Are you curious what HF is all about, but don’t have your own setup at home? Want to get an idea for what it’s like to listen to?
Check out http://www.websdr.org/. You’ll see a list of stations around the world, what frequencies they are streaming, and what kind of antennas they use for each frequency range.
Pick a station, and click the blue hyperlink in the big box for that station. For example, I picked a station in Arizona, and the link in its box was http://w7rna.dyndns-remote.com:18901. That took me to the page where I can listen to any of the frequencies listed for that station at WebSDR.org. Type your first name or callsign into the text box just so others can see who is listening (can be anything if you don’t want to give your name). Then you’ll see a waterfall load. For me, it defaulted to the ~7000 MHz band (40-meter band). I saw a few amateur stations on LSB, a couple CW stations, and an AM broadcast station.
I clicked the radio button next to AM (wide) to select the AM filter and moved the yellow slider under the waterfall under the broadcast station, and all of a sudden I was listening to a Japanese broadcast station on 7275 kHz. I got bored listening to something I couldn’t understand, so I changed to LSB mode filter and went looking for an amateur conversation.
A good signal was coming in just above 7150 kHz, so I moved the yellow slider down. On the left under the waterfall, I used the +/- tune step buttons (under the frequency text box) to fine tune until the signal sounded good and I settled on 7167 kHz and heard a conversation between a US ham and 2 fellows in Australia. From the Arizona receiver location, the VK1-something station couldn’t be heard (I heard he was on 1 watt because one of the other guys in the conversation said so), but the VK2-something station was booming in and easily understood.
By the way, playing with WebSDRs is a great way to learn some of the quirks of SSB. Place the tuner near something you think might be a voice signal – pick something in the voice range of the ham band (see a band plan for where to start looking), select USB or LSB based on which frequency you are listening to, then tune toward and then away from the station in small increments using the tune step button under the frequency text box on the left side (be sure to use the smallest step size for best effect). Take several steps toward and then past the station, and you’ll hear the characteristic change in pitch as you roll into and past the station. You should notice your ear will tell you when you’ve centered on the right frequency (or when you’re sufficiently close to it) – you’ll note the station’s voice sound the most natural at some point. Try this without looking, then check how close you got. Many stations pick even numbered frequencies like 7150 kHz, 7151, 7152, etc., to make it easy for another station to tune them in well.
Lastly, I wanted to check the time, so I thought I’d tune in WWV. I typed in 5000 into the text box and hit Enter (5000 kHz=5 MHz and it will switch automatically). Typing in the frequency puts me on exactly the frequency I want so I don’t have to worry about fine-tuning (as long as the receiver is calibrated properly!). All of a sudden, I heard the ticker, then the time called out each minute.