DIY Satellite Antenna

I have recently finished preparing the plans for making a DIY dual-band satellite antenna.

Satellite Antenna
DIY Satellite Antenna. To view larger, click here.

To learn how to build one and get started with satellite communications, click here.

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

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Accessing Satellites at Low Elevation

In a recent test I’ve conducted with my portable satellite radio setup, I’ve successfully accessed the following satellites even at elevations of only 1 to 2° (very near the horizon!): AO-91, AO-92, IO-86, SO-50, and PO-101 (DIWATA2).

Satellite’s Elevation

A satellite on the horizon is described to have an elevation of 0° (degree) and a satellite directly overhead has an elevation of 90°. A pass may have an elevation anywhere from 0 to 90°.

Low Elevation Pass Satellites
Using a DIY antenna and a portable radio setup to access satellites that are very near the horizon

Establishing Contact

While there are many factors leading to a successful low-elevation contact, the following appears to have the greatest impact:

1. Use of a well-tuned and very directional hi-gain antenna
2. Proper pointing of antennas to satellites (use a smartphone)
3. Correct polarization of antenna elements (twist until you get the best signal)
4. Use hi-power when necessary (10W)

Have you done this test lately? How low an elevation can you access the satellites? If you want to make contact with distant stations via satellite, the only way to do that would be to access satellites when they are very low in the horizon.

To learn how to access satellite repeaters, head directly to Satellite Communications.

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

 

My Satellite Antenna

Download: Satellite Antenna Plans

Satellite Antenna
DIY Satellite Antenna. To view larger, click here.

My satellite antenna is a Moxon-Yagi-Uda dual band VHF-UHF antenna with a single feed point (connects directly to the radio, no duplexer needed), based on the original design of LY3LP. This allows using a full duplex radio to simultaneously transmit in one band and receive in the other. Properly tuned, this antenna has an SWR (Standing Wave Ratio) of 1.0:1 in VHF and 1.1:1 in UHF.

4I1AWN_antenna2
The antenna’s boom may be split in the middle, for easy storage and transport.

Features

1. Very good RX and TX signals. Check out the logs on my QRZ page or hear the audio recording as received by this antenna in this video prepared by DV2JHA.
2. Easy to build. This antenna build is intended to be very easy to replicate. Very few tools and materials needed to build one. No special parts needed. Anyone can build it.
3. Elegant design. Because it only has one feed point, you only need one dual-band VHF-UHF radio to use this antenna (instead of using two different radios and feed points for each band, thereby eliminating the need for a duplexer). The coaxial cable from the radio connects directly to the antenna (no baluns). To maximize the full capability of this antenna, use it with a radio with full-duplex capability.
4. Easy to tune. You only need to adjust the gap between the Moxon (VHF) driven element, and the Yagi-Uda (UHF) driven element to achieve perfect SWR. If you wish to move the center frequency (the frequency with the lowest SWR), adjust the length of the driven elements.
5. Lightweight. You will begin to appreciate this once you compare it with other antenna designs. Heavy antennas are not particularly useful for hand-held satellite work.
6. Portable. With the split-boom feature, you can easily store and transport this antenna. If needed, you can always disassemble and collapse everything into a very small package.
7. Durable. This antenna design is built to last a lifetime of satellite work.
8. Low-cost. How much does a commercial satellite antenna cost? To build this antenna, I spent an equivalent of 5 USD.

This antenna has been fully tested to work with satellites such as AO-91, AO-92, SO-50, IO-86, and PO-101 (Diwata 2). To build your own satellite antenna, kindly refer to the antenna plans below.

4I1AWN_2019
To view at full resolution, click here. Adapted from the original design by LY3LP. This particular version with a number of modifications is created by 4I1AWN. It uses 3 mm copper tubing elements.

To see this antenna in action (a recorded ‘live’ satellite demo), head directly to Satellite Communications. To view the portable radio setup I use with this antenna, head directly to Portable Radio Setup. 

DIWATA2 LIVE DEMO CNN
The DIY antenna described on this page was used during the live contact via Diwata 2 satellite’, reported on CNN Philippines

Download: Satellite Antenna Plans
For inquiries, please email: 4i1awn@nightskyinfocus.com

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

New RF Connectors for FT60

Following the successful signal reception and decoding of the International Space Station’s (ISS) Slow Scan Television (SSTV) images, I am now eager to build a dedicated hi-gain directional antenna for satellite hunting! The first step is getting the signal to and from the radio using proper connectors.

Yaesu FT60 connectors
RG58 coaxial cable >>> PL-259 (plug) >>> SO-239 (socket) to BNC (male) converter >>> BNC (female) to SMA (male) converter >>> SMA (female) connector of Yaesu FT60. For an expanded view, click here.

With these new set of connectors, I can now connect the FT60 to a DIY antenna which I will be building soon!

Note: The configuration can be further simplified using a SO-239 (socket) to SMA (male) converter, but not applicable for my setup as I needed the BNC interface for my other antennas :)

To learn more about my progress in amateur radio, click here.
Related link: Receiving Transmissions from Space
© Anthony Urbano (Manila, Philippines)