ELNA-Radio Beacon Antennas (NDB)
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The STA 150 NDB ((or STA 115 NDB; used synonymously in this document unless stated otherwise) is a self-supporting mast antenna for many kinds of fixed non-directional radio beacons. The mast does not need guys or stands. It replaces costy and spacious wire arrangements and can be installed on room limited sites. Because of its small space requirements the antenna is also applicable for mobile and semi-mobile beacons, e. g. on board of light-vessels, offshore platforms, drilling rigs, etc. The standard height of the antenna is 14.5 m. It can be reduced to 11.5 m upon request. (STA 115 NDB ... ) The mast antenna carries a lumped top load assembly consisting of five capacitance rods, four sloping and one vertically mounted, and one air-core coil. This inductance is housed in a watertight tube assembly. The values of the top load assembly control the frequency range of the antenna. Typically, the beacons cover a frequency range within the 180 - 580 kHz corridor. The top load assembly provides a favourable voltage distribution along this quite short antenna. It also reduces the voltage values around the antenna base making the antenna more insensitive to changes in environment. Description Electrical The antenna is a centre loaded mast radiator. The values of the top load assembly control the frequency range and the bandwidth of the antenna. Different numbers of windings on the loading coil determine the different operating frequency ranges. Mechanical The antenna is a self-supporting mast antenna. It is made of glass-fibre reinforced plastic and consists of three different sections: Lower Mast section Loading Coil Assembly Top Rod Assembly The lower section is an 8 m (or 5 m) long conical tube. It carries the top load assembly consisting of loading coil and top rods. STA = Rod Antenna K = Tilt SSB = internal feeding NDB = Non Directional Radio Beacon E = Receiving Rod Antenna TR = reinforced SSB/E = external feeding EAU = Transformer SE = Transmit Antenna PM/M = dark grey (similar to RAL 7000)

Funkfeuerantennen / Radio Beacon Antenna STA 150 NDB (STA 115 NDB) Lower Sections US 80 PM and US 80 PM/ E (E for external) (or US 50 PM and US 50 PM/ E for STA 115 NDB) The lower section is a conical tubular mast with radiators embedded in the mast’s wall. The RF feed insulators, external and baseinjected ones, are carefully designed in order to avoid instable antenna impedances. The base-injection runs concentrically into the mast tube. It is held by small supports of good dielectric constant. On top of the lower section mast tube a joint armature carries the top load assembly. This joint...

Deatil B External Feeding Top Capacitance Rods The loading coil’s top joint armature holds the top rod STA 60 HV/2 (pos. 3) and the top capacitance ring (pos. 6). The top capacitance ring being tightened to the top joint armature by a second retaining hex nut (pos. 5) is kept in the given position by means of an arresting pin (pos. 13). Four capacitance rods STA 30 D (pos. 4) are fixed to that ring. They have a metric thread on their junction armature with which they are screwed to the top capacitance ring. Additional locking screws (pos. 12) on the top capacitance ring hold the rods tight...

ELNA reserves the right to make changes in specifications without notice.

Detail C Top Load Assembly 1 Lower mast section US 80 PM 2 Loading coil 3 Top rod STA 60 HV/2 4 Top capacitance rod STA 30 D (4x) 5 Hex nut 46 mm 6 Capacitance ring 7 Junction disk 8 Holding nut 9 O-Ring 10 Hollow screw M 8 11 Washer 8.2 12 Locking screw 13 Arresting pin Mounting Instructions The tilting device for the antenna is an indispensible accessory. It eases not only the first installation, but saves also avoidable costs later when the antenna must be laid down for maintenance or at extreme weather conditions (e.g. no cranes, large stages, etc.). The erection of the antenna can be...

Funkfeuerantennen / Radio Beacon Antenna STA 150 NDB (STA 115 NDB) Base Injection 1 Tilting device K 8 2 Spindle Assembly SP/G 3 Supporting Pipe TR 12/K ELNA reserves the right to make changes in specifications without notice.

Funkfeuerantennen / Radio Beacon Antenna STA 150 NDB (STA 115 NDB) External Feeding Please, choose the mounting place and the tilting direction carefully. Take care that the antenna tilts into the approximate direction of the feeder wire, if possible. Otherwise, the feeder wire had to be detached before each tilting operation. The external feed assembly is shown in picture 4 above. The nylon holding rope (pos. 4) with insulator (pos. 6) holds the feeder wire (pos. 7). The holding rope adjusts itself on the conical mast as the rope sling slips down until it fixes at its proper position...

Funkfeuerantennen / Radio Beacon Antenna STA 150 NDB (STA 115 NDB) Installation Proposal Base Injection Picture 8 ELNA reserves the right to make changes in specifications without notice.

Ground Network STA = Rod Antenna K = Tilt SSB = internal feeding NDB = Non Directional Radio Beacon E = Receiving Rod Antenna TR = reinforced SSB/E = external feeding EAU = Transformer SE = Transmit Antenna PM/M = dark grey (similar to RAL 7000)

Funkfeuerantennen / Radio Beacon Antenna STA 150 NDB (STA 115 NDB) 1 Foundation plate FP 8A 2 Stone bolt M 16 x 200 - DIN 529 (8x) 3 Counterpoise CP 18/15 (18 radials at 15 m each) Tightening torque MA = 160 Nm ELNA reserves the right to make changes in specifications without notice.

STA 150 NDB ... Standard Supplies A) Base Injected Antenna STA 150 NDB/ ... : 1 crate (approx. 825 x 45 x 50 cm) 1 x lower section US 80 PM with 1 x junction disk 1 x top rod STA 60 HV/2 4 x top capacitance rods STA 30 D 1 x flat gasket 1 wooden case (approx. 90 x 30 x 30 x cm) 1 x loading coil 1 x small material 1 x description B) External Antenna STA 150 NDB/E/ ... : 1 crate (approx. 825 x 45 x 50 cm) 1 x lower section US 80 PM/E with 1 x junction disk 1 x top rod STA 60 HV/2 4 x top capacitance rods STA 30 D 1 x flat gasket. 1 wooden case (approx. 90 x 30 x 30 cm) 1 x loading coil 1 x...