Multifeed told about, but it's not the only way to catch a number of satellites in one dish. Perhaps not the cheapest. Positioner with service engines worth $ 115 (4,000 rubles) on e-bay. Precision angular adjustment is one-tenth of a degree - just better induced examples of most devices. Let us consider: Setting a satellite dish on their own whether to do or buy engines running on Diseko protocol. Adjust the satellite dish "Tricolor" is not difficult - just catch the two devices is more complicated.
antenna pointing to the satellite
antenna pointing to the satellite
Find out the coordinates of the spacecraft - an online calculator or special program (tele-satellite.com/fxpos.exe) deem pointing angles of the antenna. Chosen place bracket assembly: a clear sky in the right direction. Unable to perform - a satellite dish is not worth buying. location: balcony wall of the house, the roof - where utilities (house manager) will allow to set. Setting more convenient to carry special device like Satfinder (500 rubles, http://www.digisat.ru/index.php? productID = 1710) or at the receiver (uncomfortable).
In the first case, the user is at the disposal of a small box, able to detect the presence of the signal in the cable. The device is powered by three-way (optional):
- According to the cable from the receiver.
- From an internal battery.
- According to the power supply circuit 13/18 In Diseko protocol.
Advanced devices able to work with switches Diseko, multiple converters - relates to a method of catching several satellites multifeed. It looks curved armature, serving a support for two or more converters (number of satellites on several on one satellite, depending on the polarization types, broadcasting ranges). The equipment is manually adjusted for all. Combined converters via a switch-Diseko. With him running Satfinder host device.
For the converter creates a setting group. Is indicated on a satellite indicates the specific. Alternately hands master aims first plate, the first converter, and the rest by the number of available (the plate should not be touched). Second, set up the next movement along the multifeed fittings (set azimuth) rotation around the axis (linear polarization - the angle of the converter to the individual satellites). Relative elevation angle: multifeed size provided form.
The angle of incidence equals the angle of reflection. The satellites are stationary relative to the Earth: hover on a geostationary orbit above the equator. From a point on the curve area looks arc (part of the ellipse). Maximum elevation is located to the south (northern hemisphere), at least - at the horizon. The further settled the longitude of the satellite is the geographic coordinates of points on the ground, the elevation of an object above the ground is less than visually. Converters, following the first one, should be higher, settling on multifeed lift curve is fixed antenna, the angle of incidence equals the angle of reflection. If not carried out - the signal drops, for satellites in the horizon damped.
Of course, the multifeed master arch own, knowing the laws of optics.
To make it easier to do, go here: http://www.tricolor78.ru/karta.html. On the map find the house of residence (increasing, decreasing scale). Flip through the satellites:
- Kindly detect spacecraft hanging opposite installation point. It gives the maximum elevation. At the latitude of Novosibirsk (55 degrees north) - 27.26 degrees.
- Race against the clock longitude. To Novosibirsk - 83 (82 degrees 55 minutes) degrees east longitude. For Hotbird, hanging above the equator at 13 degrees east longitude - 2.64 degrees (parallel to the ground).
draw a multifeed
Satellites hanging west are visible. Painting symmetrical: the angle is for satellites positioned at 153 degrees east longitude. We assess multifeed. The signals collected in the focal plane. With lowering of the satellite above the ground converter should be lifted. Suppose an ordinary antenna (not offset). Find the focal length of the ruler on the spot or on the passport - the removal of the plane position of converters from the plate center. Each (of two) extreme converter should rise above the level at the central 27.26 - 2.64 = 24.62 degrees. Knowing the focal length, calculate radius multifeed bending.
Assume, f = 45 cm - typical value for a radius of 60 cm plates. Converter arrangement line deviates from the normal 70 degrees in azimuth, at 24.62 in elevation. We obtain the support points for the curve. See picture above - front view. Multifeed bent upwards towards the edges. For the example shown 5 converters, one for 5 satellites. Horizontal deviation of 45 cm x tg 70 = 124 cm, vertically upwards - √1242 + 452 cm x tg 24,26 = 59,5 cm. This coordinate is outside the aperture, the effective area of the plates decreases in accordance. We get a chance, that one dish satellite to 13 degrees East will not catch.
The reason to put the positioner. Promised count multifeed bending radius. Easier to use graphical methods. See figure below.
bending radius multifeed
Conducted through two chords known points. At the intersection midperpendiculars defined center of the circle. We use the analytic geometry. Methods of making much. Given point:
- x = -124 cm, y = 59,5 cm.
- x = 0 cm, y = 0 cm.
- x = 124 cm, y = 59.5 cm.
The center coordinates are the X and Y (in capital letters). We derive a system of equations of the radius R:
X2 + y2 = R2;
(X + 124) 2 + (Y - 59.5) 2 = R2;
(X - 124) 2 + (Y - 59.5) 2 = R2.
A drawing X = 0. Looking for Y, is exactly equal to R. Output from the second equation:
1242 + (R - 59,5) 2 = R2;
and decide to find R:
15376 + R2 - 119R + 3540,25 = R2;
119R = 18916,25; where R = 159 cm.
radius of the arc is more than one and a half meters: most multifeed straight sections of reinforcement. It is not right.
Knowing the radius understand how to deviate ends at a distance of 60 cm from the center to the left, right, azimuth deflection relative to the antenna center:
D = R - √1592 - 302 = 159 - 156 = 3 cm. On many raised edge multifeed opposite edges of the plate. Similarly readers will count any point by inserting into the formula instead of the 30 required deviation (the deviation of the azimuth of the satellite from the direction of the central dish). To 30 cm:
Alfa = arctg (45/30) = 56,3 degrees. Calculator for arctg look at http://life-prog.ru/servis.php? id = 3. In Novosibirsk, the antenna aimed directly south - satellite longitude 26.7 and 139.3 degrees east longitude. Suffer uncomfortable with the setting, adjust the position of converters. Revealing the need to aim strictly at the center of the plates (if possible). Much more effectively customize a satellite dish using the positioner is shifted to the desired angle. Azimut often unrestricted.
Discuss setting satellite dish yourself. Diseko not needed. Adjust the satellite dish to the satellite has to service motor controlled by Diseko protocol. In any weather instrument displays the plate to the desired point. If the horizon is pure - acquires chances to catch the strong radiation of DTH (Direct To Home). In this case, set up a satellite dish, you can own, without getting up from the computer chair. Because of the guidance it will take the drive, controlled remotely from the receiver. In doing so, we can much more accurately, slowly do the surgery. Actual winter: antenna hanging on a dangerous slope of the roof or in a place like this.
So, a new review of the subject reserve Diseko protocol and that is connected with it. Readers to understand what it means to tick 22 kHz on the display device for catching satellites.