OPEN COMMUNICATION
THE LATEST IN NETWORKING AND WIRELESS TECHNOLOGIES
■ BY LOUIS E. FRENZEL W5LEF
CONVERTING TO DIGITAL TV
Fun with converter boxes and antennas.
SURELY YOU HAVE HEARD THAT AS OF FEBRUARY 17, all analog TV signals will
be shut down and new digital TV signals will be the only ones broadcasted.
That means that if you do not have a digital TV set or you do not subscribe
to a cable or satellite TV service, you won't be getting over the air (OTA) TV
signals. Most of you (over 80%) probably already have cable or satellite TV so
you won't notice any difference. If you are a diehard free OTA TV advocate,
however, you will need a new digital TV set or a converter box.
TIME FOR A NEW TV
If you have been looking for an
excuse to get a new TV, this is it. Your
best bet is to go ahead and take the
plunge. If you like TV and watch a lot,
you can justify it. Most TV sets last a
long time, and amortize over many
years the expenditure is only a tiny
part of your budget. My old 27 inch
RCA set lasted 17 years before it blew
on Thanksgiving last year. New sets are
very reliable these days, so you can
count on them lasting for a while and
simultaneously enjoy the pleasures of a
bigger, higher definition picture. You
don’t have to spend a fortune, either.
Not all DTV sets are high definition
(HD), so you can get a reasonably
DTV DEFINITIONS
• Standard Definition TV: This is the
version of DTV that is similar in resolution
to regular analog TV. It uses 480 horizontal
lines and either 704 or 640 pixels per line.
The designation is 704 x 480 or 640 x 480.
The aspect ratio (width by height
proportions) is usually 4: 3 but there is a
wide screen 16: 9 version. Scanning is usually interlaced (i) rather than progressive
(p), and occurs at a rate of 30 frames per
second (fps). SDTV is also called 480i.
• Enhanced Definition TV: This intermediate
version is also available in 704 x 480 or
640 x 480 formats in either 4: 3 or 16: 9
24
February 2009
priced standard definition digital TV
set (see the sidebar on DTV definitions)
for less than $400. Now is actually a
great time to update to HDTV as prices
for even the larger screens have
dropped considerably. HDTV is a definite improvement over older analog
TV, but if you are short on cash there
is a low cost option: a converter box.
CONVERTER BOXES
Converter boxes are the lowest
cost alternative for OTA TV. These
boxes receive the DTV OTA signals
and convert them to low resolution
analog signals for presentation on your
dated TV set. You can find converter
boxes on sale at dozens of places
aspect ratios. Scanning is usually progressive.
Frame rates of 24, 30, and 60 fps are used in
various applications. EDTV is called 480p.
• High Definition TV: HD sets use either 720
or 1,080 horizontal lines with either 1,920 or
1,280 pixels per line. Scanning can be either
interlaced or progressive at rates of 24, 30,
or 60 fps. Newer 120 fps and even 240 fps
versions are also available. Faster picture
rates produce less smearing on action
scenes, especially on LCD screens. The
aspect ratio is 16: 9. Over the air broadcast
TV and DVDs use a 720 pixel x 480 line
format. HDTV is usually called 1080p or
1080i. By the way, progressive scan gives
greater resolution than interlaced.
where you get TV sets or electronic
accessories, such as Best Buy, Circuit
City, RadioShack, Target, and Wal-Mart.
You can buy them online, as well. Prices
run between $40 to $70. Plus you can
get a discount card from the government
who is subsidizing the DTV conversion process. Each family is eligible
for a maximum of two $40 discount
cards. Just go to the website for the
National Telecommunications and
Information Administration (NTIA) at
www.ntia.doc.gov/dtvcoupon/ and
sign up. It does take several weeks to
get the card, so keep that in mind.
As for what box to buy, I don’t
have any specific recommendations.
There are dozens of manufacturers and
the products are pretty much all the
same. The boxes are black and are
approximately 9 x 6 x 2 inches in size.
They have an antenna input connector
and one or more outputs that go to the
TV antenna input or the video/audio
inputs on the TV set. All have a
remote control and most include all
the cables you need for connections.
The connections are pretty simple and
are described in detail in the included
instruction manual. However, here are
your choices in a nut shell. Figure 1
shows the back panel of my box.
• Direct RF connection. The
