Successful downlinking of satellite programs requires careful attention to the satellite specifications provided by the broadcast provider and experience using the local site's receiver equipment. Best results will occur if sites use a knowledgeable technician to program and steer the satellite dish. If that is not possible for each program, the personnel designated to downlink programs should learn as much as they can about their equipment from the technician who programs it and follow the guidance below.
Satellite program providers cannot control which satellites are used for a particular program. They have set standards for the purchase of all satellite time, e.g., full transponder capability and both C- and Ku-Band access. However, there are no guarantees. Project personnel purchase satellite time from the open market. Availability of satellite space at the time the procurement is processed determines which satellites are used.
Even if the site has determined you are capable of receiving a satellite transmission, you should always conduct a pre-broadcast test at least 30 minutes before the session start time to allow for trouble shooting. The satellite broadcasters will broadcast a test signal prior to the actual program.
The purpose of testing your downlink during this time is to make sure any technical problems are resolved before the session begins. This is also the time when the uplink and satellite transponder will be adjusted to transmit the highest quality signal. Be patient for the first three to five minutes of the test as some fine-tuning may be occurring at the uplink.
Once you are receiving the best possible signal, adjust the television monitors, receiver and video recorders for accurate color and a good picture under the actual lighting conditions you will be using during the program. If there is an image of a person on the screen, it is best to adjust the color so the skin tones look natural.
A few weeks before the program you will receive information from the satellite broadcast program provider coordinator about the technical aspects of receiving the program. The information will include the name of the satellite and coordinates, as well as the phone number to call if you experience technical difficulties.
Please note the time zone of the program and adjust the time accordingly!
Accessing a Satellite Program. In order to tune into a satellite program, you must have 1) a steerable antenna capable of receiving either C- or Ku-Band satellite transmissions and 2) the satellite coordinates designated for the particular program you are trying to access. The coordinates specify which satellites on the C- and KU-Bands are being used. You will need to program your receiver with the code that matches either of these satellites, depending on your band capability.
Programming the Analog Receiver. Most sites have satellite receivers that can be pre-programmed to access the various satellites in the arc over North America. It is critical that the programming of the receiver be done correctly and accurately. We recommend that this be done by a qualified local technician, competent with both C- and Ku-Bands, at the time of installation and updated annually.
Program Codes. The codes which the technician programs into your system are not standardized system-wide. They may vary from state to state or even from technician to technician. For example, the satellite Telstar 4 may be coded as "T4" in one receiver and "T1" in another. The specific codes used are not as critical as the fact that the technician tracks each code created and lists it in writing on a chart for you next to the satellite name. This should be done for each and every main satellite in the North American arc. The chart attached displays the most widely used satellites in North America, as well as a typical code for each. Note that the letter/number combinations can only be used once in programming a satellite. The far left hand column has been left blank for you to record your receiver's programmed codes. We recommend that you/your technician complete the entire chart, showing the codes for each satellite. Then date and post it near your equipment, so that anyone who needs this information about your system can easily access it.
Receiver Operator. Once your receiver is fully and accurately programmed, it is recommended that a particular person be designated to operate the machine at all times. An additional person should be identified and trained as a back-up. It is also recommended that the operator prepare a detailed, step-by-step "how-to operate the receiver" guide for any time that the main designee is not available.
Pre-Program Test. As soon as you obtain the coordinates for a program, immediately verify that your receiver is programmed for the satellite(s) specified. Then, utilize the test time designated (normally the day prior to the broadcast) to check the signal. Do not wait until the actual broadcast to perform this check.
Annual Code and Satellite Check. The satellite business is a dynamic one. New satellites are launched and old ones inactivated all the time. For that reason, it is critical that you have your list of codes and equipment checked by a reputable technician once a year at a minimum. This updating process will help to ensure that your receiver is accessing the right satellites for your programs.
Dual C- and Ku-Band Capabilities. Some satellites are low-powered and provide weak signals. Therefore, it would be beneficial for each downlink site to have capability to receive both C- and Ku-Bands. If both bands are accessible and properly programmed, switching from one to the other will provide you the versatility to select the stronger of the two signals, thus providing clearer reception. If you currently do not have both C- and Ku-Band capability, ask your technician what the cost would be to upgrade your system. This should not require a new dish, only hardware. The advantage of having the option to switch to a stronger, clearer satellite band when a signal is coming in weak will generally outweigh the cost associated with the upgrade.
Aligning your satellite dish correctly is a critical step.
It will ensure the best possible signal reception. Take your time in completing the sequence. In many cases, your technical staff, a rental dish vendor or other locally arranged staff will complete the satellite antenna alignment. Knowledge of the necessary steps will help you supervise this operation.
Tune your receiver to the proper transponder and audio sub-carrier frequency to receive the signal being transmitted. We do not plan to encrypt (scramble) the broadcast, but other broadcasts that you might receive may be scrambled.
Adjust the elevation of the satellite dish if needed.
Adjust the azimuth of the satellite dish if needed.
Adjust for the correct polarization, either horizontal or vertical if needed.
Repeat items 2-4 until the video signal is sharp and clear of static and interference. If your receiver has a signal strength meter, this meter should indicate it is receiving the maximum strength signal from your downlink site. This is referred to as "peaking" the signal strength meter.
The location of the satellite in the sky from your viewing site. You or your technical people will need to know how high above the horizon the satellite is, which is called the elevation. You or your technical designee will also need to know the azimuth, that is how far east or west in the southernly sky the satellite is located.
Signal polarization is either horizontal or vertical. The signal coming from the satellite to your dish will either be vibrating along a horizontal or vertical plane. The receiving equipment must be adjusted to receive the correct polarization.
The audio portion of the videoconference is sent along with the video signal, but on a different frequency. Selection of the proper audio sub-carrier will allow you to hear the audio portion of the program.
If you are not receiving a good signal there may be downlink equipment problems, local terrestrial interference (if using C band) and uplink transmission problems. Some of the local technical difficulties you may encounter are:
1. Terrestrial Interference is usually caused by local microwave transmission for telephone and paging systems operating on the same frequency as that of your C band downlink. It can vary in strength as well as how often and when it occurs. Terrestrial interference can range from little black and white dots that show up on the screen to complete interference and blockage of reception. You may need a technical person to "scout' out the source of interference.
2. Rain Attenuation can drastically weaken the signal strength if you are receiving the signal on a
Ku band. The result will be similar to the terrestrial interference described above.
3. Snow on the satellite dish, if allowed to accumulate more than four or five inches, can interfere with the signal reception. Remove the snow with a soft cloth or broom. A small amount of ice on the dish should not cause any problems.
4. Sun Spots are another common interference.
Notes:
Most often problems are at the downlink end. If you think there is a problem at the uplink or with the satellite transponder, first check other transponders on the same satellite.
If you are not receiving a clear signal on the scheduled transponder, but are receiving a good signal from another transponder or if you think the problems you are having are not local, call the technical support member. The number will be provided with the satellite coordinates.
If you are unable to receive the satellite transmission, first check with the on site technician for assistance. If that does not work, contact technical assistance at the uplink site. The number will be provided with the coordinates. If you are still unable to receive the broadcast, you have a choice of two options.
Option #1 is to listen to the broadcast on a speaker phone if it is available from the program provider. A hard copy of all the slides may be provided online for participants to see what the presenter is showing.
Option #2 would be to watch the video tape at a later date if a tape is available.
The phone number will be provided with each sessions materials. It will also be displayed across the screen during times that phone calls will be accepted. Bring one caller to the telephone. Only one caller per site will be accepted with each call. This means that if you have more than one participant wishing to present questions during the call in period, you must place each call separately. This allows other sites access to the telephone line.
When calling in, please give the following information:
1. Name
2. Site Location
3. Who the question is for (speaker, panel or entire group)
The Question:
Questions are screened before they go on the air in order to reduce repetition. Some presenters will address the questions given to them on cards, versus live. Therefore, questions could be called in throughout the program.
Wait quietly and continue to monitor the telephone while the operator checks the sound.
If the television audio can be heard over the telephone line, the operator will ask that the television set be turned down before the caller goes on the air.
When the program uses live questions, the presenter will state when he/she is ready to receive questions. Continue to stand by the telephone as the presenter may ask for clarification or feedback during the answer. An "echo" effect will result from the one-quarter second delay between the time the word is spoken at the site and relays back on television. The echo is normal and should be ignored.
When the presenter moves on to the next call, you will automatically be disconnected. Hang up the telephone and re-dial to start the process over with another caller. If the line is busy, keep trying until the interactive portion of the program is concluded.
Questions or statements made by the viewers may or may not be representative of the audience at large. The question-and-answer period should benefit all viewers with the discussions that take place between their fellow viewers across the country and expert presenters.
C-band n. A frequency used in satellite transmission.
Downlink n. A satellite dish that receives a signal from a satellite transmitter. It encompasses all the equipment at a receive site.
Ku-band n A frequency used in satellite transmission.
Satellite Dish n. The device that sends or receives satellite signals.
Satellite Receiver n. A piece of equipment used to select a satellite, and the proper transponder.
Transponder n. The part of the satellite that receives the uplink signal and then transmits it back to earth. Each satellite has between 10 and 32 transponders.
Uplink n. The satellite dish that transmits a signal up to a satellite. It is also known as an Earth Station.