M2 Antenna Systems 902-14WLC User manual

M2 Antenna Systems, Inc. 4402 N. Selland Ave. Fresno, CA 93722
Tel: [phone] Fax: [phone] Web: www.m2inc.com
©2015 M2 Antenna Systems Incoporated 05/28/15
Rev.00
Model .........................................902-14WLC
Frequency Range.......................880 To 915 MHz
*Gain ..........................................21.14 dBi
Front to back ..............................24 dB Typical
Beamwidth ...............................E=18° H=19°
Feed type ...................................Folded Dipole
Feed Impedance........................50 Ohms Unbalanced
Maximum VSWR........................1.2:2 Typical at 902
Input Connector..........................“N” Female
Power Handling..........................750 Watts
Boom Length / Dia......................15’ 4” / 1”, 1-1/4” & 3/4”
Maximum Element Length..........6-3/8”
Turning Radius:..........................100”
Stacking Distance.......................43” High & 43” Wide
Mast Size....................................1-1/2” to 2” Nom.
Wind area / Survival...................1 Sq. Ft. / 100 MPH
Weight / Ship Wt.........................6 Lbs. / 7 Lbs.
M2 Antenna Systems, Inc.
Model No: 902-14WLC
FEATURES:
The 902-14WL is the ultimate in performance and gain. The recently updated computer optimized design produc-
es excellent gain and VSWR across the band. It is ideal for stacking: a quad array will yield almost 25 dBd of real smoking
antenna gain. Tropo and EME should definitely be on your mind when owning one or more 902-14WLs! Structurally the
antenna is rugged, tapered-boom construction featuring 3/16 rod parasitics. A totally weather proof driven dipole design
means years of trouble free optimum performance. This antenna is a perfect compliment to your VHF-UHF antenna sys-
tem!
SPECIFICATIONS:
*Subtract 2.14 from dBi for dBd

1. Assemble the boom sections using the DIMENSION sheet as a guide for lengths, placement and
hardware.
2. Mount the FOLDED DIPOLE MOUNTING BLOCK to the small hole about 2-1/4" from the rear of
the boom. Orient with the feed connector facing to the front. Secure the block with an 8-32 x 1-
1/4" screw.
3. Sort out the 3/16" rod elements using the ‘SETUP’ sheet and the DIMENSION SHEET. Measure
carefully as lengths vary by as little as 1/16". Note that the Director Elements do not necessarily
diminish in length from rear to front.
4. Install elements, starting with the REFLECTOR element. Push on a black button insulator to about
1/2” from center and insert the element through the holes 1/2" from the rear of the boom. Install the
second button, snugging it up into boom. HINT: If the rods are loose in the buttons, deform the
buttons slightly first with pliers. DO NOT BOTHER WITH ACCURATELY CENTERING the
element at this time and DO NOT INSTALL the stainless steel SHAFT RETAINERS yet. This is
easier to do after all the elements are installed in the boom.
Install the 3/16” rod DIRECTOR element as you did the reflector. Then continue with the
installation of the DIRECTORS.
5. Now begin centering the elements. Use a tape measure to EQUALIZE the amount the element
sticking out on each side of the boom. Accuracy of 1/32" is adequate. Once you have all the
elements centered, sight down the element tips from the rear comparing each side. Look for any
obvious discrepancies and correct if found.
6. NOTE: The SHAFT RETAINERS, used for securing the elements, should always be used for
permanent and long term antenna installations. For portable or temporary use, or whenever it is
anticipated that the antenna will be disassembled within a short time, the retainers may be left off.
The button insulators are normally a tight fit, but if not can be squeezed a bit hold the elements
quite securely.
HINT: Keeper installation is easier, by chamfering the inner diameter of push tube.
Begin installing the stainless shaft retainers (KEEPERS). Use thumb and index finger to hold a
Shaft Retainer over end of the 3/8 x 3” push tube (Shaft Retainer dished into tube). Hold the
element firmly and start the keeper onto the rod by applying pressure with the 3/8 X 3”PUSH
TUBE. Push the Shaft Retainer until up tight against thebutton insulator (Locking pliers,
lightly clamped up against opposite button insulator will help maintain center reference.If
you push the first retainer too far, remove element from boom, push retainer completely off the
element, and start over. After the first retainer is on, install another retainer to the opposite side.
Continue installing Shaft Retainers until all
elements are locked in place.
7. Attach the angled Boom to mast plate to the
small holes about 74" and 77" from the rear
of the boom. Secure with 8-32 x 1-3/4"
screws and locknuts. 1-1/2" and 2" U-bolts
are supplied for attaching bracket to end of
mast. Keep mast as far from boom as the U-
bolts allow. Do not allow the mast to pass up
through the element plane as it WILL CAUSE
GREAT PERFORMANCE DEGRADATION.
902-14WLC ASSEMBLY MANUAL

8. Attach the feedline and route forward to the mast. Secure at regular intervals with cable ties. If
using hardline, provide support near the feed connector to relieve any stress on the dipole block
mounting screw and connector.
9. GENERAL COMMENTS. It is always a good idea to check out the
antenna with a little RF prior to installing it in some inaccessible
location. DO NOT use any PL-259 fittings or adapters at these
frequencies. Very small problems in coax and in connectors can
cause MAJOR VSWR problems. Even a loose connector will affect
the VSWR noticeably.
VSWR ADJUSTMENT:
We have found the best VSWR across the band is found when the
dipole is straight up as shown, Occasionally the VSWR can be
improved slightly by tilting the dipole forward or back just a bit. If you
do not have very good measurement equipment, we suggest you not
change the tilt. Typically the match is 1.2 to 1.4 from below 900 to
above 926 MHz. One side of the dipole is 1/4,” tubing; the other is
solid rod and will require more effort to bend. Start with the soft side,
bending it slightly one way or the other. If improvement is noted,
THEN do the same to the solid rod side. BE SURE TO SUPPORT
THE BLOCK SO AS NOT TO PUT UNDUE STRESS ON THE
MOUNTING SCREW.
VSWR may be adjusted slightly for improvement in your particular part of the band by slightly
bending the unsupported upper loop of the driven element towards, or away from, the first
director. This can be done with a screwdriver tip As shown. Bend in small increments to avoid
damage to internal balun and connections at the center of the dipole. Hold the block firmly
to the boom- bending the dipole FORWARD tends to pry the block away from the boom.
Check after each adjustment and note shift in the VSWR curve.
M2ANTENNA SYSTEMS, INC.
4402 N. Selland Ave.
Fresno, CA 93722
[phone] Fax: [phone]
www.m2inc.com Email: [email protected]
902-14WLC ASSEMBLY MANUAL

902-14WLC DIMENSION SHEET

902-14WLC ELEMENT LAYOUT

DESCRIPTION QTY
BOOM SECTION, 1 X .058 X 60” STR..........................................1
BOOM SECTION, 1 X .058 X 57” STR..........................................1
BOOM SECTION, 1-1/4 X .058 X 60" SBE....................................1
BOOM SECTION, 3/4 X .049 X 17" STR.......................................1
ELEMENTS, 3/16 ROD x Dimension Sheet ..................................39
DRIVEN ELEMENT ASSEMBLY, (917ISP DE ASSY)..................1
BOOM-TO-MAST "L" PLATE.........................................................1
U-BOLT AND CRADLE, 2".............................................................2
U-BOLT AND CRADLE, 1-1/2” ......................................................2
ASSEMBLY MANUAL....................................................................1
IN HARDWARE BAG:
BUTTON INSULATORS ................................................................80
SHAFT RETAINER, SS .................................................................80
NUT, 5/16-18 SS............................................................................8
LOCKWASHER, 5/16 SS...............................................................8
SCREW, 8-32 X 1-3/4 SS..............................................................2
SCREW, 8-32 X 1-1/2 SS..............................................................4
SCREW, 8-32 X 1-1/4 SS..............................................................2
LOCKNUT, 8-32 SS.......................................................................8
SCREW, 8-32 X 1-1/4" SS.............................................................1
CABLE TIE, NYLON ......................................................................4
PUSH TUBE, 3/8 X 3”....................................................................1
MANUFACTURED IN THE U.S.A. BY:
M2ANTENNA SYSTEMS, INC.
4402 N. Selland Ave.
Fresno, CA 93722
[phone] Fax: [phone]
www.m2inc.com Email: [email protected]
902-14WLC PARTS & HARDWARE