DCR-T FM ANTENNA

DCR-T FM ANTENNA
INSTRUCTION MANUAL
_________________________________________________________________________________________
22 Tower Rd.
Raymond, ME 04071
Phone: 800-341-9678
Revised August 2014
Table of Contents
SECTION
PAGE
1.
Unpacking
2
2.
Parts List
2-4
3.
Parts List (Radome Option)
5
4.
Bay Assembly
6-10
5.
Radome Assembly
11-12
6.
Mounting
13
7.
Power Rating
13
8.
Branch Cabling
13-14
9.
Connection Weatherproofing
14
10.
Tuning Bays
14-15
11.
Tuning Charts
15
12.
Frequency Table
16
13.
Maintenance
17
14.
Return Policy
17
1
Unpacking
As soon as the antenna is received, examine for shipping damages so that any necessary claims may be filed
with the shipping company immediately. Items received should be checked against the packing list.
Parts List
The following items in the quantities noted are required to assemble one bay.
Illustration A
Bay Parts
Ring Tuning Extension: QTY 4
Ring: QTY 2
Balun: QTY 1
2
Illustration A (Continued)
Bay Parts
Feed Strap: QTY 2
Feed Strap Backer: QTY 2
7/16 DIN Tap Point: QTY 1
Mounting Clamp: QTY 1
½” Threaded Rod: QTY 2
3
Illustration A (Continued)
Bay Parts
1/2 Flat
Washer:
QTY 4
¼-20x1”
QTY 8
3/8-18x3.25”
QTY 4
1/2 LCK Nut: QTY 1
QTY 4
1/2 Nut: QTY 1
QTY 4
3/8 Flat
Washer:
QTY 8
10-32x.88”
QTY 4
5/16 Flat
Washer:
QTY 2
#10 self tap x 1.00”
QTY 4
3/8 LCK Washer:
QTY 4
3/8 Nut:
QTY 4
¼ Flat
Washer:
QTY 16
#10 Fender
Washer:
QTY 4
¾-16 Jam Nut: QTY 1
5/16 LCK Washer: 1/4 LCK Washer:
QTY 2
QTY 8
5/16 Nut
QTY 2
#10 Flat
Washer:
QTY 16
1/4 Nut:
QTY 8
10 LCK Washer:
QTY 4
#10 Nut:
QTY 4
4
Parts List (Radome Option)
The following items are only supplied with the radome option. Parts and quantities shown below are required
to assemble and install one radome on one bay.
Illustration B
Radome Parts
Radome Top Half
QTY 1
¼-20x3/4”
Screw:
QTY 24
¼ Flat
Washer:
QTY 42
Mounting Bracket
with Threaded Inserts:
QTY 3
Radome Bottom Half
QTY 1
¼ Lock
Washer:
QTY 24
3/8-18x3.50”
Screw
QTY 2
5
Bay Assembly
Follow the steps indicated below:
Step 1
Use the 3/8 hardware to assemble the rings as shown below:
Step 2
Attach the 4 ring tuning extensions as shown using the provided ¼-20x1” hardware. Finger tight until the
antenna is tuned.
*Make sure to tighten all hardware after tuning and then re-check VSWR.
6
Bay Assembly
Step 3
Attach the tuning post as shown below using the fender washers and #10 self tapping screws supplied. This is
required on both sides of the bay.
7
Bay Assembly
Step 4
Install the tap point into the balun tube as shown below:
Use the ¾-16 jam nut provided to secure the tap point. A thread locking product should be used here.
(Locktite #242 or equivalent)
8
Bay Assembly
Step 5
Position feed strap on the tap point stud as shown using the 5/16 hardware provided. Install finger tight until
the antenna is tuned. The feed straps are made with thin material to allow twisting once the hardware has
been tightened. The feed straps attach the tap point to the upper arms as shown.
.40 to .50 inches
9
Bay Assembly
Step 6
Attach the feed strap backer using the supplied 10-32x.88 hardware. Finger tight until the antenna is tuned.
Step 7
Use the mounting clamp and ½” hardware provided to attach the antenna to a round member from 2” to 5”
diameter. The mounting bolts should be evenly tightened to 20 FT-LBS (27 Nm) at final installation.
.
10
Radome Assembly (Optional)
Follow the steps indicated below:
Step 1
Install fiberglass mounting brackets as shown below:
RE-USE 3.25” LONG
3/8-16 SCREWS AT
THESE LOCATIONS
USE 3.50” LONG 3/8-16 SCREWS
(INCLUDED IN RADOME KIT)
AT THESE LOCATIONS
11
Radome Assembly
Step 2
Install radome top half using the ¼-20 screws, flat washers, and lock washers provided (4 EA).
Radome Assembly
Step 3
Confirm input cable is dressed along the bottom of the balun tube and out through the cut-out in the bottom half
of the radome. Install radome bottom half using the ¼-20 screws, flat washers, and lock washers provided (2
locations into the fiberglass bracket). The remaining hardware (screws, nuts, lock washers, double flat washers)
will be used at the radome seam (18 locations):
12
Mounting
The antenna mount of the DCR-T bay is designed to attach to a pole or round tower leg between 2 inch (5 cm)
and 5 inches (12.7 cm) in diameter. The mounting bolts should be evenly tightened to 20 FT-LBS (27 Nm).
The bays should be mounted so that the 7/16 Din connector is located beneath the ring on the bottom of the bay.
Mounting the antenna differently will cause a phase reversal and improper operation.
In a multiple DCR-T configuration, bays should be separated by one wavelength at the operating frequency. To
determine this spacing in inches, refer to the frequency table at the end of this manual, or divide 11803 by the
frequency in megahertz ( = 11803/f inches). The spacing in centimeters can be found from an equivalent
calculation by dividing 29980 by the frequency in megahertz. For example, the spacing for 97.9 MHz would be
found as follows:
 = 11803/f = 11803/97.9 = 120.56”.
Bay spacing may deviate slightly +/- 1/2 inch. However, the antenna bay spacing should be kept as close to this
distance as possible. Contact factory for additional spacing options.
Power Rating
Each bay is rated for 1000 watts. For higher power ratings please contact factory.
Branch Cabling
DCR-T antennas are either single bay or branch fed. For single bay antennas, the transmitter connects to the
input of the single bay. Refer to Illustration B. For branch fed antennas the transmission line attaches to a
power divider with jumpers to each bay. Refer to Illustration C.
The jumpers are usually longer than necessary to reach between multiple bays. The extra length is necessitated
by RF considerations and the velocity of propagation within the cable. Extra cable length should be wrapped in
drip loops and attached to the mounting structure. The cables should be tie-wrapped or taped using electrical
tape to ensure secure mounting to the structure. Use the supplied zip ties to support the jumper on the bottom
side of the balun as shown in illustration B below. Be careful not to kink the cable in any way or to wrap the
cable too tightly. ½” flex line min. bend radius is 1 ¼” .
Illustration B – Single Antenna
13
DCR-T
JUMPER
POWER DIVIDER
X
Illustration C – Branch Fed Antenna
To determine X (bay spacing), refer to
Mounting on pg. 13 and Frequency Table on pg. 16
Connection Weatherproofing
All cable junctions should be weatherproofed with rubber electrical tape. Water entry into the cables and
connectors will damage the antenna system. Sealing materials are not provided with antenna.
Tuning Bays
There are two adjustments needed to tune each bay. A starting value is provided for each of these adjustments
based on your frequency. The starting value is the same for both the standard and the radomed versions.
First, the feed straps should be rotated on the rings until dimension A matches the corresponding value in the
chart on page 15. Second, the tuning extension should be adjusted until dimension B matches the
corresponding value in the chart on page 15.
A
B
Dimension A is an arc length.
14
Tuning Charts
15
FREQUENCY TABLE - BAY SPACING
FREQ. SPACING
FREQ.
SPACING
FREQ. SPACING FREQ. SPACING
88.1
133.75
93.1
126.75
98.1
120.25
103.1
114.25
88.3
133.50
93.3
126.50
98.3
120.00
103.3
114.25
88.5
133.25
93.5
126.00
98.5
119.75
103.5
114.00
88.7
133.00
93.7
125.75
98.7
119.50
103.7
113.75
88.9
132.75
93.9
125.50
98.9
119.25
103.9
113.50
89.1
132.25
94.1
125.25
99.1
119.00
104.1
113.25
89.3
132.00
94.3
125.00
99.3
118.75
104.3
113.00
89.5
131.75
94.5
124.75
99.5
118.50
104.5
112.75
89.7
131.50
94.7
124.50
99.7
118.25
104.7
112.50
89.9
131.25
94.9
124.25
99.9
118.00
104.9
112.50
90.1
130.75
95.1
124.00
100.1
117.75
105.1
112.25
90.3
130.50
95.3
123.75
100.3
117.50
105.3
112.00
90.5
130.25
95.5
123.50
100.5
117.25
105.5
111.75
90.7
130.00
95.7
123.25
100.7
117.00
105.7
111.50
90.9
129.75
95.9
123.00
100.9
116.75
105.9
111.25
91.1
129.50
96.1
122.75
101.1
116.50
106.1
111.00
91.3
129.25
96.3
122.50
101.3
116.50
106.3
111.00
91.5
128.75
96.5
122.25
101.5
116.25
106.5
110.75
91.7
128.50
96.7
122.00
101.7
116.00
106.7
110.50
91.9
128.25
96.9
121.75
101.9
115.75
106.9
110.25
92.1
128.00
97.1
121.50
102.1
115.50
107.1
110.00
92.3
127.75
97.3
121.25
102.3
115.25
107.3
110.00
92.5
127.50
97.5
121.00
102.5
115.00
107.5
109.75
92.7
127.25
97.7
120.75
102.7
114.75
107.7
109.50
92.9
127.00
97.9
120.50
102.9
114.50
107.9
109.25
16
Maintenance
The radiators should never be painted. We recommend that condition of the antenna be inspected twice a year.
Conditions to watch for in particular are ice damage and chafing of the cables. Should damage be noted and
require replacement parts, contact your Dielectric customer service representative.
Return Policy
Before returning any material to the factory, be sure to call your sales representative to obtain a material return
authorization (MRA) number. Use this number in all correspondence because material may be refused and sent
back at customer’s expense without the MRA.
17

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