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CARDIOID ARRAY

(Uni-directional)

When two or three identical verticals are ex-
cited directly and fed 90 degrees out of phase
with a spacing of 1/4 wave length, a cardioid
pattern results. This pattern may be switched in
either direction. By inserting a 1/4 wave length
delay line the antenna will "fire" or be directive
to that particular element.

.:

TWO VERTICALS

Figure 3

Cardioid-Unidirectional With 

Two Selectable Directions

Summary of Contents for AV-12AVQ

Page 1: ...cal and most mechanical connections NOTE If you mount the antenna then find the roof space is too small for the radial system you can droop the radials over the roof at almost any angle without seriously changing the performance of the antenna WARNING When installing your system take extreme care to avoid any accidental contact with power lines or overhead obstructions Failure to excise this care ...

Page 2: ...ssembly To become familiar with the antenna and to simplify the assembly read through the entire manual before beginning Unpack the parts and check them against the Parts List and drawings Determine where to mount your antenna rooftop or ground and what mode of transmission to use Phone or CW Take note of the dimensions in the manual For the antenna to operate at peak efficiency these measurements...

Page 3: ...ng lengths for your mode of transmission Select the proper size tubing clamp as shown in the chart When installing the clamps place the clamp near the tube end with the top of the clamp over the slot in the tube as shown in Figure 2 After adjustment of the tubing lengths tighten the clamp with a 5 16 inch nut driver socket or open end wrench until the tubing will not twist or telescope Figure 2 Tu...

Page 4: ...lect the four 4 1 4 20 x 3 4 screws nuts and lockwashers Items 12 17 and 20 and in stall on the base assembly If the antenna is to be ground mounted tighten these screws securely If the antenna is to be roof mounted refer to Figure 5 before tightening these screws A radial system must be added for proper operation when this antenna is mounted on the roof This radial system can also act as the guyi...

Page 5: ...Figure 3 Overall view with Callouts and Dimensions ...

Page 6: ...bove 6 Maximum length ground wire Not 52 Ohm coaxial cable Not Supplied NOTE For improved performance use more ground rods Any good electrical connection can be used Not Supplied Figure 4 Ground Base of Antenna Connect the coaxial cable as shown in Figures 4 and 5 Weatherproof the connection using Coax Seal or some similar substance to prevent water from ruining the coax WARNING Keep this antenna ...

Page 7: ...Figure 6 Radial Arrangement ...

Page 8: ...Figure 7 Schematic of Antenna Base Figure 8 Completed Roof Mount Installation of the 12AVQ ...

Page 9: ...dditional adjustments are indicated by the VSWR curve to put 10 meters exactly on the portion of the band you desire as your center operation frequency B If the antenna favors the high end lengthen the dimension correspondingly to move the antenna to a lower frequency as outlined above 4 Next repeat this same procedure for 15 meters to put that band on frequency 3 Beginning on 10 meters make a VSW...

Page 10: ...ubing 3 1 455644 Caplug 7 16 1 1 Not Used 1 505266 Bolt hex head 1 4 20 x 3 4 4 1 543792 U Bolt 5 16 x 15 8 x 21 4 2 1 Not Used 1 Not Used 1 555747 Nut hex 5 16 18 4 1 554099 Nut hex 1 4 20 4 1 Not Used 1 564792 Lockwasher split 5 16 4 2 562961 Lockwasher internal 1 4 5 2 565697 Lockwasher internal 10 2 Use this scale to identify lengths of bolts 1 inch 1 2 54 cm diameters of tubes etc The America...

Page 11: ...required for the 24 feet high self supporting tower The top mast extends the height to 50 feet Two units make an ideal phased array MODEL 18AVT WB S The 18AVT WB S is a multi band trap vertical for 10 through 80 meters It is completely fac tory pre tuned and exhibits an extremely low angle DX radiation pattern It is easy to as semble light weight which one man can install A single 50 ohm coaxial f...

Page 12: ...nown for its low angle characteristics When you combine two identical verticals properly spaced and phased the resultant is a concentrated low angle of energy and a power gain These antennas can be so arranged to give a definite effect on either one or two favorite bands or all band coverage with some pattern compromise and slight loss of gain The following data was experimentally derived on the T...

Page 13: ...rrangements offer an excellent ad vantage over a single vertical since either phasing combination exhibits noticeable signal gain with side attenuation of undesired signals This added gain and low angle vertical directivity is the advantage of the phased array ENDFIRE GAIN 23 dB Phased verticals may be spaced either one quarter wave or one half wave depending upon gain and directional characterist...

Page 14: ...KHz Design Frequency SPECFICATIONS Broadside End Fire Pattern width half power points 60 degrees 80 degrees Gain over single vertical 3 86 dB 2 3 dB Side attenuation 30 dB 20 dB Impedance 50 Ohms 50 Ohms Directional characteristics Bi Directional Bi Directional ...

Page 15: ...s out of phase with a spacing of 1 4 wave length a cardioid pattern results This pattern may be switched in either direction By inserting a 1 4 wave length delay line the antenna will fire or be directive to that particular element TWO VERTICALS Figure 3 Cardioid Unidirectional With Two Selectable Directions ...

Page 16: ... pattern for two 1 4 wave length verticals will be approximately 120 degrees An arrangement of three switchable verticals gives a 60 degree pattern in six selectable directions Figure 4 360 Cardioid Arrangement ...

Page 17: ... Consideration must be given to the fact that 1 2 wave spacing optional is ideal for phasing When multi banding with close and wide spac ing compromise radiation patterns must be expected In most cases a choice spacing serves 3 bands most effectively with good directional characteristics added gain and low angle per formance ELECTRICAL SPECIFICATIONS VSWR Exceptionally low SWR is present with a ph...

Page 18: ...unications In cases where close and medium distance contacts are hampered by the array s low angle characteris tics and a higher angle is required switching arrangements can select one vertical for this coverage Low loss constant impedance type coaxial switches and connectors should be used when splicing phasing lines B W multi position single or multi gang coaxial switches with Am phenol coaxial ...

Page 19: ...ects Bi Directional patterns Use SW2 for broadside position 1 Endfire position 2 C All switches in position 2 selects cardioid pattern SW4 selects direction of cardioid pattern NOTE All connecting lines are exaggerated in length These lines must be direct and short as with any coax hook up prac tice Figure 5 Typical installation 2 18HT S Phased for 80 and 40 Meters Selectable Broadside and Endfire...

Page 20: ...Note Corralate Patterns to spacing used in installation Figure 6 Radiation Patterns Typical Spacing For Broadside And Endfire Arrangements ...

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