PeanutPower

The colourful area labelled ❷ is known as the waterfall and this is a graphical representation of the radio signals being received across the spectrum. We can use this to spot where radio signals are to help tune in on them. This section should constantly be scrolling upward and, in that way, we see not only a real time visual picture of signals on the radio spectrum but also the last 5 – 10 seconds of history.

We can scroll up and down the spectrum by hovering the mouse over the waterfall and left clicking and then moving sideways (either left or right) while holding down the left mouse button. The frequency that you can actually hear is indicated by the little yellow marker at the bottom edge of the waterfall . Similarly, to tune in a signal this can be ‘grabbed’ using the mouse and moved left and right.

Here's what you should have seen and heard while trying to tune in an AM signal...if you're having problems watch this short video which demonstrates entering a frequency, selecting AM, zooming in on the waterfall and selecting different AM broadcasts either by dragging the yellow tuning indicator or by directly entering the frequency. 

If signals are present you’ll see they are a different size and shape to the broadcast stations. They are much narrower than your tuning indicator and far more sharply defined. This is because Radio Amateurs are using LSB on this band, a narrower bandwidth mode which concentrates their transmission energy into a smaller bandwidth.

In the tuning control, ❸, select the LSB button  and either use the + /- buttons or drag the yellow tuning indicator to align with a signal in the waterfall display.

Do the voices sound like they’ve been inhaling helium or like they’re muffled/garbled? You’ll need to be much more accurate with your tuning compared to AM. These voice signals are roughly 2.4kHz wide and, to generate the most powerful signal while remaining intelligible, only a part of the normal voice range is used (say ~300Hz to 2700kHz) which means the voices you hear won’t sound deep and rich like they do on your local FM radio stations and, similarly, would sound awful if you tried to play music as there are no higher frequencies…Radio Amateurs are not permitted to broadcast music so this is never really an issue!

Here's what you should have seen and heard while trying to tune in LSB Amateur Radio stations...if you're having problems watch this short video.

LSB (side band) signals can be very hard to understand at first...it may sound like you're not quite tuned in. Don't worry, this is normal and a result of the limited bandwidth used to transmit the voice. Find a loud signal with someone speaking your language (slowly) and you'll find, with a little listening, it starts to sound perfectly normal. 

The Radio Amateur Exchange

First things first, the conversation you’re listening to now is what we call simplex which means only one person can talk at a time. This is because we’re using a single frequency and you are either transmitting or receiving…if you’ve ever used a walkie talkie or CB you’ll have experienced this. It’s possible that you may only be able to hear one side of the conversation if the second station is not also in range of the WebSDR receiver.

A big part of Amateur Radio is the self-training in radio communications. This isn’t like talking on the phone where you can clearly hear the other person including when they laugh, mumble, gasp and whisper. Radio communication paths can be noisy, they can suffer interference from other transmissions or electrical noises, they’re narrow band (remember I said only a small range of the voice frequencies are transmitted) and the person you’re talking to may not share the same native language. To overcome this Radio Amateurs learn a specific way of communicating to ensure what they say is clear and understandable no matter what the reception conditions.

Here is an example of what you might hear;

So what was that all about?!!

You have to be ‘licensed’ to operate as a Radio Amateur. You first undertake some simple training and a basic exam to check your understanding and then you are issued a call-sign (in the UK this is issued by OFCOM). Your call-sign is unique to you and its prefix indicates your country. In the above example OE4HDS is a Radio Amateur from Austria being called by G0POT from the UK. When establishing a contact (and regularly throughout the exchange) the two stations will give their call signs to identify themselves (it’s a licencing requirement…broadcast stations have to do the same which is why they regularly play jingles with their station name every 30 minutes or more). But rattling off “OE4HDS” may be difficult for other stations to hear and understand therefore, when using important but unusual words like call signs, names and locations you will hear stations spelling them out using Phonetics (see https://en.wikipedia.org/wiki/NATO_phonetic_alphabet for more info).

That’s a bit rude isn’t it, calling him an ‘old man’? Actually, no…this is an endearing way to address someone when you don’t know their name yet. 

Typically the first things exchanged are ones name and location. If reception isn’t strong or if an operator has an unusual name they will typically spell that out using phonetics. Most Radio Amateurs use NATO Phonetics but you’ll hear lots of random words used when spelling words with phonetics! QTH is another way of saying my location…there are many ‘Q codes’ (see https://en.wikipedia.org/wiki/Q_code for further info) and they can help when reception is poor or when you are speaking to someone who is not a native of your language. Only a small subset of Q codes are regularly heard in use. As we’re often in communication with people from outside of our country it can help to qualify ones location by indicating your position in relation to the capital or simply that you are in the north/south of the country. Amateur Radio is great for learning geography!

To help you understand how well you are being heard at the other end Radio Amateurs exchange ‘signal reports’. For voice communications this is usually two numbers (5 and 7 in this example). The first number is Readability (R) and is on a scale from 1 – 5. The second number is signal Strength (S) and is on a scale from 1 – 9. This approach to signal measurement is called RST (See https://en.wikipedia.org/wiki/RST_code for further information) and the T or Tone part only applies when using Morse code.

Just like the beginning of the ‘over’ at the end Radio Amateurs will typically exchange call signs again so that it is clear who is handing over to whom. Here the station is asking how he is being ‘copied’ e.g. he wants to know his signal report or RST.