Antenna Plans

Build a 4 Elements Yagi

Material list for building a 4 Elements Yagi

  1. 1″ X 0.5″ Rectangular Aluminum tubing for the boom
  2. 3/8″ Aluminum tubing for antenna elements
  3. 1cm Outside diameter antenna tubing for elements holder
  4. 1pc SO239 connector
  5. Pop rivets / Rivet tool
  6. #12 AWG Copper wire with insulation (12″for Gamma match)
  7. Soldering iron
  8. 8pcs Stainless steel nuts and bolts 20mm length 3mm diameter
  9. 1, Butterfly nut and 1 bolt 18mm length 3mm diameter
  10. Aluminum plate 0.5mm thickness
  11. Collapsible tube (shrinkable tubes)

Download Yagi Dimensions Here

To build the 4 Elements Yagi you may follow the direction for building the 3 Elements Yagi except that you will add an additional parasitic element (director) which is about 5% shorter than the last element of the 3 elements yagi. The spacing are the same between the elements and when built successfully it will give you a very desirable 9.39dBi gain or about or about 7.24dBd.

To increase the performance you may also configure the antenna in stack configuration by making two antenna’s and connect it with a phasing harness for increased performance.

Antenna Gain Simulation and Signal Pattern Using 4Nec2 antenna modeling.

Front to Back Ratio: 9.92dB
Antenna Gain: 9.39dBi
Beamwitdh: 70° Vertical 54° Horizontal

Vertical Pattern 4 Elements Yagi
Horizontal Pattern 4 Elements Yagi
Combined pattern 4 Elements Yagi

11 replies on “Build a 4 Elements Yagi”

Thank you sir for this design… Napaka ganda at very light wieght i used round aluminum tubing to save na din sa mga scraft ko dito.. i hit 1.3 on the swr meter at 145.000Mhz and i tried to radio check this yagi approximately 35km away from my location scaling sugar 5 at 4 ft above d ground.. Once again sir thank you for this yagi design..

sir, okay sa alright, glad to see builders of yagi home brew antenna, reminds me of my years in amatuer radio… way back from the 1990’s to early 2000… planing to be back on air with my antique radio shack… good job sir this will help newbies to learn ham radio… 73’s. with the call dw2rvn from the club station dx2alarm…

Hi Ephraim, using a wide rectangular boom is a good idea. Because then just a thought, you can drill a thru hole for the reflector and elements to go thru and one screw on top to hole it down, eliminating a small bracket to hold the elements and two screws. And also, I question the impedance of over and below 50~52 ohms for perfect loading of the transmiter. your antennas that do not fall within 50~52 ohms impedance will require an L C network to balance it.. just my input.. maybe it will help you improve your design. thank you.

Thanks @chuck kie, I’m using through hole mounting on my dual band cross antenna build, technically the gamma match is a capacitor so to tune the antenna and make your impedance 50 ohms you just need to make the driven element more inductive so that you just need a little capacitance to bring it to resonance use the antenna analyzer inductance read out to help you lengthen or shorten your driven element and that’s for your L C network, no need to complicate things, oh by the way a little deviation from 50ohms is so much acceptable as there is no perfect materials don’t worry too much about the little impedance variations. 😉

I discovered your plan online to build the 3×5 elements 2m/70cm Yagi and now I’m motivated to repurpose a large TV antenna. Of course, I’ll need to change the size and placement of the elements but I’m wondering how this is calculated. The antenna I’ll repurpose has 16 elements. Are there specs for a Yagi with more than eight elements? Thanks!

There are lot’s of antenna plans for yagi’s with more than 8 elements, the elements length are computed using wavelength formula for the driven element which will become the basis for your center frequency usually spacing is 1/4 wavelength < or > depending on the designer of the yagi. Reflector are 5% longer than the driven and directors are 5% shorter but are not set in stone, you can tweak the design using antenna modelling personally, I’m using 4NEC2 for the antenna designs posted here.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.