Cessna SK180-26A User manual

SK180-26A
FEBRUARY 3, 1969
Title MARKER BEACON ANTENNA MODIFICATION
C ssna.
MODELS
AFFECTED
SERIALS AFFECTED
150
All
serials prior to serial
15059834
172
All
serials prior
to serial
17250075
P172
All serials
prior to
serial P17257171
180
All serials
prior to serial 18051226
182
All serials
prior to serial
18254619
185
All serials
prior
to serial 185-0549
205
All serials
prior to serial
205-0254
210
All serials
prior to
serial 21058143
PURPOSE:
To install a rod antenna
to replace
the marker beacon
wire antenna.
NOTE
Aircraft with wire
antenna installations have developed
cracks in
the antenna masts.
All such installations
may be retrofitted with
this installation of a rod antenna.
PARTS LIST:
QUANTITY
PART NUMBER
NOMENCLATURE
1
0770681-1
Antenna
Rod Assembly
-
Marker
Beacon
2
AN970-3
Washer
1
MS20365-1032C
Nut
1
AN520-10R12
Screw
1
AN936A10
Washer
1
AN742D3
Clamp
1
AN515-8R6
Screw
1
MS20364-832C
Nut
1
Installation
Instructions
INSTALLATION
INSTRUCTIONS:
a. Drill a # 10 (0.
1935 inch) hole approximately
two inches forward
of the ceramic
feed-thru insulator
connected to the existing wire marker-beacon antenna.
b. Refer to figure 1;
drill a # 10 (0. 1935 inch) hole aft of the insulator.
Refer to dimensions given to
locate this hole.
c.
Remove screws securing both antenna masts
and remove masts. Plug screw holes in
skin by re-
installing sheet metal screws.
d. Install rod
antenna as shown
in figure 1.
e. Using the
wire formerly connected to
the wire antenna,
a clamp, screw,
and nut. connect the
rod
antenna to
the feed-thru
insulator.

(SK180-26)
f. Using
a 75
mc signal
generator
on the
ground
or tests
of
the
marker
beacon
in flight,
adjust
position
of the clamp
on the rod antenna
to attain a
maximum signal.
AN520-10R12 SCREW
AN970-3
WASHER
AN936A10
WASHER
MS20365-1032C
NUT
AN970-3
WASHER
1 EA REQD
1
EA
REQD
*27. 5"
(MODEL
205-210)
*25
(MODEL
150,
172,
P172,
180,
182,
185)
(ADJUST CLAMP POSITION
FORE-AND-AFT FOR
MAXIMUM SIGNAL)
*DIMENSIONS
ARE
APPROXIMATE
AND MAY
BE
VARIED TO
ALLOW
INSTALLATION
TO CLEAR
FUSELAGE STRUCTURE.
**PART
OF ANTENNA
ASSY
NO. 0770681-1
Figure
1. Marker
Beacon
Rod
Antenna
Installation
2 of 2