Or if you actually want to send shortwave snail mail: <a href="https://en.wikipedia.org/wiki/ARRL_Radiogram" rel="nofollow">https://en.wikipedia.org/wiki/ARRL_Radiogram</a>
If you are not paying for the product then you are the product. They are not transparent at all about how they are monetizing this, which seems really scammy.
The url <a href="https://.to" rel="nofollow">https://.to</a> also works, but HN apparently doesn't support emoji domain names...
... being an ham radio operator, I was hoping to see a shortwave-to-snailmail gateway... or maybe some historical information about some shortwave telegraphy system used somewhere in the past century to send actual mail from abroad...