WHAT EQUIPMENT DO I NEED TO RECEIVE SATELLITE TV?
(Television Receive Only) System consists of the following components:
- THE DISH
This is the most visible component, a parabolic reflector which may
consist of Solid Aluminum, Perforated Aluminum or WIRE MESH. Dish
sizes vary from small (3-4 feet KU BAND, EUROPE) all the way to
16-20 Ft (USA Commercial C-BAND) with the average falling between
7-12 ft, 10 ft being most common. This device focuses the microwave
signals coming from the satellites much as the mirror in a reflecting
telescope concentrates the light from distant galaxies.
- THE MOUNT
The most common type of dish mount is called a POLAR MOUNT, so named
because it is oriented to coincide with the earth's axis, enabling
it to "track" the satellites, which are spread out in geostationary
orbit in a band of the sky called the "Clarke Belt", named after
Arthur C. Clarke, who dreamed up the concept of geostationary
communications satellites back in 1945.
The mount is installed on a 3 inch pipe, which is sunk in concrete.
Most (but not all) mounts require a 3.5" OD pole. In most (but not all)
cases this is a 3" ID pipe. Schedule 40 works well, so does used "drill
stem". In many areas, this is available from salvage dealers at very
reasonable prices. (* OD refers to OUTER DIAMETER, ID refers to
INNER DIAMETER)
- THE POSITIONER ARM (Actuator)
A device containing a motor that is used to swing the satellite dish
to allow it to focus on individual satellites, which may be as close
to one another as 2 degrees of arc. Actuator arms are most commonly
found in 18- and 24-inch lengths (the longer the arm, the wider the arc
that the dish can "see".) In addition, a more expensive aiming mechanism,
called a "horizon-to-horizon" actuator, is capable of more precise aiming
(important on Ku band and closely-spaced satellites), as well as being
able to see the entire satellite arc from your location.
Many true dish heads have also added a second actuator to control
the VERTICAL aspect (elevation) of the dish, to enable them to
track inclined orbit satellites which "wobble" or vary in the vertical
plane.
- THE LNB
This is the Little gizmo that amplifies the very weak signals from
the dish, and also converts them to a more suitable band of
frequencies. LNB means LOW NOISE BLOCKCONVERTOR. Older systems
consisted of separate components: LNA (Low Noise Amplifier) and a
downconvertor which changed the received signals (3-4 GHz, or
GIGAherz ....A GIGAHerz is one thousand megaHz....) to 70 Mhz.
The "standard block" used today is 950 to 1450 Mhz. Both C and
KU band (while they input on vastly different frequencies) output
on the 950 to 1450 Mhz block. HOWEVER there are special consider-
ations when dealing with KU (explained later)
There is also a device called an LNBF, which combines the LNB and
feedhorn into a single unit. (See below for description of feed
assembly. The LNBF device uses a simpler method for adjusting
the polarity (voltage right on the LNB cable). You can not adjust fine
skew, just H or V. This device is practical for C band only systems.
However if the LNB part goes bad, you need to replace ALL of it.
An LNBF is especially suitable for dedicated operations, such as a
smaller dish used for only one satellite. I have a 6 foot dish which
I use for Telstar 401 only, using an LNBF, and it gives excellent
service.
- THE FEED ASSEMBLY
The feedhorn acts as a microwave "funnel" if you want to think of
it that way. This device places the LNB at the focus of the dish,
and is usually just called "the feed". There are several different
types of feeds.
Single C band feed: Contains ONE C band LNB. A device called
a POLAROTOR is located inside, which allows the reception of
both vertically polarized and horizontally polarized channels.
In general practice, the EVEN channels are on ONE polarity and
the ODD channels are on the opposite polarity. The actual
polarity scheme depends on the satellite in question.
Dual C band feed: Allows the use of Two C band LNB's one for
horizontal polarization and one for vertical.
Dual Band Feed (C and KU): Has two separate LNB's, one for C
band and one for KU band.
DUAL C band and single KU band feed: (There is at least one
version of this type of feed.
The most popular Dual Band feedhorns are the Chaparral CO-ROTOR II
Gardiner and ADL, though there are others on the market. While these
are actually a compromise system, with some minor losses, in
practice they work pretty well.
- SATELLITE CABLES
This is a bundle of various wires and cables that run from the dish
to the receiver, and consist of cables for the C and/or KU LNB's,
Power to the LNB (Usually sent over the same COAXIAL CABLE) as well
as power for the positioner arm, return signals for position readout,
and control voltage for the polarotor.
Power to actuator Arm (Two conductors)
Return position readout from actuator (Two conductors)
The position readout cable from the actuator to the actuator controller
should have THREE conductors for the position sensor.For pot sensors, one
is for the tap, the other two are for the resistor.For pulse sensors, one
is ground, one is +5V, and the other is pulse input. Not all arms require
all three connections, but my scrounged Saginaw special has some nifty
hall-effect gizmo that does require power to generate pulses.
- Power to polarotor (Two conductors)
Polarotors come in two different varieties. The "old style" just used a 12V
motor to rotate the probe. Apply power, it moves. Reverse polarity, it
changes direction. The new ones use a three wire connection. One for +5V,
one for ground, and one for "pulse".
RG-6U cable (rather than the often-seen RG-59U) is the cable of choice
for the higher frequencies of satellite TV.
WHO SHOULD OWN A SATELLITE SYSTEM:
Most owners of Satellite TV systems these days fall into the following
categories:
1. Those who can not get cable due to isolated location.
2. Those who wish to receive programs not available on their
local cable system.
3. People who desire the sharpest "blow you away" video picture
possible (Studio Quality, far better than cable or over air)
Or those who want DISCRETE stereo sound from channels or
networks that are not carried in stereo in their local
area.
4. News Junkies who want to see unedited news coverage from the
source location, before it gets chopped up and packaged.
5. Experimenters and techy hobby types who enjoy tinkering.
6. Audiophiles who want to hear HUNDREDS of music services in
superior quality.
7. Digital Information Junkies desiring info-text services.
8. Those who desire foreign Language programming.
9. Individuals who like to see certain TV shows BEFORE they
are aired over the networks, often without commercials.
10. Those in search of additional programming, including pay per
view movies.
11. SPORTS NUTS... There is more sports on satellite than any
human being can STAND. Virtually EVERY game of EVERY team
is up there SOMEWHERE.... Much of it as "Backhauls" which
are not scrambled, and often do not have commercials.
12. Those who want to watch programs earlier or later than seen on
their local stations. For example, on the West Coast you can
watch David Letterman at 9:30 PM PST (or watch it at 3:30
AM Eastern time on the Pacific feed). If you see a music video
you *really like* on the MTV Eastern feed, you can tape it 3
hours later on the MTV Western feed.
13. Those who want to watch Gene Scott 24 hours a day.
14. RADIO NUTS. With the proper additional equipment there are
hundreds of additional audio services receivable, including
AM and FM stations from major cities, TALK SHOWS, every
kind of music imaginable, and very SPECIALIZED formats. Some
Satellite owners actually spend more time LISTENING to the
signals on their dish than WATCHING. (See the SCPC Paragraph
further down this FAQ list for more info)
15. Culture Vultures. If you like Ballet, Art Films, Concerts,
documentaries, Foreign Films, There are many opportunities
here, including a FREE Art Channel that runs snippets of
Concerts and Performances WITHOUT COMMERCIAL INTERRUPTION
24 Hours a day.
Just about everyone could find themselves in ONE of the above categories.
WHAT TYPES OF THINGS CAN I SEE WITH A SATELLITE SYSTEM THAT I MIGHT NOT FIND ON CABLE BROADCAST TV OR DBS?
Live uncensored coverage of news feeds, with no anchor man or reporter,
just see the news as it happens before live cameras. Major events like
the WACO debacle and the L.A. riots from multiple feed points, YOU select
the angle and shot you want to watch.
Teleconferences and meetings of various businesses and organizations, whilemany of these are scrambled, quite a few are not.
Specialty and narrowcast shows, some examples include a 24 hour gold
prospecting channel, a channel for long haul truckers, etc.
College lectures and advanced courses, not just the simple brain dead stuffof the Mind extension University, but REAL graduate level stuff, watch for
knowledge, or take the course for credit.
BBC TV Breakfast News, ITN news, News from Moscow TV, RTS TV from Serbia,
TV Madrid, German TV 24 hours a day, Italian TV, a channel of TV from the
Asian subcontinent which runs popular Indian and Pakistani films with no
commercial interruptions (Subscription required). Portuguese TV, Japan TV, A
Greek Channel, Chinese TV, A channel for Eskimos (Inuit), Arab TV, and many
other international broadcasts.
IN REFERENCE TO A SATELLITE COMMUNICATIONS SYSTEM, WHAT DOES A BACKHAUL MEAN, AND WHAT DOES IT PHYSICALLY REPRESENT??
Backhauls are signals sent from a remote location back to a network operating
center. Usually, but not always on KU band, these are special events and
sports. Since the commercials are usually added by the network, the backhaul
has no commercials, and you get to hear the announcers talk and see them play
with the video effects when the signal is not being broadcast to the world
(before, after the event and during commercial breaks).
What is needed at the backhaul site are cameras, microphones, audio and video
mixing and effects equipment, and an uplink transmitter and small dish to
send the signal to the satellite.
At the network operating center, there is a downlink (receive) dish, and
a receiver to pick up the signal, and pipe it into the audio and video chain
of the network so that it can be sent to those unlucky people who don't have
satellite dishes and have to watch these broadcasts on regular TV or Cable
WHAT ABOUT SCRAMBLING, ISN'T IT ALL SCRAMBLED THESE DAYS?
This is a common misconception. While it is true that most of the CABLE services are scrambled, many of us see this as a feature. If you DO
desire HBO, THE DISCOVERY CHANNEL, ETC, you WILL need a[ descrambler, AND
a subscription to these services. However, there are over 150 channels of
programming "In the clear" that is NOT scrambled, and many of these
provide a lot of entertainment and information. It all depends on your
personal taste. Most of the sporting events are not scrambled. PBS is
not scrambled (Four separate feeds) and many other services are also
available free for the taking. NOT to mention HUNDREDS of audio services.
There is more on satellite that you can get for FREE than you would ever
have time to watch.
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