Satellite Reception Setup
DVB Device Installation
Install the DVB card and driver according to the instructions in the package and connect it to the antenna. Alternatively connect the DVB router to the network interface and configure the reception parameters following the guides. All DVB installation guides are included in the EUMETCast CD/DVD and the latest versions are available for download at:
ftp://ftp.eumetsat.int/pub/OPS/out/user/EUMETCast_Support/EUMETCast_Licence_cd/EUMETCast Client Package for Linux and Windows
|Table of Contents|
Satellite Dish pointing and LNB alignment
Adjusting the satellite dish at regular interval for best reception is very important, even for small antennas as over time the pointing will degrade due to wind load.
For new installations you will need to find the exact elevation, azimuth and skew that gives you the optimal reception. In order to get a clear signal, you need a clear path from your dish to the satellite - no trees or buildings in the way.
There are three steps to successfully installing the satellite dish and optimising it for DVB-S2 reception.
The first step involves finding your “look angle”, the direction in which the dish needs to be pointed to receive the signal. This can be done by utilising the website http://www.dishpointer.com/ where to find the “look angle” you enter your location and the required satellite. Alternatively you can call a local technician for assistance.
The second step is aligning the satellite dish/antenna to the satellite using the azimuth and elevation angles. Use a compass or get the direction from Google maps to select the azimuth. Select the elevation by using the elevation angle scale on the mount bracket. Then use a dish pointer tool to optimise the signal. Connect the DVB device and check if you have selected the correct transponder (see the following section) and that EUMETCast can be received.
The third step is optimising your reception. We suggest a laptop is used in close proximity to the dish and your already configured DVB receiver, or alternatively remote control software, to enable you to see and optimise the reception via the instantaneous changes in levels.
Follow the DVB receiver setup guide to configure the receiver for the DVB downlink. Make sure you already receive EUMETCast data and read the link margin or EsNo or C/N (or other quality parameter) while moving the dish.
Try moving the dish in very small steps towards the East or West to find the maximum link margin and fix the azimuth. Then move it fractionally up or down to get the best link margin value. Wait until the parameters have stabilised. Repeat these steps several times. Then tighten the screws. Sometimes tightening the screws will de-point the dish again. You may have to try several times.
For the DVB-S2 reception in KU band (on EUTELSAT 10A), the 'skew' angle of the LNB is very important. The 'skew' angle represents the horizontal/vertical plane of the LNB. When a satellite dish is facing towards a satellite at due south, the plane of the LNB will be vertical (straight down). As the dish is moved around either East or West to receive other Satellites the LNB will need to be tilted (rotated), clockwise for West and counter clockwise for East (as viewed from the rear of the dish). The best way to adjust the LNB skew is to set it at zero degree and then to rotate it in very small steps both ways while keeping an eye on the link margin. Adjust for optimal link margin.
If the user’s LNB supports focussing, the user should try to find the best focus point to get the higher possible link margin, moving the LNB towards the dish or away from it.
Note: If the user satellite dish is within the specification the measured clear sky link margin should be more than 4 dB for Ku band and more than 2.5 dB for C band which is sufficient to give the target availability of 99.98%.
A more comprehensive antenna pointing guide is available on the EUMETCast CD/DVD and for download at;
KU band dual feed setup
This section describes the installation and pointing of a dual feed system, in order to be ready for reception from the EUMETCast backup transponders on HB13.
Inspect the antenna if existing rails for mounting multiple LNBs exists, and if it is long enough to span the range from 10° E to 13° E, with enough margin. A curved rail is recommended, such that all LNBs point to the centre of the dish. For most of the LNB mounts there are kits available to install multiple LNBs.
Use a DVB-S2 signal analyser / satellite finder supporting ACM/VCM and the MODCODs used by EUMETCast, or a DVB router /DBV card with PC/Laptop to analyse the reception. For the optimisation in the following steps always optimise for maximum C/N or link margin or EsN0, whatever is available, for HB13 use the list of active transponders listed in the section above.
Starting from an antenna pointed to E10A with an LNB in the focus, mount the curved rail kit for the LNBs you are intending to use. In Figure 7 the standard 40mm LNB mounts are used.
put LNB (for the E10A) in the centre of the rail, close to the original position reception from E10A should still work
mount the second LNB on the left (west), back to back next to the first LNB
Note: on smaller dishes (<90 cm) the standard 40 mm LNBs are too large,
use small diameter so-called rocket LNBs to be able to achieve small enough distances
optimise azimuth position on the rail for both LNBs
optimise skew angle of both LNBs
optimise twist angle for Hb13
then optimise the elevation of the complete antenna for E10A
repeat optimisation of elevation and twisting until the maximum for both LNBs is found
After this procedure the E10A performance should close to the original performance, and in addition reception from HB13 should be possible.
The image shows a dual feed solution between 21° and 10°. For HB13 the LNBs will be so close that they touch each other.
Figure 7: Dual-Feed system
The LNB is a crucial analogue component for reception of the weak satellite signals in Ku band and for delivering the down-converted L-band signal to the DVB receiver. That’s why the user should check the existing LNB and decide if there is a need for it to be replaced. The LNB should also match the antenna geometry.
The noise figure of the LNB is a measurement of how much noise the LNB will add to the signal you may be intending to receive. The gain is a measure of the amplification factor. The lower the noise figure of the LNB and the higher the gain the better the LNB will be able to receive weaker signals. Although high gain LNBs might be useful to compensate losses from long antenna cables, it is more efficient to use low loss cables in this case. The cross-polar isolation is a measure of how much the signals from neighbouring transponders on the different polarisation are suppressed.
Some companies advertise the "0.1dB" noise figure specification. This is utterly meaningless. Once the noise figure is below 0.6dB right across both bands (Hi and Lo), then lowering it further would make no discernible difference to reception. With low price consumer LNBs a quality selection by specification cannot be made. It is better to just test different LNBs if the result is not satisfactory. High priced quality LNBs can give an improvement in link margin of more than 0.5 dB compared to the average consumer device.
In order to increase the link margin it is more cost effective to invest in a larger dish compared to a high priced LNB. EUMETSAT suggests for Ku band a Universal LNB (HD Reception) which can feed the DVB-S2 receiver in the full Ku band range (10.7 to 12.75 GHz). For C band an LNB supporting the C band range with LOF of 5150 MHz and power supply via coax cable is suggested. These LOF frequencies are compatible with the EUMETSAT provided DVB devices configurations and guides.
Where a user has two or more receivers, multi output LNB (Dual or Quad LNB) can be used, each output supporting the full Ku band range. Please see the “Redundant receivers and multiple transponders” section below for more information.
Cabling - Connectors
It is recommended that the user checks the existing wiring and IF connectors. Be sure that the cable is in a good condition and shows no signs of damage or kinking. Ensure that the inner core and braiding are not shorted and that both have electrical continuity. If the user finds that the wiring needs replacing, EUMETSAT suggests using only high-quality cable with proper insulation. For distance less than 20 m it is recommended to use the standard 75 ohm Coaxial Cable Type-F RG 6/U or similar. For longer cables up to 200m a low loss coax cable type 75 ohm RG-11 should be used. Using an amplifier to compensate cable losses will not achieve the same performance compared to using shorter or low loss cables.
The user should also check that the F-connectors are fitted correctly. If the copper insulation touches the inner copper wire, or if the F-connector doesn't touch the outer braid, strong interference can occur resulting in degradation in signal quality.
Redundant receivers and multiple transponders
Where a user has two or more receivers which should be connected to one or more transponders there are many solutions possible:
Using passive splitters
Using multi-output LNBs (Dual or Quad LNB)
Using separate dedicated antennas
Using multi-switches and DiSEqC
The pro and cons of the different choices are briefly explained.
A minimum hardware upgrade to support 2 transponders is shown in Figure 8. A passive splitter is inserted in the antenna cable and splits the incoming IF signal (0.9 – 2.1 GHz) into multiple output ports to which the DVB receivers can be directly connected. They usually allow DC pass- through from the receivers in order to feed power to the LNB. This solution is only possible if the two (or more) transponders are operated in the same polarisation and frequency band.
As a variation of the splitter solution multi output LNB (Dual or Quad LNB) can be used. In fact the splitter function is moved to the antenna and longer cables must be used to connect the antenna to the receivers. The advantage of this solution is that each LNB output port can support the full Ku band range and different polarisation, however the correct KLNB type must be chosen.
Alternatively, if the multiple receivers are using the same frequency band and polarisation, passive splitters can be used at the input side of the receivers.
Figure 9 shows a variation of the splitter solution where the existing system is maintained as much as possible and the new transponder is served by separate reception PC. This solution requires a dedicated license and EKU for the second reception PC.
Figure 10 shows a high availability and fully redundant solution. It is a duplication of the splitter solution with the advantage that a completely separate system allows down time of one of the systems without impact on the overall reception service. Such a down time might be caused by problems or might be necessary for maintenance.
Figure 8: Minimum hardware upgrade
Figure 9: Hardware upgrade keeping existing system untouched
Figure 10: fully redundant reception chains (recommended)