Tools and Materials:
-Metal Clothes Dryer 21 (0.5m) x 52 “(1.3m) (or wire mesh);
-Bar 1 x 1 x 52 inches (2.5 X 2.5 x 130 cm);
-Bar 1 x 2 x 24 (2.5 X 5 x 60.9 cm)
-Copper wire 1,6 mm;
-Connector “F” 75 Ohm; -Soldering accessories;
Step one: copper wire
If there is no copper wire without insulation, then you need to prepare it. The wizard removes the insulation from the wire and cuts it into 16 pieces of 500 mm each.
Step two : frame
Attaches a metal frame (dryer) to a 130 cm long bar. Drills a hole in the lower part of the block and bolts the smaller block.
Step Three: Building
Next, you need to make the first two butterflies. We take two pieces of wire 500 mm each and bend them in the middle. We form open triangles with a width of 139 mm. We tighten two screws 11.5 mm apart and 69.5 mm below the top of the long wooden board, as shown in the diagram. The next two screws will be 150mm below the top screws and the wire ends will be secured by tightening the screws. This way all eight butterflies should be installed.
Next, you need to cut off two insulated wires and, starting from the top, crossing the wires, solder them to the ends of the copper wire. The next two wires will go straight down, connecting the second compartment to the third compartment. The third and fourth compartments intersect again and so on until the end.
The middle part is where the 75 Ohm connector will be installed. You can solder the connector or coaxial cable.
After installation, you need to check the soldering, the installation of the connector, jumpers. If everything is ok, let's proceed to testing.
Step four: test
The master designed the antenna to have the best possible performance over the entire range. The gain is relatively stable up to 520 MHz, where there is a small dip, and then up to 580 MHz (32 channels), where it drops sharply. If you want the best response outside of channel 32, simply remove a couple of centimeters from each butterfly. This will result in a higher frequency response, giving more gain up to channel 36, 602 MHz.
In the first diagram, the technician compared the readings with a signal generator and field strength meter using a simple dipole that has a theoretical gain of 2.5. The dipole is what other antennas are compared to when calculating the gain. The master measured the gain of this antenna at 21 points, and then did the same with the butterfly antenna array. He then averaged the difference between the two readings and got an average of 12.79 dBd. This gain is comparable to the gain of a good multi-element Yagi antenna.
The second circuit was made with a tracking generator, which is a sweep generator and spectrum analyzer in one device.
The master is pleased with the operation of this antenna, and when connected to the TV it also showed yourself well.