[vhold]

If you do, you probably should use https.

https://time5.nrc.ca/timefreq/bulletin_tf-b.html

There's probably some really weird MITM attack possibilities here if people have automated systems fetching and using these files. Also, following the link from the article, it would seem the US government's official source is unencrypted FTP?

[DKnoll]

Yes very true. In fact the NRC should probably set up an HTTPS redirect and HSTS.