Hi CDMA is very much alive and kicking in the US.
Bob On May 1, 2012, at 7:00 PM, paul swed wrote: > Thought the cdma signals were all gone. > > On Tue, May 1, 2012 at 6:50 PM, Pete Lancashire > <p...@petelancashire.com>wrote: > >> I am playing around with a OT-20 "Office Time" that I pulled out of a >> dumpster some time ago. I've only just powered it up last weekend and >> it without an antenna will illuminate its CDMA green status LED in >> about 10 minutes. I've not tried an antenna or hooked up a terminal to >> its serial port. >> >> -pete >> >> On Tue, May 1, 2012 at 9:40 AM, Mark Spencer <mspencer12...@yahoo.ca> >> wrote: >>> Sorry to resurrect an old thread, but I thought someone might find this >> of interest. >>> >>> I purchased a 2700 intending to harvest the PRS10. Prior to cracking >> open the case I powered up the unit to ensure it was basically working so I >> could return it if needed. I noticed that despite not having an antenna >> connected it seemed to find and track CDMA signals and after a few hours >> the 10 Mhz output was in a few parts of 10E-12 of my GPSD0. >>> >>> After a bit of investigation I found the following >>> >>> Adding an external antenna didn't seem to make much difference to the >> performance. >>> >>> The 1pps output is approx. 75ms out of sync with the 1pps output from my >> Fury GPSD0. >>> >>> From time to time the 10 Mhz output experiences phase jumps of several >> tens of ns. Manipulating the unit (ie. connecting to the RS 422 port) may >> induce this. Power cycling the unit seems to cure the problem and the unit >> usually takes an hour or two to re lock. It's possible that the lack of a >> proper ground in my instalation may be causing some of the issues as well. >> This problem would be a show stopper for me in terms of using this unit >> to replace my GPSDO's. I'm not sure if this issue is specfic to my unit or >> not. >>> >>> I've attached some initial ADEV plots showing the typical performance of >> the 10 Mhz output vs three of my other references. (I wouldn't put a lot >> of emphasis on the results of taus of less than 100 seconds or more than >> 6,000 or so..) I doubt I'm going to put much more time into this unit but >> it's an interesting novelty in it's original state. The results of other >> units may well differ (: >>> >>> Regards >>> Mark Spencer >>> >>> >>> --- On Thu, 11/24/11, Charles P. Steinmetz < >> charles_steinm...@lavabit.com> wrote: >>> >>>> From: Charles P. Steinmetz <charles_steinm...@lavabit.com> >>>> Subject: Re: [time-nuts] Symmetricom TimeSource 2700 >>>> To: "Discussion of precise time and frequency measurement" < >> time-nuts@febo.com> >>>> Received: Thursday, November 24, 2011, 11:17 PM >>>> Kevin wrote: >>>> >>>>> I use the Craft connector for monitoring with BTMon >>>> rather than the RS-232 port. >>>>> It appears the Craft output, while spontaneously >>>> emitting alarm/events, does respond >>>>> to queries from BTMon on the Craft input. >>>> >>>> Everything I reported previously involved the Craft port >>>> feeding a PC COM port using the RJ45-to-DB9 cable supplied >>>> by Symmetricom. >>>> >>>>> Do you happen to have a RS-422/485 interface? I don't, >>>> but I'm interested to see >>>>> if any spontaneous output occurs on the TOD port. >>>> >>>> I have a 422/485 card here somewhere, but I haven't used it >>>> (maybe even seen it) in more than 10 years. >>>> >>>> I poked a scope at the TOD jack. The TS2500 manual >>>> says that (in a TS2500) Pin 1 should be PPS (positive), Pin >>>> 6 should be PPS (negative), Pin 5 should be TXA output >>>> (positive), Pin 9 should be TXA output (negative), and Pins >>>> 7 and 3 should be a 20 V external supply positive and >>>> return, respectively. >>>> >>>> I found PPS positive and negative on Pins 1 and 6. >>>> Logic low is about 1.2 V positive with respect to case >>>> ground, and logic high is about 3.8 V above case ground, for >>>> a logic range of approximately 2.6 V. The PPS pulses >>>> are 500 uS wide with rise and fall times of ~20-25 nS. >>>> >>>> I did not see any data on the TXA outputs -- the positive >>>> TXA output just sits at logic low and the negative TXA >>>> output sits at logic high. >>>> >>>> There is 20 V between Pins 7 and 3. As for the >>>> unspecified pins -- Pin 2 sits at nominally 0 Vdc, and Pins >>>> 4 and 8 sit at nominally 0.168 Vdc. All three have >>>> around 20 mVp-p of hum and noise. >>>> >>>> While I was at it, I poked at the RS232 connector, as >>>> well. Pin 3 (TX Data) has a 16 or 17 mS burst of data >>>> every 5 seconds (approximately), from -10 V to +10 V with >>>> respect to case (henceforth, 232 low and high, >>>> respectively). Between bursts, it sits at 232 >>>> low. Pins 4 and 7 (DTR and RTS, respectively) sit at >>>> 232 high. All other pins sit at ground. >>>> >>>> Best regards, >>>> >>>> Charles >>>> >>>> >>>> >>>> >>>> >>>> _______________________________________________ >>>> time-nuts mailing list -- time-nuts@febo.com >>>> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>> and follow the instructions there. >>>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts@febo.com >>> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.