User's Manual

d. Install battery backup wiring between the DME transmitter cabinet and the battery backup assembly.
The battery ground lead should connect to the grounding bus bar and the battery hot wire (+48V)
should connect to TX1 DC breaker located on the 1A26 Status Panel Assembly.
e. When supplied with two battery kits then connect the hot wire (+48V) from the second battery set to
the TX2 DC breaker; otherwise install the jumper wire between TX2 DC breaker and TX1 DC breaker
as provided in the battery kit.
f. Install safety cover(s) over batteries or lid(s) on battery backup box.
CAUTION: Shorting the battery leads can cause a fire or explosion.
1.5.10 Primary AC Power Installation
AC wiring for the DME will require a separate circuit breaker for the DME system and DME obstruction
lights. The convenience outlet located on the front of the 1A26 Status Panel is powered from the
obstruction light breaker.
a. Insure DME system AC and DC circuit breakers are in the OFF position
b. Insure that shelter DME system circuit breaker is in the OFF position.
c. Connect primary AC power to DME as detailed in Figure Error! Reference source not found..
1.5.11 Shelter to Tower Conduit Connections
a. Using a 2-1/4" hole saw, cut a hole in the wall between the DME transmitters and the antenna tower at
a height above the top of the DME transmitter cabinet.
b. Refer to Figure Error! Reference source not found.. Slide 2" x 5" threaded conduit into hole. Install
reducing washer and 2" locknut on each end of threaded conduit. Tighten locknut.
c. Install protective bushing on exposed threaded conduit threads of interior shelter wall. Install 2" PVC
female adapter on threaded conduit of outer shelter wall.
d. Refer to Figure 1-7. Cut 2" PVC appropriate length to center of tower directly under antenna.
e. Install 2" PVC hole adapter in bottom of triangular tower adapter plate. Install reducing washer and 2"
locknut onto hole adapter. Install protective bushing over exposed threads.
f. Cut 2" PVC appropriate length to extend from triangular tower adapter plate to 2" PVC from shelter.
Insure that 2" PVC from triangular tower adapter plate is cut so that PVC from shelter slopes slightly
downward as it runs to tower.
g. Install 2", 90 degree PVC connector and 2" conduit adapters between the two pieces of 2" PVC and
insure that all pieces fit. Drill a 1/8" hole in the bottom of 2" 90 degree PVC connector. This will
allow any water seepage to drain. Pre-fit all pieces to insure proper mating.
1.5.12 Obstruction Light Installation and Wiring
The obstruction light assembly is shipped separately from the DME antenna and it is necessary to attach the
obstruction light to the top of the DME antenna; and the wiring that extends from the antenna must be
connected to the bulb sockets. Figure 1-8 shows the assembly details.
NOTE
The mounting hole on the top of the DME antenna is threaded for a
3/4" pipe thread. There are two versions of obstruction light assemblies
available: one is threaded for a 3/4" pipe thread; the other is threaded
for a 1" pipe thread. For the 3/4" pipe version, a 1" to 3/4" reducer and
a 3/4" by 1-1/2" nipple stainless steel combination should be used.
a. Remove lens and bulbs.
b. Remove the hole cap at the top of the DME antenna and fish out the AC wires using stiff wire bent into
a hook.
c. Route the three wire AC cable from the DME antenna through the required pipe adapters and into the
bulb sockets.