Re: [time-nuts] combining same frequency for redundancy
Quoting Tony Greene tonygreen...@inbox.com: About 50 years ago I ran into a Frequency Division Multiplexer that used a redundant master frequency system. I beleive they combined the same frequency for the master oscillator, but it was something like a special hybrid combiner. I remember that they used a phase angle of 135 degrees - and then if they lost one signal, the power went down by 3 db on the main pilot. Anybody no any details on this type of system ? What I am looking for is to have an input to a distribution amplifier where I can connect and disconnect two different inputs and keep the output systems up and running. It seems that the HP 58502A distribution has this feature : From the documentation : The controller block input select line state (at power on from the factory) selects input A over B, if valid signals are present at both connectors, but will switch to input B automatically, if the signal at input A fails. If input B fails and input A signal reappears, the controller block will select input A again as the valid input signal source. If both inputs fail, no select line state change will occur. Claude. FREE ONLINE PHOTOSHARING - Share your photos online with your friends and family! Visit http://www.inbox.com/photosharing to find out more! ___ 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.
Re: [time-nuts] I can't get a nice waveform from my rubidium !
Thanks for your replies. With a 50 ohms resistor (about 49 ohms in fact), I've got something interesting but not perfect (I will try to find a 50 ohms terminaison). Unfortunately it didn't work with the counter as terminaison (see attachments). The two outputs have the same waveforms, I will open the case and try to understand how this is done. And yes it's a 10A-R (the new name is A10-M). Claude On Thursday, 17 April 2014, 21:43, cfo xne...@luna.dyndns.dk wrote: On Thu, 17 Apr 2014 06:32:52 +0100, Claude Fender wrote: My unit has two outputs with no options. The problem is the shape of the waveform (see attachments), it's the same shape for the two outputs. When I connect an output directly to the oscilloscope, the shape is nearly squared and when I use a probe, the shape is nearly sine ! According to the pict , the low output is supposed to be a CMOS square Is it called A10-R ? www.technical-sys.com/QL%20A10-R%20DS.pdf But termination would as other say be an issue. Dig into your drawer and pull out a BNC-T , and one of those 50ohm termination resistors you know you saved , when you were running old coax based ehternet on rg-58 cable. Have saved me a few times on my Rigol that hasn't got 50 termination built in. Else use your freq counter as termination , it ought to have 50ohm termination. BNC-T on scope , rubi on one end of tee , and counter on other end of tee (50 ohm terminated). CFO Denmark ___ 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.attachment: 50ohms_resistor.gifattachment: 1megaohm_counter.gifattachment: 50ohms_counter.gif___ 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.
Re: [time-nuts] Measuring the accurcy of a wrist watch
Hello, I've seen that on a forum (in french sorry) : http://www.forum-mdp.com/t16731-un-chronocomparateur-pour-petit-budget It's an application for iPhone called Kello, look at the picture and you will understand. The most difficult part seems to find the right position of the microphone. Claude On Thursday, 17 April 2014, 19:55, DaveH i...@blackmountainforge.com wrote: Something to consider is that most pickups are biased with a fairly strong magnetic field. Don't know if this would cause any damage or changes in operation of a mechanical watch but something to consider... http://www.guitarnuts.com/wiring/pickups.php Dave -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Ulrich Bangert Sent: Thursday, April 17, 2014 01:15 To: 'Discussion of precise time and frequency measurement' Subject: Re: [time-nuts] Measuring the accurcy of a wrist watch Chris, I do not own a guitar with single coil pickups but I will surely give it a try to find out whether the humbuckers of my Gibson Firebird SG Standard will also do the trick! Best regards Ulrich -Ursprungliche Nachricht- Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im Auftrag von Chris Albertson Gesendet: Mittwoch, 16. April 2014 20:56 An: Tom Van Baak; Discussion of precise time and frequency measurement Betreff: Re: [time-nuts] Measuring the accurcy of a wrist watch I just did an experiment. Place a simple quartz movement wrist watch on top of a Fender Stratocaster guitar. I get a very strong and easy to detect signal. A loud and sharpt ping once per second. More then 1 volt peak to peak. I can cancel almost all the background hum and hiss in the normal way by using the selector switch on the guitar. The guitar has a pickup coil with many thousands of turns of #40 wire. With the selector with at #2 position there is a second coil some inches away that is wound in the opposite direction and the two are added canceling any field that is filing the room. I tried the same with a wall clock and all I had to do was hold the clock an inch away. The wrist watch was placed on top of the strings a few mm above the bridge PU. These is likely about 3 oz of #40 magnet wire on a guitar PU. If I were building a sensor I'd do it just like the guitar. one coil to pick up the signal and another identical coil some inches away to to pick up ambient noise and then wire the two in parallel but in anti-phase. If yu happen to have a guitar around, you have a watch sensor. On Wed, Apr 16, 2014 at 10:43 AM, Tom Van Baak t...@leapsecond.com wrote: Tom, can you explain what exactly you understand by a large coil of wire? Sorry, by large I meant a large number of turns; the coil itself is quite small. Rather the winding one myself I just used the pickup coil from an old cheap plastic self-impulsed pendulum clock. The wire is extremely fine and there must be thousands of turns since the spool diameter is only 15-20mm and the net resistance is 3.5k. Here are some iPhone photos I just took: http://leapsecond.com/pages/Junghans/coil.htm Did you make the easurements on the Junghans with a DIY sensor or with one of the commercially available? Both. The commercial ones sold by Bryan Mumford are excellent; his instrument includes signal conditioning, adjustable high gain, and other useful features. It's meant for watchmaker types with no electronics background. It works perfectly out of the box. The Junghans wristwatch is extremely well engineered for long-life and the leaked magnetic signal is the weakest of any watch I've measured. Still, it can be measured. The placement of the pickup coil on the watch face needs to be optimized for best reception, or any reception at all for that matter. By contrast, a typical AAA-battery desk/wall quartz clock movement generates a huge magnetic signal. It is so clean that you can clearly see both the start (+) of the impulse and the end (-) of the impulse about 30 ms later. In fact I suspect it's actually 31.25 ms, or 1/32 s, since that's 1024 cycles of a 32.768 kHz oscillator. See: sensor placement: http://leapsecond.com/pages/Junghans/quartz-clock.jpg output to scope: http://leapsecond.com/pages/Junghans/coil-aa.gif I have made some basic tests with a coil coming from a loudspeaker's cross over network. It has a few hundred windings, R=1.3 Ohms, 2.3 mH, but the only thing i receive with this coil is a strong 10 Mhz signal...perhaps no real surprise in a time nuts laboratory. I suspect your 1.3 ohms means the number of turns is far too low. I don't see any RF here, nor even very much
Re: [time-nuts] How dies a Rubidium ?
Thanks for your answer. Actually, I use a 5334B counter locked on a GPS to record the output of the rubidium 24/7, with gate times of 10s and 100s . The measurements are constants between 10,000,000.002 and 10,000,000.004 Hz, the resolution is 1 mHz for 10s and 0.1 mHz for 100s. I have not enough records to see a drift. In your opinion, with this method, when the Rb will become older, I will see some short jumps in frequency from time to time ? I agree this is an heavy method compared to your blink-ometer but I am still learning ! Claude De : paul swed paulsw...@gmail.com À : Claude Fender lab...@yahoo.fr; Discussion of precise time and frequency measurement time-nuts@febo.com Envoyé le : Samedi 20 avril 2013 17h58 Objet : Re: [time-nuts] How dies a Rubidium ? In my experience with numbers of less expensive cel tower pulls, they blink out and re-ignite and then relock this is infrequent. But occurs more and more often. If RB is suspected of going to the darkside, I use the blink-ometer to catch this. What the heck is a blink-ometer? Simply one of those little pedometer counters that I have tapped into and through a opto coupler allow the blink to trigger a count. Happy to sell you one for $199 plus shipping and if you act now will include another for postage and handling The other clue is the lamp voltage. This is a relative clue if your unit even gives you access to it. The FRS start at 9 or so volts and seem to start to blink about 3. Its relative and your milage will vary. Regards Paul WB8TSL On Sat, Apr 20, 2013 at 5:13 AM, Claude Fender lab...@yahoo.fr wrote: Hi, I would like to know if there is a way to know if a Rubidium is at his end of life or not : when it stops working, does this happen suddenly or are there percursory symptoms ? I am looking fora method that does not need to open the case (I have a 5680A and I am waiting a Racal Dana). Thanks for your advices ! Claude ___ 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] How dies a Rubidium ?
Hi, I would like to know if there is a way to know if a Rubidium is at his end of life or not : when it stops working, does this happen suddenly or are there percursory symptoms ? I am looking fora method that does not need to open the case (I have a 5680A and I am waiting a Racal Dana). Thanks for your advices ! Claude ___ 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.
Re: [time-nuts] Z3805A/58503A time receiver : 2 questions
Thanks you both for your answers. I had another jump (positive this time, 24h after the first one) and the efc curve came back to its previous state, see : http://uppix.net/f/4/d/c5a277798ca58bb04b41481ece6e7.png. The receiver is a 6 channels and it outputs two 10 MHz and one PPS. The antenna has noname and it is installed on a balcony, that's why it has a poor reception. Sure this is not perfect and I have to improve that. The log is running every 5 minutes and I didn't notice a holdover mode of the oscillator. (I've bought this GPSO to check the frequency of my 5334B for gates times of 60s and 100s. I know I can use the 10MHz of the GPSDO as Frequency Reference for the 5534B but I wanted to check its frequency first !) De : Volker Esper ail...@t-online.de À : time-nuts@febo.com Envoyé le : Jeudi 28 février 2013 2h12 Objet : Re: [time-nuts] Z3805A/58503A time receiver : 2 questions If your unit is exactly like that on ebay 251226027893, it has a 10 MHz HP oscillator in a double oven, and it's absolutely sure that it's got a 6 channel receiver. I should have read before, sorry. I'm still not sure about your antenna, is it a Garmin? Well, it's most likely an active type, so what gain does it have? If you installed it on a roof top, it should see sufficient field strength. Then do that simple test: disconnect your antenna from the receiver unit and measure with a multimeter the voltage at the center pin of your N connecter antenna plug. It has to show 5 Volts, otherwise your antenna can't be working well. Volker Am 28.02.2013 01:26, schrieb Volker Esper: Hi Claude! Said says, you should see 6+ sats, I guess he means _at_least_ six. I'm almost sure, you've got a 6 channel receiver, so you naturally cant't get more than 6 sats at a time. There are some different models of the Z3805A out there, though they're all named the same. I've got two units, one with an 8 channel and one with a 16 channel receiver. My 8channel unit never receives more than 6 sats at a time, never. So I'm shure, it's a 6 channel type... Maybe I should improve my antenna. But the same antenna provides enough voltage to receive 12 to 14 sats at once with the 16 channel unit. On the other hand, my 6/8 channel gizmo very rarely shows less than 6 sats, so, like Said, I too think, that there is some space for improving your antenna. What antenna do you have? One day, while using the 16 channel unit, I experienced the same hops as you did. All time nuts told me that it had to be a crystal jump. I read about such phenomenons and all I found was, that the jump in my receiver was too big to fit to the idea of a crystal jump. Unfortunately my receiver gained fun in jumping. Now I'm absolutely not sure what it is. Maybe it's a faulty oscillator. Which one do you have built in? A 5 or a 10 MHz type? I've got a 10 MHz HP and a 5 MHz Symmetricom oscillator. Cheers Volker Am 28.02.2013 00:17, schrieb Claude Fender: Hello, This is my first message here although I read this list for a few weeks. I bought a Z3805A/58503A frequency receiver and I didn't notice on the pictures that the model number was not written on the front panel. It's not important but is there a reason for that, if you know ? The item : http://cgi.ebay.fr/ws/eBayISAPI.dll?ViewItemitem=251226027893 I log some parameters of the receiver and today I notice a gap in the frequency. Picture : http://uppix.net/e/2/4/cf39ac772e5a69fc616f5cf30f208.png I have a Rubidium and I measure it's frequency with a 5334B counter locked to the GPS, and I can see the gap too : http://uppix.net/f/b/a/d86c2737ad135264e4a2b78e503d5.png measurements are with Gate Time of 10s, 60s and 100s, Do you know why this happens and how to prevent this behaviour ? Thanks for yours advices Claude ___ 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] Z3805A/58503A time receiver : 2 questions
Hello, This is my first message here although I read this list for a few weeks. I bought a Z3805A/58503A frequency receiver and I didn't notice on the pictures that the model number was not written on the front panel. It's not important but is there a reason for that, if you know ? The item : http://cgi.ebay.fr/ws/eBayISAPI.dll?ViewItemitem=251226027893 I log some parameters of the receiver and today I notice a gap in the frequency. Picture : http://uppix.net/e/2/4/cf39ac772e5a69fc616f5cf30f208.png I have a Rubidium and I measure it's frequency with a 5334B counter locked to the GPS, and I can see the gap too : http://uppix.net/f/b/a/d86c2737ad135264e4a2b78e503d5.png measurements are with Gate Time of 10s, 60s and 100s, Do you know why this happens and how to prevent this behaviour ? Thanks for yours advices Claude ___ 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.
