Don is a retired engineer and shares his experiences and knowledge with his readers to help them as technology gets more complicated.
RV Technology, Satellite TV and How it Works
Living in the limited amount of floor space in a typical camper for any extended period of time, can quickly become bothersome and even boring, even for those of us who are uncomfortable entertaining themselves.
And satellite TV is possibly the most popular form of entertainment for evenings in an RV, or just when the weather is bad. Thus satellite TV is one of the technologies RV owners are interested in adding.
Well, being an engineer myself, I am familiar with how satellite TV works and I thought I could help my fellow campers understand how to set up and operate their satellite TV systems.
This article will describe, in simple terms, some of this specialized entertainment technology for the reader and hopefully explain some tips on how to use it properly.
The Satellite in the Sky; How Does it do That?
Satellites are hanging out in in a fixed position in our skies. I often have people ask me just what keeps them up there.
Well, let me explain this thing called "geosynchronous orbit" as simply as I can.
First of all, our planet is a spinning ball; a spinning ball that has gravity. Gravity is a force that pulls things towards the center of all planets, including our Earth.
Things such as people, cars, rocks, and everything that is loose on the surface of Earth, would normally be tossed into space if it were not for this gravitational force that pulls on everything.
Powerful rockets are used to put satellites and space ships into the sky. The further one of these rockets gets from the surface of the earth, the weaker is the force of the gravitational pull on the rocket. Once they travel far enough from this gravitational force, the rockets place their payloads into their own orbit around the planet.
Well, if you can imagine this, when an item is traveling away from the surface, at some distance determined by it’s size and speed, (usually tens of thousands of miles away from the surface), it reaches a point where, if it goes further, it will escape gravity and continue into space.
And, of course, if it’s just a few feet short of this point, it will eventually, weigh too much and start to tumble back through the atmosphere and eventually crash onto the planet’s surface.
The art of satellite technology is to get a satellite to this specific point, then stopping it and being able to keep it in this exact place, for a long time.
This positioning is done by monitoring the exact position and speed of the satellite itself, usually from the ground, and then using small jets placed onto the body of the satellite which can “nudge” it back into its proper position.
Requirements for an Antenna for Satellite Service
Receiving good satellite signal just requires 3 things:
- a LEVEL antenna
- that points in the right DIRECTION
- and points at the right ELEVATION.
Data Goes From Earth to the Satellite and Back
A permanently placed satellite is used to send signals to a very large section of the earth's surface.
People on the ground transmit a dense stream of data directly at the satellite: TV network data, codes to authorize your receiver for reception, and much, much more.
The electronics inside the satellite itself decode this data, reformat it, and then retransmit it back to the planet in the form of specially encoded TV channels that your receiver is designed to receive.
So, here we are, people all over the US (and world) sitting in our homes, or in my case in my motorhome, and we want to have TV for our evenings entertainment.
Well, the problem for many RV owners who travel around the USA is that there is no conventional TV signal available in many campgrounds. So, the satellite TV companies have designed a way for us to pick up hundreds of TV network channels simply by providing us with a small receiver box for use with their system.
This receiver box can decode the specific signals from the company’s satellite and provide an HDMI connection to a standard TV for everyone’s entertainment, at home, or again, like me, wherever I happen to go park my motorhome.
Now, one more thing needs to be explained; the receiver box needs to be connected to a special outdoor antenna that collects the satellite signal and provides it for the the receiver box to use.
These received signals are transmitted from the satellite at very low power levels, so what is received needs to be amplified and cleaned up in some way.
Antennas Contain a Curved Surface and an LNB Amplifier
An antenna is a curved, dish-shaped reflectors with a strange looking thing called an LNB (Low Noise Buffer Amplifier) hanging on an arm pointed at the center of the curved antenna surface.
Simply said, the signal that hits the curved surface of the antenna is reflected at the LNB and is thus “concentrated" at this point, giving the signal the same effect as being amplified.
The LNB itself gets a DC voltage from the receiver, via the connected coaxial cable, which powers it up so that it can do two things; amplify the desired signal, and at the same time, reject any unwanted signals or noise and keep them from going to the receiver box.
This received and amplified signal is sent to the receiver box via the same coaxial cable that provides the DC voltage for the LNB.
There are all kinds of antennas available for use with satellite receiver systems, from your simple fixed reflector designs with a single LNB, to more complicated models with multiple LNBs, and even motorized scanning antennas in self-contained domes, all of which are controlled by the receiver box software.
Satellite Antenna Alignment: Pointing Your Antenna at the Satellite
So, you can now see that the first thing needing to be done for good signal reception from the satellite is to point the antenna as directly as possible at that place in the sky were the satellite is seemingly, just hanging.
Try to picture the size of the whole United States and you can quickly understand that a person on the West Coast has to point his or her antenna in an entirely different direction than someone on the East Coast, or someone in Texas, or New York, etc.
One way to determine where to roughly point an antenna is to use a fixed location that is always the same. In the USA. we have such a thing and it’s called our Zip Codes. Each Zip code is for a specific area of land in the US, and it never changes.
So, using these zip codes, and the fixed location of the satellite, some engineers have come up with a data table that provides two unique numbers for anyone that gives the person on the ground a way to exactly align their antenna for signal reception, wherever they may be.
Azimuth: The First Number You Need
It’s really relatively simple mathematics, using triangulation, to set your antenna to the right elevation, or azimuth.
Using your zip code, you can look up the appropriate elevation to set your antenna to for proper alignment.
You just place your manual antenna in a level position and adjust its manual elevation to the number provided by the satellite service company.
Direction: The Next Number You Need
The next thing you need to do is to determine the exact direction where the satellite is, in your sky.
This number is also provided to you by the satellite service company and is given as the actual compass point you need to use to align your antenna. This number is in degrees and is easy to determine using a simple magnetic compass.
Once you “point” your antenna to the proper elevation and then to the right compass direction you are ready to check if your receiver has signal.
But, what do you do if you have no signal at all after setting up your antenna? Hills, trees, tall buildings, and even the occasional heavy storm overhead can become a problem if they are positioned between your antenna and the location of the satellite in the sky.
Finally, here’s the rule for placing your external satellite antenna. When you align your antenna, there must be no obstructions; no trees, no building, no hills, nothing!
The signal transmitted from the satellite is at a very low level and comes from a long distance away, often circling at a distance of over 20,000 miles away from the earth.
So, even with your parabolic dish reflector helping concentrate the signal, the level can still be just too low for your receiver, even if you are only a few degrees out of alignment.
How to Manually Align an Antenna
There are two ways an antenna can be aligned: manually and automatically. Here is how to manually align a simple parabolic dish-type antenna, because you will often need to “fine tune” your antenna for an optimum signal level.
This can be a problem for you if you don’t understand a few things about aligning an antenna. Here is a list of facts that you need to follow;
Rough Alignment Procedure:
- First determine the direction and elevation your antenna should be pointed.
- Check your campsite and pick a location for your antenna where there are no obstructions to that area of the sky.
- Set up and level your antenna, on a tripod or some steady surface.
- Then, set the physical antenna for the direction and elevation numbers you have already determined.
- Once the antenna is set up roughly, you should easily be within less than five degrees (left or right or up or down) of your potential peak signal level.
Fine Tuning Procedure:
If your antenna is level and mounted on a firm base. your rough alignment might be enough for a good signal, but, if not, you will be very close.
So, the next step of “fine tuning” should be easy. There are several ways to get the optimal signal level for the location and here are a few tips to help.
- Purchase a simple, inline signal level meter. This meter, when placed in between the antenna and the receiver, will indicate when the received signal increases or decreases usually with a movement of the needle.
- If you have no such meter, then you can set up your satellite receiver to indicate the received signal level on your TV display.
Either way, follow these steps;
- Move the antenna one or two degrees to the left and then check for an indication of signal on your receiver/TV.
- If this doesn’t work, move the antenna back to the center and then one or two degrees to the right and then recheck for an indication of signal.
- If there is still no signal then repeat the above steps, but go four degrees from center, this time.
- If there is still no signal after testing for six or more degrees, then you should reset the antenna to the center and try the same tests with the elevation (or azimuth).
- If, after all of this, you still have no signal, then you either have an obstruction in your line of sight or your cables to the receiver are not connected properly.
Using Automatically Aligning Antennas
For those of you who are lazy like myself, I recommend that you purchase one of the newer automatically aligning, antennas available at most RV parts stores.
These antennas work really well, from my experience, and they take all of that manual alignment confusion out of your setup, such as the guess-move-check, then guess-move-check process that drives so many people crazy.
Essentially, with these new receiver/automatic antenna combinations, you are aligned by the system, or you have a specific kind of problem to consider.
I, myself, use a DISH receiver in my motorhome and I have a dome-type automatic adjusting antenna called a Tailgater, which is popular with campers as well as people who, well, tailgate.
It works this way;
- First you check for the direction of the satellite dome just as explained with the manual method.
- Then you set your Tailgater antenna dome on a level surface, and point the handle to the North.
- After connecting a cable between the antenna and the DISH Receiver, you go through a short startup procedure with the antenna and receiver connected via a coaxial cable and you connect the TV to the receiver.
- Once you have finished this, the receiver will detect the antenna and control it as it starts stepping the antenna, inside the dome, to the general direction needed.
- Then it will continually step through different alignments, vertical and horizontal, until an optimal signal is detected.
- At this point your TV will start receiving your favorite TV channels. If it tells you you have no signal, follow the instructions on the TV screen to get a resolution.
Selecting a Satellite Service
DISH has a package specifically for the occasional camper or the mobile camper. With this package, you pay for the months you need their service, and you aren’t held to any contract that makes you pay for those months you are not camping.
Setting Up an Antenna
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.