Club Project YagiKent Britain WA5VJB
This antenna has been built in over a dozen meetings as a club project fornew hams. Simple, cheap, and can be built in three versions for a few bucks.
Using the same boom, the student can build one in a matter of minutes for 432 MHz weak signal,AMSAT, or for the FM repeater band.

One thing nice about this design is it is not critical on the dimensions. So you don’t need amicrometer to measure out the elements. A good old yardstick is accurate enough.
Before the class I will make up a batch of booms. I like to use ½” x ¾” trim wood, but any wood
about ½” thick will work. You don’t want to use anything much thicker, it will change the tuningof the antenna. So ½” x ½” or ½” x 1” can also be used.
I am fairly careful marking where the holes will go for the first boom, then I can use that boom on
my drill press as the template for the next dozen or so booms. Sometimes more students show up
than I have pre-drilled booms. That’s when you make them a team project and it’s up to them as to
who takes it home. But they both know it’s easy to make more.
Elements
The antenna is designed for 1/8” diameter element material. I do not recommend changing theelement diameter. A lot of material can be used for the elements. 1/8” Aluminum Ground Rod
wire works well, Bronze Welding Rod, Aluminum Welding Rod, Hobby Tubing, and even thoserolls of #12 Aluminum wire used to suspend drop ceilings can be used. The rolls of wire areusually cheapest and the Bronze Welding Rod the strongest. One trick to straighten rolled wire is
to take a good length of it, 5 to 10 feet,pull on it hard, and then twist it a turn or two. Amazing how it straightens out and hardens.

Driven Element
For the Driven element it is much easier if you use something you can solder to.
The Bronze welding rod works well as does #10 or #12 solid Copper wire.
The loop in the driven element can be ½ to 1 inch wide. The width of the loop is not a criticaldimension.

Securing the Elements
A drop of glue holds the elements in place. Epoxy, Silicon Glues and others can be used. I
usually use a drop of “Super glue” but on the Driven Element glue the element in place after you
have soldered on the coax. Glue it first and you get a cloud of hot fumes while you solder thecoax. And those “Super Glue” fumes are nasty.
Not sure which version they want? Suggest the 432 MHz version. This is one of the few Yagi
antennas designed to be modified with wire cutters.
Securing the Coax
Cable ties work pretty well. But garbage bag ties, bread ties, electrical tape, and even a big wad ofglue have also been used. The solder joints on the driven element need some stress relief. Forthe coax itself, most any 50 Ohm coax can be used. Keep the free ends of the coax as short aspractical. Long leads will change the resonate frequency of the driven element.
Tune Up
Simply built to the dimensions the SWR is usually better than 2 to 1, certainly good enough formost work. But I like to bring along the equipment to tune them.
An antenna analyzer is good, a rig and SWR meter is plenty. This makes sure they really work.
Over the years there have been some very creative ways to interpret the instructions, and we arealso testing their construction. For the instructor you might want to bring also some 1/8” brass orCopper hobby tubing. For the student that ‘Cut it off twice and it’s still too short’ you can solder on
an inch or so of tubing on the tip of the element as in this Photo.
Suggested Kit
Pre-Drilled ½” wide wood booms
Element Material About 6’ for each antenna
Tape Measure or Yard Stick
Soldering Iron and Solder
Cable Ties
GlueCoax ends with connectors
Hobby knife
Wire Cutters (Bolt Cutters if using Bronze Welding Rod)Antenna Analyzer or Rig with SWR meter
Dimensions
Spacing
all versions
Reflector
0”432 MHz435 MHz

445 MHz

13.5”

13.4”

13.0”

DrivenElement

2.5”

12.75”

12.7”

12.5”

Dir 1

5.5”

12.4”

12.4”

12.25”

Dir 2

11.25”

12.0”

12.0”

11.75”

Dir 3

17.5”

12.0”

12.0”

11.75”

Dir 4

24.0”

11.0”

11.0”

11.0”