DIY 40 m, 20 m, 15 m HF Dipole

I have built a multi-band DIY fan-dipole antenna for 40-meter, 20-meter, and 15-meter HF bands. A fan dipole consists of several dipoles fed at a common feed point, through an optional 1:1 balun. I have tested this antenna and I have confirmed QSOs from Philippines to Brazil (other side of the world from the Philippines, via FT8 on 15 meters) and Philippines to Sydney, Australia (SSB voice on 15 meters).

A fan dipole may be designed to operate on a number of bands simply by adding new elements to an already existing dipole, but adding new elements may change the tuning of the already tuned dipoles, making it difficult to build one that is designed to operate on too many bands. In this particular antenna build, I combined three dipoles—for 40 meters, 20 meters, and 15 meters—to form a multi-band fan dipole on a single feedline.

DIY Fan-Dipole Antenna


The driven elements are 12-gauge insulated wires, center-fed (split in the middle). I used a 7 meter RG8 coaxial cable feedline with 1:1 BU-50 balun. The feed point is housed in a weatherproof metal enclosure that has been placed on an elevated concrete ledge. I used non-metallic material to raise and anchor the ends of the wires, such as nylon rope.

The 40 meter band has 10 meters of wire on each sides (total of 20 meters both sides), the 20 meter band has 5 meters of wire on each side (total of 10 meters), while the 15 meter band has 3.38 meters of wire on each side (total of 6.77 meters). Adjust the lengths of the elements for lowest SWR on the desired operating frequency. Since there is likely interaction between the elements, always check the tuning of all the other bands when tuning the antenna for a specific band.

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Night Sky in Focus | Astronomy and Amateur Radio
© Anthony Urbano | Manila, Philippines


DIY Dual-Band VHF-UHF Dipole

I have built a DIY dipole antenna for VHF (2 meter) and UHF (70 cm ) bands. I used 1/4 in diameter copper tube elements. The VHF driven element is center-fed while the UHF element is coupled (placed in close proximity but not connected to the coaxial cable) with the VHF driven element. A 5 meter RG8 coaxial cable feedline is used, with no balun. The feed point is housed in a weatherproof plastic enclosure, with one side of the VHF dipole connects to the coaxial cable’s center conductor and the other side connected to the outer conductor.

DIY VHF-UHF antenna

In this particular antenna, the VHF element has a total length of 984 mm (split in the center, to form two 1/4 wavelength element with 492 mm on each side) and the UHF element is 325 mm (1/2 wavelength element, not split in the middle). Adjust the lengths of the VHF and UHF elements for lowest SWR on the desired operating frequency.

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Night Sky in Focus | Astronomy and Amateur Radio
© Anthony Urbano | Manila, Philippines


DIY Antenna Rotator | DU1AU

I’ve built a DIY motorized antenna rotator using a geared DC motor, a pair of metal gears taken from a laminating machine, bearings, and a power window switch. The large gear is free to rotate and is attached to the mast with metal bearings. The antenna attaches to the large gear using a clamp. The small gear is attached directly to the geared DC motor. A metal bar attached to the mast is used to fix the drive motor in place, so that the gears mesh perfectly. The motor is powered by a 4.5V to 15V variable power supply to allow adjustment of the slew speed of the rotator. A 5-pin power window switch is used to control the clockwise and counterclockwise movement of the rotator. Paint is used to weatherproof the whole rotator assembly.

The DIY rotator is low cost and can be made with simple tools and materials. It is relatively easy to scale up using larger motors and better gear combination. I have tested the rotator to carry a 3-element by 4-element VHF-UHF Yagi antenna.

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Night Sky in Focus | Astronomy and Amateur Radio
© Anthony Urbano | Manila, Philippines

DIY SARCNET Satellite Tracker

I have built a DIY satellite tracker based on the SARCNET project. It is a simple Arduino-based motorized azimuth and elevation rotator that uses DC motors to move the antenna, and gets position feedback using an accelerometer and compass.

Home-brewed satellite tracker

The tracker receives satellite’s azimuth and elevation info using the tracking software Gpredict. Hamlib is then used to establish a link between the computer and Arduino through USB connection via EasyComm II protocol.

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Night Sky in Focus | Astronomy and Amateur Radio
© Anthony Urbano | Manila, Philippines

DIY Satellite Antenna DU1AU

A satellite antenna can be made from 3 mm copper or aluminum elements, PVC boom, and some parts you may already have at home. This antenna has been tested to work with the Philippine Oscar (PO)-101 satellite Diwata 2.

DIY Satellite Antenna

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Night Sky in Focus | Astronomy and Amateur Radio
© Anthony Urbano | Manila, Philippines

DIY SATNOGS Satellite Tracker

I’ve recently finished building a satellite traker based on SATNOGS satellite tracker. The automated tracker uses an Arduino to control a pair of stepper motors that move two cross-yagi antennas (VHF and UHF).

DIY SATNOGS satellite tracker

The Arduino receives satellite’s azimuth and elevation info using the tracking software Gpredict. Hamlib is then used to establish a link between the computer and Arduino through USB connection via EasyComm III protocol. The tracker uses two A4988 stepper motor driver, and two geared stepper motors. A weatherproof metal box is used as a case, and rubber seals prevent water from entering.

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Night Sky in Focus | Astronomy and Amateur Radio
© Anthony Urbano | Manila, Philippines