M2 Antenna Systems 2MXP20 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 05/27/15
Rev.03
Model .........................................2MXP20
Frequency Range.......................144 To 146 MHz
*Gain ..........................................15.3 dBi
Front to back ..............................25 dB Typical
Beamwidth ...............................E=30° H=34°
Feed type ...................................“T” Match
Feed Impedance........................50 Ohms Unbalanced
Maximum VSWR........................1.5:1
Input Connector..........................“N” Female
Power Handling..........................2.5 kW
Boom Length / Dia......................21’ 7” / 1-1/2” To 1”
Maximum Element Length..........40-1/2”
Turning Radius:..........................146”
Stacking Distance.......................11’ 6” High & 12” Wide
Mast Size....................................1-1/2” to 2” Nom.
Wind area / Survival...................1.9 Sq. Ft. / 100 MPH
Weight / Ship Wt.........................8 Lbs. / 12 Lbs.
M2 Antenna Systems, Inc.
Model No: 2MXP20
FEATURES:
This dual polarized yagi was computer designed for the serious Moonbouncer.The very good G/T is a result of
low side and back lobes and the design has been optimized for stacking. This antenna is remarkable in that the stacking
gain for four antennas exceeds 6 dB. Even using a single Horizontal/Vertical relay, you have a moonbounce package
that can outperform larger, linear arrays. Additional relay switching providing 4 different types of signals. Losses from spe-
cial polarity and Faraday rotation virtually disappear. EME reliability approaches 100%. M2's new 2MXP20 antennas,
power dividers and phasing lines (using Times' new light-weight, low-loss LMR400 and/or LMR600 cable) coupled with ‘T’
brace kits, fiberglass H-frame packages, OR2800P Azimuth Rotator, and our New MT-1000 Elevation Motor provide the
building blocks for a whole new generation of high performance EME arrays.
SPECIFICATIONS:
*Subtract 2.14 from dBi for dBd
2MXP20 4 Bay Array

1. Start by laying out the boom sections using the DIMENSION sheet as a guide. Use 8-32 screws
and locknuts to join sections. Sections are swaged to fit each other.
2. Lay out the elements by length and position as shown the DIMENSION sheet. Start with the
HORIZONTAL reflector (longest) element and push on a black button insulator to about 1/2” from
center. Push 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 SHAFT RETAINERS yet. This is
easier to do after all the HORIZONTAL elements are installed in the boom.
3. Install the 3/16” rod DRIVEN ELEMENT as you did the reflector. Then continue with the installation
of the HORIZONTAL DIRECTORS. Note that the Director Elements do not consistently diminish in
length from rear to front, so pay close attention to length and position.
4. Now begin centering the elements. Use a tape measure to EQUALIZE the amount the element
sticking out 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.
5. 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, normally a tight fit, hold the elements quite securely.
Begin installing the stainless shaft retainers. Use thumb and index finger to hold a Shaft Retainer
2MXP20 ASSEMBLY MANUAL

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 push tube. Push the Shaft Retainer
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 Shaft Retainer too
far). Repeat for the opposite side. Continue installing Shaft Retainers until all The HORIZONTAL
elements are locked in place. NOW repeat steps 2-5 for the VERTICAL elements.
6. Mount the DRIVEN ELEMENT T-MATCH BLOCKS per the position on the DIMENSION SHEET
using a single 8-32 X 1-1/4" screw for each. Orient the HORIZONTAL block with feed connector
facing to center the VERTICAL block with the feed connector facing the rear. VERTICAL block
orientation may be reversed if you wish LEFT HAND CIRCULAR.
7. Before installing the baluns, thread a 3/8” SEAL NUT all the way onto each connector, with the
black Neoprene side out. Now coil the rear or HORIZONTAL balun so it will not extend beyond the
reflector when installed. Attach balun to the Block and tighten the connectors gently using a 7/16"
end wrench. Once the connectors are tight, back the Seal Nuts out and finger-tighten firmly up
against the face of the connectors (or tighten gently with 1/2” end wrench). A lot of torque is
unnecessary. Squeeze the balun coil across the middle until it is close to the boom and secure to
boom with a nylon cable tie. Tie should be snug but not crushing or kinking the coax.
8. Install the 8-32 x 1/4” set screws (internal Allen head - tool supplied) into the SHORTING BARS.
Slide the bars onto the 3/16” rod driven element tips and then onto the Driven Element Block
Rods. Position the Shorting Bars as specified on the DIMENSION SHEET: the distance given is
between the outer edge of the Driven Element Block and the inner edge of the Shorting Bar. Align
the bars and rods with each other and tighten the setscrews.
9. The boom to mast plate is normally mounted at 116” from rear of boom. This should be the perfect
position when using the M2“T” BRACE KIT. Use two 1-12" U-bolts and the stainless nuts and lock
washers provided. DO NOT OVER TIGHTEN. 2” and 1-1/2” U-bolts are provided for mounting the
antenna to your 2” or 1-1/2” mast.
THIS COMPLETES THE ANTENNA ASSEMBLY.
10. MOUNTING AND STACKING INFORMATION for 4 antennas.
Stacking distance is BEST at 144” to 152”. Be sure all antennas are oriented so the
HORIZONTAL and VERTICAL driven element blocks are on the SAME SIDE of the boom and
NOT MIRROR IMAGE to each other. Holes in rear 1 inch boom section are provided for the “T”
brace kit mounting. Route the phasing lines onto the vertical legs of the “T” brace kit and then
forward to the main “H” frame cross boom. To minimize phasing line length, cutting across the
corners is fine and will not cause pattern degradation. M2can provide low loss LMR400 or LMR600
phase lines and 4 port power dividers.
M2ANTENNA SYSTEMS, INC.
4402 N. SELLAND AVE.
FRESNO, CA 93722
[phone] FAX: [phone]
www.m2inc.com Email: [email protected]
2MXP20 ASSEMBLY MANUAL

2MXP20 DIMENSION SHEET

2MXP20 (FM 145-148) DIMENSION SHEET
40.125
38.625
36.813
36.00
35.50
35.125
34.625
34.375
34.50
35.188
VERTICAL
ELEMENT
DIMENSIONS
FOR FM BAND
14-148 MHZ

DESCRIPTION QTY
BOOM, 1.0 X .058 X 51” ALUM. TUBE................................1
BOOM, 1.0 X .058 X 45.5” ALUM. TUBE............................. 1
BOOM, 1-1/4 X .058 X 60 SOE, ALUM................................2
BOOM, 1-1/2 X .058 X 60 SBE ALUM. ................................1
BOOM TO MAST PLATE, 3/16 X 4 X 6” .............................. 1
TURN BUCKLE PLATE, 1/8 X 2 X 4” (M2APT0102)...........1
‘T’ MATCH BLOCK ASSEMBLY ..........................................2
BALUN CABLE RG-6U, HALF WAVE..................................2
DACRON, 3/32” X 20 FT.....................................................1
ELEMENT, 3/16 X SEE DIMENSION SHEET....................20
ASSEMBLY MANUAL................. ........................................ 1
HARDWARE BAG #1
U-BOLT AND CRADLE, 2”...................................................3
U-BOLT AND CRADLE, 1-1/2”............................................. 5
HARDWARE BAG #2
NUT SEAL............................................................................ 4
BUTTON INSULATOR, 3/16” POLY ..................................40
KEEPER, 3/16” SS............................................................. 44
TURNBUCKLE, 1/4”............................................................. 2
NUT, 5/16-18 SS................................................................ 10
LOCKWASHER, 5/16” SPLIT RING SS............................. 10
SCREW, 8-32 X 1-3/4” SS, PHILLIPS.................................. 4
SCREW, 8-32 X 1-1/2” SS, PHILLIPS.................................. 4
SCREW, 8-32 X 1-1/4” SS, PHILLIPS.................................. 2
SET SCREW, 8-32 X 1/4” SS............................................... 8
LOCKNUT, 8-32 SS.............................................................8
SHORTING BLOCK .............................................................4
U-CLIP, 3/16” ROD ..............................................................2
NYLON TIE, (MEDIUM) .......................................................4
ALLEN WRENCH, 5/64”.......................................................1
PUSH TUBE, 3/8” X 3” ALUM..............................................1
2MXP20 FM KIT
ELEMENT, 3/16 X SEE DIMENSION SHEET....................10
KEEPER, 3/16” SS............................................................. 22
M2ANTENNA SYSTEMS, INC.
4402 N. SELLAND AVE.
FRESNO, CA 93722
[phone] FAX: [phone]
www.m2inc.com Email: [email protected]
2MXP20 PARTS & HARDWARE