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)

 

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My Satellite Antenna

My satellite antenna is a Moxon-Yagi dual band VHF-UHF antenna with a single feed line. 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.

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The Moxon part of this antenna is supposed to be rectangular in shape, but I soon found out that I could bend the rectangle to achieve a perfect SWR!

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

antenna
The antenna’s boom may be split in the middle, for easy storage and transport. Note that this is an earlier photo, no bends have been made yet in the elements of the Moxon part of the antenna.

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)