Tom Van Baak
tvb at leapsecond.com
Sat Jun 11 16:38:43 EDT 2005
My impression is the RF and subcode data lock
should still work; it's just the NIST timecode data
bits that are no longer valid (GOES itself is still
100% operational - all they did was stop sending
the NIST timecode and sat pos info).
Yes, the receivers make a very nice clock display,
and the IRIG, 1 PPS, or other outputs are useful.
Given the clean board layout, it should be quite
simple for someone to turn it into a stand-alone
clock; either by simulating the manchester code
that goes to the uC, or by piggy-backing on the
existing display drivers. There's hundreds of nice,
used GOES receivers out there so there might
be a market for someone with time on their hands
to develop such a retrofit gizmo.
One could, for example, make a black box that
takes a GPS NMEA and 1 PPS output and
converts it to something a 468-DC can lock on
to; either through the antenna input or directly
onto one of the test points on the board.
----- Original Message -----
From: "Mike Feher" <mfeher at eozinc.com>
To: "'Tom Van Baak'" <tvb at leapsecond.com>; "'Discussion of precise time and
frequency measurement'" <time-nuts at febo.com>
Sent: Saturday, June 11, 2005 12:33
Subject: RE: [time-nuts] DC-468
I think you may be right since I remember the last time you asked a question
about this and I believe I was the only one that replied. Right now it is
not convenient for me to look inside as the 468 is on top of a tall
entertainment center in my office with some other junk on top of it. The
antenna is facing one of the windows. It may be easier for me to look at the
IF coming back down the coax to see if there is RF lock or not. I have a BNC
T on the rear of the 468 so it is easy to connect it to the SA and see the
downlink IF depending on which bird it is locked to. BTW, as I mentioned to
you some years ago the manual does have an error in one of the IF
frequencies. I do not remember if it is the east or the west. I guess it is
of little consequence now. I really like the large displays on the 468 and
would like a similar clock to replace it. Any ideas? - 40 years ago I would
have just built one, now it seems like too much trouble. - Mike
Mike B. Feher, N4FS
89 Arnold Blvd.
Howell, NJ, 07731
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Tom Van Baak
Sent: Saturday, June 11, 2005 10:59 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] DC-468
> Does any one still have a DC-468 that is keeping time and locked on? Mine
> quit ages ago. It is a lot more than 50 ms off. - Thanks - Mike
Maybe you and I are the only ones with GOES
receivers still powered on?
After 30 years the GOES time service officially
went off the air on January 1. But it has been on
and off a few times since then (and with reduced
accuracy). My last signal lock was in April or
May, I think. I stopped logging at that point and
all my receivers have been blinking for a month.
Even if you don't get time lock, do you still get
RF lock and/or data lock on your 468-DC (the
two LED's inside)?
For good reading see :The GOES Time Code
Service, 1974-2004: A Retrospective"
More information about the time-nuts