Keith, I think few hams have the know how on doing this and it will take work.
Using a PC might be much easier. There are many sources for this. 73, ron, n9ee/r >From: Keith McQueen <[EMAIL PROTECTED]> >Date: 2007/11/12 Mon PM 11:32:02 CST >To: [email protected] >Subject: RE: [Repeater-Builder] Dallas Semiconductor Real-Time Clock (Was >RC-96 Controller Problem) > >You can purchase a GPS receiver for less than $100 that outputs an acurate >time signal in NMEA serial format. Here's one: >http://www.byonics.com/tinytrak/gps.php It wouldn't take much of a micro >controller to convert that into the signal you need. If you can't find a way >to interface with the repeater controller, you could probably roll something >that would key up a radio and generate appropriate DTMF codes to set the >clock. Keith [EMAIL PROTECTED] -----Original Message----- >From: [email protected] [mailto:[EMAIL PROTECTED] On Behalf >Of Eric Lemmon >Sent: Monday, November 12, 2007 10:15 PM >To: [email protected] >Subject: RE: [Repeater-Builder] Dallas Semiconductor Real-Time Clock (Was >RC-96 Controller Problem) > > >Nate, > >I appreciate your suggestions and comments, even though we have differing >opinions about accuracy. In my area, starting an ARES or MARS net a minute >or two early or late is not acceptable. We pride ourselves at beginning the >net exactly on the second. After all, we're Hams, and we have access to >WWV, don't we? I realize that some folks on this forum may be rolling their >eyes at that statement, but hey- if sloppy operating is okay with them, let >them do their thing! > >My obsession (yes, that's probably what it is!) with time accuracy began >when I was Chief Engineer at WLRW, an FM station in Champaign-Urbana, >Illinois, back in the late 60's. There was an IGM (International Good >Music) automation machine that played music and ran commercials and IDs >during the periods when live talent wasn't on the mike. The machine was >designed to join the ABC Network News feed every hour on the hour, and being >a minute early or late was not an option. The problem was that the AC power >was locally generated, and was not synchronized to the national power grid >as it is today. Even though the timer in the IGM controller made >preparations to join the ABC Network exactly on the hour, the small >variations in the AC power frequency caused the connection to be made >several seconds off, either early or late, and the station owner was on my >case constantly. He didn't want to spring for a Favag or Western Union >precision time service, so I cooked up a crystal-controlled power oscillator >to drive the IGM schedule timer with a TCXO-stabilized power source. It >used a Hewlett-Packard oven time base at 10 MHz as a standard, making it >easy to synch to WWV. It was a kluge, to be sure, but it worked. > >With this background information, perhaps you can understand that all I >really need is some signal that occurs at exactly some point in time, every >day, that can be used to synchronize a repeater controller automatically. >Most real-time clock chips, including those made by Dallas Semiconductor, >have sufficient short-term accuracy to "flywheel" through one day without >getting more than a second off. If I can tweak such a clock once a day to >bring it to the exact time, that is enough. I really don't want to add >phone lines, IRLP links, wireless networks, or anything else to make this >happen. > >It would be great if the next-generation repeater controllers had a BNC or >TNC connector on the back labeled "GPS antenna" or "WWVB antenna" and all I >needed to do was install one simple antenna, and the controller would know >the time! > >73, Eric Lemmon WB6FLY > >-----Original Message----- >From: [email protected] >[mailto:[EMAIL PROTECTED] On Behalf Of Nate Duehr >Sent: Monday, November 12, 2007 11:57 AM >To: [email protected] >Subject: Re: [Repeater-Builder] Dallas Semiconductor Real-Time Clock (Was >RC-96 Controller Problem) > >Eric Lemmon wrote: >> Don, >> >> The "on-the-hour" tone is an 800 ms burst of 1500 Hz. I have built a PLL >> 1500 Hz tone detector into a Hamtronics WWV receiver, and it works fine- >> giving me a relay contact closure exactly on the hour. Unfortunately, that >> would only allow me to jam-set the minutes and seconds to zero, and would >> not correct an hour error- such as when DST starts and stops. > >Eric, > >There are a number of "easy" WWV and GPS projects to drive things like >Nixie clocks, etc... from simple microcontrollers like the Microchip PIC >and Atmel AVR. Those are a good starting point for a project to set a >controller's time remotely. > >Adding code to the microcontroller to then drive a DTMF encoder (or even >an R2R ladder for sine-wave output from multiple digital outputs if your >micro is fast enough) to set a controller's time, is fairly simple. > >One of the local clubs here in town has had such a system for a long >time, but hasn't published anything about it. From talking with their >techs, they receive WWV at a ham's house, set the clock in the Atmel, >and then it has a transmitter on a common control receiver frequency for >all of their machines. > >They had DST hard-coded to specific weeks of the year in their >microcontroller code, and had to modify their code during the great DST >mess that Congress created (with little to zero impact on energy use, >which was supposedly their goal) the last couple of years. > >My club never built such a gadget, we just go in and bump the time >around as necessary and don't get too wigged out if it's off by a minute >or two. Everyone has network-synced cell phones in their pockets these >days, and worrying about the repeater time just doesn't seem "worth it" >at this point. We get it close and then have to deal with DST. > >We also got rid of the hourly chimes/announcements/etc. The only time >you hear the time announced is after an autopatch, and that's really >just in case we had a need to record the autopatch calls for abuse, etc. > >Building an auto-time set device and having another transmitter just >seems like it breaks the KISS principle. > >As someone else mentioned, an IRLP node that is properly NTP >synchronized can also handle sending DTMF time-set commands easily. > >Nate WY0X > > Ron Wright, N9EE 727-376-6575 MICRO COMPUTER CONCEPTS Owner 146.64 repeater Tampa Bay, FL No tone, all are welcome.
