M2 Antenna Systems 248CP22A 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 Incorporated 9/15/15
Rev.00
Model .........................................248CP22A
Frequency Range.......................235 To 260 mHz
*Gain ..........................................13.8 dBi
Front to back ..............................20 dB Typical
Beamwidth ...............................E=36° H=40°
Feed type ...................................“T” Match
Feed Impedance........................50 Ohms Unbalanced
Maximum VSWR........................1.5:1 Typical
Input Connector..........................“N” Female
Power Handling..........................1 kW
Boom Length / Dia......................139-1/2” / 1”
Maximum Element Length..........25”
Turning Radius:..........................84”
Stacking Distance.......................68” High & 71” Wide
Mast Size....................................1-1/2” to 2” Nom.
Wind area / Survival...................0.93 Sq. Ft. / 100 MPH
Weight / Ship Wt.........................5 Lbs. / 8 Lbs.
M2 Antenna Systems, Inc.
Model No: 248CP22A
SPECIFICATIONS:
*Subtract 2.14 from dBi for dBd
FEATURES:
The 248CP22A is high performance circular polarized antenna with a remarkably clean pattern. The pattern is
important in order to match the antenna’s noise temperature with modern low noise preamps. This antenna is ideal for
satellite work but is also excellent for terrestrial uses like ATV, repeater operation, and long haul tropo DX.
The CNC machined driven element module is O-ring sealed and weather tight for low maintenance and long-term
peak performance. Internal connections are encapsulated in a space-age silicone gel that seals out moisture and im-
proves power handling. The 3/16” 6061-T6 rod elements are centered to minimize interaction and maintain good elliptici-
ty. Insulators are UV stabilized and locked in place with stainless keepers. Rugged construction, uncompromising perfor-
mance for the boom length: that’s the M2248CP22A!

248CP22A DIMENSION SHEET

248CP22A ASSEMBLY MANUAL
TOOL REQUIRED FOR ASSEMBLY: screwdriver, 11/32 nut driver or wrench, 7/16” and 1/2” socket or end
wrenches, measuring tape.
1. Assemble the boom using 8-32 X 1-1/4 screws and locknuts to join sections. (SEE DIMENSION SHEET).
ASSEMBLING THE HORIZONTAL ELEMENTS
2. Lay out the elements by “Horizontal” length and position as shown the DIMENSION SHEET. Start with the
reflector (longest) element. Balance it on your finger to find rough center and push on a black button
insulator to about 1/2” off center. Push the element through the holes 1.937” from the rear of the boom and
install the second button, snugging it up into boom. DO NOT BOTHER CENTERING the element at this time
and DO NOT INSTALL the stainless steel shaft retainers yet. It is easier to do it 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
DIRECTORS. Note: 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. Stainless steel SHAFT RETAINERS lock the
elements in place. They should always be
used for permanent and long term antenna
installations. For portable or temporary use,
the button insulators are adequate for holding
the elements and the retainers may be left
off. To install the stainless steel SHAFT
RETAINERS, use thumb and forefinger to
hold the retainer over the end of the PUSH
TUBE ( 3/8" x 3" tube, supplied in the kit),
internal fingers on retainer dished into tube.
HOLD THE ELEMENT FIRMLY TO
PREVENT IT FROM SLIDING OFF CENTER
and press the retainer onto the element end
and continue until retainer butts on insulator
button. 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). Install another retainer to the opposite side of the element. Continue installing
retainers until all elements are secured.
6. Mount the HORIZONTAL P.S. DRIVEN ELEMENT ASSEMBLY to the TOP of the boom using a single
8-32 X 1-1/4" screw (SEE PICTURE).
7. Install the 8-32 x 1/4” set screws (internal Allen head - tool supplied) into the SHORTING BARS. Slide the
bars onto the 1/4" Driven Element Block Rods and the 3/16" driven element rod. Position the Shorting Bars
as shown on dimension sheet.

248CP22A ASSEMBLY MANUAL
ASSEMBLING THE VERTICAL ELEMENTS
Note: The vertical element set is shifted forward on the boom by 1/4 wave lengths. This increases isolation
between element planes, improving circularity and ease of phasing / matching the two element sets.
8. Repeat steps #2 through #5 for the Vertical elements, using the Dimension Sheet as your guide to lengths and
spacing.
INSTALLATION OF THE VERTICAL DRIVEN ELEMENT BLOCK DETERMINES THE CIRCULARITY OF
THIS ANTENNA. THE ORIENTATION OF THE BLOCK FOR RHC - RIGHT HAND CIRCULARITY, IS
SHOWN ON THE DIMENSION SHEET.
9. Viewed from the rear of the boom (rearmost Reflector HORIZONTAL), the VERTICAL Driven Element Block
mounts to the LEFT hand side of the boom with the two Balun connectors oriented to the FRONT. Secure with
8-32 x 1-1/4” screw. Install the Shorting Bars as in step #7.
10. Before installing the Baluns and Matching / Phasing Harness, thread 3/8” SEAL NUTS fully onto all
connectors, with the black Neoprene face of the nuts facing out. Attach Baluns and Phasing lines to the
Driven Element Blocks and Junction Block as shown on the picture below. 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.
Depending on model and polarity, the Vertical balun may loop around another element. This is normal. Form
balun coax until it is close to the boom and secure with a nylon cable tie. Also secure the other balun and the
matching / phasing harness coax with cable ties. Ties should be snug but not crushing or kinking the coax.
11. Use good quality coax and “N” connector for your feedline (see Installation Tips). Secure feed coax near
connector on Junction Block, to provide stress relief. Allow about 60” of coax to hang in a loop between the
rear end of the boom and the reattachment point (at least 12” beyond element tips) on the mast or crossboom.
Do not route feedline thru boom to mast plate as exiting antenna here will adversely affect circular
field.
12. The boom to mast plate is normally mounted to the boom at the balance point (SEE DIMENSION SHEET).
Since the feed line represents significant weight it is best to have it attached and fastened to the boom with
cable ties before final mounting the plate. Use two 1" U-bolts and the stainless nuts and lock washers
provided. DO NOT OVER TIGHTEN. 2” U-bolts (and stainless steel nuts / lock washers) are provided for
mounting the antenna to your NON-CONDUCTIVE mast or crossboom. Other size u-bolts and cradles are
available upon request.
M2ANTENNA SYSTEMS, INC.
4402 N. SELLAND AVE.
FRESNO, CA 93722
[phone] FAX: [phone]
www.m2inc.com Email: [email protected]

248CP22A D.E. & PHASING LINE DETAIL
D.E. BALUN
PHASE LINE
1/4 WAVE
PHASE LINE
3/4 WAVE SCREW
8-32 X 1-1/4”
P.S. BLOCK JUNCTION
BLOCK
D.E. BALUN
D.E. BLOCK
2.75
1.625

248CP22A BOOM TO MAST

DESCRIPTION QTY.
Boom section #1, 1 x .058 x 55" SOE ................................1
Boom section #2, 1 x .058 x 60" SOE .................................1
Boom section #3, 1 x .058 x 23”...........................................1
Boom extension tube, 1” x 0.058 x 10-1/2”...........................1
Elements, 3/16" alum. rod x (see dimension sheet) ............22
Driven Element Block Assembly...........................................1
Polarity Switch Block Assembly............................................1
Junction Block Assembly (SADE0065) ................................1
Balun, RG-6U X 20”, halfwave length...................................2
Phasing Line, RG6-U X 11”, quarterwave length ................1
Phasing Line, RG6-U X 31”, three quarterwave length........1
Shorting Bars, 0.75 x 1.532 x .250" (M2ASB0090) ..............4
Boom to Mast Plate, 3 x 4 x .125" (M2APT0019).................1
Assembly instructions ..........................................................1
HARDWARE BAG #1
U-bolt and cradle, 2".............................................................2
U-bolt, 1" no cradle ..............................................................2
Nut, 5/16-18 ss.....................................................................4
Lockwasher, 5/16" ss ...........................................................4
Nuts, 1/4-20 ss .....................................................................4
Lockwasher, 1/4-20 ss .........................................................4
IN HARDWARE BAG #2
Button insulators, 3/16" black ..............................................44
Shaft Retainers, 3/16" ss......................................................44
Screw, 8-32 x 1-1/4" pan head,ss .......................................7
Set screw, 8-32 x 1/4" ss .....................................................8
Locknut, 8-32 ss...................................................................4
Seal nuts, 3/8-32 gold zinc...................................................8
Allen wrench, 5/64" ..............................................................1
Push tube, 3/8 x 3" (for retainer installation) ........................1
Nylon cable ties, 8"...............................................................4
M2ANTENNA SYSTEMS, INC.
4402 N. Selland Ave.
Fresno, CA 93722
[phone] Fax: [phone]
www.m2inc.com Email: [email protected]
248CP22A PARTS & HARDWARE