Triax TD Unique.pdf

MULTI RECEPTION DISH<br />

- new high-performance standard for multi satellite reception<br />

TRIAX <strong>Unique</strong> Multi Reception Dish<br />

• Only one dish for reception of<br />

2 - 5 satellites<br />

• <strong>Unique</strong>ly shaped dish giving high<br />

and constant gain within a 30<br />

deg. range.<br />

• No moveable parts<br />

• Quick and easy to mount<br />

• Simple and easy adjustment<br />

• Individual setting of each LNB<br />

• Prepared for future satellites<br />

• High mechanical strength and<br />

resistance to corrosion<br />

Bjørnkærvej 3<br />

DK-8783 Hornsyld<br />

Tel.: +45 76822200<br />

Fax: +45 75687966<br />

www.triax.dk

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TRIAX <strong>Unique</strong> Multi Reception Dish<br />

- a technical description<br />

Multi Satellite Reception<br />

With the increasing number of satellites follows the wish to receive signals<br />

from different (satellite) directions.<br />

There are several approaches to this, each with its own advantage and<br />

disadvantage.<br />

1) One dish for each satellite. Technically this is the best solution, as each<br />

dish can be optimized with respect to size and position. However to<br />

receive many satellites you need a lot of dishes!<br />

2) Sidemounting of LNB’s. Using this method an adjacent satellite can be<br />

received by offsetting an LNB from the true focus, thereby changing<br />

the beamdirection of the dish.<br />

However this “twisting” of the beam reduces gain - and the further<br />

away from the true focal point, the more gain is lost and so the available<br />

satellite signal. Offsetting two LNB’s symmetrically to each side of<br />

the focalpoint generally gives a better compromise, with less reduction<br />

of each signal.<br />

3) A motorized dish. With this solution one dish is covering all available<br />

satellites, however only one position can be received at a time and the<br />

installation and adjustment can be complicated.<br />

All three types of installations are used - depending on the individual<br />

requirement of the customers. And TRIAX offers the right products for<br />

each of these solutions.<br />

Fig. 1 Shows reduction in gain vs. change in azimuth beam angle on a<br />

<strong>TD</strong>78 dish with sidemounting.<br />

<strong>TD</strong> Dish 78 Reduction with offset-mounting of LNB<br />

Ref. val (dB): 37.00 - Scale/div. (dB): 1.00<br />

[dB ]<br />

0<br />

Advantage of TRIAX <strong>Unique</strong><br />

Multi Reception Dish<br />

The <strong>Unique</strong> Multi Reception Dish is the result of research into semi-parabolic<br />

shapes and the influence on available gain in both main and sidedirections.<br />

Through a special shaping we have streched the focal point into<br />

a focalline and still letting each LNB utilize all of the dish’s surface. Thus<br />

succesfully combining efficient area utilization of sidemounting with the<br />

broad and uniform azimuth beam coverage of the torus antenna.<br />

Fig. 3 TRIAX <strong>Unique</strong> Multi Reception Dish gain.<br />

<strong>TD</strong> <strong>Unique</strong> Multi Reception Dish<br />

Ref. val (dB): 37.00 - Scale/div. (dB): 1.00<br />

[dB ]<br />

0<br />

-1<br />

-2<br />

-3<br />

-4<br />

-5<br />

-30 -25 -20 -15 -10 -5 0 5 10 15 20 25 30<br />

[deg ]<br />

It is quite obvious, how the TRIAX <strong>Unique</strong> Multi Reception Dish design<br />

retains gain even at large changes of azimuth beam angles<br />

- where it really matters for multisatellite reception!<br />

-1<br />

-2<br />

-3<br />

Technical Specifications<br />

-4<br />

-5<br />

Type<br />

<strong>TD</strong> <strong>Unique</strong> Multi Reception Dish<br />

Part No.<br />

126390<br />

-30 -25 -20 -15 -10 -5 0 5 10 15 20 25 30<br />

[deg ]<br />

On a standard dish the LNB is placed in focus for best gain.<br />

A second LNB can be sidemounted for reception of an adjacent satellite.<br />

However gain is lost as this LNB is out of focus, and the losses increase<br />

dramatically with large offsets.<br />

For neighbouring satellites having 3 to 6 deg spacing this is uncritical -<br />

additional losses may be limited to 0,2 - 0,5 dB; however for separations<br />

of 10 deg or more, the losses quickly rise to 3 - 6 dB!<br />

Fig. 2 Comparison of gain distribution vs. azimuth beam angle using a<br />

standard <strong>TD</strong>78 dish and the TRIAX <strong>Unique</strong> Multi Reception Dish.<br />

Frequency range<br />

Gain (@ 11.7 GHz)<br />

X-polarisation<br />

Offset angle<br />

Reflector type<br />

Beam width<br />

10,7 - 12,75 GHz<br />

37.1 dBi<br />

> 20 dB<br />

26°<br />

Offset (F/D ratio 0.6)<br />

2.6°<br />

<strong>TD</strong>78 and <strong>TD</strong> <strong>Unique</strong> Multi Reception Dish Comparison<br />

Ref. val (dB): 37.00 - Scale/div. (dB): 1.00<br />

[dB ]<br />

Elevation range<br />

5 - 50 deg.<br />

0<br />

-1<br />

-2<br />

-3<br />

LNB adjustment<br />

(azimuth)<br />

Material<br />

+/- 17 deg.<br />

Pregalvanised steel<br />

-4<br />

-5<br />

-30 -25 -20 -15 -10 -5 0 5 10 15 20 25 30<br />

[deg ]<br />

There are certain antenna designs, where several LNB’s may be placed<br />

next to each other for multi satellite reception without change in individual<br />

performance. One such design is the torus dish, which has a rectangular<br />

reflector using a combination of a parabolic and circular shape.<br />

This design has the advantage that the focuses are placed on a line in<br />

front of the dish, where all LNB’s are placed. The disadvantage is, that<br />

each LNB only utilizes a minor part of the reflector, and as a consequence<br />

the gain is equivalent to that of a smaller dish.<br />

Finish<br />

LNB holder<br />

Size (w x h)<br />

Weight (kg)<br />

Windload (42m/s)<br />

Mast dimension<br />

Wall bracket<br />

Chromate, polyester powder coat<br />

Plastic feed holder<br />

Ø25/Ø40<br />

100 x 111 cm<br />

11<br />

950N<br />

Ø 28-Ø 63 mm<br />

- optional extra<br />

AB.17.4.02