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6. BOOM ASSEMBLY:  Inspect the CENTER BOOM SPLICE for any nicks or scratches.  File smooth if 
any found.  Locate Boom Section (3” X 0.125” X 180”) swaged (1) end & Boom Section (3” X 0.125 X 
180”) straight. Before joining boom pieces together, lightly oil or lubricate the COUPLING RINGS & 
insert Boom Stiffener assembly into straight boom section. Insert Boom Stiffener assembly 
approximately  17” from the end. Make note: This is end must be positioned to the rear of the 
completed boom.  This will center boom stiffener over the boom to mast plate (see dimension sheet). 
Add final Boom Section (3” X 0.125” X 180”) swaged (1) end to complete boom. Secure all boom 
sections using 1/4-20 x 3-1/2 bolts and locknuts. 
 
7. Orient the eyebolt eyes to the top of the boom. Place the boom on bucks or equivalent to get it to a 
convenient working height. Position one PARASITIC CENTER SECTION one inch from the end of the 
boom, add the saddle clamps and the four 1/4-20 x 3” bolts (a dab of Noalox on the threads make 
insertion easy). Align the top of the clamp to the eyebolt and tighten the saddle clamps evenly. Next, 
refer to the DIMENSION SHEET and using a tape measure and a marking pen or piece of tape, mark 
the ELEMENT LOCATIONS on the boom.  Your choices are: 
 
  CW-LO 

FONE  FULL 

BAND 

REFL 

 0” 

   0” 

D.E.   54.50” 

  61.000” 

D1 

  116.00” 

  127.00 

D2 

  323.00” 

  325.00” 

D3 

  528.00” 

  528.00” 

 
Dimensions represent the edge of the rear clamp block for each element.  Now mount the center 
element assemblies on the boom the same as the reflector.  Align each with the reflector and tighten. 
 
8. HAIRPIN MATCH ASSEMBLY: Refer to the HARDWARE ARRANGEMENT drawing.  Insert a 1/4-20 
X 2-1/4” bolt from inside the band clamp and Install the band clamp loosely positioned about 30” inches 
in front of the driven element. Mount the BALUN using the 2-1/2” U-bolt and cradle but do not over 
tighten. Remove the finger tight nuts over the hairpin clamp blocks and place the balun lead lugs over 
the studs and replace the nuts finger tight.  Next, slide the short bent end of the 3/8” tubes into the 
small hairpin clamp blocks and flush the ends of the tubes with the blocks. Align and tighten the clamp 
block bolts lightly. Install the shorting bar on the straight ends of the tubes and add the 1/4-20 x 1/4” set 
screws, but do not tighten on to the tubes yet. Set to the proper shorting bar dimension, align and 
tighten the set screws securely. Move the band clamp under the shorting bar, add the 3/8” spacer tube 
on the stud and drop the shorting bar over the stud and add the locknut. Tighten the band clamp, and 
then tighten the nut.. The dimension for your selected band coverage is: 
 

CW LO FONE 

 

FULL BAND 

 28.00” 

   31.500” 

 
Refer to the DIMENSION SHEET. This dimension is from the inner edge of the shorting bar to the inner 
edge of the tube. Install the main feedline or feed line jumper on the 1:1 balun. Tape the connector up 
carefully. Use the large cable ties to secure the cable to the boom. 
 
9.  INSTALLING THE ELEMENT TIP SECTIONS:  Start with the REFLECTOR tip sections and insert 
each double wall 1” element butt into the 1-1/4” center sections. align the holes and insert the 8-32 x 1-
1/2” screws.  Add the locknuts and tighten securely. Continue adding the other tip sections until the 
antenna is complete. 
 

20M5-125 ASSEMBLY MANUAL 

Содержание 20M5-125

Страница 1: ...M2 Antenna Systems Inc Model No 20M5 125 FEATURES The 20M5 125 is the perfect balance between wind area and performance It features improved gain and F B across the 20 meter band The 20M5 125 mph is...

Страница 2: ...e actual number but in most cases the things above the ground Houses buildings and heavy trees all eat up the part of your pattern needed to generate ground gain To put this in perspective take the ca...

Страница 3: ...assembly into the end of a 1 x 48 element section with holes at 1 2 and 1 1 2 from end Use 8 32 x 1 1 4 screws and locknuts at the joint Tighten securely Slide a 7 8 x 32 SLEEVE SECTION into the butt...

Страница 4: ...8 HAIRPIN MATCH ASSEMBLY Refer to the HARDWARE ARRANGEMENT drawing Insert a 1 4 20 X 2 1 4 bolt from inside the band clamp and Install the band clamp loosely positioned about 30 inches in front of the...

Страница 5: ...uckle 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...

Страница 6: ...20M5 125 DIMENSION SHEET NOTE DRAWING NOT TO SCALE...

Страница 7: ...20M5 125 ASSEMBLY DETAILS...

Страница 8: ...GENERIC COMPRESSION CLAMP DETAIL...

Страница 9: ...le plate 2 x 5 x 3 16 M2APT0110 1 Dacron rope black 5 16 x 36 ft 1 Turnbuckle forged 3 8 2 Eyebolt forged 3 8 x 6 2 Band clamp 2 1 2 to 3 1 2 ss 1 Poly disc 1 1 4 M2ADI0020 2 Cable ties large 3 U bolt...

Страница 10: ...FULL BAND PLOTS CW LO FONE PLOTS 20M5 125 ANTENNA PLOTS...

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