Newswift Maintenance; Dish; Azimuth Internal Spur Gear; Polarisation Drive - Advent VISLINK Newswift 90 Technical Operation Handbook

VISLINK
5.

NEWSWIFT MAINTENANCE

The following maintenance is to be carried out every 3 months during normal service. If the
equipment is in heavy use in extreme environmental conditions, then the maintenance period
should be reduced.
WARNING: - Before carrying out any maintenance, ensure that power is disconnected
from the system.
5.1

DISH

Inspect the dish front reflecting surface for damage. Any damage may affect performance or
produce dangerous levels of RF radiation.
5.2

AZIMUTH INTERNAL SPUR GEAR

Wipe any dirt and grease from the gear teeth, (This process may be eased by removing the
gear cover, held in place by 4 screws). (Figure 1).
Re-apply a small amount of low temperature grease – Kluber Isoflex LDS 18 (Advent part
number G04-000004) or similar.
5.3

POLARISATION DRIVE

Wipe any excess dirt from the worm and wheel gears (Figure 2).
Spray the worm and wheel gears with WD40 or similar.
Lightly wipe off any excess oil.
5.4

REAR FEEDHORN PLASTIC BUSH

Wipe any dirt from the front and rear of the plastic bush.
If dirt appears to be present in the bush, then remove and clean the bush as follows.
Loosen the front feedhorn C-section clamp. Care should be taken to ensure that the screws
are not fully undone (Figure 3).
Supporting the feedhorn, remove the rear clamp screws (a cut down allen key may be
needed to access both screws). Remove the C-section clamp (Figure 4).
While still supporting the feedhorn, slide the bush forward to give access to its inner surface.
Wipe any dirt from inside the bush, and the outside of the feedhorn that mates up with the
bush (Figure 5).
If the surface of the bush is scored or otherwise damaged, then replace with a new bush.
Push the bush back over the feedhorn and re-tighten the feedhorn clamps. Locate the bush
flange in the recess in the rear C-section clamp (Figure 6). Care should be taken to ensure
that the location pin (Figure 7) in the front of the feedhorn fits into its recess in the front
clamp, and that the worm and wheel gears line up with each other (Figure 8).
5.5

FEEDHORN WINDOW

Check that the feedhorn window is not cut or damaged (Figure 9).
If the window is damaged, contact Advent Communications for a replacement.
5.6

FLEXIBLE WAVEGUIDE

Inspect all flexible waveguide for degradation of the rubber that may indicate internal damage
Replace any damaged waveguide. When replacing waveguide, check the condition of the
waveguide shims. If a metal shim is used, replace it. If gore (rubber) shims are used, then
they may be re-used if they are still in good condition (replace if not). If the gore shim being
replaced is bonded in place, any adhesive left on the flange surface should be cleaned off
using isopropyl alcohol or similar prior to fitting the new shim.
Newswift 90-180 Motorised Antenna 45