[time-nuts] Arduino Uno and Pro Mini use ceramic resonators not crystals
A warning to any time nut considering the Arduino Uno, Pro Mini, and maybe the Nano, is that they use poor accuracy ceramic resonators rather than crystals. On the Uno and maybe Nano, you can connect a wire from the USB/serial chip, which has a crystal, to the clock input of the ATmega328, but it is said that the reason they didn't do that on the official boards is that the 16MHz square wave broadcast too much noise to get FCC certification. Something similar to the Arduino Micro can be had on Ebay for $5.30 shipped (ebay#181286407447). Like the Leonardo it dispenses with the USB to serial chip and uses the ATmega32U4 with USB built in, for its CPU. Because ceramic resonators aren't good enough for USB, it is forced to use a crystal. Unfortunately the cheap one on Ebay uses a pinout different than the official Arduino Micro. Even the official LED blink example code doesn't work without modifying the source to change pin numbers. It seems to use the circuit and pinout of the Spark Fun Pro Micro board. There is an interesting possibility with the Micro and Leonardo for those of us that don't have computers with good fast serial ports, and are forced to use USB to serial converters. With USB there is an unpredictable delay of a millisecond or two waiting for permission to transmit a PPS notification to the host computer. I think the ATmega32U4 has an interrupt upon completion of sending a USB packet to the host. Thus perhaps the delay waiting to send could be measured and the error reported to the host as an extra custom NMEA string or something. This would only work if there was no slow USB hub, either built in or external, intervening between the Arduino and the host, to add another random couple milliseconds delay. ___ 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] TIC model
Another variation is to use a single 125 style buffer device (eg 74LVC1G125) to charge and discharge a capacitor (in reality an RC network when the ADC input is taken into account) via a series resistor. The input to the buffer is driven by the input to a conventional synchroniser whilst the buffer output enable is driven by the synchroniser output. The buffer output being enabled whilst the synchroniser output is low (for a 0-> 1 PPS input transition) and disabled whenever the synchroniser output is high. This ensures that the capacitor network is discharged to zero between PPS events without requiring an additional device (or a resistor) to discharge the RC network. The capcitor reset level sensitivity to leakage currents is greatly reduced over that when a 1M discharge resistor is used. The nonlinearity can be calibrated by using a statistical fill the buckets technique. This requires a relatively noisy test signal generator (RC oscillator??) to drive the synchroniser input. However its essential to ensure that this oscillator isnt injection locked to the synchroniser clock. Bruce Lars Walenius wrote: Hi Bruce You are absolute right that it is wise to put some time in the estimation of such effects as asynchronous Clocks. An iteration between thinking and building seems always to be necessary but we all have different capabilities for that. For the Arduino I came to an end with the interrupts as I am not good at uP´s. The Arduino GPSDO has two interrupts. One is synchronous with the 10MHz and comes from timer1 overflows. The other is synchronous with the 1PPS. So it is three asynchronous clocks right now in the GPSDO controller. As I understand my problem it is that an interrupt takes some time to execute and if you get the two interrupts to close you will have a problem with timing as you can´t execute both at the same time? Of course the easy solution could be to have the needed resoulution higher than the time it takes to execute the interrupts but in the GPSDO I want a resolution of 200ns (5MHz Clock) and the shortest interrupt is 3us. I would be glad if somebody (Chris?) could have a look in the Aduino GPSDO code to see if it possible to get rid of the uncertainty due to the interrupts from the timer1 overflow. Another question: Does a PIC not need overflow interrupts to count say 500 counts as I do in the Arduino? Lars From: Bruce Griffiths Sent: söndag den 16 februari 2014 20:14 To: time-nuts@febo.com The response time to an external asynchronous interrupt is never deterministic. The external interrupt has to be synchronous with the uP clock to avoid the non deterministic synchronisation delay. Even when the external event is synchronous with the clock input to the uP and the uP uses a divider to produce its internal clock then there is the issue of divider phase shift. This phase shift can lead to sampling the waveform before the peak across the sampling cap. This is far from ideal, its better to sample at or slightly after the peak when the sensitivity to timing variations is far smaller. To complicate the issue further the time of occurrence of the peak is temperature dependent and the sampling switch on resistance is nonlinear so that peak delay varies with temperature and input signal amplitude. Its generally quicker and cheaper to estimate the magnitude of such effects and make appropriate choices than just build a sequence of breadboards each of which then needs to be extensively characterised. Bruce Chris Albertson wrote: You all are "inventing problem". Solve them AFTER you find a problem you can measure. Interrupts are not an issue on a UP like the AVR because they are completely deterministic. It don't matter the lenth of time as long as it is 100% deterministic and predictable. On a multi-tasking OS running on a super scaler CPU you have unknowable latentcy but this is not the problem on a chip that does one machine cycle per clock cycle. On Sat, Feb 15, 2014 at 6:50 PM, Brian Lloyd wrote: On Sat, Feb 15, 2014 at 7:10 PM, Tom Van Baak wrote: For Arduino and other less fortunate uC you can always use external chips to obtain optimal and jitter-free charge/discharge timing. I'm not that familiar with Atmel chips; could capture/compare be used instead of interrupts somehow? One should investigate the Propeller. -- Brian Lloyd, WB6RQN/J79BPL 706 Flightline Drive Spring Branch, TX 78070 br...@lloyd.com +1.916.877.5067 ___ 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] FE-5680A sweep range setting
Hello everyone, I have a 5680 which is failing to lock. My DDS frequency is 8388608Hz, but it's sweeping between about 8388638 and 8388740. My unit has 3 levels of PCBs in the DDS/VCO corner and there is no trimcap labeled C217. Does anyone know how to adjust the sweep center frequency on this type of 'triple decker' unit? Thanks, =Simon= ___ 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] Full Moon Curse
Hi Tom: Just watched the hour video talk. It's a must see for any time nut. He goes into all sorts of things including General Relativity. He's a great speaker. He also found the Soviet rover that was missing since the 1970s because the sensitivity of their setup is about 70 times better than any previous lunar ranging system. It includes a gravity meter that phenomenal. They use a 100 nS gate on the photo detector and must change it for every return pulse to account for all sorts of things including the moon to telescope distance, the tectonic plate height which is a function of Solar and Lunar tides, local gravity (the position of the dome changes that), barometric pressure pushes down on the bed rock, etc. It's on the UCSD page I linked before and also on YouTube: http://www.youtube.com/watch?v=nLCqBSdheB8#t=3505 Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Tom Van Baak (lab) wrote: Thanks Brooke, nice link. I've always enjoyed the work that Murphy does. The technical article is here: http://arxiv.org/pdf/1309.6274.pdf Years ago I got to see a laser ranging telescope at a NASA site. Talk about green flash. Truly amazing. I remember at the heart of it was... a 5370 counter! /tvb (i5s) On Feb 17, 2014, at 11:30 AM, Brooke Clarke wrote: Hi: This has a high Time Nuts content. When the moon was full they could not make ranging measurements to the moon, but could any other time. http://ucsdnews.ucsd.edu/feature/source_of_moon_curse_revealed_by_eclipse -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html ___ 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] strange behavior of 53230A or is the light on, but nobody in?
Hi I have a 53230, but have not gotten around to looking at it’s PLL cleanup process. Bob On Feb 17, 2014, at 2:38 PM, Tom Van Baak (lab) wrote: > Bob, > > I'm wondering if you (or any else) has measured the PLL performance of the > 53230-series? > > I agree it will "clean up the crud" but this assumes the ext ref is dirtier > than the internal osc. > > What I found instead was that if you use a good external ref the PLL actually > makes it worse. This was very disappointing. The XO version of the counter > performed worse than the OCXO version even with a maser as the ext reference. > Did your reading of the schematic show a way to directly use the ext ref, > bypassing the noisy PLL? > > The other thing I found was that the ref out signal was a very polluted copy > of the ref in. > > /tvb (i5s) > >> On Feb 17, 2014, at 7:04 AM, Bob Camp wrote: >> >> Hi >> >> If you dig into the schematics (when they supplied them … ): >> >> The external reference goes into a phase detector. It’s one of those digital >> ones that can lock up to many inputs. You could feed 3. MHz in as a >> standard input as well as 0.5, 1, 2.5, 5, and 10 MHz. The internal >> oscillator (or an internal oscillator) is phase locked to the external input >> through a fairly narrow analog loop. The idea is to clean up the crud on the >> standard line. >> >> With no external reference, the PLL drops out and you go back to what ever >> the local reference is. >> >> Yes there’s a little more to it than that and no the circuit is not exactly >> the same on every counter HP ever made. >> >> Bob >> >>> On Feb 17, 2014, at 7:55 AM, wb6bnq wrote: >>> >>> Hi Mike, >>> >>> The most likely answer is when you select external time base for an input, >>> it disables the connection for the internal oscillator. The external input >>> signal is probably also routed straight to the reference output jack. >>> >>> However, it would be good to read the manual, as they usually cover how >>> those connections work. Otherwise, perhaps someone that owns one could >>> provide further insight. >>> >>> BillWB6BNQ >>> >>> mike cook wrote: >>> Something that must be simple to explain, but that I can't get my head round. I got a new 53230A. When first using it, I measured my T-Bolt 10MHz using the internal 10MHz timebase and it came up short of 10MHz, 9.999 998 5xx. I wasn't worried about it as the counter only has a TCXO internal oscillator. So I fired up my PRS10 and after leaving that on for some time, connected it to Ext Ref. , changed to the ext time base and measured again. This time 10.000.000.00x. Then I switched the two references, measuring the PRS10 against the T-Bolt. Again I got 10MHz down to the 11th digit. All that looked good so I have been using it with either the PRS10 locked to GPS, or the T-Bolt as the external time base. After leaving it on (but not inactive) for a month, I did an Autocal. No problem. I was wondering if that would have changed the internal time base frequency, but no, using that still gave similar figures to the above. So at that point I decided to measure the Internal TB against my reference. So I connected the Int. Ref. Out to channel 1, connected my PRS10 ref to Ext. Ref In, selected the EXT time base and found that the count was 10MHz dead on? I don't get that at all. in summary: DUT against internal TB counts < 10MHz.To me that means that the internal timebase is a bit fast. Is that assumption correct? DUT against Ext.Ref counts 10MHz Internal TB against Ext.Ref counts 10MHz. If my assumption above is correct, the count should be greater than 10MHz, no? Can anyone shed any light on that? ___ 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/
Re: [time-nuts] Full Moon Curse
Thanks Brooke, nice link. I've always enjoyed the work that Murphy does. The technical article is here: http://arxiv.org/pdf/1309.6274.pdf Years ago I got to see a laser ranging telescope at a NASA site. Talk about green flash. Truly amazing. I remember at the heart of it was... a 5370 counter! /tvb (i5s) > On Feb 17, 2014, at 11:30 AM, Brooke Clarke wrote: > > Hi: > > This has a high Time Nuts content. > When the moon was full they could not make ranging measurements to the moon, > but could any other time. > http://ucsdnews.ucsd.edu/feature/source_of_moon_curse_revealed_by_eclipse > > -- > Have Fun, > > Brooke Clarke > http://www.PRC68.com > http://www.end2partygovernment.com/2012Issues.html > > ___ > 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] Full Moon Curse
Hi: This has a high Time Nuts content. When the moon was full they could not make ranging measurements to the moon, but could any other time. http://ucsdnews.ucsd.edu/feature/source_of_moon_curse_revealed_by_eclipse -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html ___ 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] strange behavior of 53230A or is the light on, but nobody in?
Bob, I'm wondering if you (or any else) has measured the PLL performance of the 53230-series? I agree it will "clean up the crud" but this assumes the ext ref is dirtier than the internal osc. What I found instead was that if you use a good external ref the PLL actually makes it worse. This was very disappointing. The XO version of the counter performed worse than the OCXO version even with a maser as the ext reference. Did your reading of the schematic show a way to directly use the ext ref, bypassing the noisy PLL? The other thing I found was that the ref out signal was a very polluted copy of the ref in. /tvb (i5s) > On Feb 17, 2014, at 7:04 AM, Bob Camp wrote: > > Hi > > If you dig into the schematics (when they supplied them … ): > > The external reference goes into a phase detector. It’s one of those digital > ones that can lock up to many inputs. You could feed 3. MHz in as a > standard input as well as 0.5, 1, 2.5, 5, and 10 MHz. The internal oscillator > (or an internal oscillator) is phase locked to the external input through a > fairly narrow analog loop. The idea is to clean up the crud on the standard > line. > > With no external reference, the PLL drops out and you go back to what ever > the local reference is. > > Yes there’s a little more to it than that and no the circuit is not exactly > the same on every counter HP ever made. > > Bob > >> On Feb 17, 2014, at 7:55 AM, wb6bnq wrote: >> >> Hi Mike, >> >> The most likely answer is when you select external time base for an input, >> it disables the connection for the internal oscillator. The external input >> signal is probably also routed straight to the reference output jack. >> >> However, it would be good to read the manual, as they usually cover how >> those connections work. Otherwise, perhaps someone that owns one could >> provide further insight. >> >> BillWB6BNQ >> >> mike cook wrote: >> >>> Something that must be simple to explain, but that I can't get my head >>> round. >>> >>> I got a new 53230A. >>> When first using it, I measured my T-Bolt 10MHz using the internal 10MHz >>> timebase and it came up short of 10MHz, 9.999 998 5xx. I wasn't worried >>> about it as the counter only has a TCXO internal oscillator. So I fired up >>> my PRS10 and after leaving that on for some time, connected it to Ext Ref. >>> , changed to the ext time base and measured again. This time >>> 10.000.000.00x. Then I switched the two references, measuring the PRS10 >>> against the T-Bolt. Again I got 10MHz down to the 11th digit. >>> All that looked good so I have been using it with either the PRS10 locked >>> to GPS, or the T-Bolt as the external time base. >>> >>> After leaving it on (but not inactive) for a month, I did an Autocal. No >>> problem. >>> I was wondering if that would have changed the internal time base >>> frequency, but no, using that still gave similar figures to the above. >>> >>> So at that point I decided to measure the Internal TB against my reference. >>> So I connected the Int. Ref. Out to channel 1, connected my PRS10 ref to >>> Ext. Ref In, selected the EXT time base and found that the count was 10MHz >>> dead on? I don't get that at all. >>> >>> in summary: >>> DUT against internal TB counts < 10MHz.To me that means that the >>> internal timebase is a bit fast. Is that assumption correct? >>> DUT against Ext.Ref counts 10MHz >>> Internal TB against Ext.Ref counts 10MHz. If my assumption above is >>> correct, the count should be greater than 10MHz, no? >>> >>> Can anyone shed any light on that? >>> >>> >>> >>> >>> >>> >>> >>> >>> >>> >>> ___ >>> 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.
Re: [time-nuts] strange behavior of 53230A or is the light on, but nobody in?
Hi If you dig into the schematics (when they supplied them … ): The external reference goes into a phase detector. It’s one of those digital ones that can lock up to many inputs. You could feed 3. MHz in as a standard input as well as 0.5, 1, 2.5, 5, and 10 MHz. The internal oscillator (or an internal oscillator) is phase locked to the external input through a fairly narrow analog loop. The idea is to clean up the crud on the standard line. With no external reference, the PLL drops out and you go back to what ever the local reference is. Yes there’s a little more to it than that and no the circuit is not exactly the same on every counter HP ever made. Bob On Feb 17, 2014, at 7:55 AM, wb6bnq wrote: > Hi Mike, > > The most likely answer is when you select external time base for an input, it > disables the connection for the internal oscillator. The external input > signal is probably also routed straight to the reference output jack. > > However, it would be good to read the manual, as they usually cover how those > connections work. Otherwise, perhaps someone that owns one could provide > further insight. > > BillWB6BNQ > > mike cook wrote: > >> Something that must be simple to explain, but that I can't get my head round. >> >> I got a new 53230A. >> When first using it, I measured my T-Bolt 10MHz using the internal 10MHz >> timebase and it came up short of 10MHz, 9.999 998 5xx. I wasn't worried >> about it as the counter only has a TCXO internal oscillator. So I fired up >> my PRS10 and after leaving that on for some time, connected it to Ext Ref. >> , changed to the ext time base and measured again. This time 10.000.000.00x. >> Then I switched the two references, measuring the PRS10 against the T-Bolt. >> Again I got 10MHz down to the 11th digit. >> All that looked good so I have been using it with either the PRS10 locked to >> GPS, or the T-Bolt as the external time base. >> >> After leaving it on (but not inactive) for a month, I did an Autocal. No >> problem. >> I was wondering if that would have changed the internal time base frequency, >> but no, using that still gave similar figures to the above. >> >> So at that point I decided to measure the Internal TB against my reference. >> So I connected the Int. Ref. Out to channel 1, connected my PRS10 ref to >> Ext. Ref In, selected the EXT time base and found that the count was 10MHz >> dead on? I don't get that at all. >> >> in summary: >> DUT against internal TB counts < 10MHz.To me that means that the >> internal timebase is a bit fast. Is that assumption correct? >> DUT against Ext.Ref counts 10MHz >> Internal TB against Ext.Ref counts 10MHz. If my assumption above is >> correct, the count should be greater than 10MHz, no? >> >> Can anyone shed any light on that? >> >> >> >> >> >> >> >> >> >> >> ___ >> 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] strange behavior of 53230A or is the light on, but nobody in?
Hi Mike, The most likely answer is when you select external time base for an input, it disables the connection for the internal oscillator. The external input signal is probably also routed straight to the reference output jack. However, it would be good to read the manual, as they usually cover how those connections work. Otherwise, perhaps someone that owns one could provide further insight. BillWB6BNQ mike cook wrote: Something that must be simple to explain, but that I can't get my head round. I got a new 53230A. When first using it, I measured my T-Bolt 10MHz using the internal 10MHz timebase and it came up short of 10MHz, 9.999 998 5xx. I wasn't worried about it as the counter only has a TCXO internal oscillator. So I fired up my PRS10 and after leaving that on for some time, connected it to Ext Ref. , changed to the ext time base and measured again. This time 10.000.000.00x. Then I switched the two references, measuring the PRS10 against the T-Bolt. Again I got 10MHz down to the 11th digit. All that looked good so I have been using it with either the PRS10 locked to GPS, or the T-Bolt as the external time base. After leaving it on (but not inactive) for a month, I did an Autocal. No problem. I was wondering if that would have changed the internal time base frequency, but no, using that still gave similar figures to the above. So at that point I decided to measure the Internal TB against my reference. So I connected the Int. Ref. Out to channel 1, connected my PRS10 ref to Ext. Ref In, selected the EXT time base and found that the count was 10MHz dead on? I don't get that at all. in summary: DUT against internal TB counts < 10MHz.To me that means that the internal timebase is a bit fast. Is that assumption correct? DUT against Ext.Ref counts 10MHz Internal TB against Ext.Ref counts 10MHz. If my assumption above is correct, the count should be greater than 10MHz, no? Can anyone shed any light on that? ___ 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] Good use for an HP 10811
It's alright - he just reciprocated :) - Mike Mike B. Feher, EOZ Inc. 89 Arnold Blvd. Howell, NJ, 07731 732-886-5960 office 908-902-3831 cell -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Brian Lloyd Sent: Monday, February 17, 2014 9:46 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Good use for an HP 10811 On Mon, Feb 17, 2014 at 8:31 AM, David J Taylor < david-tay...@blueyonder.co.uk> wrote: > @uhf_satcom just tweeted: > > "Finally, a signal from ESA Rosetta @ 755Million Km distance! Best DX > so far @uhf_satcom FFT; http://pjm.uhf-satcom.com/ > twtr/rosetta_8422496_170214.jpg ... - antenna 1.8M diameter" > > https://twitter.com/uhf_satcom/statuses/435339066024808448 > > Hope the link works! > > His receiver chain is synced to an HP 10811, allowing him to use > sub-Hz bandwidths to get that singal with just a 1.8 m dish. Very well done! > > (and apologies for it being frequency and not time!) > But it is! Time is just 1/f. Or is frequency 1/t? I can never remember which is which. ;-) -- Brian Lloyd, WB6RQN/J79BPL 706 Flightline Drive Spring Branch, TX 78070 br...@lloyd.com +1.916.877.5067 ___ 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] strange behavior of 53230A or is the light on, but nobody in?
In message , mike cook writes: >So at that point I decided to measure the Internal TB against my >reference. So I connected the Int. Ref. Out to channel 1, connected >my PRS10 ref to Ext. Ref In, selected the EXT time base and found >that the count was 10MHz dead on? I don't get that at all. On all the HP kit I have, "ref out" is the frequency used by the instrument, so if you feed it an external reference, it is just a copy of that external reference. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ 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] Good use for an HP 10811
On Mon, Feb 17, 2014 at 8:31 AM, David J Taylor < david-tay...@blueyonder.co.uk> wrote: > @uhf_satcom just tweeted: > > "Finally, a signal from ESA Rosetta @ 755Million Km distance! Best DX so > far @uhf_satcom FFT; http://pjm.uhf-satcom.com/ > twtr/rosetta_8422496_170214.jpg ... - antenna 1.8M diameter" > > https://twitter.com/uhf_satcom/statuses/435339066024808448 > > Hope the link works! > > His receiver chain is synced to an HP 10811, allowing him to use sub-Hz > bandwidths to get that singal with just a 1.8 m dish. Very well done! > > (and apologies for it being frequency and not time!) > But it is! Time is just 1/f. Or is frequency 1/t? I can never remember which is which. ;-) -- Brian Lloyd, WB6RQN/J79BPL 706 Flightline Drive Spring Branch, TX 78070 br...@lloyd.com +1.916.877.5067 ___ 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] Good use for an HP 10811
@uhf_satcom just tweeted: "Finally, a signal from ESA Rosetta @ 755Million Km distance! Best DX so far @uhf_satcom FFT; http://pjm.uhf-satcom.com/twtr/rosetta_8422496_170214.jpg … - antenna 1.8M diameter" https://twitter.com/uhf_satcom/statuses/435339066024808448 Hope the link works! His receiver chain is synced to an HP 10811, allowing him to use sub-Hz bandwidths to get that singal with just a 1.8 m dish. Very well done! (and apologies for it being frequency and not time!) Cheers, David -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ 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] strange behavior of 53230A or is the light on, but nobody in?
Hi It locks up the internal reference to the external reference when the external reference is present. It’s the same behavior as the 5334,5335,5345,5360,5370,5318x,and 5313x. Bob On Feb 17, 2014, at 8:31 AM, mike cook wrote: > > Le 17 févr. 2014 à 13:49, gandal...@aol.com a écrit : > >> Hi Michael >> >> "Internal reference out" is likely to be of the actual reference in use, ie >> with an external reference connected that's what will be on the output >> connector and would explain what you're seeing. >> >> Your initial test, using the T'bolt and internal reference should be giving >> you the accurate measure of the internal reference. >> > Thanks guys. That would explain it, but there is nothing I can see in the > doc which confirms it. I will see if I have a 5MHz or 1MHz oscillator that I > could use to check that. > >> Regards >> >> Nigel >> GM8PZR > > ___ > 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] strange behavior of 53230A or is the light on, but nobody in?
Le 17 févr. 2014 à 13:49, gandal...@aol.com a écrit : > Hi Michael > > "Internal reference out" is likely to be of the actual reference in use, ie > with an external reference connected that's what will be on the output > connector and would explain what you're seeing. > > Your initial test, using the T'bolt and internal reference should be giving > you the accurate measure of the internal reference. > Thanks guys. That would explain it, but there is nothing I can see in the doc which confirms it. I will see if I have a 5MHz or 1MHz oscillator that I could use to check that. > Regards > > Nigel > GM8PZR ___ 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] strange behavior of 53230A or is the light on, but nobody in?
Did you disconnect the external reference from the 53230A before doing the test? If no, I'll bet that the external reference being connected overrides the internal reference Regards, David Partridge ___ 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] strange behavior of 53230A or is the light on, but nobody in?
Something that must be simple to explain, but that I can't get my head round. I got a new 53230A. When first using it, I measured my T-Bolt 10MHz using the internal 10MHz timebase and it came up short of 10MHz, 9.999 998 5xx. I wasn't worried about it as the counter only has a TCXO internal oscillator. So I fired up my PRS10 and after leaving that on for some time, connected it to Ext Ref. , changed to the ext time base and measured again. This time 10.000.000.00x. Then I switched the two references, measuring the PRS10 against the T-Bolt. Again I got 10MHz down to the 11th digit. All that looked good so I have been using it with either the PRS10 locked to GPS, or the T-Bolt as the external time base. After leaving it on (but not inactive) for a month, I did an Autocal. No problem. I was wondering if that would have changed the internal time base frequency, but no, using that still gave similar figures to the above. So at that point I decided to measure the Internal TB against my reference. So I connected the Int. Ref. Out to channel 1, connected my PRS10 ref to Ext. Ref In, selected the EXT time base and found that the count was 10MHz dead on? I don't get that at all. in summary: DUT against internal TB counts < 10MHz.To me that means that the internal timebase is a bit fast. Is that assumption correct? DUT against Ext.Ref counts 10MHz Internal TB against Ext.Ref counts 10MHz. If my assumption above is correct, the count should be greater than 10MHz, no? Can anyone shed any light on that? ___ 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.
