The move to HDTV broadcasts in the USA
has brought consumers a new world of picture clarity and resolution.
However, the move of most major channels from VHF frequency broadcasts
to UHF has brought reception problems to some viewers. The key to
successfully receiving HDTV broadcasts is to know which channels you
want to watch and whether they are broadcast on VHF or UHF frequencies.
Once you know this, you can use the appropriate antenna(s) for your
area.
1)
Determime which channels can be received in your area, their signal
strengths, and what frequencies are used by each TV station.
Goto
http://www.tvfool.com/
and enter your address or zip code.
TV Fool is one of many websites which allow you to
see which TV channels are broadcasting in your area that you can
reasonably receive with a proper antenna. The key here is to go down
the list of channels listed in order of relative dB signal strength
until you see 0dB (or a negative number, eg. -6dB). With a good
antenna, you should be able to receive all of the channels at 0dB or
higher; you'll need a great antenna, typically a large rooftop antenna,
in order to receive any TV channel with a negative relative signal
strength - these are simply too far from you, or broadcasting with too
little power for you to receive.
In the Los Angeles/Orange County area, for example,
most TV stations are on UHF - the major exceptions are channels 9, 11,
and 13, which are still broadcasting on VHF frequencies. Thus, you will
need a separate VHF antenna for these three stations unless you are
close to these broadcast towers.
Some UHF channels are so far, you will not be able
to receive them unless you have a good antenna. For example, in Zip
Code 92683, TV Fool shows channel 31 (which includes all subchannels,
such as channel 31.1, 31.2, 31.3, etc) at around -6dB relative signal
strength. Thus, a crafty UHF antenna is needed to pickup this
low-power, distant channel.
2) Here is
an antenna design that works well (out to Orange County in 92683) for
all UHF channels broadcasting in Los Angeles all the way down TV Fool's
list to channel 31 at -6dB.
You will easily pickup 72+ digital HDTV channels
with this antenna if placed in a north-facing window indoors, however,
channels 9, 11, 13 will require a separate VHF antenna.
The cheap fix for these VHF channels in
Los Angeles? Simply buy a pair of rabbit ear VHF antennas and
connect to the transformer for this project and/or directly to your TV.
Typically $1-2 for a pair of rabbit ear antennas.
If you have anything blocking your north-facing
view, live in a heavily shielded structure, or have other sources of
interference, you may need a better antenna or one placed on the
rooftop. A more powerful VHF antenna may be necessary to pickup any VHF
channels in your area. The
ANTENNA mounted on the roof is usually the only way you can receive all
channels in very distant/troublesome locations.
In any case, this coat-hanger antenna works
significantly better than the Radio
Shack single bow-tie UHF antenna they have for sale. Although the Radio
Shack single-bow tie does pickup most UHF channels just fine, it does
not pickup the 31.x channel in Los Angeles and requires some adjustment
of location to pickup all channels well. The coat-hanger antenna
pickups all UHF channels (72+ channels) well once placed in a
north-facing window, including the -6dB 31.x channels; our large
roof-top antenna naturally picks up all channels, UHF and VHF, without
any trouble.
Due to it's low cost, I would suggest that you try
this coat hanger antenna first rather than buying the single bow-tie
antenna. If it doesn't work well for you, you'll likely need to
investigate even better performing indoor and outdoor antennas. It's
small 10x15" size also allows for great portability, and you can attach
a nice picture to the outside of the foam board so it blends better
with the surroundings.
3) What
you'll need
a) $2-5.
Foam
board
(2
pieces, 10x15x1/4")
You can find this at Michael's
craft store, Target, and office supply stores. Typically, you'll need
two pieces that are 10x15" width x height, 1/4" thick. You can buy one
large foam board and cut it to size if it's cheaper. You can substitute
any stiff board (cardboard, plastic board, wood, etc) for this;
however, do not use anything made of metal.
If you don't care about
appearance, the exposed sharp ends of the antenna, or having the
internals visible for all to see, you can use just (1) one board
instead and save money.
b) Free to <$1 each from any dry cleaner shop.
Wire coat hanger (2 hangers, metal, bare)
You usually get these for free
when you dry clean clothes. If you don't have any in your home, beg
them from friends. Otherwise, most dry cleaners will sell them to you
for <$1 each. You want the bare metal ones since they are easier to
strip to make a good electrical contact; if you have coated ones, it'll
take slightly more work to strip the plastic/paint coating off the
corners.
c) Free to <$1 each.
Metal wire (1 foot length at most, any type)
You'll need some metal wire to
connect everything together, and you can use anything you have handy.
Old cords you can cut apart, plant wire, speaker wire, Ethernet cable,
etc. You'll need them only to connect the coat hangers together, and
some extra to connect to the transformer (only if you don't want to
attach the transformer directly to the coat hangers - either way is
fine if you want to save money, but connecting the transformer to a
pair of wires attached to a pair of coat hangers is more convenient
when making adjustments).
d) Free to <$1.
Tape. (1 foot length at most, any type)
You will need tape to hold down
everything. Clear tape, packing tape, etc. will do.
e) Free to <$5.
300 Ohm to 75 Ohm TV transformer (1)
These used to come with VCRs,
TVs, etc. when you bought them. Nowadays, you may need to visit your
local $0.99 store, Radio Shack or other parts store to buy these. They
are super-cheap and unless you're in a hurry, you should be able to buy
one for $1-$2 at most. You will see one pair of leads for connecting
the UHF antenna, one pair of leads for the VHF. On the other end, you
will see a standard 75 Ohm, round, antenna plug that will go into your
TV's round antenna jack.
You should buy one with a cable
long enough to reach your TV.
f)
OPTIONAL
Free to <$1.
Two Binder Clips (2x, small)
To clip the two pieces of foam
board together. You can skip this if you use tape, staples, etc, and
don't care about easily taking the antenna apart later on.
4) Antenna
Assembly
This is easy and will take about 15-60 minutes
depending on your skill level and speed. Very easy and shouldn't be
hard at all.
![](pics/hdtv1.jpg)
Figure 1: Transformer taped to outside of foam board. UHF leads
attached to UHF antenna wires, taped together.
![](pics/hdtv2.jpg)
Figure 2: Inside face of foam board. Two wire hangers cut in half,
attached to wires which lead in parallel to the other side.
a) Cut the wire hangers in half, discard the top
part that hangs on knobs. You don't need to be exact with this, simply
cut away! You can make a slight half-cut in the hanger, then bend it
back and forth (either with pliers - safer - or your hands) until it
breaks if you don't have the arm strength to cut the hangers all the
way through. The hanger halves should retain their original shape.
b) At each corner of the hanger halves where the
wires will connect, use a file, the concrete sidewalk, or brick surface
to file away the coating until you can see the shiny, silver-colored
metal. You need to do this so that the electrical current can flow from
hanger to wire to hanger to transformer.
c) Place the hanger halves on the 10x15" board as
shown - trim ends as necessary to fit within the board space.
The only major point? Two corners
of the hangers pairs are approximately 6" from the next pair below them
(See figure 2) and about 1 1/2-2" from each other. You can simply place
the pieces on the 10x15" board as shown in Figure 2.
d) Strip each wire end of it's plastic coating. Wrap
them around each corner of the wire hanger several times to get a good
connection (if you have a soldiering iron, you can solider everything
together) as shown in figure 2 (the vertical, black wires connect the
two lower hanger halves to the upper hanger halves). You will either
connect the transformer's UHF leads directly to one pair of hanger
halves, or as shown, to a pair of wires that are connected to one pair
of hanger halves. The latter is more convenient if you want to mount
the transformer on the outside of the foam board, and for adjusting the
antenna later on.
e) Use tape to securely fasten the wires to the
hangers, then tape the hangers down on the foam board.
f) If you are using two pieces of foam board, place
the second board on top of the first one, and secure using the two
binder clips (Figure 1). The antenna is now safely secured between two
foam boards. (Otherwise, if you're only using one foam board, it will
look like Figure 2.) You can tape the transformer UHF leads to the
antenna wires, then tape the transformer itself to the board.
g) You can mount the board anywhere, and tape a nice
photograph, painting, etc. to the front facing foam board to hide it.
It's only ~9oz, so it's lightweight and portable.