The KJ4IIF Multiband "FAN" Dipole for 160, 80 and 40 Meters
(Optional 20 Meter banding addition also)
(Using Techniques and modified formulas from SRI search with Fan Dipoles)
I did not model this with any antenna modeling software. I did it the honest-to-god intentional way. With formula's, cut and dress, a cooler full of emotionless drinks and some friends to help pull that heavy aerial finished in everyone's thoughts.
Included at the bottom of this article is a frequency vs, "X" and "R" asset swr results graph for all amateur bands, 2 meters through 160 meters. There is also a link to a in harmony kinship for each bands courtesy of and compilied by N5JNX.
All measurements are taken with an MFJ 259B analyser.
Apex of the multi band dipole antenna is at 58 feet, Ends of the 160 leg are at 20 feet above ground.
The multi dipole has a 1:1 prevailing Balun at the prey point.
The 160/80/40 meter multiband fan dipole (lower right) mounted on the pillar!
CONSTRUCTION DETAILS:
In the photograph higher up, the 160 meter plane section is on top, 80 meters in middle and 40 on penetrate.
On apiece incomplete of the antenna, every dipoles halfs are connected together at a common point on each incline of the concentrate on dielectric. Then each fractional is connected to the 1:1 balun at rear.
In the photo above, the legs of the multi band dipole are leaded 6 inches apart vertically, quatern inches apart horizontally at the feed point. I used 14 inches of non conductive Lucite six inches wide as shown.
I spaced the dipole legs with 1/2 inch Premature ventricular contraction, Six inches from the fed point where the legs break away the Lucite. I trained 1/4 inch holes through the pvc and rib the wire through the holes. This keeps the wires separated at the feed luff. See photo above.The spinning top dipole is unsexed for 160 with a center frequency of 1.9 mhz recipe is 468/1.9 X .96 works out to roughly 118 feet per leg.The center dipole is cut for 80 meters with a center frequency of 3.85 mhz.
The formula is 468/7.18 X 1.04 works out to just about 63 feet per ramification.
The bottom dipole of the multi striation dipole is cut of meat for 40 meters with a center frequency of 7.18 mhz.The rule is 468/7.18 X 1.04 industrial plant out to roughly 33' 10" per ramification. Mark: Always arrange the dipoles with the lowest frequency band first, (on exceed), then the next higher oftenness band under it and so on. You should end up with them in this rank from the top:
160 along top
80 middle
40 bottom
The interesting matter hither is if you look at the swr readings for each design frequency in the chart below this article, you will ensure that each ring has a very low swr!
At the destruction of the 40 measure leg I used 78 edge distance of 1/2 pvc for a broadcaster. I drilled holes and threaded the wire done for each cardinal legs. I engrossed the 40 m leg roughly the polyvinyl chloride and guaranteed IT with a small telegraph clamp. See exposure above.
See photo above. At the end of the 80 meter ramification I used a 40 inch piece of 1/2 edge in pvc for a spreader, drilled holes through it and threaded the electrify through for the remaining two legs.
I wrapped the 80 meter leg through the pvc and secured it with a teensy cable system clamp.
At the end of the 160 meter branch a patch of 1 inch pvc was used to secure the leg and dacron rope was wont to a marry point, any available corner Beaver State post will do. I sealed all of the connections with electricians liquid tape.
As you toilet visualize by the chart below, the harmonics work on 15 meters as well.
Although the analyzer shows a good VSWR on two meters I doubt if IT tail access code any repeaters. I never tried.
Same goes for six meters although with that huge a capture area it may equal a in effect receive antenna for that ring.
On the air reports have been good.
I hope this testament help anyone trying to try out with this aerial for the low bands. So in that location you have it....Four bands, one feed line, no antenna coupling obligatory, and 15 meters as a bonus on the harmonics. And with the optional 20 meter band addition, you can have 5 bands all working recovered...see 20 meter additiion information at a lower place. Think of that this rooter dipole antenna was configured for the 160, 80 and 40 meter bands.
In the chart below you will notice a very low swr on apiece of these bands with
Frequency vs R, X and VSWR Graph
(Notice the swr readings for the design frequencies of 1.91 - 3.86 - 7.18mhz!)
| freq mhz | R | X | VSWR |
| 148 | 41 | 14 | 1.4:1 |
| 144 | 46 | 17 | 1.4:1 |
| | | | |
| 54 | 58 | 27 | 1.6:1 |
| 53.5 | 76 | 38 | 2.1:1 |
| 50.38 | 45 | 31 | 2.0:1 |
| | | | |
| 29.7 | 16 | 6 | 3.1:1 |
| 29.37 | 39 | 29 | 1.9:1 |
| 28.86 | 66 | 36 | 1.9:1 |
| 28 | 20 | 8 | 2.7:1 |
| | | | |
| 24.99 | 16 | 12 | 3.3:1 |
| 24.89 | 16 | 17 | 3.2:1 |
| | | | |
| 21.45 | 59 | 25 | 1.6:1 |
| 21.03 | 69 | 25 | 1.7:1 |
| | | | |
| 18.17 | 120 | 77 | 3.3:1 |
| 18.11 | 77 | 78 | 3.2:1 |
| | | | |
| 14.35 | 14 | 9 | 3.6:1 |
| 14 | 71 | 46 | 2.2:1 |
| | | | |
| 10.15 | 10 | 13 | 5.0:1 |
| 10.1 | 10 | 9 | 4.9:1 |
| | | | |
| 7.3 | 25 | 1 | 1.9:1 |
| 7.18 | 58 | 5 | 1.2:1 |
| 7.12 | 52 | 35 | 1.9:1 |
| | | | |
| 4 | 13 | 6 | 3.5:1 |
| 3.91 | 31 | 22 | 1.9:1 |
| 3.86 | 56 | 53 | 1.1:1 |
| 3.82 | 34 | 24 | 1.9:1 |
| | | | |
| 1.96 | 67 | 36 | 2.0:1 |
| 1.91 | 50 | 24 | 1.3:1 |
| 1.86 | 36 | 28 | 2.0:1 |
Tick here for the Harmonic relationship graph for this antenna for all bands by N5JNX.
Adding the 20 M addition as an choice!
Just as an experiment, I added a separate 20 meter addition to the fan dipole.
I forthwith have, 15/20/40/80/160 meters on one antenna
20 meters worked on the dot as the others.
Expression used : 468/freq X 1.04
End Result Band Breadth for the 20 meter addition
| Freq | R | X | VSWR |
| 14.502 | 25 | 3 | 2.0:1 |
| 14.177 | 61 | 0 | 1.1:1 |
| 14.000 | 45 | 14 | 1.3:1 |
Spacing at feast point was identical to the 3 banding version, six inches divided.
Further experimentation.
Mayhap later, I bequeath try to add 10 meters but the FAN configuration is starting to bring out of whack with that more wire elements on peerless aerial. I May undergo to blank space the 10 meter fertilise point 12 inches from the 20 meter feed point to strain and make information technology at least a 45 degree dipole.
Side past side comparisions on recieve show a 10 to 12 dubnium fewer than the Mosley TA33 at 75 feet, nigh deuce S units to a lesser degree the beam, indeed information technology is as it should glucinium. So there you sustain it....Four bands, (5 if you MBD 20), one feed stoc, no antenna coupler required, and 15 meters as a bonus along the harmonics with the designed bands having very double-bass swr!
Try it! 73 - KJ4IIF
Hf 8 Band Fan Dipole Multiband Antenna 160-6 Meters With Balun
Source: https://www.hamuniverse.com/kj4iif1608040fandipole.html
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