Re: [time-nuts] Frequency doubler 5/10 and distribution amplifier forLucent KS-24361
Am 05.01.2015 um 02:41 schrieb Dave M: Good job on the doubler/distribution amp, Gerhard! Which PCB design software did you use to make the PC board? Could you share the files for it? Thanks, I use the Altium Designer here. The files are available. 1:1 .pdfs of the layout are already in the hands of interested people. I don't mind if someone makes boards or has them made. regards, Gerhard ___ 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] Any reason not to use one power amplifier and splitter for distribution amplifier?
Bruce wrote: A 10nF cap connected to the emitter winding [instead of the collector] avoids capacitively coupling collector power supply noise to the output (assuming that the collector supply isnt ground.). Good point. I take pains with power supply design and very rarely have problems with supply noise in practice, but you're right, taking the output from the emitter winding should help reduce PS noise coupling if it were a problem. I foresee no countervailing adverse consequences, so that should be considered the preferred connection for the two-winding variant of the circuit. 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.
Re: [time-nuts] HP 58503A Com 4 conflict
To add a small dose of additional complexity, Visual Basic 6.0 (and I suspect other dev tools of that generation) only support COM ports up to 16. Not as bad as 4, but still a problem on occasion. Didier KO4BB On January 4, 2015 12:03:05 PM CST, Bob Camp kb...@n1k.org wrote: Hi Ok, off into serial land …. The GPSDO does not really know or care what port it’s on. It will be just as happy on port 119 as on port 4. It (by design) does care about the baud rate / data bits / parity / stop bits. This is as true with a USB to serial as with a direct serial card. That’s the good news. Now for the rest of the news. If your computer operating system is old enough, you may only *have* 4 com ports. Bad news there = upgrade the computer. Typically this is a Windows 95 and earlier issue. If the software running on the computer is old enough it may only *know* how to use 4 com ports. Bad news is same = upgrade the software. Typically this is a Windows 95 era (mid 90’s) issue. If the drivers on the serial to usb converter are old enough, they may only talk as 4 com ports (I’ve never seen this on a modern OS). Same news = upgrade the driver. All this relates to Windows. The cutoff times and versions for other OS’s are a bit more obscure. The same basic details apply. If you are running on an XP or newer machine, you should have far more than 4 com ports available. If you are running any of the newer ( = past 2000) software to talk to the box, it should be quite happy to deal with more than 4 com ports. My *guess* is that you need a different piece of software. Exactly what you are doing will determine which one you need. ( = more info required). - On Jan 4, 2015, at 10:50 AM, James Robbins jsrobb...@earthlink.net wrote: My new old HP58503A wants to connect to my PC on Com 1-4. Other PC devices are already using those 4 Com ports. Is there any way to connect it to a Com port other than one of those 1 to 4? I currently use an Edgeport USB-to-Serial Converter which works very well to communicate with the PC and to assign Com ports to my various GPS units. But, as far as I know, the chosen Edgeport Com port must fall within the range of Com ports which for which the device is designed. If this has been answered, please point me to the discussion. Many thanks. And, Happy New Year to all, with wishes for a more peaceful (and timely - couldn't resist) year. I have this terrible urge to start a calendar thread revolving around “new” years … so far I’ve resisted the urge. It’s *very* difficult ….arhhh…. Bob Jim Robbins N1JR ___ 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. -- Sent from my Motorola Droid Razr HD 4G LTE wireless tracker while I do other things. ___ 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] Any reason not to use one power amplifierand splitter for distribution amplifier?
Hi Ok, so what does the math look like with no injection locking: If you have two equal tones, obviously you have a hard time figuring out which one is the correct 10 MHz. That’s not going to be the situation with a distribution amp. If you have a threat signal that’s 60 db down from the 10 MHz “carrier” that’s a single sideband signal. Run it through a limiter and you get a phase modulated / frequency modulated signal. Frequency modulating your standard line is probably not a good idea. How much FM do you get from a signal X db down? 1) It’s a function of how far off the signal is 2) It’s a function of the level of the signal. 3) It’s a function of the limiter If you have an objective of 1x10^-11 at 1 second, what’s that come out to? Phase sidebands 86 db down at 1 Hz off will put you at 9.6 ppt against your 10 ppt budget. Bob On Jan 4, 2015, at 11:58 PM, Bill Hawkins b...@iaxs.net wrote: Thanks, Bruce. That does clear it up, although pulling an oscillator through a FET gate to a 50 ohm cable seems a stretch. If things are not that simple, e.g., a wiring harness to a front panel selector switch, then maybe. I'm assuming the source oscillator is well buffered against the world outside the oven can. I should have said 10base2, not T, meaning coaxial cable with BNC connectors and T connectors at the receivers, terminated at the far end. The allusion to audiophiles had to do with people who pay hundreds of dollars for a line (mains) cord that has special properties to make the sound from their amplifier somehow more pleasant. They do this because marketing told them so, ignoring what goes on in the house wiring to the wall outlet. There are people who need to handle time distribution very carefully (lest they get FTL neutrinos), but most of the list seems to buy their equipment from eBay. Bill Hawkins -Original Message- From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Bruce Griffiths Sent: Sunday, January 04, 2015 3:39 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Any reason not to use one power amplifierand splitter for distribution amplifier? Almost all frequency counters have an internal source which is a potential means of injection locking an external reference if the isolation between the internal source and the external source is inadequate. High impedance taps on a single terminated line ensure that the isolation between such internal sources and the shared line is limited by the isolation afforded by the internal source selection gating/switching of each device.adding or removing a tap invariably changes the phase shift between the source and each of the other receivers.The minimum isolation required can be estimated from the maximum acceptable frequency shift, the resonator Q and internal reverse isolation between the source output and the resonator Q. Frequency distribution systems like the Spectracom 8140 with wide range ADC tend to degrade the source phase noise significantly with respect to non agc distribution systems. Bruce On Sunday, 4 January 2015 9:41 PM, Bill Hawkins b...@iaxs.net wrote: Friends in Time, There's been a large amount of discussion about distribution amps on this list. People may be using them just because that's what's done. So I ask you: What are we trying to isolate? The destination devices do not generate an interfering signal, n'est ce pas? The receiving devices do not need to have 50 ohms input impedance if the source cable is properly terminated, no? If I use high impedance receivers tapped off a terminated line, how is this different from 10 base T? Yes, there will be cable delay between receivers, but how were you going to avoid that with your distribution amp? Put another way, why do counters like the Racal 1992 allow you to choose 50 ohm or high impedance at the input? Please, no take it on faith audiophile answers. HNY. Bill Hawkins ___ 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] Lucent KS-24361 / Z3810A : problem with Z3812A/REF 0 unit power up?
Hi On Jan 4, 2015, at 6:51 PM, Gerhard Hoffmann dk...@arcor.de wrote: Am 04.01.2015 um 23:42 schrieb Stan: I just received my Lucent KS-24361 and set it up on my bench to power it up. I connected the Z3809A interconnect cable between the two units (Z3811A/REF 1, and Z3812A/REF 0) and applied +24VDC to the appropriate pins on the two DE-9 connectors. The Z3811A/REF 1 ran through a sequential test of the four LEDS and then after a few seconds it settled in with the amber NO GPS and the red FAULT LEDs illuminated. Meanwhile, the Z3812A/REF 0 unit never lit a single LED and is still sitting there with all LEDs dark. The LED’s on *both* units should go through a “dance” at power on. The cycle of LED’s lighting up during boot is similar on both units. The process on the slave unit (REF0) appears to be controlled by the REF1 unit. Since the signaling between the two is very simple, a lost connection on the cable could cause this sort of thing. LED’s out *after* boot is normal until the GPS locks up to location on the REF1 and then starts sending data to the REF0. Bob Both units are drawing current: the Z3811A/REF 1 draws about 700 mA steady state, and the Z3812A/REF 0 draws only slightly less: 600 mA steady state. So far, I've swapped power connectors between the units and saw no difference, and I tried to power up the Z3812A/REF0 alone, but still no joy. Am I missing something about the setup, or do I have a defective Z3812/REF 0 unit? That's normal. The pair goes ON only when it sees GPS for quite some time. BTW the POWER consumption is fixed. If you have more voltage, the current will drop. regards, Gerhard ___ 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] June 30 2015 leap second
Just announced: there will be a positive leap second at the end of June 30 2015 UTC (that's Wednesday July 1st for most of the world). As usual we time nuts will have a leap second party -- where we capture and share the magic hh:59:60 display on as many different clocks and instruments as possible. /tvb More info: ftp://hpiers.obspm.fr/iers/bul/bulc/bulletinc.dat http://hpiers.obspm.fr/eop-pc/ And for those of you who want to know how long each day really is: ftp://hpiers.obspm.fr/iers/bul/bulb_new/bulletinb.dat ___ 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] schematics of frequency counter
Hi
I've confirmed that it's 198ns between start and stop with my racal dana
1992. I've spent days to learn how to compensate this 2ns in Quartus.
However, it's not something easy for me to do. I will ask some
hardware colleague for help.
Two days ago, I assembled my 2 mv89a to PCB ,put them into 2 metal
boxes. The test time is longer than before since it's in the holiday. These
data confused me more. I got bigger frequency difference if sig=ref.
Things are getting more and more compilcated. :(
raw data: http://www.qsl.net/bi7lnq/freqcntv4/test/20150105/0105.zip
Thanks
2014-12-29 4:35 GMT+08:00 Bob Camp kb...@n1k.org:
Hi
On Dec 28, 2014, at 9:19 AM, Li Ang lll...@gmail.com wrote:
Hi Bob,
I did some test according to your suggestions. DUT is a symmetricom x72
rb oscillator. Also, I've tried signal generator as the DUT. RS SMY01 is
not as good as HP8662A but that the best I've got. The signal geneator is
also using FE5650 as ref clock.
According to my test with the TDC today, this unit is not producing
very
stable data.
I don't have accurate pulse generator, so this is how I test the TDC:
0) power the board with battery.
1) use FPGA to generate time pulse:
reg [15:0] shift;
always @(posedge refclk10M) begin
shift = {shift[14:0], sw_gate};
end
assign tdc_start = shift[3];
assign tdc_stop1 = shift[5];
2) use MCU to pull down sw_gate, the FPGA sync it to refclk10M domain and
generate input signal for TDC.
3) use TDC to test the time betwen tdc_start and tdc_stop1
The result is in tdc_test.zip. number * 100ns = time between tdc_start
and
tdc_stop1. (TDC highspeed clock is refclk10M/2).
There 2 issues from the test:
1) As we can see from the data, the number is around 1.98x not 2.00x. So
there is about 2ns delay between tdc_start and tdc_stop1 for this simple
test code. If it is from the PCB trace and something inside FPGA, this
part
should be a constant value at certain temperature.
So far all correct. If you are using Quartus, you can fire up the timing
analyzer and take a look at what it guesses for timing / delay on the
pulse. It is not a perfect number, but I’d bet it will confirm that the 2
ns does come from the FPGA.
I can calculate it by
measuring 2 cycles and 3 cylces. My current code has not implement this
part, it should provide some improvement. 2ns time error for 1s gate,
that
is something.
The delay probably is from the input / output fabric on the FPGA ( =
output driver). The test you propose should demonstrate this.
2) For a 90ps TDC, I think the result should be something like +-0.001
cycle. But I get something like +-0.003 cycle. I do not know the reason
for
now.
Two reasonable *guesses* would be crosstalk and noise.
1) If there are any other clocks running around during this test, I’d see
if they can be shut down. Things like an free running OCXO are good for
this - they are easy to isolate.
2) Noise could be internal to the TDC. If it’s 90 ns at one sigma, then
you will indeed see +’/- 3 X that (or more) depending on how long you watch
it. At least by my math the one sigma on the data is 149 ps. That’s a bit
over 90 ps, but not terribly far.
Delaying the signals relative to each other (clock and output) as Magnus
suggests in another post is probably a real good idea for sorting some of
this out.
Bob
2014-12-27 22:58 GMT+08:00 Bob Camp kb...@n1k.org:
Hi
(In reply to several posts. It’s easier for me this way)
Ok, that’s good news !!! (and useful data)
Your counter performance degraded a bit when you put in 5 db and not
much
when you put in 8 db.
It’s also maybe *too* good news. I suspect that cross talk between the
channels may be impacting your results.
Next step is to try it with two independent sources and a bit more
attenuation. When you try it with two sources, you need to attenuate
first
one source and then switch the attenuators to the other source. That
will
help you see if crosstalk from one channel is more of a problem than
from
the other channel.
One parts hint:
Cable TV attenuators are much cheaper than their fancy 50 ohm
MIniCircuits
cousins. They are also something you can pick up down at the corner
electronics store. For this sort of testing they are perfectly fine to
use.
At this point in the testing the mismatch between 75 ohms and 50 ohms is
not a big deal. You will need to adapt connectors, but you probably
still
will save money.
===
Op-amps that have enough bandwidth and performance for a high input
impedance counter input are rare items. They also are not cheap. Often
they
come as some sort of current feedback part with low(er) input
impedance. If
you want your counter to work to 300 MHz, it should accept a 300 MHz
square
wave. That might mean passing the third or even the fifth harmonic of
the
square wave. An input channel with 900 or 1500 MHz
Re: [time-nuts] HP 58503A Com 4 conflict
Thanks Bob, Didier and Rex for the consult on the Com 4 Conflict and the teaching. Update: First, sorry for not posting adequate information in my question to start with. The result of some emails was a clarification that it was not the 58503A which was causing the issue with the Com ports, but SatStat which only allowed Com 1-4 (a very old program). I was able to switch to using GPSCon instead of SatStat and it provided many unused Com port choices. So, the 58503A and my ThinkPad are both happy campers. Jim Robbins N1JR ___ 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] schematics of frequency counter
Hi Bob,
There are 2 oscillator on board, one 8MHz for MCU one 125MHz for FPGA.
I've took it down from the board, and changed MCU to use internal RC
oscillator for MCU and PLL to mutilply refclk to 200MHz for FPGA.
I will try do the same test tonight thanks.
2014-12-29 4:35 GMT+08:00 Bob Camp kb...@n1k.org:
Hi
On Dec 28, 2014, at 9:19 AM, Li Ang lll...@gmail.com wrote:
Hi Bob,
I did some test according to your suggestions. DUT is a symmetricom x72
rb oscillator. Also, I've tried signal generator as the DUT. RS SMY01 is
not as good as HP8662A but that the best I've got. The signal geneator is
also using FE5650 as ref clock.
According to my test with the TDC today, this unit is not producing
very
stable data.
I don't have accurate pulse generator, so this is how I test the TDC:
0) power the board with battery.
1) use FPGA to generate time pulse:
reg [15:0] shift;
always @(posedge refclk10M) begin
shift = {shift[14:0], sw_gate};
end
assign tdc_start = shift[3];
assign tdc_stop1 = shift[5];
2) use MCU to pull down sw_gate, the FPGA sync it to refclk10M domain and
generate input signal for TDC.
3) use TDC to test the time betwen tdc_start and tdc_stop1
The result is in tdc_test.zip. number * 100ns = time between tdc_start
and
tdc_stop1. (TDC highspeed clock is refclk10M/2).
There 2 issues from the test:
1) As we can see from the data, the number is around 1.98x not 2.00x. So
there is about 2ns delay between tdc_start and tdc_stop1 for this simple
test code. If it is from the PCB trace and something inside FPGA, this
part
should be a constant value at certain temperature.
So far all correct. If you are using Quartus, you can fire up the timing
analyzer and take a look at what it guesses for timing / delay on the
pulse. It is not a perfect number, but I’d bet it will confirm that the 2
ns does come from the FPGA.
I can calculate it by
measuring 2 cycles and 3 cylces. My current code has not implement this
part, it should provide some improvement. 2ns time error for 1s gate,
that
is something.
The delay probably is from the input / output fabric on the FPGA ( =
output driver). The test you propose should demonstrate this.
2) For a 90ps TDC, I think the result should be something like +-0.001
cycle. But I get something like +-0.003 cycle. I do not know the reason
for
now.
Two reasonable *guesses* would be crosstalk and noise.
1) If there are any other clocks running around during this test, I’d see
if they can be shut down. Things like an free running OCXO are good for
this - they are easy to isolate.
2) Noise could be internal to the TDC. If it’s 90 ns at one sigma, then
you will indeed see +’/- 3 X that (or more) depending on how long you watch
it. At least by my math the one sigma on the data is 149 ps. That’s a bit
over 90 ps, but not terribly far.
Delaying the signals relative to each other (clock and output) as Magnus
suggests in another post is probably a real good idea for sorting some of
this out.
Bob
2014-12-27 22:58 GMT+08:00 Bob Camp kb...@n1k.org:
Hi
(In reply to several posts. It’s easier for me this way)
Ok, that’s good news !!! (and useful data)
Your counter performance degraded a bit when you put in 5 db and not
much
when you put in 8 db.
It’s also maybe *too* good news. I suspect that cross talk between the
channels may be impacting your results.
Next step is to try it with two independent sources and a bit more
attenuation. When you try it with two sources, you need to attenuate
first
one source and then switch the attenuators to the other source. That
will
help you see if crosstalk from one channel is more of a problem than
from
the other channel.
One parts hint:
Cable TV attenuators are much cheaper than their fancy 50 ohm
MIniCircuits
cousins. They are also something you can pick up down at the corner
electronics store. For this sort of testing they are perfectly fine to
use.
At this point in the testing the mismatch between 75 ohms and 50 ohms is
not a big deal. You will need to adapt connectors, but you probably
still
will save money.
===
Op-amps that have enough bandwidth and performance for a high input
impedance counter input are rare items. They also are not cheap. Often
they
come as some sort of current feedback part with low(er) input
impedance. If
you want your counter to work to 300 MHz, it should accept a 300 MHz
square
wave. That might mean passing the third or even the fifth harmonic of
the
square wave. An input channel with 900 or 1500 MHz bandwidth is quite a
challenge.
One very simple solution is to just grab a high speed comparator like
the
one used by Fluke / Pendulum (ADCMP565). Drive it directly with your
input
or clock. Make it your front end device. That’s not an ideal solution,
but
it will give you the bandwidth and a reasonable
[time-nuts] Any reason not to use one power amplifier and splitter for distribution amplifier?...
I assume you're talking about splitting the 10 MHz signal from a reference source. I used to use a video amp but it developed problems after about 30 years of use. I started looking at other video amps and along the way I started to use a passive TV type 6-way splitter, the type in a solid metal case with F-Connectors. This has actually worked quite well and my various counters as well as my HP-3586B and HP-3336A are happy with the levels. At the moment I don't recall the output level of my DATUM 9390-52054 receivers, but it's quite healthy and when I was using a Video DA I had to put a 10 dB pad on the input to keep from frying the innards. A passive splitter may not be the best way to distribute my House Reference, but it works well, and really, that's all I want. I use a 6 spigot version of this: http://www.solidsignal.com/pview.asp?p=SKY23308ss=412546 Burt, K6OQK At 03:30 PM 1/5/2015, time-nuts-requ...@febo.com wrote Happy New Years All! I have seen a number of discussions on various approaches to distribution amps discussed on Time-Nuts ranging from DYI to products intended for Video. I thought I my weigh in with one point of interest; It seems like long term performance is pretty easy, but a low phase noise solution is quite a different story. Looking at the number of application specific products from MicroSemi/Symmetricom and other manufactures claimed and even more so real world specs vary a great deal so apparently it s not easy to just throw something together with great or even good close in phase noise. So depending on your labs direction in the future it may be worth researching and investing in an application specific distribution amp. I like the MicroSemi 4036B but there are a number of very good products out there on the surplus market selling for a small fraction of their original cost. Cheers; Thomas Knox From: bill.ric...@verizon.net To: time-nuts@febo.com Date: Sun, 4 Jan 2015 08:29:34 -0500 Subject: Re: [time-nuts] Any reason not to use one power amplifier andsplitter for distribution amplifier? A cheap and dirty equivalent of a pass thru terminator that I use is a BNC t connector with a 52 ohm bnc terminator. I guess you could use a CATV 75 ohm F type with an adapter. Maybe that combination would produce too much garbage. 73, Bill, WA2DVU Cape May Burt I. Weiner Associates Broadcast Technical Services Glendale, California U.S.A. b...@att.net www.biwa.cc K6OQK ___ 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] Any reason not to use one power amplifier and splitter for distribution amplifier?
Hi Any time you run into terms like “low noise” it pays to think about what that means to you and your system. A quick scan of the posts here over the years will show that different definitions of low noise do exist. The same is true of system requirements. An offset that matters to one may have no impact at all on another system. In some cases -155 dbc/Hz at 10KHz or 100 KHz is “low noise”. In other cases “low noise” is -180 dbc/Hz. In either case, *delivering* a clean signal without spurs and crud is far from simple. In many long cable run cases, the cost of fancy cables, high performance magnetics, and all the other “stuff” is more than the cost of simply locking up a quiet oscillator on the end of a “dirty” cable. I don’t think I’ve ever seen a setup that tries / needs to “distribute” -170 dbc/Hz signals over anything bigger than a rack. I’ve seen *lots* of systems that regenerate those sort of signals many times over (= in many different boxes) to get around distributing them. Bob On Jan 5, 2015, at 2:15 PM, Tom Knox act...@hotmail.com wrote: Happy New Years All! I have seen a number of discussions on various approaches to distribution amps discussed on Time-Nuts ranging from DYI to products intended for Video. I thought I my weigh in with one point of interest; It seems like long term performance is pretty easy, but a low phase noise solution is quite a different story. Looking at the number of application specific products from MicroSemi/Symmetricom and other manufactures claimed and even more so real world specs vary a great deal so apparently it s not easy to just throw something together with great or even good close in phase noise. So depending on your labs direction in the future it may be worth researching and investing in an application specific distribution amp. I like the MicroSemi 4036B but there are a number of very good products out there on the surplus market selling for a small fraction of their original cost. Cheers; Thomas Knox From: bill.ric...@verizon.net To: time-nuts@febo.com Date: Sun, 4 Jan 2015 08:29:34 -0500 Subject: Re: [time-nuts] Any reason not to use one power amplifier and splitter for distribution amplifier? A cheap and dirty equivalent of a pass thru terminator that I use is a BNC t connector with a 52 ohm bnc terminator. I guess you could use a CATV 75 ohm F type with an adapter. Maybe that combination would produce too much garbage. 73, Bill, WA2DVU Cape May --- This email has been checked for viruses by Avast antivirus software. http://www.avast.com ___ 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.
Re: [time-nuts] Any reason not to use one power amplifier and splitter for distribution amplifier?
Happy New Years All! I have seen a number of discussions on various approaches to distribution amps discussed on Time-Nuts ranging from DYI to products intended for Video. I thought I my weigh in with one point of interest; It seems like long term performance is pretty easy, but a low phase noise solution is quite a different story. Looking at the number of application specific products from MicroSemi/Symmetricom and other manufactures claimed and even more so real world specs vary a great deal so apparently it s not easy to just throw something together with great or even good close in phase noise. So depending on your labs direction in the future it may be worth researching and investing in an application specific distribution amp. I like the MicroSemi 4036B but there are a number of very good products out there on the surplus market selling for a small fraction of their original cost. Cheers; Thomas Knox From: bill.ric...@verizon.net To: time-nuts@febo.com Date: Sun, 4 Jan 2015 08:29:34 -0500 Subject: Re: [time-nuts] Any reason not to use one power amplifier and splitter for distribution amplifier? A cheap and dirty equivalent of a pass thru terminator that I use is a BNC t connector with a 52 ohm bnc terminator. I guess you could use a CATV 75 ohm F type with an adapter. Maybe that combination would produce too much garbage. 73, Bill, WA2DVU Cape May --- This email has been checked for viruses by Avast antivirus software. http://www.avast.com ___ 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] Fwd: Bulletin C number 49
Fellow time-nuts, We will have a leap-second this June. Cheers, Magnus Forwarded Message Subject: Bulletin C number 49 Date: Mon, 05 Jan 2015 14:25:49 +0100 From: IERS EOP Product Center services.i...@obspm.fr Reply-To: IERS EOP Product Center services.i...@obspm.fr To: bulc.i...@obspm.fr INTERNATIONAL EARTH ROTATION AND REFERENCE SYSTEMS SERVICE (IERS) SERVICE INTERNATIONAL DE LA ROTATION TERRESTRE ET DES SYSTEMES DE REFERENCE SERVICE DE LA ROTATION TERRESTRE DE L'IERS OBSERVATOIRE DE PARIS 61, Av. de l'Observatoire 75014 PARIS (France) Tel. : 33 (0) 1 40 51 22 26 FAX : 33 (0) 1 40 51 22 91 e-mail: services.i...@obspm.fr http://hpiers.obspm.fr/eop-pc Paris, 5 January 2015 Bulletin C 49 To authorities responsible for the measurement and distribution of time UTC TIME STEP on the 1st of July 2015 A positive leap second will be introduced at the end of June 2015. The sequence of dates of the UTC second markers will be: 2015 June 30, 23h 59m 59s 2015 June 30, 23h 59m 60s 2015 July 1, 0h 0m 0s The difference between UTC and the International Atomic Time TAI is: from 2012 July 1,0h UTC, to 2015 July 1 0h UTC : UTC-TAI = - 35s from 2015 July 1,0h UTC, until further notice: UTC-TAI = - 36s Leap seconds can be introduced in UTC at the end of the months of December or June, depending on the evolution of UT1-TAI. Bulletin C is mailed every six months, either to announce a time step in UTC or to confirm that there will be no time step at the next possible date. Daniel Gambis Head Earth Orientation Center of IERS Observatoire de Paris, France ___ 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] Any reason not to use one power amplifier and splitter for distribution amplifier?
A cheap and dirty equivalent of a pass thru terminator that I use is a BNC t connector with a 52 ohm bnc terminator. I guess you could use a CATV 75 ohm F type with an adapter. Maybe that combination would produce too much garbage. 73, Bill, WA2DVU Cape May --- This email has been checked for viruses by Avast antivirus software. http://www.avast.com ___ 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] HP 58503A Com 4 conflict
You left out a lot of details, like what OS your PC is running, Assuming it is Windows XP or greater, you may be able to juggle the assigned com port. If you are using a USB/serial adapter, be sure it is plugged in so it shows on the devices list. You need to open Device Manager. One way is Start/settings/Control Panel. If it is Win 7+ Device Manager should be in the list. If XP, select System, the Hardware tab at the top, then the Device Manager button. -- I don't have a Win 8 machine; I assume it is the same as Win 7. Find your serial device under 'Ports (Com LPT)'. If you are not sure which one and it is a USB adapter, you can unplug it and see which one goes away. Double-click on the one you want to change. In the window that opens, select the Port Settings tab at the top. You'll get a window with the baud rate, etc. Select the Advanced button. Then in the lower left of the window is the assigned Com Port. Click the pull-down triangle button and you'll get a list where you can select a different Com Port number. If all the ones you want are flagged with (In use), you may have to back out and try to find a listing for the device that is using a low Com port and select it to change its number higher to free the one you want to use. I'm not sure what happens if you try to change to a port that is (In use). Maybe it tries to work it out for you. I haven't tried it. I'd suggest Com 4 or Com 2 as your best choices. So I don't have an exact answer. It depends on what is using the lower numbers now, Hopefully you can rearrange them using this method to find something that works. On 1/4/2015 7:50 AM, James Robbins wrote: My new old HP58503A wants to connect to my PC on Com 1-4. Other PC devices are already using those 4 Com ports. Is there any way to connect it to a Com port other than one of those 1 to 4? I currently use an Edgeport USB-to-Serial Converter which works very well to communicate with the PC and to assign Com ports to my various GPS units. But, as far as I know, the chosen Edgeport Com port must fall within the range of Com ports which for which the device is designed. If this has been answered, please point me to the discussion. Many thanks. And, Happy New Year to all, with wishes for a more peaceful (and timely - couldn't resist) year. Jim Robbins N1JR ___ 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] Symmetricom/Datum cesium tube interchangeability
Does anyone know if a Symmetricom/Datum cesium tube model 7613a/077 will plug and play in a 4065 clock? Or if not plug and play if they can be used in the 4065 at all. I have a couple 4065's with tired tubes and a fairly fresh 7613A. Thanks; Thomas Knox ___ 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] If your 5335A is acting goofy or dead...
Update. I replaced the relay socket anyway with a 27E213 from Digi-Key. It fits perfectly. The socket I removed was a 27E129. It would seem that the 27E129 should have a ground strap. The one I removed doesn't. Otherwise, the 27E213 should be identical. The Digi-Key part number is PB806-ND. Although the bad contact with the socket caused enough heat to discolor the base of the relay, I don't think the relay was harmed. I also did the extra wiring from the service note to add a second set of contacts in parallel for the 5V supply. Hopefully this problem is fixed for the next decade or two. Orin. On Sat, Dec 27, 2014 at 9:06 PM, Orin Eman orin.e...@gmail.com wrote: While evaluating my LTE Lite and testing my buffer board, my 5335A started acting goofy - random hangs/crashes etc.. This morning, the fan came on, but no display. To make a long story short, the problem was exactly as described in Service Note 5335A-26B. I found evidence of overheating on the power supply relay. The 5V (and 3V) supply was down. During investigating the fault, I disturbed the power supply relay and reseated it. The instrument worked again. Further investigation revealed a cold looking solder joint on the relay socket and spread contacts on the relay socket. About 1V was dropped across the relay socket and the relay itself. I resoldered the socket and 'persuaded' the contact with a small screwdriver. All now seems to be back to normal. FWIW, do not believe the part number on the relay. It is really a 6PST NO beastie for which I have not yet found a replacement. The above mentioned service note adds a second pair of contacts for the 5V supply after replacing the 120V fan with a 24V fan fed from the power switch. This uses the relay contacts that used to be used to drive the 120V fan. Ideally, you replace the relay and its socket as well, but good luck finding the relay. My unit has the 24V fan, but I have yet to do the rewiring for the second pair of contacts, so I suspect the fix might not last. Still, it's 22 years since the date on the service note, so I might have a few years. So, if your 5335A fan comes on, but no display, check the 5V supply first and if it's down, suspect the power supply relay/socket. Orin. ___ 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.
