The fury already has a fat pps correct? Sent from mobile
> On Oct 26, 2013, at 7:31 PM, Frank Hughes <hp_cisco...@yahoo.com> wrote: > > > > Discretion being the better part of valor, and I need plug & play for this > piece, in order to save time for other things that need attention, so I > ordered : > "Symmectricom 58535A" > > After I got the Fury working, noted an interesting anomaly (that turned out > to be my fault, but interesting) > > Connected the 10Mhz from the Fury to the HP 5087A distribution amp feeding > 10Mhz to all the HP and Agilent equipment needing a stable reference. > > One of the ancient HP things ( 59309A) said it had no 10Mhz external > oscillator! > The 59309A worked w/ the Trimble, not the Fury. > > Did some troubleshooting, the Fury 10Mhz signal is about 2 or 3 db less than > the Trimble. > > This attenuation was enough to prevent the 59309A from locking on to the > signal. > All the other HP and Agilent worked fine with either 10Mhz source. > > I remembered that I had been too lazy to actually set the no-load voltage on > each of the 5087A output amplifiers > the last time I had it apart. > > So I pulled the 5087A out of the rack, took the cover off and and set the > levels correctly. 59309A happy. > > Anyway, when I finished all that, went to see how to get both the Trimble and > Fury operating in parallel. > > - Trimble feeds 1PPS to the FreeBSD NTP server via the "FAT PPS" serial port > circuit. > - Fury feeds the HP 5087A distribution amp for all the HP/Agilent to sync to. > > The FAT PPS won't fit on the Fury, Fury=male null modem DB9, TB=Female > straight DB9. > > So I will use both GPSDO boxes. Which led me to the splitter.......... > > 73 and thank again for the great ideas! > Frank > KJ4OLL > > > > > > On Saturday, October 26, 2013 5:49 PM, "time-nuts-requ...@febo.com" > <time-nuts-requ...@febo.com> wrote: > > Send time-nuts mailing list submissions to > time-nuts@febo.com > > To subscribe or unsubscribe via the World Wide Web, visit > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > or, via email, send a message with subject or body 'help' to > time-nuts-requ...@febo.com > > You can reach the person managing the list at > time-nuts-ow...@febo.com > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of time-nuts digest..." > > > Today's Topics: > > 1. Re: Splitter for GPS antenna suggestions? (Tom Knox) > 2. Re: Splitter for GPS antenna suggestions? (Bob Camp) > 3. Re: Splitter for GPS antenna suggestions? (Magnus Danielson) > 4. Re: Splitter for GPS antenna suggestions? (Brooke Clarke) > 5. Re: Time stamping with a PICPET (Chris Albertson) > 6. Re: Time stamping with a PICPET (Hal Murray) > 7. Re: Splitter for GPS antenna suggestions? (Charles Steinmetz) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Sat, 26 Oct 2013 10:54:40 -0600 > From: Tom Knox <act...@hotmail.com> > To: Time-Nuts <time-nuts@febo.com> > Subject: Re: [time-nuts] Splitter for GPS antenna suggestions? > Message-ID: <col130-w31bae6e1605519eb154c97df...@phx.gbl> > Content-Type: text/plain; charset="iso-8859-1" > > I think this discussion could use some parity. Some many options have been > presented. But to return to one of the first posts, I would buy a Symmetricom > Splitter on eBay. They have really become the industry standard and can be > had for a reasonable price. There are certainly products that could be > selected to meet your needs for less money but it will have some compromises, > and there are others that could meet or perhaps even exceed Symmetricoms > performance but are usually more money and are much less common on the > surplus market. I would buy one with more ports then you need in case you > ever want to test or install an additional GPS receivers. Remember "If you > buy the best you only cry once" > > Thomas Knox > > > >> From: li...@rtty.us >> Date: Sat, 26 Oct 2013 08:00:32 -0400 >> To: time-nuts@febo.com >> Subject: Re: [time-nuts] Splitter for GPS antenna suggestions? >> >> Hi >> >> Pretty much all of the MiniCircuits splitters seem to happily pass DC. The >> same is true of all of the TV splitters I've tried. The standard circuits >> (as in the lowest cost) have a transformer or transmission line that has no >> DC path to ground. >> >> Bob >> >>> On Oct 26, 2013, at 12:58 AM, David <okdavid5...@cox.net> wrote: >>> >>> Hello -- >>> >>> I'm not very knowledgeable electronically, but I am currently using a >>> Minicircuits ZAPD-3DB-1575-3 splitter to connect one TrueTime 142-400 GPS >>> antenna to a Spectracom 8183 and a Spectracom 8183-A. I use the Spectracoms >>> only as precise digital clocks, and they seem to work just fine. >>> >>> I bought the Minicircuits splitter on eBay for $30, buy-it-now, as I recall, >>> but it's been a while ago. >>> >>> Hope that's helpful. >>> >>> David in Oklahoma City >>> >>> -----Original Message----- >>> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On >>> Behalf Of Frank Hughes >>> Sent: Friday, October 25, 2013 5:31 PM >>> To: time-nuts@febo.com >>> Subject: [time-nuts] Splitter for GPS antenna suggestions? >>> >>> Hi, >>> I want to see if it is possible to feed both the Trimble TB and the Jackson >>> Labs Fury from the existing antenna. It appears both the TB and the Fury are >>> 5vdc antenna power. >>> >>> Checked the auction site for splitters, but before I randomly buy anything, >>> could someone please suggest what they use that works? >>> >>> Thanks, and 73 >>> Frank >>> KJ4OLL >>> _______________________________________________ >>> 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. > > > ------------------------------ > > Message: 2 > Date: Sat, 26 Oct 2013 13:22:56 -0400 > From: Bob Camp <li...@rtty.us> > To: Discussion of precise time and frequency measurement > <time-nuts@febo.com> > Subject: Re: [time-nuts] Splitter for GPS antenna suggestions? > Message-ID: <ea8028de-f5aa-4003-b6ac-092f4fdc3...@rtty.us> > Content-Type: text/plain; charset=us-ascii > > Hi > > The Symmetricom / HP splitters are way more than just a splitter. They have > an amp and some filtering in addition to the split. They also pass DC from > only one port and correctly DC terminate the other ports so you don't get an > "antenna missing" error. > > Bob > >> On Oct 26, 2013, at 12:54 PM, Tom Knox <act...@hotmail.com> wrote: >> >> I think this discussion could use some parity. Some many options have been >> presented. But to return to one of the first posts, I would buy a >> Symmetricom Splitter on eBay. They have really become the industry standard >> and can be had for a reasonable price. There are certainly products that >> could be selected to meet your needs for less money but it will have some >> compromises, and there are others that could meet or perhaps even exceed >> Symmetricoms performance but are usually more money and are much less common >> on the surplus market. I would buy one with more ports then you need in case >> you ever want to test or install an additional GPS receivers. Remember "If >> you buy the best you only cry once" >> >> Thomas Knox >> >> >> >>> From: li...@rtty.us >>> Date: Sat, 26 Oct 2013 08:00:32 -0400 >>> To: time-nuts@febo.com >>> Subject: Re: [time-nuts] Splitter for GPS antenna suggestions? >>> >>> Hi >>> >>> Pretty much all of the MiniCircuits splitters seem to happily pass DC. The >>> same is true of all of the TV splitters I've tried. The standard circuits >>> (as in the lowest cost) have a transformer or transmission line that has no >>> DC path to ground. >>> >>> Bob >>> >>>> On Oct 26, 2013, at 12:58 AM, David <okdavid5...@cox.net> wrote: >>>> >>>> Hello -- >>>> >>>> I'm not very knowledgeable electronically, but I am currently using a >>>> Minicircuits ZAPD-3DB-1575-3 splitter to connect one TrueTime 142-400 GPS >>>> antenna to a Spectracom 8183 and a Spectracom 8183-A. I use the Spectracoms >>>> only as precise digital clocks, and they seem to work just fine. >>>> >>>> I bought the Minicircuits splitter on eBay for $30, buy-it-now, as I >>>> recall, >>>> but it's been a while ago. >>>> >>>> Hope that's helpful. >>>> >>>> David in Oklahoma City >>>> >>>> -----Original Message----- >>>> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On >>>> Behalf Of Frank Hughes >>>> Sent: Friday, October 25, 2013 5:31 PM >>>> To: time-nuts@febo.com >>>> Subject: [time-nuts] Splitter for GPS antenna suggestions? >>>> >>>> Hi, >>>> I want to see if it is possible to feed both the Trimble TB and the Jackson >>>> Labs Fury from the existing antenna. It appears both the TB and the Fury >>>> are >>>> 5vdc antenna power. >>>> >>>> Checked the auction site for splitters, but before I randomly buy anything, >>>> could someone please suggest what they use that works? >>>> >>>> Thanks, and 73 >>>> Frank >>>> KJ4OLL >>>> _______________________________________________ >>>> 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. > > > > ------------------------------ > > Message: 3 > Date: Sat, 26 Oct 2013 19:52:41 +0200 > From: Magnus Danielson <mag...@rubidium.dyndns.org> > To: Discussion of precise time and frequency measurement > <time-nuts@febo.com> > Subject: Re: [time-nuts] Splitter for GPS antenna suggestions? > Message-ID: <526c0169.6010...@rubidium.dyndns.org> > Content-Type: text/plain; charset=ISO-8859-1 > >> On 10/26/2013 07:22 PM, Bob Camp wrote: >> Hi >> >> The Symmetricom / HP splitters are way more than just a splitter. They have >> an amp and some filtering in addition to the split. They also pass DC from >> only one port and correctly DC terminate the other ports so you don't get an >> "antenna missing" error. > Both good points. The added filtering means increased selectivity, which > translates to better resistance to RF power emissions outside of the > 2,046 MHz bandwidth. > > Wideband splitters does not have that benefit, but has it's use if you > can live with it. > > Cheers, > Magnus > > > ------------------------------ > > Message: 4 > Date: Sat, 26 Oct 2013 11:16:21 -0700 > From: Brooke Clarke <bro...@pacific.net> > To: Frank Hughes <hp_cisco...@yahoo.com>, Discussion of precise time > and frequency measurement <time-nuts@febo.com> > Subject: Re: [time-nuts] Splitter for GPS antenna suggestions? > Message-ID: <526c06f5.3020...@pacific.net> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed > > Hi Frank: > > I've used TV splitters and in line amplifiers, see: > http://www.prc68.com/I/4GPS.shtml > > Have Fun, > > Brooke Clarke > http://www.PRC68.com > http://www.end2partygovernment.com/2012Issues.html > > Frank Hughes wrote: >> Hi, >> I want to see if it is possible to feed both the Trimble TB and the Jackson >> Labs Fury from the existing >> antenna. >> It appears both the TB and the Fury are 5vdc antenna power. >> >> Checked the auction site for splitters, but before I randomly buy anything, >> could someone please suggest what they use that works? >> >> Thanks, and 73 >> Frank >> KJ4OLL >> _______________________________________________ >> 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. > > > > ------------------------------ > > Message: 5 > Date: Sat, 26 Oct 2013 12:02:43 -0700 > From: Chris Albertson <albertson.ch...@gmail.com> > To: Tom Van Baak <t...@leapsecond.com>, Discussion of precise time and > frequency measurement <time-nuts@febo.com> > Subject: Re: [time-nuts] Time stamping with a PICPET > Message-ID: > <cabbxvhuayrn+ajxc6x8prbpm2rxwk-hj3vdvvgctkgfxnqw...@mail.gmail.com> > Content-Type: text/plain; charset=ISO-8859-1 > > Good idea but you assume NTP could generate a pule with better accuracy > then it can measure them. That is likely not true. On a modern system we > can mures puss with about +/- 2 uSec jitter. We can not export a clock > with that level of precision. > > The reason is that all the normal outputs get queued while the DCD > interrupt works better than you'd think. Also we don't need to fix it > because the weal link is transferring tine OUT of the system over the > network > > > On Sat, Oct 26, 2013 at 1:37 AM, Tom Van Baak <t...@leapsecond.com> wrote: > >>> What kind of accuracy do the picket's have. You can log pulses using >> the >>> PPS system on bare PC hardware and get the time of the pulse logged to >>> within about 2 uSec. Simply connect the pulse to DCD line of a real >> serial >>> port. >>> >>> If you need better than 2 uSec then yes you need external hardware. >> >> The current version of picPET is 400 ns resolution given a 10 MHz clock. >> It was designed for applications needing millisecond- to microsecond-level >> accuracy. Not bad for a $1 8-pin chip. >> >>> If those pickets are much better than 2 uSec then they make a GREAT front >>> end for a NTP server. Question: how do you transfer accurate time into >> the >>> PIC? >> >> They are a form of T2D or TDC (time to digital converter) or TSC >> (continuous time-stamping counter) for making zero-dead time measurements, >> not real-time clocks for the purpose of maintaining time of day, or day or >> year. >> >> If all you need is a 1PPS source use a GPS timing receiver, or a GPSDO >> with 1 PPS output, or a 10 MHz external clock and a picDIV divider. See >> http://leapsecond.com/pic/ for many different dividers. >> >> ---- >> >> As far as NTP is concerned, I wonder if you've ever considered turning the >> tables on how it works. AFAIK, NTP gets an external time reference (e.g., >> 1PPS) as an interrupt. With modern computers, this is horrible. There are >> far too may layers of h/w jitter (pipelines, multiple levels of cache, TLB >> misses, etc.) and s/w jitter (interrupt handling, spinlocks, interrupt >> masking, priority levels, etc.). >> >> For best timing, perhaps a better solution is not to have NTP receive a >> 1PPS as *input* and try to pretend to measure it internally in s/w but for >> NTP to *output* a 1PPS and measure that externally with sub-microsecond h/w >> (like a picPET). >> >> That bypasses all the jitter associated with asynchronous events; >> replacing it instead with a synchronous event. If NTP takes an internal s/w >> timestamp before and after the pulse is output, and you obtain (via serial >> port) the timestamp reading made by external h/w you can then correct the >> NTP paper clock, with far less h/w and s/w jitter. >> >> The mental shift is to stop treating a PC+NTP as a precise clock and pulse >> measurement instrument and start treating a PC+NTP as a precise clock and >> pulse generation instrument. >> >> /tvb >> >> _______________________________________________ >> 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. > > > > -- > > Chris Albertson > Redondo Beach, California > > > ------------------------------ > > Message: 6 > Date: Sat, 26 Oct 2013 14:47:01 -0700 > From: Hal Murray <hmur...@megapathdsl.net> > To: Tom Van Baak <t...@leapsecond.com>, Discussion of precise time and > frequency measurement <time-nuts@febo.com> > Subject: Re: [time-nuts] Time stamping with a PICPET > Message-ID: > <20131026214701.48962406...@ip-64-139-1-69.sjc.megapath.net> > Content-Type: text/plain; charset=us-ascii > > > t...@leapsecond.com said: >> As far as NTP is concerned, I wonder if you've ever considered turning the >> tables on how it works. AFAIK, NTP gets an external time reference (e.g., >> 1PPS) as an interrupt. With modern computers, this is horrible. There are >> far too may layers of h/w jitter (pipelines, multiple levels of cache, TLB >> misses, etc.) and s/w jitter (interrupt handling, spinlocks, interrupt >> masking, priority levels, etc.). > > You have to have your time-nut hat on before that makes a difference. > > Has anybody measured it? It should be easy to hack the kernel PPS interrupt > routine to flap a printer port signal and measure the delay between the PPS > signal and printer port. > > >> For best timing, perhaps a better solution is not to have NTP receive a 1PPS >> as *input* and try to pretend to measure it internally in s/w but for NTP to >> *output* a 1PPS and measure that externally with sub-microsecond h/w (like a >> picPET). > > The Trimble Palisade and Acutime work that way. > > > > -- > These are my opinions. I hate spam. > > > > > > ------------------------------ > > Message: 7 > Date: Sat, 26 Oct 2013 17:47:26 -0400 > From: Charles Steinmetz <csteinm...@yandex.com> > To: Discussion of precise time and frequency measurement > <time-nuts@febo.com> > Subject: Re: [time-nuts] Splitter for GPS antenna suggestions? > Message-ID: <20131027014729.lsfiv...@smtp4h.mail.yandex.net> > Content-Type: text/plain; charset="us-ascii"; format=flowed > > Bob wrote: > >> The Symmetricom / HP splitters are way more than just a splitter. >> They have an amp and some filtering in addition to the split. They >> also pass DC from only one port and correctly DC terminate the other >> ports so you don't get an "antenna missing" error. > > And they were designed for precision timing systems, so thought was > given to minimum propagation time and to equal delay between > channels. PT is about 20nS, and very consistent channel-to-channel. > > Best regards, > > Charles > > > > > > ------------------------------ > > _______________________________________________ > time-nuts mailing list > time-nuts@febo.com > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > End of time-nuts Digest, Vol 111, Issue 70 > ****************************************** > _______________________________________________ > 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.
