It’s time to talk about some of the most fun and exciting parts of amateur radio: satellite and space operations, contesting, and operating activities.
Satellites
There are dozens of amateur radio satellites that you can communicate with in space, and there is even an amateur radio repeater on the International Space Station that you can use with just a Technician License.
Satellite Beacons
One of the easiest ways to get started with operating satellites is by receiving information from satellite beacons.
A satellite beacon is a transmission from a satellite that contains status information.
A satellite beacon may send info like its callsign or identification, as well as telemetry data, which is typically the health and status of the satellite.
Anyone is permitted to receive telemetry from an amateur radio satellite – you don’t need special permission, you don’t need to be a control operator, and you don’t even need a license.
You can listen to the ISS repeater with just a handheld ham radio without any special equipment.
Communicating via Satellites
Once you get your Technician license, not only can you receive telemetry data from satellites, but you can also transmit to the satellite and make contact.
Satellites work like “repeaters” in the sky – a ham radio station on the ground transmits data on one frequency (the uplink), the satellite receives it, and retransmits it down to earth on a different frequency (the downlink).
Amateur radio satellites support various modes of operation: SSB, FM, and CW/data. All of these choices are correct when asked what type of transmission is commonly used by amateur radio satellites on the exam.
Many satellites operate in U/V mode.
- The U stands for UHF, for the 70 cm band (appx. 420 – 450 MHz)
- The V stands for VHF, for the 2-meter band (appx. 144 – 148 MHz)
So when a satellite is operating in U/V mode, that means the satellite uplink is in the 70-cm band and the downlink is in the 2-meter band.
Satellites often use a different band for the uplink and downlink in order to avoid self-interference and facilitate better communications. This is also referred to as cross-band operations.
In order to make a satellite contact, you need to set your transmit frequency to the satellite uplink frequency and your receive frequency to the satellite downlink frequency.
You should be careful not to transmit too much power into the satellite. The impact of using excessive effective radiated power on a satellite uplink is blocking access by other users.
One way to determine whether your satellite uplink power into a linear transponder satellite is neither too low nor too high is to check that your signal strength on the downlink should be about the same as the beacon.
Satellite Tracking
The vast majority of ham radio satellites are LEO satellites, which means Low Earth Orbit, usually between 160 and 2,000 kilometers in altitude.
From your stationary location on earth, the satellites are moving overhead extremely fast at approximately 17,000 miles per hour, and can complete a full rotation around the earth in only 100 minutes.
So from where you’re standing on Earth, the satellite will appear on the horizon, pass over your head, and disappear again in just 10 to 12 minutes.
That means in order to make ham radio contacts with a satellite, or listen to satellite beacons, you need to use a satellite tracking program.
Satellite tracking programs provide all the information you need:
- Maps showing the real-time position of the satellite over Earth
- The time, azimuth, and elevation of the start, maximum altitude, and end of a pass
- The apparent frequency of the satellite transmission, including the effects of the Doppler shift
All of these choices are correct on the exam.
Satellite tracking programs use the Keplerian elements as an input to calculate and predict the satellite’s position. Keplerian elements are a set of numbers that determine the orbital path.
Doppler Shift
As the satellite moves quickly overhead, the frequency you receive will shift slightly from a higher frequency to a lower frequency. This is called the Doppler shift, an observed change in the signal frequency caused by relative motion between the satellite and an earth station.
Think about when a police car or ambulance speeds past you on the highway. When the police car is approaching, the sound is higher-pitched, and then after it passes, it becomes lower-pitched.
This is similar to the Doppler shift that occurs with satellites. As the satellite speeds towards you at 17,000 miles per hour plus, the radio wave gets compressed, making the frequency slightly higher.
Then, as the satellite moves away from you, the radio wave gets stretched, making the received frequency slightly lower.
The satellite may also rotate while it orbits in space. Rotation of the satellite and its antennas can cause spin fading of satellite signals.
Getting Started
You can get started tracking and listening to satellites and the ISS with just a handheld ham radio and a regular antenna.
But to make satellite contacts, you’ll need a directional antenna such as a Yagi antenna, and you’ll need to operate in split mode and account for the Doppler shift, which is a bit more complicated.
If you want to learn more about amateur radio satellites, we’ve created a full step-by-step course for satellite and space operations taught by experts in the field.
Contesting
Ham radio contesting is a great way to have fun in ham radio while sharpening your operating skills.
Contesting involves contacting as many stations as possible during a specified period.
Ham radio contesters like to move fast to get as many contacts as possible. So, good practice is sending only the minimum information needed for proper identification and the contest exchange.
The contest exchange is an extra piece of information you say over the air during the contest, which could be a location identifier, like your state or a grid locator.
A grid locator is a letter-number designator assigned to a geographic location.
We usually use 4 or 6-digit grid locators, also called grid squares, in ham radio, to tell other operators our approximate location. For example, from my home in Georgia, my grid square is EM73UW.
If you’re interested in contesting or other on-air activities, create a free account at www.WorldRadioLeague.com. You can see other active ham radio operators near you and keep track of upcoming contests and events. It also has a built-in logbook and live, real-time ham radio contacts and scoreboards.
Direction Finding
Radio direction finding is a method used to locate sources of noise interference or jamming.
Radio direction finding is used by the FCC or other ham radio operators to find stations that are causing intentional interference. It’s a technical challenge that involves specialized equipment and sometimes advanced techniques like triangulation across multiple receivers.
Ham radio operators can practice direction finding by setting up a hidden transmitter and then locating the device using receivers and specialized antennas.
We call this a fox hunt, and it’s like a high-tech scavenger hunt that combines technical skill, navigation, and maybe even some exercise.
A directional antenna is useful for a hidden transmitter hunt because you can use the signal direction to zero in on the location.
Lesson Recap
Let’s recap. In this lesson, you learned that a satellite beacon is a transmission from a satellite that often contains telemetry such as health and status.
You learned that there are dozens of amateur radio satellites overhead, usually in Low Earth Orbit, that act as repeaters in the sky on various modes such as SSB, FM, and CW.
You learned that satellites usually operate in U/V mode, with the uplink on 70cm and the downlink on 2-meter, to avoid self-interference, and that you should avoid transmitting too much power into the satellite, which could block access for other users.
Finally, we discussed contesting, which involves contacting as many stations as possible during a specified period, and radio direction finding, a method used to locate sources of noise interference or jamming.
