I see that cw operators often use the phrase 20wpm, 18db (say) SNR. What does this mean? 20wpm is self explanatory, is SNR Signal to Noise Ratio, so what does the 18db SNR part mean, TIA.
The signal is 18dB above the noise. Or a touch over 63 times stronger.
Another term you may come across (often in professional texts) is sinad.
This comes from the way signal quality is measured.
Take the incoming signal (with noise) as reference amplitude. Filter out the signal with a narrow filter. What is left is the noise.
By difference, Sinad compares signal with signal and noise. Alternatively snr can be calculated.
When a spot appears like this:
It is being generated by “RBNHOLE” a neat piece of software that takes input from the RBN network, and posts a spot. The SNR value is provided by the SDR skimmer that received the activators signal, in this case the receiver is owned by KM3T. So in the context of your question, it is not a CW operator manually giving this information - that would be unusual, I think.
RBNHOLE is well worth knowing about if you activate using CW.
More details here from Andrew, its author: RBNHole | VK3ARR's SOTA Blog
And on the Reverse Beacon Network that it pulls from here: RBN - Reverse Beacon Network
Thanks for your replies, chaps, that explains what’s what. When/if I get back properly into cw I’ll look into this RBNHOLE business. 73s John.