I thought I would post this here, cuz of the Japanese theme to this section of the Forum.
Lately I bought 2 nice SEIKO DL305W night-table digital clocks, one for myself, one for wifey.
( https://www.yodobashi.com/product/100000001003696278/ )
They only sync to the Japan Time Radio Signal (JJY), and not to any other.
Now, since at the moment I am not yet living in Japan (next year we probably will though), I would love to sync those properly every day, just like all my Casio Multibands do.
I found an App for Android and iPhone, called JJYEmulator, which does the job in a "manual" fashion, using Headphones, which need to be placed right next to the clock for it to work. For some reason it doesn't work with my Android speakers, most probably they cannot get to that 40-60khz frequency. (EDIT: my old Bose noice cancellation headphones won't work, but the new Sony MX I got work fine).
Now, I thought, since I am a programmer, and I have a linux PC sitting at home always on, that I would just wing it, and create a proggy which would then play through some speaker/tweeter (TV/Monitor or even remote via DLNA) loud enough so the clocks can hear it from my bedroom.
I found a proggy created by a german dude called "timegen", but it's pretty limited, and I don't think it does JJY anyway.
I will now try to write my own version for it to work realtime: i.e. a small loop that grabs the current time from NIST, and plays it through the speakers, then it loops again, and again, say for about 5 mins. And set it as a cronjob at 4 AM say.
Once I have solved it, I will post it here with full source, for whoever is interested.