M2 Antenna Systems 303CP26 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 Incorporated 08/24/22
Rev.03
Model .........................................303CP26
Frequency Range.......................298 To 308 MHz
*Gain ..........................................15.14 dBic
Front to back ..............................20 dB Typical
Beamwidth ...............................30° Circular
Feed type ...................................“T” Match
Feed Impedance. .......................50 Ohms Unbalanced
Maximum VSWR........................1.5:1
Input Connector..........................“N” Female
Power Handling ..........................1.5 kW
Boom Length / Dia......................140.625” / 1”
Maximum Element Length..........20”
Turning Radius: ..........................Call
Stacking Distance.......................Call
Mast Size....................................1-1/2” to 2” Nom.
Wind area / Survival ...................0.6 Sq. Ft. / 100MPH
Weight / Ship Wt.........................5 Lbs. / 7 Lbs.
M2 Antenna Systems, Inc.
Model No: 303CP26
FEATURES:
The 303CP26 is a practical sized, yet 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.
The CNC machined driven element module is O-ring sealed and weather tight for low maintenance and long-term peak
performance. Internal connected are encapsulated in a space-age silicone gel that seals out moisture and improves
power handling. The 3/16” 6061-T6 rod elements are centered to minimize interaction and maintain good ellipticity.
Insulators are UV stabilized and locked in place with stainless keepers. Rugged construction, uncompromising
performance for the boom length.
SPECIFICATIONS:
*Subtract 2.14 from dBi for dBd

303CP26 ASSEMBLY MANUAL
Before beginning assembly, read over the parts list and check for missing or damaged parts. Contact the M2
Antenna Systems, Inc. directly at 559-432-8873 if any discrepancy is found.
Tools required: A medium size flat blade screwdriver, an 11/32 nut driver or equivalent, a 1/2 inch wrench or not
driver, a 7/16 inch wrench and a tape measure.
1. The driven element is partially assembled at the factory. Starting 11-3/8” (11.375”) from the rear of the
female “F” connectors point toward the front of the antenna. Secure with an 8-32 x 1-1/4” screw. Next, slide
the 3/16 x 18.0 inch long rod through the open holes just below it and add two black button insulators. Cen-
ter the rod in the boom. Add the shorting blocks, positioning them at the ends of the shorter rod elements.
When everything is adjusted, tighten up the set screws.
2. Repeat this operation for the second driven element, mounting it a t 20-3/8” (20.375”) from the rear and with
the two “F” connectors facing the rear driven element just installed and on the left side of the boom per the
sketch. Proper positioning per the sketch will guarantee RIGHT HAND CIRCULARITY.
3. Assemble the boom per the antenna dimension sheet, secure the joints with the 8-32 x 1-1/4” screws,
lockwasher and nuts. Final tightening and alignment will be done after the elements are all in place.
4. Now mount the phasing block 9-1/4 inches from the rear of the boom using an 8-32 x 1/4” screw. Position the
block on the same side of the boom as the rear driven element so the large “N” connector is facing to the rear.
REFER TO THE CABLE ASSEMBLY SKETCH FOR STEPS 6, 7 & 8.
5. Connect the two 14.5 inch long balun cables to the two close spaced connectors on each driven element
block. Tighten the connectors first by hand and then gently but firmly with a 7/16 inch end wrench. TO
PREVENT POSSIBLE CABLE DAMAGE hold the body of the connector with pliers so it doesn’t rotate during
this final tightening operation.
6. Connect the long, 22-1/2” phasing cable to the single TOP connector on the FRONT driven element and
route the cable back to the side connector on the phasing block. Again, tighten both ends first by hand and then
finally with the 7/16 inch wrench.
7. Connect the short 7-1/2 inch phasing cable to the single connector on the rear driven element block and
route the cable to the in line connector on the phasing block. Tighten as before.
8. Once the cables are all in place form them neatly against the boom and hold in place with the black nylon
ties. In places where director rod elements will come through the boom, do not tighten the nylon ties all the way
so the cables may be moved slightly for clearance around the rod elements.
INSTALLING THE ELEMENTS
9. Separate te rod elements into two (2) sets. Using just one set, install the 18-7/8” rod element in 5/16 inch di-
ameter hole 5 inches form the rear of the boom. Use the black button insulators on either side where the ele-
ment passes through the boom. At this time just position the element near center. Final centering can be done
later when all the elements in one plane are in place.
10. The elements taper in length so continue installing the rods down the boom using the button insulators as
described in step #10.
11. When all the elements in one plane are in place, start at one end using a tape measure: center each
element to 1/16 inch or better. We recommend you DO NOT install the keepers at this time, just center each
element. When centering is complete, stand at the end of the boom and sight down the tips of the elements
noting any irregularities. The tips should form a gentle curve, and each side should look like a mirror image of
the other. This is just a crude check to catch major errors or any irregularities. Correct if found.

303CP26 DIMENSION SHEET
H V

303CP26 ASSEMBLY MANUAL
12. The stainless steel element keepers are stiff so grasp the element firmly while sliding the keepers in place.
USE THE 3/8 X 3 TUBE TO AID IN THE INSTALLATION. Double check your centering dimensions and them
push the keepers up tight against the button insulators.
13. Repeat steps 10 through 13 for the other set of elements.
14. Now that all the elements are in place, sight down the boom looking for element alignment irregularities
around the boom splice joints. Align and tighten.
15. Pick up the boom and find the weight balance point. Remember the feedline will attach at the rear and add
a bit more weight on that end. Position the boom to mast plate accordingly, attaching it to the boom with the 1-
1/8 inch U-bolts, cradles and nuts.
16. Circular polarized antennas such as this antenna must be mounted on non-metallic masts or support booms
and the feedlines must run off the back of the boom so as not to disturb the standing wave ratio and the circular
properties of the antenna. If this antenna is to be mounted as a pair of transmit-receive antennas a 6 to 8 foot
long by 1-1/2 inch diameter crossboom is recommended. When attaching the main 50 Ohm feedline, tape or
nylon tie it securely to the rear stub of the boom to remove stress on the male “N” connector.
THIS ANTENNA HAS BEEN CAREFULLY MANUFACTURED BY:
M2 Antenna Systems, Inc.
4402 N. Selland Ave.
Fresno, CA 93722
[phone] Fax [phone]
www.m2inc.com email: [email protected]

303CP26 PARTS & HARDWARE
303CP26 PARTS LIST
DESCRIPTION .............................................................................. QTY
BOOM SECTION, 1.0” X .058 X 60” SOE ..................................... 1
BOOM SECTION, 1.0” X .058 X 58” SOE ..................................... 1
BOOM SECTION, 1.0” X .058 X 27.625” STR .............................. 1
ELEMENT SET, 3/16” X SEE DIMENSION SHEET ..................... 26
DRIVEN ELEMENT ASSEMBLY................................................... 2
PHASING BLOCK.......................................................................... 1
BALUN, 14.5” RG-6 ....................................................................... 2
PHASING CABLE, 22.5” RG-6 ...................................................... 1
PHASING CABLE, 7.5” RG-6 ........................................................ 1
BOOM TO MAST PLATE, .188 X 4” X 6” ...................................... 1
U-BOLT, 1-1/2” AND CRADLE ...................................................... 2
U-BOLT, 1-1/8” AND CRADLE ...................................................... 2
ASSEMBLY MANUAL.................................................................... 1
HARDWARE BAG
SHORTING BARS, 1/4 X 3/4 X 1-1/2 ALUMINUM........................ 4
BUTTON INSULATORS ................................................................ 52
ELEMENT KEEPERS .................................................................... 52
SCREW, 8-32 X 1-1/4 SS.............................................................. 7
SET SCREW, 8-32 SS................................................................... 8
LOCKWASHER, SPLIT-RING #8 .................................................. 4
NUT, 8-32 SS................................................................................. 4
NUT, 5/16-18 SS............................................................................ 8
LOCKWASHER, 5/16-18 SS ......................................................... 8
NYLON TIE .................................................................................... 5
PUSH TUBE, 3/8 X 3”.................................................................... 1
ALLEN WRENCH, 5/64 ................................................................. 1
M2ANTENNA SYSTEMS, INC.
4402 N. SELLAND AVE.
FRESNO, CA 93722
[phone] FAX: [phone]
www.m2inc.com Email: [email protected]