Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!swrinde!cs.utexas.edu!csc.ti.com!ti-csl!m2.csc.ti.com!m2!djohnson From: johnson@m2.ti.com (Doug Johnson) Newsgroups: sci.electronics Subject: Re: Message-ID: Date: 21 May 91 23:16:23 GMT Sender: johnson@m2.ti.com Reply-To: johnson@m2.ti.com Distribution: sci Organization: Texas Instruments VLSI Design Laboratory Lines: 24 Nntp-Posting-Host: mycroft.csc.ti.com >chucks@iplmail.orl.mmc.com (chuck strickland) writes: >> I am interested in building a reciever to sync my computer with WWV. >> I want to receive the CHU timecode that is broadcast at 30 seconds after >> the minute. In brief it is a IRIG timecode encoded with a 300 baud modem >> and placed on the carrier. In short it seems that all I need is a >> simple superhet receiver and send the output to a modem and then the modem >> output over the serial line to the computer. >What about the clock with a serial output that heathkit sells? I have the Heath GC-1000 as a timebase for our local net. It has some shortcomings. First, it needs a good outside antenna (at least in Dallas). It starts to drift off fairly badly if it loses the WWV signal for any length of time. Worse, it doesn't tell you it has lost WWV until it has been lost for 24 hours or so. (There is a light on the front panel, but the RS-232 data stream doesn't encode it.) Finally, the WWV data stream is not error corrected, or even checksummed. While the GC-1000 has some heuristics to minimize bad data, it will get confused sometimes and show some wildly bad time. Having said all that, the GC-1000 mostly works and is 5-20 times cheaper than better alternatives. -- Doug