Best practices question

Hal Murray hmurray at
Wed Jun 26 08:16:33 UTC 2019

> What about Radio? I.e. WWVB, JYY, DCF77, etc.?

(I'm in the US.)

Short version:
  GPS has captured the market for time.  There are no good alternatives.
  In the US, LORAN has been de-funded.

  WWVB and friends don't work very well - relative to GPS.
  It might be more interesting if you live close to the transmitter.

Long version:

WWVB changed their modulation scheme several years ago.

In the old days, there were two types of radio receivers.  The low cost 
version used a small ferrite rod for an antenna.  It just gives you a carrier 
signal, typically on a modem control pin.  You can get timing via the PPS 
logic.  There is code to parse the pattern and turn it into a useful signal.

The fancy/expensive version had software and a good crystal and was setup for 
an external antenna.  They worked much better.  At least until your 
neighborhood EMI in the 60 KHz range from crappy switching power supplies or 
industrial gear crept up enough.  Dave Mills has several good rants and 
stories.  (He's at extreme range.)  But they stopped working with the new 
modulation scheme.

I don't know of any fancy versions that work with the new modulation scheme.

The old simple receivers still work but not as well as they used to.

There is only one chip available that works with the new modulation.  (that I 
know of)

The ES-100 uses SIO or one of the similar 2 wire type I/O interfaces.  Should 
be easy on a Pi, but I don't have directions.  I don't know how to do it on a 

These are my opinions.  I hate spam.

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