[time-nuts] Time Code generator

Collins, Graham CollinG at navcanada.ca
Fri Dec 3 18:49:35 UTC 2010


The suitability of use of the WWV or CHU audio depends on where you
live. I live within ground wave propagation of CHU's transmissions on
3,330khz. A simple receiver would be all I needed to have the audio
available to record. 

I only got off on the tangent of a more proper time code as being an
alternative to an audio recording of a time signal with the possibility
in that is would be machine readable. As a simple time stamp for making
off the air loggings the recording of the WWV or CHU audio is probably
quite sufficient. A local machine generated and readable time code just
takes the process up a level (or two).

And, since the requirement is to be able to do all this while portable
or mobile swings it all more in favour of a PC generated time code (less
bits and pieces to be carried around and set up)

Cheers, Graham 


-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Bill Hawkins
Sent: December 3, 2010 13:34
To: 'Discussion of precise time and frequency measurement'
Subject: Re: [time-nuts] Time Code generator

WWV is not necessarily audible at all times. 2.5 MHz seems a poor
choice because it has 1/4 of the power at the higher frequencies,
except 20 MHz.

I went through a phase of acquiring Datum time code generators back
in 2003. Thought I'd turn them into rack-mounted shack clocks, but
never got around to it. These things generate and receive most IRIG
frequencies, but IRIG B at 100 HZ is the most commonly used.

They come in 1, 2, or 3 rack units height. They're built with late
seventies parts on plug-in cards and weigh about 15-20 pounds. Some
have crystal ovens at 1 MHz. Most can use an external 1 MHz. You
have to preset the time of day and push a start button after a
power cycle.

Also have some IRIG clocks, which only decode an IRIG signal.

I'd like to get these units to people who can use them, so shipping
is going to be the main cost. Don't know what it takes to ship to
Canada.

Bill Hawkins
bill at iaxs.net


-----Original Message-----
From: Collins, Graham
Sent: Friday, December 03, 2010 6:28 AM
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] Time Code generator

On another list to which I subscribe, the question was asked about the
suitability of recording WWV 2.5mhz audio as one track when recording
off the air signals of interest as a time reference.

The person who asked the question didn't really state his intentions but
they seem very similar to my immediate needs. That is, simply a time
reference - that is "the time", the start of the minute, and periodic
references (i.e. seconds) between the announcements.

It seems that recording the audio of something like WWV or CHU is ideal.

However, another approach would be recording a more proper time code
signal as you might have available from a "precision clock". Of course,
a decoder would also be required. 

A quick Google search turned up lots of leads which I have yet to sort
through. In the interim I thought I would pose the question to the
learned members of this group for their suggestions. Keep in mind KISS
and that a very high degree of accuracy is not required.

Is there an opensource/freeware PC app that will generate an appropriate
time code signal that can be recorded on one track of an audio recorder
(either PC based i.e. Audacity or standalone) that will also decode via
soundcard or other input?


Cheers, Graham ve3gtc



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