Signal Reports can be very helpful in determining how well your signal is being received, provided they are used properly. Unfortunately, many people don’t use them properly, either through laziness, time constraints (such as during a contest), or ignorance of the RST reporting system. I can’t do anything about the first two, but I can help you to better understand and use the RST Signal Report system.
There a a few parts to the system, they consist of Readability (R), Signal (S), and Tone (T), and should be given in that order (RST). Only Readability and Signal are used when you are giving/receiving a signal report in the phone modes (LSB, USB, AM). Tone is only applicable to CW. Its kind of hard to judge tone on a phone signal ;-).
Readability is how well the signal is understood, and is rated from 1, completely unreadable, to 5, perfectly readable. Unfortunately, I hear a lot of people giving a readability report of 5, even when they had to keep asking the other station to repeat themselves. If you need to ask the other station to repeat themselves, the readability should not be 5, perfectly readable. Some would argue that if they were perfectly readable, you would not need to ask them to repeat themselves; if you are asking, the readability would more likely be a 3 or even a 2, but certainly not a 5. While this is true, as far as it goes, it actually falls short of reality. The reality being that newer ops and/or slower ops may not be able to copy you the first time around, and thus need to ask for repeats.
Signal Strength (S)
Signal Strength is, as the name suggests, how strong the received signal is. Probably the easiest way to determine the strength of the signal is to look at your S–Meter, if you have one. Not all rigs do, so if yours doesn’t, you will need to guess. The table below can help you with this if you don’t have an S–Meter.
If the signal is above a 9 on your S–meter, then it is said to be plus, as in 59+, this is only really used in the phone modes, for CW 9 is as high as I’ve heard. Most S–meters will even show you how many dB over 9 the signal is, in which case you can include that information as well, if you wish (e.g “59+10” or “10dB over”, or even “10 over”).
Tone is only applicable to CW (Morse Code), and describes the received signal’s, well, tone. Is the tone harsh with a noticeable hum? Then the tone is a 1. If the tone is a perfect, clear sine wave, then the tone would be a 9. Most modern rigs will all have a tone of 9, but some homebrew and older rigs, especially tube rigs, might have something other than a 9 for the tone, so it’s helpful to know. This one is one that you will need to determine by ear, but, again, the table below should be able to help you with that.
There are two additional, though uncommon, things that can be added to the tone report. If there is a noticable chirp you would append a “C” (e.g. 457C), and if there is a noticeable click, you would append a “K” (e.g. 457K). Again, you probably will never hear this on modern rigs, but it is good to know.
|1||Unreadable||Faint||Harsh Tone with Hum|
|2||Barely Readable||Very Weak||Harsh Tone with Modulation|
|3||Readable with Difficulty||Weak||Rough Tone with Hum|
|4||Almost Perfectly Readable||Fair||Rough Tone with Modulation|
|5||Perfectly Readable||Fairly Good||Wavering Tone, Strong Hum|
|6||—||Good||Wavering Tone, Strong Modulation|
|7||—||Moderately Strong||Good Tone, Slight Hum|
|8||—||Strong||Good Tone, Slight Modulation|
|9||—||Very Strong||Perfect Tone, No Hum or Modulation|