M2 Antenna Systems 20M5-125, Руководство пользователя

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10. Determine the BALANCE POINT of the assembled antenna and mount the BOOM TO MAST
PLATE using two 3 inch U-bolts, stainless steel lockwashers and nuts.
11. OVERHEAD BOOM SUPPORT SYSTEM.
A. Attach one end of the Dacron cord to the rear eyebolt using two turns around the eyebolt and a
series of three half hitches or equivalent knots. Without cutting the cord, secure other end at the front
eyebolt. Pull on the knots HARD to SET them and tape the excess cord back to main cord tightly with
black vinyl electricians tape. Seal ends with heat or flame to prevent fraying.
B. TEMPORARILY insert a standard 2” U-bolt through the turnbuckle plate and add two nuts so about
1/2 inch of the threads stick out. Insert U-bolt studs through the top set of 2” U-bolt holes in the boom
to mast plate from the boom side and add two more nuts. Open the two turnbuckles up until just a
thread or two from each end shows inside the body of the turnbuckle. Hook the turnbuckles into the
holes at the edge of the turnbuckle plate. Equalize the Dacron cord over the plate and cut it. Take two
wraps of the cord through the eye of the rear turnbuckle, PULL the cord as tight as possible and make
the knots as before. Repeat for the front cord section and turnbuckle. Cut off any excess over one foot
long and again seal and tape the excess cord back to the main cord.
C. Now DISASSEMBLE the U-bolt from the boom to mast plate. The guy assembly is now centered
and the turnbuckle plate ready to be installed to the mast and raised until the boom is straight.
If practical, after the final assembly and before installation, let the overhead guy system support the
boom and take a set overnight: Install a 2’ to 3’ temporary 2” mast section to the boom to mast plate
and attach and raise the turnbuckle plate. Support the antenna at the boom to mast plate. The Dacron
cord DOES NOT STRETCH UNDER LOAD but cord and knots will take a SET and the boom may
droop just a bit. Reset turnbuckle plate. If your boom droops again following this adjustment, check
your knots - they may be may be slipping. If an overnight set is not possible, then after installing
antenna on mast, lean on or pull on the cords to increase the tension and help the knots take their final
“set.” Make sure the knots are not slipping. When the guy system has taken a “set”, loosen the 2” U-
bolt and adjust turnbuckle plate height until boom is straight and level.
After final installation, do any minor boom straightening with the turnbuckles. Then safety wire to
prevent changes to settings.
12. THIS COMPLETES THE ASSEMBLY. When the antenna is installed in position on the mast, the
main feedline can be attached and sealed at that time. REMEMBER to support the feedline at the
antenna boom and on the mast. Leave an adequate feedline loop for rotation around the tower. Mount
horizontally polarized VHF and UHF antennas at least 40” above or below this antenna to minimize
interaction.
CAREFULLY DESIGNED AND MANUFACTURED BY:
M
2
ANTENNA SYSTEMS, INC.
4402 N. SELLAND AVE.
FRESNO, CA 93722
(559) 432-8873 FAX: 432-3059
www.m2inc.com Email: sales@m2inc.com
20M5-125 ASSEMBLY MANUAL