What do the digit and the last letter add, and how do I read a whole designator?
You already know the first symbol says how the carrier is modulated. The second symbol says what kind of signal does the modulating.
The second-symbol characters
| Symbol | Meaning |
|---|---|
| 0 | No modulating signal |
| 1 | Single channel, quantized or digital information, without a modulating sub-carrier |
| 2 | Single channel, quantized or digital information, with a modulating sub-carrier |
| 3 | Single channel containing analogue information |
| 7 | Two or more channels containing quantized or digital information |
| 8 | Two or more channels containing analogue information |
| 9 | Composite system |
| X | Cases not otherwise covered |
"Quantized" means digital: information broken into steps. "Analogue" means a smoothly varying signal such as your voice.
The third symbol
The third symbol tells you the type of information sent. This course needs one: E is telephony, meaning speech.
Decoding J3E
Take J3E one symbol at a time:
- J is single sideband, suppressed carrier.
- 3 is a single channel containing analogue information.
- E is telephony.
Together, J3E is SSB voice. This is the emission that the 2.667 power rule from the first lesson applies to.
You now know
- The second symbol describes the signal modulating the carrier: 0 none, 1 and 2 single-channel digital, 3 single-channel analogue, 7 multichannel digital, 8 multichannel analogue, 9 composite, X other.
- The third symbol E means telephony.
- J3E is single sideband, suppressed carrier, single analogue channel, telephony: SSB voice.