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GENERAL DESCRIPTION

UNPACKING

Unpack the antenna and check the parts against the Parts List and the drawings.  This will simplify
the antenna assembly.  Parts have been separated when possible to aid in assembly.  Make sure you 
have the necessary room to assemble the antenna before unpacking.  This antenna will be very large
when finished.  Try to assemble it in a large open area clear of obstructions and people.  A driveway and
a couple of saw horses or other means of support will make it easy to handle the antenna when putting
it together.   Assembly over grass is not recommended.  There are lots of small things that can get lost
forever in grass.  Some parts may have extras included so don’t worry if you have some left over when 
your done.   The design of the antenna makes it very easy to assemble.  

Tools you will need

WARNING

WHEN INSTALLING YOUR SYSTEM, TAKE EXTREME
CARE TO AVOID ANY ACCIDENTAL CONTACT WITH 
POWERLINES OR OVERHEAD OBSTRUCTIONS.
FAILURE TO EXERCISE THIS CARE COULD RESULT
IN SERIOUS OR FATAL INJURY

The LFA (Loop Fed Array) Low-Noise Yagi is very different from the traditional dipole fed Yagi in many ways 
with its primary benefit being unwanted noise rejection. The LFA has a rectangular shaped, full wave loop 
driven element that is laid flat on the boom between and in-line with the parasitic elements .  Then there is the 
way in which the loop functions. The smaller end sections which run parallel to the boom, are engineered to be 
180 degrees out-of-phase with each other. This provides the same effect as is seen within ladder-line feeder; each 
side cancels the other out and therefore, minimum radiation occurs.  In practice this translates to highly 
suppressed side lobes and side-on signal rejection. This feature also plays a role in reducing F/B (Front to Back 
ratio), F/R (Front to Rear ratio) and broad-banding of the antenna too. It is these attributes which help give the 
LFA class-leading all-round performance at almost any boom length and for any given band.

Tape measure in inches.

  A tape measure in feet and inches will do but you will have to convert.

7/16 wrench and/or nut driver
½ inch wrench
Phillips screwdriver
Flat head screwdriver

 for hose clamps

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Содержание LFA-6M4EL

Страница 1: ...rating Equipment 308 Industrial Park Road Starkville MS 39759 USA Tel 662 323 9538 Fax 662 323 6551 VERSION 1A LFA 6M4EL 6 Meter 4 Element Loop Feed Antenna INSTRUCTION MANUAL Cushcraft Amateur Radio Antennas Cushcraft Amateur Radio Antennas ...

Страница 2: ...IN SERIOUS OR FATAL INJURY The LFA Loop Fed Array Low Noise Yagi is very different from the traditional dipole fed Yagi in many ways with its primary benefit being unwanted noise rejection The LFA has a rectangular shaped full wave loop driven element that is laid flat on the boom between and in line with the parasitic elements Then there is the way in which the loop functions The smaller end sect...

Страница 3: ...nto the boom to mast bracket until they meet at the center Tighten the bolts Install the U bolts using the 5 16 nuts 555747 385142 1 385144 1 562961 554099 and the 5 16 split washers 564792 555747 564792 540067 Long tube 85 inch Short tube 75 inch Front of antenna You may place the boom on a temporary mast or support it from each end This will make assembly and measurements easier Find a location ...

Страница 4: ... boom and work forward The measurements are given in total inches from the rear of the boom If you need the distance from each element to the next you may subtract the bracket measurements to obtain this value Total distance is given for better accuracy in element placement Distance between elements measurements will cause cumulative errors as each element is placed 1 4 20 x 3 4 10 24 x 1 4 20 x 3...

Страница 5: ...om the center of the boom to the outer edge of the loop end Slide a 4 hose clamp over the loop ends before installing Verify the measurements and tighten the clamps on the reflector and directors Leave the clamps on the loop end loose The loop end needs to move for final tuning of the antenna Install the 7 16 tube caps on the ends of the elements Loop End Don t tighten loop clamps until final tuni...

Страница 6: ...h the 1 bracket Seal the Coax where the conductors split using an appropriate sealant Water should never be allowed to enter the coax conductor Use of a balun is recommended An example of a coaxial balun is shown below You may use this method or any commercial version you wish Placement of the balun does not have to be at the mast It is better to have it close to the feed point RF Choke 12 turns o...

Страница 7: ...h sides the same amount Move them a small amount each time and recheck the SWR The dip point should move up as you move the loop ends in toward the boom Continue this adjustment until the frequency you desire has the lowest SWR If the frequency is too high then move the loop ends out away from the boom in the same manner Do not tighten the loop clamps each time you adjust the distance The loop end...

Страница 8: ...NOTES 8 ...

Страница 9: ...9 ...

Страница 10: ...10 ...

Страница 11: ...961 1 4 LOCK WASHER 44 171329 5 8 CLAMP 2 170413 1 1 4 X 058 X 75 1 170415 1 1 4 X 058 X 85 1 455630 1 1 4 TUBE CAP 2 475639 7 16 tube cap 6 174869 6 mtr loop end 2 190002 5 8 x 7 5 tube 10 461057 5 8 insulator 2 504069 10 24 x 1 bolt 2 554071 10 24 nut 4 565697 10 lockwasher 4 745 3104S 4 hose clamp 14 385142 1 boom to mast 1 385144 1 backup plate 1 540067 u bolt 2 564792 5 16 split washer 4 5557...

Страница 12: ......

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