Eric, I've been toying around with this idea for a couple of years - set the SCOM 7K clock to atomic standards. As you know, the 7K's are prone to drifting with their time of day clock.
The idea is to have a stable WWV signal that "listen" to the top of the hour signal. I'm thinking that is a 1000 kHZ tone, but I could be wrong about that. If someone could build a circuit to decode the top of the hour signal from WWV, you could command the controller, through macros, to reset the clock. Shouldn't be all that difficult. The designers of the new SCOM controller recognized that problem earlier, and as I am told, have placed a new crystal / circuit in the time of day clock to address that problem in the 7330 line. With all of the 7K's out in the field, if a simple circuit could be made it would eliminate the drifting problem. Don, KD9PT ----- Original Message ----- From: "Eric Lemmon" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Sunday, November 11, 2007 3:27 PM Subject: [Repeater-Builder] Dallas Semiconductor Real-Time Clock (Was RC-96 Controller Problem) > Mike and others, > > The Dallas Semiconductor "Nonvolatile Timekeeping RAM" found in many > popular > controllers, including the Link RLC-1 Plus, is Part Number DS1643-150. > The > 11-page datasheet can be downloaded here: > > <www.datasheetarchive.com/pdf/1235806.pdf> > > Notice that the "-150" indicates 150 ns access time. The replacement > device > offered by Dallas/Maxim has either 70 ns or 100 ns access time, and I have > no idea if the newer device will work properly where a 150 ns device was > used. > > On page 5 of the datasheet is a paragraph entitled "Internal Battery > Longevity" which states that the device can operate for 10 years in the > absence of VCC power. When powered as it would normally be in a typical > application, the note states that the lifetime can be as long as 20 years. > The battery is not accessible for replacement. > > I see that the guaranteed accuracy of the DS1643 clock is within +/- 1 > minute per month, and there is no capability to tweak the crystal to get > better accuracy. One of the Hams in my area is experimenting with a > scheme > to use a so-called atomic clock to jam-set the correct time once per day. > With regular synchronism to WWVB, the time announcements will normally be > no > more than a second off. Once he gets this idea working, perhaps I can get > him to write an article about it. I and many other "time-and-frequency > geeks" think that time announcements should be correct. > > 73, Eric Lemmon WB6FLY > > > -----Original Message----- > From: [email protected] > [mailto:[EMAIL PROTECTED] On Behalf Of Mike Morris WA6ILQ > Sent: Sunday, November 11, 2007 12:29 PM > To: [email protected] > Subject: Re: Re: [Repeater-Builder] RC-96 Controller Problem > > I don't have my Dallas Semi book handy, but if I remember correctly > the "10 years" > spec was 10 unpowered years - if the Smartwatch was in a device that > was powered > up the battery was not being drained. But you still had to factor in > the shelf life of the > internal coin cell. > > At 03:44 AM 11/10/07, you wrote: >>Eric, >> >>As Kevin said if your 96 has one of the Dallas Smartwatch the >>battery in some of them had a life of 10 years. It was basically >>the shelf life of the battery. >> >>Most of the Smartwatch's I've seen used a RAM as the memory rather >>than a EPROM. The battery maintained the memory when power was >>lost. The battery could power and maintain memory for the life of >>the battery which again was spec'd for 10 years although most often >>lasted 12-14 years. Kinda gets into the area of some rigs having >>their OS in battery backed RAM. >> >>The Smartwatch was made by Dallas Semiconductor. >> >>73, ron, n9ee/r >> >> >> >> >> >From: "Kevin Berlen, K9HX" <[EMAIL PROTECTED] <mailto:k9hx%40arrl.net> > >> >Date: 2007/11/10 Sat AM 02:42:39 CST >> >To: [email protected] > <mailto:Repeater-Builder%40yahoogroups.com> >> >Subject: Re: [Repeater-Builder] RC-96 Controller Problem >> >> > >> >What version of software is in your controller? With rev 5 of >> thesoftware, a Dallas >> >Smartwatch was added to the RC-96 to provide a real-time clock. As >> Irecall, the >> >smartwatch occupied one of the eprom sockets, and the affected >> eprom wasplugged >> >into a socket on top of the device. If yours has the smartwatch, >> it maybe the culprit. 73. >> > >> >Kevin, K9HX >> > >> > >> >At 10:10 PM 11/9/2007, you wrote: >> > >> >One of the repeaters I maintainhas been working perfectly for almost a > year >> >since its last checkup. It is a 6m repeater that has a link toseveral >> >other 6m repeaters, and is controlled by an ACC RC-96 controller. Itis >> >powered from a very large commercial UPS that ensures no-breakpower. >> > >> >One evening, the controller went berserk, for no apparent reason. It >> >started transmitting a string of Morse characters on both the primaryand >> >secondary ports: "dit dah dit ... dah dah dah dah dah dah dah dahdah dah >> >..." for about two minutes. It would then be quiet on both ports >> >forabout >> >30 seconds, and would then repeat. During the brief silent periods,the >> >repeater would operate as a repeater, but the Morse string muted >> >anyother >> >audio, once it began. The controller would not respond to my >> >DTMFcommands >> >on either the primary or secondary ports. To make matters worse, the >> >telephone line that gives me backup control to knock down the >> >repeaterwas >> >dead at the hilltop end! I had to make a hasty trip to the > mountaintopsite >> >to take the beast off the air. >> > >> >As a result of this experience, I am adding a dedicated UHF control > linkto >> >give me positive control of the repeater. >> > >> >Has anyone else had a similar problem with the RC-96 controller? >> >Notethat >> >there is no lithium or similar memory battery inside the box that >> >mightgo >> >bad. Oddball malfunctions like this can add more gray hairs than Iwant! >> >Any ideas, case histories, or suggestions will be appreciated. >> > >> >73, Eric Lemmon WB6FLY >> > >> > >> > >> >No virus found in this incoming message. >> >Checked by AVG Free Edition. >> >Version: 7.5.503 / Virus Database: 269.15.26/1119 - Release >> Date:11/8/2007 5:55 PM >> > >> > >> > >> > >> >No virus found in this outgoing message. >> >Checked by AVG Free Edition. >> >Version: 7.5.503 / Virus Database: 269.15.27/1121 - Release Date: >> 11/9/2007 7:29 PM >> >> >>Ron Wright, N9EE >>727-376-6575 >>MICRO COMPUTER CONCEPTS >>Owner 146.64 repeater Tampa Bay, FL >>No tone, all are welcome. >> >> >> >> >> >> >> >>Yahoo! Groups Links >> >> >> > > > > > > > > > > > > Yahoo! Groups Links > > > > > !DSPAM:1016,47377405978151342210631! > >
