M2 Antenna Systems 420-450-11HP User manual

M2 Antenna Systems, Inc. 4402 N. Selland Ave. Fresno, CA 93722
Tel: [phone] Fax: [phone] Web: www.m2inc.com
©2022 M2 Antenna Systems Incoporated 08/16/22
Model .........................................420-450-11HP
Frequency Range.......................420 to 450 MHz
*Gain ..........................................13.44 dBi
Front to back ..............................20 dB Typical
Beamwidth ...............................E=34° H=43°
Feed type ...................................Folded Dipole
Feed Impedance. .......................50 Ohms Unbalanced
Maximum VSWR........................1.2:1
Input Connector..........................“N” Female
Power Handling ..........................3 kW
Boom Length / Dia......................60” / 1-1/2”
Maximum Element Length..........40-5/8”
Stacking Distance.......................28”
Mounting.....................................1-1/2” to 2” Nom.
Wind area / Survival ...................0.1 Sq. Ft. / 125 MPH
Weight / Ship Wt.........................6 Lbs. / 7 Lbs.
M2 Antenna Systems, Inc.
Model No: 420-450-11HP
FEATURES:
The 420-450-11HP is the high powered version of the standard model 420-450-11. The driven element has been engi-
neered to handle up to 3 kW PEP. Computer optimization has allowed the antenna to cover the entire amateur 70CM
band. It is ideal for repeater linking or any point to point application. Comparing it to a common reference, the KLM 420-
450-11, it has the same usable bandwidth with a full on dB more gain and the pattern is much cleaner. Clean patterns in
most applications provide more reliable communications with less inter-mod. An optional stacking harness is available
when more than one antenna is required for reduced beamwidth or additional gain. Because the antenna covers the
whole band, many users fit it a natural for ATV and general repeater use. Users are surprised by the performance of this
compact but potent antenna.
Construction is classic M2 for long term electrical and mechanical integrity. Elements are 3/16” 6061-T6 rod, mounted
through the boom on UV stabilized insulators and locked in place with stainless steel shaft retainers. The driven element
module is CNC machined and all connectors are O-ring sealed. Internal connections are encapsulated in a space-age
silicone gel.
SPECIFICATIONS:
*Subtract 2.14 from dBi for dBd

420-450-11HP ASSEMBLY MANUAL
ASSEMBLY INSTRUCTIONS
Tools required: phillips #2 screwdriver, tape measure or scale.
1. Lay out the ten 3/16” rod elements and arrange them according to the lengths on the Dimension sheet from REFLECTOR
(rear most) to FRONT DIRECTOR (front most).
2. The 5/16” polyethelene, black button insulators are provided for element mounting.ASSEMBLY TIPS: A. Using a pocket or
deburring too, lightly champher each hole to remove the sharp edge left from the drilling operation. This deburring will make
the insulators slide in easier.
3. Starting with the REFLECTOR element, push the rod half way
through an insulator. Insert the smaller diameter side of the insulator in
the rear hole of the boom and push in until the insulator shoulder is
against the boom. Now add the second insulator on the other side of
the rod and push it tight against the boom.
4. Continue adding elements to the boom until all are in place except
for the DRIVEN ELEMENT FOLDED DIPOLE. Now center the
elements carefully to within at least 1/16” using a tape measure or
scale.
5. Using the provided 3/8” aluminum “push tube”, install the element
keepers on both sides of each element and push them tight against the
button insulators.
6. Install driven element to boom and secure with two 8-32 x 1-1/4”
screws and lockwashers. Orient the feed connector to the rear.
7. Provide strain relief to feedline connector by securing feedline to
boom with the supplied cable ties. Tie feedline near driven element
and again where it meets the mast. Ties should hold firmly but not
crush or kink feedline .
8. As shipped, the driven element tilts forward on the boom and best
match is from 420 to 450 MHz. However, this match may vary from
unit to unit, so a slight adjustment may be neccessary. The match
can be optimized simply by adjusting the tilt of the driven element tubes. To adjust, insert a screwdriver or similar tool
through the loop, near the outer end, and rotate each side equally, in small increments, as shown in drawing.
CAREFULLY DESIGNED AND MANUFACTURED BY
M2 ANTENNA SYSTEMS INC.
4402 N. Selland Ave.
Fresno CA, 93722
559-432-8873 FAX [phone]
www.m2inc.com email: [email protected]

420-450-11HP PARTS LIST
DESCRIPTION QTY
BOOM, 1.5 x 60”, SLEEVED..........................................................1
PARASITIC ELEMENT, 3/16” ROD x 13.75 .........................1
x 12.375 .......................1
x 11.813 .......................1
x 11.688 .......................1
x 11.437 .......................2
x 11.313 .......................1
x 11.062 .......................1
x 10.375 .......................1
x 10.313 .......................1
DRIVEN ELEMENT ASSY., HP, 420 - 450 MHz ...........................1
ASSEMBLY MANUAL ....................................................................1
IN HARDWARE BAG:
SCREW, 8-32 X 1-1/4”, SS ............................................................2
LOCKWASHER, 8-32, SS..............................................................2
3/16” POLYETHELENE INSULATORS, BLK.................................20
3/16” KEEPERS, (SHAFT RETAINERS), SS ................................20
PUSH TUBE, 3/8 x 3”.....................................................................1
CABLE TIE, BLACK .......................................................................3

420-450-11HP System Parts List (Optional)
DESCRIPTION QTY
EXTENSION TUBES, SPECIAL FOR PLATFORM ACCESS:
REAR, 1” SQ. x 60” ................................ 5
FRONT, 1” SQ. x 51” .............................. 5
STANDARD EXTENSION TUBE, 1” SQ. x 60”`...................................................... 55
420-450-11HP, YAGI ANTENNA............................................................................. 60
SYSTEM ASSEMBLY DRAWING ........................................................................... 1
IN HARDWARE BAG:
CAPTIVE QUICK RELEASE ASSEMBLY ............................................................... 5
BOLT, 1/4-20 x 1-1/2, SS......................................................................................... 120
LOCKNUT, 1/4-20, SS............................................................................................. 120