BARKER & WILLIAMSON MK-112 MAST KIT User manual

BARKER&WILLIAMSON
6025TECHNOLOGYDR
WMELBOURNE, FL 32904
321-676-8354
MK-112 MAST KITS
ROOFMOUNT
www.bwantennas.com
The MK-112 Mast Kits are designed to support the BWD/BWDS/BWDI series of folded dipole antennas as well as theAC/
ACS/ACI series of End-Fed Vee antennas. The roof mount series includes the MK112-RM mounting foot which is designed
to secure the bottom of the mast to a variety of roof tops. The roof mount foot is hinged so that it can be used on flat, sloped,
or peaked roofs. The mast sleeve is able to be pivoted, allowing assembly of the mast while it is laying down, and then lifting
with the guys into the upright position.
AntennaPreparation
If you are using a folded dipole antenna (BWD/BWDS/BWDI), assemble the MK112-CM center mount to the antenna.
Refer to the seperate instruction sheet that comes with the mount. For permanent mounting, attach the clamps to the back
of the mount and to the top mast pole. In this case, the halyard line and pulley on the center mast pole is not used. Attach the
end lines to the antenna (Figure 3). Tie the line through the holes in the end spreader. The line to the top of the antenna should
be tied approx 3 inches shorter than the bottom line. This will pull harder on the top antenna wire and prevent windmilling.
Once the antenna is up on the masts, if it does not hang vertically, you may need to further shorten that top line.
The End-Fed antennas (AC/ACS/ACI) do not need any preparation.
MastAssembly
(1) Takethebottomsectionof theantennamast andinsertit intothemast sleeve. Thebottomsection hastwoholes init. Turn
ittoaligntheholesinthemastpolewiththeholesinthesleeve. Usingthefigurebelowasaguide,assemblethebolts,flatwashers,
and locknuts through the supports, sleeve and mast. Tighten the upper bolt which only goes through the sleeve and mast pole.
The bolt which goes through the supports should be tightened so that the mast sleeve is still just able to be rotated.
(2) Place the assembly where it is to be mounted, and attach it with lags or bolts as appropriate. There will be little force on
this mount as the guy lines support the mast, but ensure that you are attaching to something that is structurally sound.
(3) Pivot the mast down to the roof. You may attach the balance of the mast at this time. Refer to the instruction sheet which
comes with the mast.
3/20

FIG3 (Folded Dipole Only) FIG4 FIG5 FIG6
(4) Assemble the mast sections together (Figure 4). The joiner pieces go into the mast pole ends. Line up the holes, and insert
the 1/4-20 hardware. Tighten until just snug - do not crush the fiberglass. If you are assembling a 24 foot mast, the middle guy
ring must be placed onto the mast end before joining the next piece (Figure 5). The mast pole with the halyard pulley goes on
top.
(5) Place the guy ring on top of the mast, near the pulley (Figure 6). Clip the guy lines onto the guy ring(s). A12 foot mast
uses 25 foot guys (blue marker). A 24 foot mast uses 25 foot guys (blue marker) for the lower ring, and 50 foot guys (red
marker) for the upper ring. Use 25 foot lines (blue marker) for halyards on end masts. (If you need a center halyard use a
50 foot line for a 24 foot mast, or a 25 foot line for a 12 ft mast. The halyard line will not have a snap hook or color marker.)
Straighten out all lines along the mast, in preparation for standing the mast up. Now is the time to get rid of any tangles.
Attach the coaxial cable to a hard affixed folded dipole at this time.
(6) If you are mounting a folded dipole (BWD/BWDS/BWDI) you must attach the antenna to the mount, and partially unroll
theendsbeforeraisingthemast. Itishelpfultohaveanadditionalpersonforeachantennaendtokeeptheantennafromtangling.
Tohard affix this to themast, attach the mount tothetop mast pole with thesuppliedclamps. (If you have the ability,you may
find it easier to erect the mast and then attach the antenna/mount to the top after guying.)
(7) Whenallisready,raisethemast. Youmusthavepeoplepullingonboththemiddleandtopguylinestokeepthemaststraight
while raising. Do not allow the top of the mast to whip when it gets near vertical.. When it is stood up straight tie off the mast
guy lines, and then tighten the nut on the base.
The guy lines must be at a 45 degree angle to the mast, or greater.
If you do not pull the mast up carefully, keeping it straight and supported with all of the guys, you will break it.
(8) Raisingtheend-fedantenna (AC/ACS/ACI)isquitesimple. After unrolling,tiethe centerhalyardlineto theinsulatorthat
is preassembled onto the antenna wire. Hoist the antenna to the top with the lanyard.
(9) If you are not hard affixing a folded dipole, it may be pulled up with the center halyard line attached to the top of the
center mount. Clip the halyard lines on the end masts to the rings on the antenna ends. Pull the end lines just enough to snug
the antenna. Do not try to make the antenna wires perfectly straight - you will use too much tension. A little droop is okay.
Retension the mast guy lines at this time if necessary to keep the masts vertical.