A machine translated article on a JJY (40 kHz timecode station in Japan) receiver

 Previously I mentioned using the internet to help translate DX ham magazines:

https://wb9kzy.blogspot.com/2022/10/idea-use-online-tools-to-translate-dx.html

I found another article from the April 1998 issue of CQ Ham Radio by JS1RSV.  It's an active filter based receiver for JJY, the Japanese timecode station on 40 kHz that's the equivalent of WWVB here in the USA.  

Here is the first page:

and the second page:

In 1998 I didn't have access to internet translation (I did have dial up email access though :) so I never got further in looking at the idea except to "decompile" the active filter sections:

Compared to an audio active filter the gain and Q are pretty high, usually an audio filter will keep the gain at roughly 1 and the Q well below 10.  The author does address this:

first page column 1

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first page column 2

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first page column 3

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second page column 1

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second page column 2

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second page column 3

As with the previous attempt the translation isn't perfect but I get the idea - he had a lot of trouble with CRT & TV causing interference at 40 kHz.  He tried a commercial clock but it didn't work.  He can't buy 40 kHz crystals like they used in the commercial clock so he decided to extend the active filter concept up above audio to RF at 40 kHz.  The circuit uses a bipolar power supply.  He budgeted 120 dB of gain which seems to work well at his location.  

I was going to try this at 60 kHz for WWVB for a possible kit but never moved too far with the idea.

He did have a second article so I'll find it and try translating for tomorrow's blog.

Best Regards,
Chuck, WB9KZY
http://wb9kzy.com/ham.htm