"Welcome to the Hobby - Start Here"
This page was created to help those who are interested in the hobby of HF radio monitoring and want to learn more. In addition to resources in this Wiki, there is also a special forum for beginners on the HF Underground Message Board where you can ask questions in a friendly environment.
Click on highlighted text links to learn more about a specific subject. Do not get frustrated if you don't understand all that is presented to you. This page is designed to help you with getting started successfully monitoring HF radio by offering bite sized pieces of information to you.
Links associated with frequencies (such as 5000 kHz) will take you to an online receiver that is tuned so you have a chance to hear it live. Be sure to visit KiwiSDR Operating Information to learn more about how to operate these online receivers. There is a list and map or receivers available to use worldwide. Using an online receiver allows you to try HF monitoring before investing in your own equipment. They are also helpful if you have limited capabilities to erect a large antenna or if your location has a lot of radio frequency interference.
What Can I Hear?
There are a wide variety of things to listen to on HF and it would be impossible to cover them all here. To get a taste for what is available see the examples below to get you started. Much of what is presented here is from a North American perspective but can be helpful to new hobbyists located elsewhere.
Patience is one of your most important tools. Unlike radio stations on your FM dial, many, if not most, stations broadcast on a limited basis and are not on the air continuously. There are many factors that can help and impede your chances of reception so if you are not successful on your first attempt, keep trying!
Understanding radio propagation will help you determine what stations you can hear and when you can hear them. Shortwave radio signals can arrive at your receiver from the transmitter in two ways. If you are very close to the transmitter the radio waves will travel across the ground to your receiver (ground wave propagation). If you are farther away the radio waves will bounce off the ionosphere in the atmosphere (sometimes multiple times) before arriving at your receiver (ionospheric propagation or "skip"). Watch this short Youtube video to get a basic understanding of this process.
Some key factors to remember are:
- Radio propagation can be forecasted but you can never be 100% certain.
- The presence of sunspots will significantly enhance radio propagation especially at higher frequencies. The lack of sunspots will reduce propagation.
- Your location is also important. The propagation at the transmitter site may be completely different from the propagation at the receiver.
- Time of day is very important. The ionosphere changes during the day and reflects signals of different frequencies at different times.
Since radio propagation is a natural phenomenon it can be unpredictable. It can also change very quickly. Sometimes propagation is excellent. Sometimes it is very, very poor. The pursuit of the elusive radio signal is the thrill of HF radio monitoring. As you get started in this hobby, start with the easier stations to hear and work upward toward the harder ones. This will hone your listening skills and improve your chances.
Easy to hear
(Propagation tip: night time favors lower frequencies, day time favors higher ones)
Time stations - 24/7 broadcast of accurate time:
CHU (Canada) - 3330 kHz, 7850 kHz, 14670 kHz
These time stations are often used by more experienced hobbyists to quickly check propagation in North America and to check to see if their receivers and antennas are functioning properly.
Amateur (Ham) Radio
Amateur radio operators are people who are licensed to use parts of the HF radio spectrum. Their interests span from technical, emergency communications, or to just having conversations with other stations. There are many amateur radio bands on HF. Operators also operate many different modes - voice (AM, LSB, USB), digital, Morse Code, etc. Many of these modes can be monitored on online receivers without any special equipment. Some modes require special decoding hardware or software. The easiest to listen to would be voice communications. Here are a couple of examples of frequencies that have regular activity or nets. Again, propagation can affect whether or not stations can be heard or not.
75 meter band - 3875 kHz, 3885 kHz (AM voice activity)
40 meter band - 7253 kHz, 7255 kHz (LSB nets)
20 meter band - Slow Scan TV (SSTV) - 14230 kHz (with SSTV decoder on)
More details about amateur radio can be found on the ARRL website.
Moderately easy to hear
Pirate radio stations are stations that broadcast without a license. [add more info]
Numbers (Spy) Stations - While more prevalent in the past there are still some stations that are still operating. These stations are rumored to be used by governments to send coded information to their intelligence assets on the ground. You won't be able to decode any of the message but they are nonetheless interesting. A group called Priyom operates a website that makes it easier to hear these stations. The website has a schedule of expected transmission and a link that will automatically take you to an online receiver that has a good chance of receiving it.
More difficult to hear
Rare, exotic stations are hunted by groups of listeners called DXers. Often they listen for days, weeks, months, or years in the hope of receiving a specific station. A combination of patience, luck, equipment, and propagation can determine whether the elusive station will be heard. These stations can be low power stations that are target a local audience, political clandestine stations that are short lived and operating illegally in their country, or stations that have a very restricted on the air schedule. Sometimes propagation cooperates and allows easier reception of these stations. Hobbyists operating "out of band" above and below the amateur radio bands, especially around 6600-7000 kHz and around the CB band (11 meters) and 10 meter amateur band 25-30 MHz (freebanding, usually from roughly 25600 kHz to 28000 kHz, during band openings).
Where to Listen Online
A quick place to start is to use the links supplied on this page to go directly to an online receiver tuned to the correct frequency. This is only intended to be an aid and not a guaranteed method of hearing any particular station. Remember that not all stations are on the air 24/7 and propagation will effect whether or not you can receive them.
Propagation, Time of Day, and Location
Propagation is the study of how signals can get from the transmitter to the receiver and can vary according to the sun, the Earth's atmosphere, frequency, time of day, and your location. All of this adds to the enjoyment and excitement of radio monitoring. At times a very strong reliable station will become weak and a rare weak station can become strong enough to hear. With practice you can use propagation tools to help you predict the best time to hear a station.
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