What frequency did wireless telegraphs send and receive telegraphs at? Were there multiple frequencies?
For instance, this comment says Titanic operated around 1 MHz. Was there a range of frequencies available for use, or could operators choose any frequency and others would still be able to receive the signals?
I also read on some websites (for example, this one and this one) that wireless telegraphs spam the entire electromagnetic spectrum which is why they are illegal. Somehow, this seems hard to believe. I don't believe telegraphs are illegal, or that they spam the entire spectrum. Is there any truth in this?