Satellite Reception Setup

Satellite Reception Setup

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:


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.

  1. 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.

  2. 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.

  3. 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.

During the antenna alignment, some users accidentally align the antenna with the Astra satellite on 19°E or Hotbird13 on 13°E. If you suspect such a case, then you can use the transponder parameters on the Astra satellite shown in table 4 below. If you receive a signal with the Symbolrate and MODCOD as indicated in the table for Hotbird13 or Astra then this means the antenna is aligned to the wrong satellite.

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;


Neighbouring Satellites Transponder table

The transponder table (table 4) helps to identify the satellites in the neighbourhood of E10A using similar downlink frequencies as EUMETCast. This table was valid at the time of writing this document. See https://www.lyngsat.com/* for latest status on active transponders.

* Reliance on links and references to third party websites or services, that are not controlled by EUMETSAT and made available only as a convenience, is at your own risk. We cannot be held responsible for the content and make no warranty, either express or implied, as to the accuracy, availability or content of information made available through third party websites and services.

Satellite position

Pol

RF freq.

L-band freq., LOF=9750 MHz

Symbolrate

MODCOD

Satellite

10°E

H

11262 MHz

1512 MHz

33.000 MSymbol/s

8PSK 3/5,
16APSK 2/3

(E10A, EUMETCast transponder)

13°E

H

11258 MHz

1508 MHz

27.500 MSymbol/s

8PSK 3/4

(Hotbird13, not EUMETCast transponder)

13°E

V

11278 MHz

1528 MHz

27.500 MSymbol/s

8PSK 3/4

(Hotbird13, not EUMETCast transponder)

19°E

H

11273 MHz

1523 MHz

22.000 MSymbol/s

8PSK 2/3

(Astra, not EUMETCast transponder)

Table 4: Active transponder table, EUMETCast and transponders on neighbouring satellites


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 table 4.

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 11 the standard 40mm LNB mounts are used.

  • put LNB (for 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 (maximise EsNo or link margin) 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 11: Dual-Feed system


Antenna pointing requirements

This section describes the impact of pointing errors on the link margin. The requirements for mobile reception systems are exactly the same as for fixed antenna systems. An implicit requirement is of course that the pointing accuracy must be maintained good enough to prevent a significant degradation in the link margin.

For example:

For the Europe DVB-S2 High Volume Service an antenna size of 2.4 m is sufficient for nearly all European sea areas, and for Atlantic areas not too far from the European coast. See antenna size plots in Antenna size recommendations for more details. The table on the right shows the gain loss (= link margin degradation) versus the pointing error. From this the pointing accuracy for a 2.4 m antenna should be better than 0.2°.

The degradation for other antenna sizes and in C-band can be calculated using this tool: http://www.satellite-calculations.com/Satellite/off_peak.htm*

2.4 m antenna Ku band

2.4 m antenna Ku band

pointing error

gain loss

0.1°

0.2 dB

0.2°

0.8 dB

0.3°

1.8 dB

0.38°

2.87 dB

Table 5: gain loss versus pointing error


LNB

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 LNBs (Twin, Quad or Quattro LNBs) 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 (Twin, Quad or Quattro LNBs)

  • Using multi-switches and DiSEqC

The pro and cons of the different choices are briefly explained. High availability and fully redundant solution can be built by duplication of one of the solutions described below.

 

Single chain reception system using multi-switches

A minimum single reception chain supporting all future transponders on prime and backup satellite is shown in Figure 12. A single multi-feed dish with 2 Quattro LNBs is used and LNBs are connected to a single DVB multi-switch with minimum 6 output ports. Each output port can be connected to any of the input LNB port an thus give access to any transponder on the two satellites. Therefore, any transponder change can be supported by configuration of the DVB receivers without hardware change. The built-in amplifier allows long cables between multi-switch and DVB receiver.

6 DVB receivers are required to support all prime and backup transponders, it could be less if a DVB receiver supports multiple transponders.

The disadvantage of this solution is that the DVB receivers must support DiSEqC signalling in order to switch between the input satellites. The multi-switch needs a power supply and is an active element and can therefore degrade or fail.

A single reception station is the minimum to receive all services, but in can be expanded to more reception stations for redundancy or load sharing

Figure 12: Recommended single chain reception system using multi-switches

 

 

Single chain reception system using passive splitters

Figure 13 shows an alternative solution using signal splitters, designed for the planned transponders. The RF distribution network is passive and therefore the risk of degradation and failure is very low. The cable length between LNBs and DVB receiver is limited and transponder changes may need hardware changes or at least changes in the connections between LNBs and DVB receivers.

 

Figure 13: Recommended single chain reception system using passive splitters