There are many transponders on a typical satellite, each capable of supporting one or more communication channels. In a few limited instances, satellite transponders can transmit directly to other satellites; this is known as satellite mesh topologies. These systems tend to be more expensive to build, and services are more expensive for end users. Register for Webinar. Join your peers for the unveiling of the latest insights at Gartner conferences.
Expert insights and strategies to address your priorities and solve your most pressing challenges. The subsystem, which provides the connecting link between transmitting and receiving antennas of a satellite is known as Transponder. It is one of the most important subsystem of space segment subsystems. Transponder performs the functions of both transmitter and receiver Responder in a satellite. Transponder performs mainly two functions.
Those are amplifying the received input signal and translates the frequency of it. In general, different frequency values are chosen for both uplink and down link in order to avoid the interference between the transmitted and received signals. We can easily understand the operation of Transponder from the block diagram itself. The simplest test is to turn off your engine and see whether it goes away. The buzzing and clicking lasts from a few seconds to a minute at a time.
Switch off heating systems and see whether the problem goes away. If the problem persists when you turn the heating system back on, the problem could be with the thermostat, which may need to be repaired or replaced. To find out if a particular switch is causing the problem, try turning the lights off one at a time.
Many people are now using low power LED lights instead of the more traditional varieties. However, if the original light used a transformer rather than directly running off the mains, it is possible the transformer is causing the interference.
This is because the transformer would have been designed to operate at the higher power and not the lower power the LED lights use. This has the potential to cause electrical interference. Street lamps. Street lamps can sometimes cause buzzing and crackling sounds on your FM radio. Keeping a note of when each lamp comes on and goes off will help to identify whether this is the cause of your interference.
If it is, contact your local council. Passing traffic. A faulty or uncompressed engine can cause a distinct buzzing 'whine' which varies with engine speed - motorcycles tend to be the worst. Try to move your radio away from the street or use an external aerial. Electric motor. An electric motor is used in many appliances such as electric lawnmowers, washing machines, drills and hairdryers etc.
A faulty motor can cause electrical interference. Check any appliance with an electric motor by moving your radio away from it to see whether the sound improves. If you have several appliances with electric motors you may need to turn them all off and try the above one at a time.
With all of these potential causes, it is worth keeping a log for at least two weeks to determine whether there are any patterns or trends to the interference. This can be due to:. Reduced transmitter power. Use our transmitter tool to see whether your local transmitter is currently affected by maintenance work.
Stereo Signal. Try moving the radio to another position, such as near a window, higher up, or another room. If you get hiss when listening to a stereo signal try switching to mono.
Stereo reception needs a stronger signal than mono. If you have a portable radio you will be able to pick up more of the receivable signal if your telescopic aerial is fully extended. If you have an external or loft aerial check they are functioning correctly. Tuning to the wrong transmitter.
Use our transmitter tool to check you are tuned to the best frequency for your area, as you can often pick up more than one signal. Very occasionally, the weather, usually high pressure, can result in a weakened signal. There is nothing anyone can do about this and the only answer is to wait for the weather to change.
For more information see our guide on how weather can affect radio reception. Help receiving TV and radio. Reception and interference main navigation Menu. Which transponders does the BBC use?
Reception Problems If you have a reception problem with one service in a multiplex you will also have problems with all the other services in that multiplex.
Check out our tools Use our problem assistant to help you diagnose problems with reception and interference View tool. Check the status of the transmitter you are using and find out TV and radio channels and frequencies View tool.
My DAB reception has started to drop out, is this due to poor reception? How can weather affect DAB reception? Tuning Most DAB radios can be tuned easily at the touch of a button. Telescopic aerials Telescopic aerials on portable radios should be fully extended to receive a good signal.
Outdoor aerials An externally mounted aerial can be attached to many types of DAB portable radio and hi-fi systems. Cables and Connectors If you have an external aerial, a radio signal will always lose some of its strength as it passes along the cable and through the connectors. Works and Warnings Check whether there are any known works or warnings that might be causing the problem. Tuning DAB uses multiplexes to group services together.
External aerials It is important to check the cables and the aerial for damage and that they are operating correctly. Damaged Cables Water can get into external cables and can cause reception problems. Car Radios Radio reception can drop out when on the move due to changes in topography. Weather Radio signals can be affected by fine weather including high pressure. Lost reception of one or more station within a multiplex If all other stations are working ok and you have just lost one station.
If your car radio is showing no signal or no service for a station you usually receive, this could be down to one of the following things: DAB Transmitter Fault If you know your location, you can use our transmitter checker to see whether there is a problem. Interference Poor DAB reception can also be caused by equipment used in the vehicle.
Topography When travelling in the car, your signal can be affected by natural features of the land, for example, hills, valleys, rivers, etc. How to find these services It is best to re-tune your radio when they are broadcasting, so it will store the station in its memory. Checking for problems Check cables and leads within your property to ensure the problem is not a simple installation fault.
Electrical interference There are differences between a reception problem and one caused by electrical interference. Why is this? My Television reception is usually good in the day, so why does my television reception sometimes deteriorate in the evenings? Why are subtitles sometimes delayed or out of sync?
Why am I receiving a voice commentary over my picture. What is this, and how can I turn this off? Freeview Help Guides What is a good Freeview installation? Aerials There are all kinds of aerials available on the market and some which are specific to certain frequencies. Height Your aerial should be as high as possible pointing towards the transmitter with the best signal.
Loft and indoor aerials If you live close to a transmitter or can get a strong TV signal, then it could be possible to use an aerial in your loft or an indoor portable aerial. Cable and connectors A television signal will always lose some of its strength as it passes along the cable and through the connectors. Amplifier These are not recommended unless absolutely required as they can introduce unexpected reception problems. Polarisation Depending on the transmitter you are using, your aerial elements will need to be mounted flat horizontal or on its side vertical.
Qualified Installer We cannot recommend individual installers. Troubleshooting your Freeview Television reception Basic Installation It is important to check that your installation is intact.
Works and Warnings Check our Works and Warnings section to see whether there are any known problems. Transmitter faults Using our Transmitter Checker , check your transmitter is not undergoing any work. Weather Television signals can be affected by fine weather including high pressure atmospherics and the only solution is to wait for the weather to change, you should not retune during this time.
Trees During wet weather, when covered in moisture, all trees can have an appreciable effect on signals. Manual Retune A manual retune is more effective than an auto-retune as it only tunes your television to the transmitter your aerial is pointing towards.
Interference If you are still having problems, it is possible an unwanted signal is the cause. Qualified Installer We cannot recommend individual Installers. How to check your cables for water damage If possible, check the external cable for any signs of damage, such as cracking and tears. Damaged cables can cause reception problems and can allow water into your installation. Find the cable that goes from your aerial or satellite dish into your television, radio or set top box and unplug it.
This may be from a socket on the wall or a direct cable through the wall. If you are using a satellite dish to receive your television, you will also need to check the LNB and cap for any signs of water damage. You may need to instruct a qualified installer to assist you with this. If it is a direct cable, check for any obvious signs of water or a green build-up on the connector.
If it is from a wall socket check both the connector on the cable and on the wall socket for any signs of water or green build-up. A green build-up is a sign that water has at some point got into your installation.
If you find water damage then it is likely that the cable will need replacing by a qualified aerial installer. How to better my signal using an amplifier or attenuator When to use an amplifier A signal amplifier should only be used as a last resort when the television signal is weak.
Problems using amplifiers Amplifiers themselves are a common source of reception problems. Masthead These fit directly under an outside aerial and usually the best type of amplifier to fix weak signals. Set-back These fit between the aerial socket in the wall and your television. Distribution These split the TV signal from a single aerial and allow the signal to be sent to several different televisions in the building.
Combined amplifiers Some amplifiers are a mix of the above. Attenuators When to use an Attenuator If you are experiencing pixellation or picture break up, it may be that your signal is too strong as this often presents itself similarly to a weak signal.
Problems with television and radio services in North Yorkshire and Teesside What's happened at Bilsdale transmitter? What if channels do not come back following the retune?
Essential engineering work affecting listeners in the north of England FM radio at Holme Moss has been undergoing antenna re-engineering works since the 29th June. Engineering works. Image credit: mb Latest Radio works and warnings Problems with television and radio services in North Yorkshire and Teesside What's happened at Bilsdale transmitter? Why can I hear a foreign radio station?
Why is medium wave reception worse at night? Radio Help Guides Troubleshooting FM radio B asic Installation It is important to check your installation is working properly and that your radio is in the best possible position. Works and warnings Check whether there are any known works or warnings that may be causing the problem. Transmitter faults and frequencies Use our Transmitter Checker to check the transmitter is not undergoing any work and to see which FM radio services you can receive from your location.
Hi-Fi radios If you are using a Hi-Fi tuner and stereo reception is hissy, but mono is fine, your aerial may not be powerful enough. Weather FM radio signals can be affected by fine weather including high pressure and the only solution is to wait for the weather to change, you should not re-tune during this time.
Pirate Radio In some urban areas Pirate Radio can be a problem. Distorted S and Z sounds sibilance This can happen when your radio receives more than one signal. Twittering and whistling This often sounds like birds tweeting and happens if there is another frequency being transmitted near the one you are listening to. Hissing and fading This normally means that the signal you are receiving is not strong enough. Buzzing, clicking and pops This may mean an electrical item in your home or nearby, is interfering with the reception of your FM radio and is causing the buzzing, clicking or pops you can hear.
Distortion - fuzzy, gritty, scratchy sound This is commonly caused by the FM signals being bounced off objects or hillsides and reaching your radio by different paths. So, more simply, we can say that a satellite transponder is a series of interlinked devices that form a single communication channel between transmitter and receiver. A combination of a transmitter-receiver system employed together to execute communication between the two is called a transponder.
We know that whenever there is a need for a signal to get transmitted or received between the two ends then a need for a channel exists through which the transmission or reception can take place.
Some signals do not require any specific medium and simply get propagated through a vacuum. But in the case of satellite communication, radio waves cover a quite large space of earth, thus, a proper channel is required which can support the propagation of radio waves from an end to another.
This channel is known as a transponder. It is to be noted here that the bandwidth of the transponder shows dependency on the nature of the signal being carried out by the satellite and the technology used for the transmission. For typical C-band satellite service, the bandwidth allotted is around MHz and this is divided among various sub-bands where each sub-band is allotted to a single transponder.
The bandwidth of a typical transponder is 36 MHz. If we employ 12 such transponders with 4 MHz of guard band between each transponder, then accommodation of 12 transponders in MHz bandwidth is achievable. Satellite communication is a crucial pillar of the global telecommunications system.
0コメント