	O
feed	O
on	O
4.1	O
to	O
Media	O
General-owned	O
WISH-TV	O
,	O
whose	O
CBS	O
affiliation	O
was	O
assumed	O
by	O
WTTV	O
)	O
.	O
</s>
<s>
Digital	B-Device
subchannels	I-Device
are	O
also	O
used	O
to	O
relay	O
stations	O
beyond	O
their	O
traditional	O
signal	O
coverage	O
areas	O
to	O
reach	O
an	O
entire	O
market	O
.	O
</s>
<s>
In	O
the	O
Upper	O
Peninsula	O
of	O
Michigan	B-Device
and	O
northern	O
Minnesota	O
,	O
many	O
of	O
these	O
stations	O
are	O
on	O
duplicate	O
frequencies	O
to	O
cover	O
a	O
large	O
market	O
area	O
.	O
</s>
<s>
The	O
most	O
prominent	O
example	O
is	O
the	O
Granite	O
Broadcasting	O
Corporation	O
's	O
virtual	O
quadropoly	O
in	O
Duluth	O
,	O
Minnesota	O
,	O
which	O
consists	O
of	O
two	O
separate	O
full-power	O
stations	O
,	O
NBC	O
affiliate	O
KBJR-TV	O
and	O
CBS	O
affiliate	O
KDLH	O
,	O
which	O
combined	O
carry	O
three	O
subchannels	B-Device
(	O
two	O
affiliated	O
with	O
major	O
networks	O
–	O
CW	O
Plus	O
affiliate	O
"	O
Northland	O
CW	O
2	O
"	O
on	O
KDLH	O
and	O
MyNetworkTV	O
affiliate	O
"	O
My9	O
"	O
on	O
KBJR	O
–	O
and	O
the	O
third	O
,	O
a	O
local	O
weather	O
subchannel	B-Device
on	O
KBJR	O
)	O
.	O
</s>
<s>
While	O
KDLH	O
carries	O
the	O
CW	O
subchannel	B-Device
on	O
their	O
DT2	O
feed	O
and	O
KBJR	O
carries	O
the	O
MyNetworkTV	O
subchannel	B-Device
on	O
its	O
DT2	O
feed	O
on	O
their	O
primary	O
signals	O
,	O
all	O
five	O
channels	O
are	O
carried	O
on	O
satellite	O
station	O
KRII	O
in	O
Chisholm	O
,	O
providing	O
the	O
Iron	O
Range	O
region	O
(	O
located	O
north	O
of	O
Duluth	O
)	O
programming	O
from	O
networks	O
that	O
were	O
previously	O
unavailable	O
over-the-air	O
.	O
</s>
<s>
In	O
the	O
Traverse	O
City-Cheboygan	O
market	O
in	O
Upper	O
Michigan	B-Device
,	O
NBC	O
affiliate	O
WPBN/WTOM	O
also	O
simulcasts	O
sister	O
station	O
WGTU/WGTQ	O
,	O
providing	O
that	O
station	O
's	O
ABC	O
programming	O
to	O
the	O
entire	O
market	O
;	O
CBS	O
affiliate	O
WWTV/WWUP	O
carries	O
its	O
Fox-affiliated	O
sister	O
WFQX/WFUP	O
on	O
their	O
DT2	O
subchannel	B-Device
to	O
expand	O
their	O
coverage	O
area	O
further	O
north	O
into	O
the	O
eastern	O
portion	O
of	O
the	O
Upper	O
Peninsula	O
.	O
</s>
<s>
In	O
many	O
cases	O
,	O
these	O
"	O
new	O
"	O
channels	O
are	O
existing	O
secondary	O
channels	O
that	O
were	O
carried	O
by	O
a	O
low-power	O
or	O
Class	O
A	O
station	O
or	O
by	O
a	O
cable	O
television	B-Application
channel	O
.	O
</s>
<s>
Often	O
,	O
the	O
owner	O
of	O
a	O
full-power	O
television	B-Application
station	O
acquires	O
or	O
already	O
owns	O
a	O
low-power	O
secondary	O
station	O
in	O
the	O
same	O
market	O
to	O
carry	O
another	O
network	O
.	O
</s>
<s>
The	O
use	O
of	O
a	O
digital	B-Device
subchannel	I-Device
on	O
a	O
full-power	O
television	B-Application
station	O
as	O
a	O
replacement	O
for	O
low-power	O
station	O
greatly	O
increases	O
the	O
available	O
coverage	O
area	O
for	O
its	O
programming	O
.	O
</s>
<s>
Because	O
of	O
interference	O
issues	O
that	O
stations	O
transmitting	O
on	O
the	O
low	O
VHF	B-Algorithm
band	I-Algorithm
(	O
channels	O
2	O
to	O
6	O
)	O
often	O
experience	O
,	O
some	O
stations	O
broadcasting	O
on	O
these	O
frequencies	O
are	O
relayed	O
on	O
the	O
subchannels	B-Device
of	O
stations	O
that	O
are	O
less	O
prone	O
to	O
interference	O
.	O
</s>
<s>
While	O
WRGB	O
broadcasts	O
its	O
main	O
digital	O
on	O
VHF	B-Algorithm
channel	O
6	O
in	O
high	B-Device
definition	I-Device
,	O
CW-affiliated	O
sister	O
station	O
WCWN	O
relays	O
a	O
standard-definition	B-Device
subchannel	B-Device
feed	O
of	O
WRGB	O
over	O
its	O
digital	O
channel	O
45	O
.	O
</s>
<s>
Some	O
of	O
this	O
was	O
due	O
to	O
the	O
2016	B-Algorithm
United	I-Algorithm
States	I-Algorithm
wireless	I-Algorithm
spectrum	I-Algorithm
auction	I-Algorithm
,	O
but	O
most	O
have	O
been	O
due	O
to	O
companies	O
who	O
use	O
sidecar	O
companies	O
to	O
create	O
virtual	O
duopolies	O
via	O
local	O
marketing	O
agreements	O
when	O
they	O
are	O
not	O
legally	O
able	O
to	O
own	O
a	O
duopoly	O
outright	O
.	O
</s>
<s>
In	O
the	O
latter	O
scenario	O
,	O
the	O
station	O
whose	O
programming	O
is	O
on	O
an	O
LMA	O
station	O
is	O
moved	O
to	O
a	O
subchannel	B-Device
of	O
a	O
station	O
that	O
is	O
owned	O
outright	O
by	O
the	O
station	O
that	O
own	O
the	O
non-licensed	O
assets	O
of	O
other	O
stations	O
.	O
</s>
<s>
Many	O
companies	O
such	O
as	O
Sinclair	O
Broadcast	O
Group	O
(	O
via	O
Cunningham	O
Broadcasting	O
,	O
Deerfield	O
Media	O
,	O
&	O
Howard	O
Stirk	O
Holdings	O
)	O
,	O
Nexstar	O
Media	O
Group	O
(	O
via	O
Mission	O
Broadcasting	O
&	O
Vaughan	O
Media	O
)	O
,	O
and	O
Gray	O
Television	B-Application
(	O
via	O
American	O
Spirit	O
Media	O
&	O
SagamoreHill	O
Broadcasting	O
)	O
have	O
been	O
doing	O
this	O
,	O
partially	O
due	O
to	O
regulation	O
pressure	O
.	O
</s>
<s>
Networks	O
dedicated	O
to	O
sports	O
programming	O
have	O
been	O
launched	O
specifically	O
for	O
use	O
on	O
digital	B-Device
subchannels	I-Device
.	O
</s>
<s>
Until	O
2010	O
,	O
CBS	O
affiliates	O
often	O
subdivided	O
four	O
temporary	O
subchannels	B-Device
in	O
order	O
to	O
show	O
all	O
of	O
the	O
early	O
round	O
games	O
of	O
the	O
NCAA	O
men	O
's	O
basketball	O
tournament	O
in	O
addition	O
to	O
those	O
broadcast	O
on	O
the	O
main	O
digital	O
channel	O
(	O
this	O
was	O
superseded	O
as	O
a	O
result	O
of	O
a	O
new	O
television	B-Application
agreement	O
with	O
the	O
NCAA	O
that	O
took	O
effect	O
in	O
2011	O
,	O
which	O
gave	O
cable	O
networks	O
TBS	O
,	O
TNT	O
and	O
TruTV	O
partial	O
rights	O
to	O
the	O
tournament	O
)	O
.	O
</s>
<s>
Most	O
of	O
the	O
major	O
professional	O
sports	O
leagues	O
,	O
however	O
,	O
have	O
strict	O
prohibitions	O
against	O
using	O
subchannels	B-Device
for	O
carrying	O
multiple	O
game	O
broadcasts	O
and	O
only	O
allow	O
one	O
game	O
to	O
be	O
aired	O
in	O
a	O
market	O
at	O
one	O
time	O
(	O
outside	O
of	O
Los	O
Angeles	O
,	O
where	O
if	O
the	O
Rams	O
and	O
Chargers	O
play	O
at	O
the	O
same	O
time	O
,	O
Fox	O
is	O
allowed	O
to	O
broadcast	O
the	O
second	O
game	O
on	O
MyNetworkTV	O
affiliate	O
KCOP-TV	O
,	O
or	O
CBS	O
on	O
independent	O
KCAL-TV	O
,	O
depending	O
on	O
the	O
game	O
's	O
carrier	O
that	O
specific	O
week	O
)	O
;	O
all	O
four	O
of	O
the	O
major	O
sports	O
leagues	O
(	O
the	O
NFL	O
,	O
the	O
NBA	O
,	O
Major	B-Application
League	I-Application
Baseball	I-Application
and	O
the	O
NHL	O
)	O
have	O
out-of-market	O
sports	O
packages	O
that	O
require	O
a	O
pay	O
television	B-Application
subscription	O
and	O
generate	O
significant	O
revenue	O
for	O
the	O
leagues	O
.	O
</s>
<s>
Most	O
sports	O
programming	O
on	O
digital	B-Device
subchannel	I-Device
broadcasters	O
has	O
been	O
relegated	O
to	O
low-budget	O
content	O
such	O
as	O
amateur	O
athletics	O
,	O
extreme	O
sports	O
,	O
and	O
hunting	O
and	O
fishing	O
programming	O
geared	O
toward	O
outdoorsmen	O
,	O
though	O
minor	O
league	O
baseball	O
,	O
American	O
Hockey	O
League	O
hockey	O
and	O
other	O
minor	O
league	O
sports	O
may	O
also	O
be	O
seen	O
.	O
</s>
<s>
Prominent	O
team	O
sports	O
programming	O
on	O
digital	B-Device
subchannels	I-Device
is	O
rare	O
;	O
the	O
general	O
trend	O
for	O
sports	O
programming	O
tends	O
to	O
eschew	O
the	O
free-to-air	O
model	O
that	O
digital	B-Device
subchannels	I-Device
use	O
,	O
and	O
the	O
cost	O
of	O
rights	O
fees	O
for	O
most	O
sports	O
requires	O
that	O
they	O
air	O
on	O
channels	O
that	O
air	O
on	O
cable	O
and	O
satellite	O
television	B-Application
services	O
and	O
thus	O
can	O
recuperate	O
costs	O
through	O
retransmission	O
consent	O
.	O
</s>
<s>
Channels	O
such	O
as	O
Sportsman	O
Channel	O
(	O
and	O
the	O
now-defunct	O
Universal	O
Sports	O
)	O
that	O
began	O
as	O
digital	B-Device
subchannel	I-Device
networks	O
now	O
operate	O
as	O
cable	O
and	O
satellite-exclusive	O
services	O
.	O
</s>
<s>
There	O
are	O
nonetheless	O
a	O
few	O
multicast	B-Device
channels	I-Device
that	O
have	O
broadcast	O
familiar	O
sports	O
programs	O
:	O
Bounce	O
TV	O
,	O
for	O
instance	O
,	O
carried	O
college	O
football	O
from	O
historically	O
black	O
colleges	O
and	O
universities	O
until	O
2013	O
.	O
</s>
<s>
In	O
January	O
2016	O
,	O
Sinclair	O
Broadcast	O
Group	O
launched	O
a	O
24-hour	O
feed	O
of	O
its	O
American	O
Sports	O
Network	O
sports	O
syndication	O
service	O
on	O
subchannels	B-Device
of	O
ten	O
stations	O
owned	O
and/or	O
operated	O
by	O
the	O
group	O
;	O
the	O
ASN	O
multicast	O
network	O
was	O
subsequently	O
replaced	O
by	O
Stadium	O
in	O
August	O
2017	O
,	O
following	O
the	O
formation	O
of	O
a	O
multi-platform	O
network	O
venture	O
with	O
the	O
Chicago	O
White	O
Sox	O
's	O
Silver	O
Chalice	O
unit	O
and	O
120	O
Sports	O
.	O
</s>
<s>
Although	O
not	O
to	O
the	O
same	O
level	O
as	O
in	O
the	O
late	O
2000s	O
due	O
to	O
the	O
population	O
of	O
entertainment-based	O
multicast	O
services	O
,	O
many	O
local	O
stations	O
have	O
used	O
or	O
currently	O
use	O
subchannels	B-Device
to	O
carry	O
continuous	O
news	O
or	O
local	O
weather	O
content	O
;	O
in	O
particular	O
,	O
there	O
have	O
been	O
at	O
least	O
four	O
networks	O
that	O
have	O
been	O
created	O
to	O
serve	O
this	O
audience	O
:	O
NBC	O
Weather	O
Plus	O
(	O
a	O
service	O
exclusive	O
to	O
NBC	O
stations	O
that	O
operated	O
from	O
2004	O
to	O
2008	O
)	O
,	O
The	O
AccuWeather	O
Channel	O
,	O
WeatherNation	O
TV	O
(	O
which	O
also	O
maintains	O
limited	O
exclusive	O
distribution	O
on	O
pay	O
television	B-Application
services	O
)	O
and	O
TouchVision	O
.	O
</s>
<s>
Locally	O
programmed	O
news	O
subchannels	B-Device
(	O
such	O
as	O
News	O
9	O
Now	O
/	O
News	O
on	O
6	O
Now	O
on	O
KWTV	O
in	O
Oklahoma	O
City	O
and	O
KOTV	O
in	O
Tulsa	O
,	O
Oklahoma	O
or	O
NewsChannel	O
5+	O
on	O
WTVF	O
in	O
Nashville	O
,	O
Tennessee	O
)	O
often	O
carry	O
rebroadcasts	O
and	O
simulcasts	O
of	O
local	O
news	O
programs	O
seen	O
on	O
the	O
station	O
's	O
main	O
feed	O
,	O
in	O
some	O
cases	O
displaying	O
a	O
ticker	O
with	O
news	O
headlines	O
and	O
weather	O
forecasts	O
to	O
provide	O
updated	O
information	O
.	O
</s>
<s>
Subchannels	B-Device
also	O
allow	O
stations	O
to	O
air	O
news	O
programs	O
without	O
fully	O
pre-empting	O
normally	O
scheduled	O
programing	O
on	O
the	O
station	O
's	O
main	O
feed	O
.	O
</s>
<s>
During	O
significant	O
breaking	O
news	O
or	O
severe	O
weather	O
events	O
,	O
for	O
instance	O
,	O
a	O
station	O
may	O
choose	O
to	O
air	O
extended	O
news	O
coverage	O
on	O
either	O
its	O
main	O
channel	O
or	O
a	O
subchannel	B-Device
and	O
air	O
network	O
programming	O
on	O
the	O
other	O
.	O
</s>
<s>
Some	O
sports	O
leagues	O
,	O
most	O
notably	O
the	O
NFL	O
,	O
have	O
strict	O
rules	O
against	O
their	O
game	O
broadcasts	O
airing	O
on	O
a	O
subchannel	B-Device
.	O
</s>
<s>
The	O
first	O
major	O
nationally	O
distributed	O
general	O
entertainment	O
digital	O
multicast	O
television	B-Application
network	O
,	O
or	O
diginet	O
,	O
for	O
use	O
on	O
subchannels	B-Device
was	O
Retro	O
Television	B-Application
Network	O
in	O
2005	O
.	O
</s>
<s>
Diginets	O
generally	O
are	O
reliant	O
on	O
national	O
advertising	O
revenue	O
and	O
,	O
in	O
some	O
cases	O
,	O
pay	O
stations	O
to	O
be	O
carried	O
on	O
their	O
subchannels	B-Device
,	O
prizing	O
lower	O
channel	O
numbers	O
.	O
</s>
<s>
Many	O
PBS	O
member	O
stations	O
around	O
the	O
United	O
States	O
broadcast	O
their	O
main	O
channel	O
in	O
high	B-Device
definition	I-Device
and	O
up	O
to	O
three	O
standard	B-Device
definition	I-Device
subchannels	B-Device
;	O
however	O
,	O
a	O
few	O
reconfigure	O
their	O
digital	O
channels	O
depending	O
on	O
daypart	O
,	O
carrying	O
four	O
standard	B-Device
definition	I-Device
channels	O
during	O
the	O
daytime	O
,	O
reducing	O
them	O
to	O
one	O
HD	O
and	O
one	O
SD	O
channel	O
at	O
night	O
due	O
to	O
technical	O
limitations	O
at	O
the	O
station	O
's	O
level	O
that	O
may	O
prevent	O
it	O
from	O
carrying	O
PBS	O
programming	O
in	O
HD	O
full-time	O
and	O
maintain	O
multiple	O
full-time	O
subchannels	B-Device
like	O
other	O
member	O
stations	O
.	O
</s>
<s>
In	O
the	O
Washington	O
,	O
D.C.	O
area	O
,	O
MHz	O
Networks	O
is	O
available	O
as	O
ten	O
subchannels	B-Device
transmitted	O
by	O
two	O
stations	O
,	O
with	O
their	O
virtual	B-Protocol
channels	I-Protocol
mapped	O
uniformally	O
,	O
making	O
them	O
appear	O
as	O
if	O
they	O
are	O
transmitted	O
by	O
one	O
station	O
.	O
</s>
<s>
In	O
some	O
U.S.	O
states	O
,	O
statewide	O
educational	O
,	O
cultural	O
or	O
public	O
affairs	O
services	O
are	O
carried	O
on	O
a	O
digital	B-Device
subchannel	I-Device
of	O
a	O
PBS	O
member	O
station	O
or	O
network	O
(	O
such	O
as	O
the	O
Minnesota	O
Channel	O
,	O
PBS	O
Wisconsin	O
's	O
Wisconsin	O
Channel	O
,	O
or	O
New	O
York	O
State	O
broadcaster	O
ThinkBright	O
TV	O
)	O
.	O
</s>
<s>
The	O
use	O
of	O
subchannels	B-Device
has	O
also	O
allowed	O
educational	O
television	B-Application
broadcasters	O
to	O
sell	O
off	O
former	O
secondary	O
PBS	O
analogue	O
stations	O
to	O
commercial	O
broadcasters	O
(	O
such	O
as	O
WNEQ	O
in	O
Buffalo	O
,	O
which	O
its	O
sister	O
station	O
WNED-TV	O
sold	O
in	O
1999	O
to	O
LIN	O
TV	O
(	O
now	O
owned	O
by	O
Nexstar	O
Media	O
Group	O
)	O
to	O
become	O
WNLO	O
,	O
now	O
a	O
CW	O
affiliate	O
)	O
,	O
as	O
the	O
additional	O
educational	O
content	O
these	O
separate	O
stations	O
once	O
provided	O
can	O
now	O
be	O
carried	O
by	O
multiple	O
subchannels	B-Device
of	O
a	O
single	O
parent	O
station	O
.	O
</s>
<s>
Subchannels	B-Device
also	O
allow	O
some	O
educational	O
stations	O
to	O
devote	O
an	O
entire	O
channel	O
to	O
telecourses	O
,	O
which	O
are	O
recorded	O
by	O
instructors	O
and	O
students	O
for	O
later	O
use	O
,	O
allowing	O
the	O
station	O
's	O
main	O
channel	O
to	O
air	O
a	O
generalized	O
schedule	O
in	O
the	O
morning	O
and	O
overnight	O
hours	O
.	O
</s>
<s>
Subchannels	B-Device
and	O
transmitter	O
reconfigurations	O
have	O
been	O
used	O
to	O
temporarily	O
restore	O
service	O
from	O
a	O
station	O
that	O
is	O
unable	O
to	O
broadcast	O
for	O
technical	O
,	O
weather-related	O
,	O
or	O
other	O
reasons	O
using	O
the	O
facilities	O
of	O
another	O
.	O
</s>
<s>
This	O
use	O
dates	O
to	O
the	O
early	O
days	O
of	O
digital	O
television	B-Application
:	O
in	O
the	O
immediate	O
aftermath	O
of	O
the	O
September	O
11	O
attacks	O
,	O
which	O
destroyed	O
the	O
primary	O
TV	O
transmission	O
site	O
in	O
New	O
York	O
City	O
,	O
WWOR-TV	O
was	O
broadcast	O
as	O
a	O
subchannel	B-Device
of	O
co-owned	O
WNYW-DT	O
.	O
</s>
<s>
Competing	O
stations	O
in	O
a	O
market	O
have	O
even	O
offered	O
each	O
other	O
support	O
;	O
in	O
2009	O
,	O
Weigel	O
Broadcasting	O
offered	O
the	O
use	O
of	O
a	O
subchannel	B-Device
to	O
Milwaukee	O
's	O
WTMJ-TV	O
when	O
its	O
transmitter	O
was	O
disabled	O
by	O
lightning	O
,	O
only	O
for	O
WTMJ	O
to	O
reciprocate	O
the	O
next	O
year	O
when	O
flooding	O
took	O
Weigel	O
's	O
WDJT-TV	O
out	O
of	O
service	O
for	O
three	O
days	O
.	O
</s>
<s>
For	O
five	O
months	O
from	O
October	O
2019	O
to	O
2020	O
,	O
commonly	O
operated	O
WBBH-TV	O
and	O
WZVN-TV	O
in	O
Fort	O
Myers	O
,	O
broadcast	O
from	O
the	O
former	O
's	O
facility	O
on	O
one	O
multiplex	B-Device
to	O
allow	O
for	O
an	O
overhaul	O
of	O
the	O
latter	O
's	O
antenna	O
.	O
</s>
<s>
In	O
rare	O
cases	O
,	O
digital	O
television	B-Application
broadcasters	O
have	O
included	O
a	O
service	O
known	O
as	O
DTV	O
radio	O
,	O
in	O
which	O
the	O
audio	O
of	O
a	O
commonly	O
owned	O
broadcast	O
radio	O
station	O
is	O
simulcast	O
over	O
a	O
subchannel	B-Device
(	O
for	O
instance	O
,	O
KPJK	O
in	O
San	O
Mateo	O
,	O
California	O
broadcasts	O
former	O
FM	O
sister	O
KCSM	O
on	O
its	O
DT3	O
signal	O
)	O
.	O
</s>
<s>
WANN-CD	O
in	O
Atlanta	O
offers	O
six	O
radio	O
stations	O
owned	O
by	O
iHeartMedia	O
,	O
in	O
addition	O
to	O
ten	O
television	B-Application
channels	O
.	O
</s>
<s>
Non-broadcast	O
content	O
,	O
subscription	O
television	B-Application
channels	O
or	O
datacasting	O
operations	O
unrelated	O
to	O
the	O
main	O
television	B-Application
programming	O
are	O
also	O
permitted	O
by	O
the	O
digital	O
television	B-Application
standards	O
but	O
are	O
less-commonly	O
used	O
.	O
</s>
<s>
USDTV	O
was	O
an	O
over-the-air	O
pay	O
television	B-Application
service	O
that	O
used	O
H.264	B-Application
compression	O
instead	O
of	O
standard	O
MPEG-2	B-Algorithm
.	O
</s>
<s>
Mobile	B-Application
DTV	I-Application
now	O
uses	O
MPEG-4	B-Algorithm
compression	O
,	O
which	O
like	O
H.264	B-Application
yields	O
a	O
much	O
lower	O
bitrate	O
for	O
the	O
same	O
video	B-Device
quality	I-Device
.	O
</s>
<s>
For	O
example	O
,	O
the	O
Sezmi	O
TV/DVR	O
service	O
uses	O
broadcast	O
digital	B-Device
subchannels	I-Device
(	O
not	O
in	O
the	O
clear	O
)	O
in	O
selected	O
cities	O
to	O
stream	O
a	O
limited	O
number	O
of	O
"	O
cable	O
"	O
channels	O
to	O
its	O
subscribers	O
for	O
an	O
additional	O
fee	O
to	O
supplement	O
its	O
otherwise	O
free	O
digital	B-Application
video	I-Application
recorder	I-Application
(	O
DVR	O
)	O
service	O
allowing	O
recordings	O
of	O
local	O
broadcast	O
channels	O
and	O
free	O
and	O
subscription	O
internet	O
content	O
.	O
</s>
<s>
Digital	O
television	B-Application
supports	O
multiple	O
digital	B-Device
subchannels	I-Device
if	O
the	O
19.39	O
Mbit/s	O
(	O
megabits	O
per	O
second	O
)	O
bitstream	O
is	O
divided	O
.	O
</s>
<s>
Therefore	O
,	O
station	O
managers	O
and	O
broadcast	O
engineers	O
could	O
run	O
any	O
of	O
the	O
following	O
scenarios	O
using	O
one	O
6MHz	O
channel	O
(	O
note	O
that	O
the	O
actual	O
bitrate	O
moves	O
up	O
and	O
down	O
,	O
due	O
to	O
usage	O
of	O
variable	B-General_Concept
bitrate	I-General_Concept
encoding	I-General_Concept
)	O
:	O
</s>
<s>
With	O
improvements	O
in	O
MPEG	O
encoding	O
,	O
and	O
tighter	O
VBR	B-General_Concept
encoding	O
,	O
more	O
subchannels	B-Device
can	O
be	O
combined	O
.	O
</s>
<s>
For	O
a	O
frame	O
rate	O
of	O
30p	O
or	O
60i	O
,	O
uncompressed	B-General_Concept
DTV	O
channels	O
have	O
the	O
following	O
data	O
rates	O
in	O
megapixels	O
per	O
second	O
:	O
</s>
<s>
For	O
ATSC	B-Device
,	O
these	O
must	O
be	O
compressed	O
into	O
19.4Mbit/s	O
total	O
per	O
physical	O
6MHz	O
RF	O
channel	O
over	O
the	O
air	O
,	O
and	O
38.8Mbit/s	O
for	O
cable	O
.	O
</s>
<s>
The	O
primary	O
distinguishing	O
feature	O
of	O
HD	O
Radio	O
has	O
been	O
its	O
ability	O
to	O
multiplex	B-Device
an	O
FM	O
radio	O
signal	O
.	O
</s>
<s>
As	O
HD	O
Radio	O
never	O
achieved	O
widespread	O
popularity	O
in	O
the	O
United	O
States	O
(	O
unlike	O
television	B-Application
,	O
radio	O
is	O
not	O
required	O
to	O
turn	O
off	O
its	O
analog	O
signals	O
due	O
to	O
HD	O
Radio	O
being	O
in-band	O
on-channel	O
and	O
thus	O
compatible	O
with	O
analog	O
,	O
plus	O
the	O
greater	O
quantity	O
and	O
difficulty	O
in	O
signal	O
conversion	O
of	O
radios	O
compared	O
to	O
fixed-link	O
television	B-Application
sets	O
)	O
,	O
its	O
use	O
has	O
largely	O
been	O
to	O
serve	O
as	O
a	O
legal	O
fiction	O
.	O
</s>
<s>
Since	O
HD	O
Radio	O
was	O
introduced	O
in	O
the	O
United	O
States	O
in	O
the	O
late	O
2000s	O
(	O
decade	O
)	O
,	O
the	O
FCC	O
has	O
allowed	O
American	O
broadcasters	O
to	O
use	O
low-powered	O
translators	O
to	O
transmit	O
HD	O
Radio	O
subchannels	B-Device
in	O
analog	O
FM	O
.	O
</s>
<s>
AM	O
broadcasting	O
generally	O
lacks	O
the	O
bandwidth	O
to	O
multiplex	B-Device
;	O
though	O
in	O
theory	O
an	O
AM	O
station	O
could	O
transmit	O
two	O
separate	O
channels	O
using	O
C-QUAM	O
AM	O
stereo	O
,	O
there	O
is	O
a	O
limit	O
to	O
how	O
far	O
the	O
two	O
audio	O
channels	O
can	O
be	O
separated	O
,	O
and	O
thus	O
crosstalk	O
is	O
inevitable	O
.	O
</s>
<s>
A	O
proposed	O
FCC	O
rule	O
would	O
require	O
stations	O
that	O
wish	O
to	O
multiplex	B-Device
their	O
digital	O
AM	O
signals	O
to	O
request	O
and	O
receive	O
permission	O
to	O
do	O
so	O
.	O
</s>
