M2 Antenna Systems 2M8WL, 2M8WLHD Assembly Manual

M2 Antenna Systems, Inc.

Model No: 2M8WL

SPECIFICATIONS:

Model ......................................... 2M8WL

Frequency Range ....................... 144 To 144.6 MHz

*Gain .......................................... 18.5 dBi

Front to back .............................. 26 dB Typical

Beamwidth ............................... E=20° H=21°

Feed type ................................... “T” Match

Feed Impedance. ....................... 50 Ohms Unbalanced

Maximum VSWR ........................ 1.5:1

Input Connector .......................... “N” Female

*Subtract 2.14 from dBi for dBd

Power Handling .......................... 2.5 kW

Boom Length / Dia ...................... 55’ / 2-1/2” To 1-1/2”

Maximum Element Length .......... 21-3/16”

Turning Radius: .......................... 29’

Stacking Distance ....................... 17’ High & 17’ Wide

Mast Size .................................... 1-1/2” to 2” Nom.

Wind area / Survival ................... 5.5 Sq. Ft. / 100 MPH

Weight / Ship Wt. ........................ 50 Lbs. / 59 Lbs.

FEATURES:

The 2M8WL provides the user with not just improvements in gain and front to back ratio but also features a robust
boom design, making the antenna capable of handling winds over 100 MPH. The 2M8WLHD features the same highly
reliable, CNC machined, driven element components used on our other VHF and UHF yagis. The boom tapers from 2.5"
in the 23 foot middle section to 1.5" at the rear and front. It is top guyed with dacron cord. A single 2M8WL provides the
gain requirement to make EME contacts with even small 4 yagi stations. It passes the echo test by producing its own
audible echoes even when pointed up with no ground gain! Obviously it is dynamite on Tropo! There's absolutely nothing
else like it.

M2 Antenna Systems, Inc. 4402 N. Selland Ave. Fresno, CA 93722

Tel: [phone] Fax: [phone] Web: www.m2inc.com

©2009 M2 Antenna Systems Incoporated

5/8/09

Rev.00

TOOLS REQUIRED: Scr ewd ri ver , 11/32 wr enc h, s oc ket or sp in ti te, a 7/16" an d 1/2" w ren ch or so ck et,

tape measure. Please review these instructions and the 2M8WLHD DIMENSION SHEET before a ssembly.

1. BOOM ASSEMBLY
Refer to the 2M8WLHD DIMENSION SHEET as a guide. Note the FRONT and REAR locations of the

antenna and that it is pictured looking from underneath. Prior to beginning the assembly of the boom find a
LONG level surface to work on. Start by laying out the boom sections. Use 1/4-20 x 2” bolts and locknuts to
join 1-1/2” to 2” sections; 2-1/2” bolts for 2” to 2” sections and 2” to 2-1/2” sections; 3” bolts for 2-1/2” to 2­1/2” sections. You will notice that several of the boom sections are the same length. The following notes will
help you determine which-one-goes-where:

1-1/2” sections: The rear section has 4 through holes for the elements and one through hole

perpendicular to the others. Orient this section piece with the cross bolt holes facing towards the front.
2 x 48” sections: The rear section has the 5/16” elem ent through hole closer to its swaged end.
2 x 95” sections: Bo t h t h e f r o n t and r ear s ec tio n s h av e 11/32” ho l es for t h e e yeb o l ts. Th e r ear

section has a through hole for an element closer to its unswaged end.
2-1/2 x 95” SOE: The front section has a through hole for an element closer to its unswaged end.

2-1/2 x 95” SBE: The rear end has a through hole closer to a swaged end.
After assembly, double check boom sections against ELEMENT SPACING figures on Dimension Sheet.

2. BOOM TO MAST PLATE
At this time it may be convenient to add the boom to mast plate. The 6 x 8 x 1/4” plate mounts approximately

24” from the front element hole on the center most section of the boom. Use two 2-1/2 inch U-bolts and

cradles and the 5/16” stainless steel lockwashers and nuts. TEMPORARILY position the plate under the

boom. This way the boom can be laid across a bench or bucks and the plate will keep the boom from

rotating while installing the elements.

3. ELEMENT ASSEMBLY
Lay out the elements by length and position as shown the DIMENSION sheet. Start with the reflector

(longest) element. Balance across finger to find center and push on a black button insulator to about 1/2”

from center. Insert the element through the holes 1/2" from the rear of the boom and install the second

button, snugging it up into boom. DO NOT BOTHER WITH ACCURATELY CENTERING the element at this

time and DO NOT INSTALL the stainless steel internal locking “KEEPERS” yet. This is easier to do after all

the elements are installed in the boom. Note that the Director Elements do not consistently diminish in

length from rear to front, so pay close attention to length and position. We have en c l o s ed a 1:1

scaled dimension chart to help sort out the 21 elements.
Now begin centering the elements. Use a tape measure to EQUALIZE element length on each side of the

boom. 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.

4. ELEMENT KEEPER INSTALLATION
Begin installing the stainless “keepers.” Use thumb and index finger to hold a keeper over end of the 3/8 x 3”

push tube (keeper dished into tube). Hold the element firmly and start the keeper onto the rod by applying

pressure with the push tube. Push the keeper until up tight against the button insulator (Locking pliers, lightly

clamped up against opposite button insulator will help maintain center reference and keep you from pushing

the first keeper too far). Repeat for the opposite side. Continue installing keepers until all elements are

locked in place.

5. DRIVEN ELEMENT INSTALLATION
Mount the DRIVEN ELEMENT “T” MATCH ASSEMBLY to the BOTTOM of the boom using a single 1/4-20 x

1-3/4" bolt and lockwasher. Orient the block with feed connector facing to center and balun connectors

facing to rear.