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Figure 2A VSWR for Both

Vertical and Horizontal

Polarization

Figure 2B Driven Element

Cutting Chart

Stacking

This antenna can be easily stacked for ap-
proximately 3 dB more gain each time the
number of yagi is doubled. Refer to Figure 3 for
stacking and phasing harness cutting informa-
tion.

The two phasing lines coming from the two an-
tennas to the "T" connector can be any odd
multiple of 1/4 wavelength in the 75 ohm trans-
mission line. See Figure 4.

NOTE: When phasing two antennas, the Driven
Element halves that are connected directly to
the phasing lines should be on the same side of
the array.

Figure 3 Stacking Two (2)

Antennas

Summary of Contents for VB-25FM

Page 1: ...lied balun matches the input to 50 ohms If you are using transmission line with a characteristic impedance other than 50 ohms or 200 ohms a matching device must be made Refer to any current Amateur Handbook for information on constructing a matching device Specifications Mechanical Boom Length 75 1905 mm Longest Element 39 5 8 1006 mm Net Weight 2 9 lbs 1 3 kg Turning Radius Max 73 1854 mm Wind Su...

Page 2: ... optimum performance over the entire 144 148 MHz band If you wish to optimize the antenna for a frequency higher than 146 MHz cut 1 4 off of the total element lengths for each MHz higher than 146 Driven Element SWR can be lowered to less than 1 2 1 at a desired frequency by carefully trimming the driven element Keep The element symmetrical by cutting the same amount from each side Typical SWR curv...

Page 3: ...bled Refer to Figure 3 for stacking and phasing harness cutting informa tion The two phasing lines coming from the two an tennas to the T connector can be any odd multiple of 1 4 wavelength in the 75 ohm trans mission line See Figure 4 NOTE When phasing two antennas the Driven Element halves that are connected directly to the phasing lines should be on the same side of the array Figure 3 Stacking ...

Page 4: ...rizontally for FM or SSB CW respectively Circular polarization can be obtained by using two yagis For information about which polarization is best consult local Amateurs who use the frequencies you desire Step by Step Assembly WARNING Do not allow any part of the antenna to touch power lines This could cause severe burns or fatal injuries When mounting two dissimilar antennas on the same mast be s...

Page 5: ...oom to Mast 23 Nut hex 1 4 20 13 Caplug 11 4 24 Lockwasher split 5 16 15 U Bolt 5 16 18 x 3 5 8 26 Lockwasher internal 1 4 Figure 5 Boom to Mast Clamp Assembly Item No Description 1 Tube Boom aluminum 1 1 4 x 75 18 Eyebolt 5 16 10 24 x 1 1 2 22 Nut hex 10 24 25 Lockwasher internal 10 27 Half Washer aluminum Figure 5 Detail A Parasitic Element Attachment ...

Page 6: ...ordingly before tightening the bolts securely Select the 3 16 x 39 5 8 R1 tube Item No 6 use pencil to place a mark at the center of the rod 19 13 16 from either end and place two more marks 5 8 from each side of the center mark Place a 10 24 x 11 2 eyebolt Item No 18 into the R1 slot as shown in Figure 5 Detail A Slide the R1 through the holes and the eyebolt until the outer two marks on the Rl a...

Page 7: ...oom to mast bracket and fasten it to the mast securely Tape the coax feedline to the boom and to the mast Be sure to insulate any connections from the boom or the mast This completes your installation Item No Part No 1 170386 2 175157 3 160040 4 385142 5 385144 6 160036 7 160016 8 160019 9 160021 10 871704 11 465420 872073 12 16326 13 45563 14 47563 15 54006 16 50526 17 50016 18 54006 19 50015 20 ...

Page 8: ...r warranty provided the product is returned postage prepaid to Hy Gain with a personal check cashiers check or money order for 8 00 covering postage and handling 3 Under no circumstances is Hy Gain liable for consequential damages to person or property by the use of any Hy Gain products 4 Out of warranty Service Hy Gain will repair any out of warranty product provided the unit is shipped prepaid A...

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