Re: [time-nuts] Frequency counter recommendation
Bob Bownes wrote: Comments inline. On Mon, Dec 20, 2010 at 11:17 PM, Chris Albertsonalbertson.ch...@gmail.com wrote: I looked. I think we should keep the design goals modest for a first revision. Shoot for a spec that can be hand built on perf board. So I'd relax those numbers by a factor of 1000. The top frequency is in Mhz, not Ghz and the time resolution closer to ns than ps. It's good to have a cheap option. Many people are happy with an FCC1 Try for the next step after that with a goal of actually matching the state of the art in steps. My initial thinking was to be better than a pictic ii, preferably on par with, or better than a 5370. I'm not sure you can do that on perfboard. I suppose if the speed is kept low it can be done that way. Around 25ps jitter is the likely lower limit with such construction techniques. Others have pointed out (offline) 20Ghz isn't reasonabe with a decent noise figure or prescalers. What do people think a reasonable number is? What about resolution? I'd like to get better than a ns, preferably a lot better. 1ps resolution is trivial just use a sufficiently high resolution ADC (16bit) with a short TAC interpolator range (10ns?) Achieving a commensurate jitter is somewhat trickier. Around 3ps or so rms short term jitter should be easy enough, the Wavercrest 2075 does this without using anything particularly esoteric. 10ps jitter should be very easy. The latest Agilent time interval counters counters achieve around 9ps or so. 1ps rms jitter shouldn't be beyond reach (at least with the ringing tank method). However a good layout together with at least a 4 layer board will likely be necessary. Adequate grounding and shielding will also be necessary. Why no through holes? I don't see the point of banishing them. I to agree with the rest. SMT that is hand solderable by a skilled tech but now reflow ovens or solder past masks should be required . You might place a limit on component size too like 0.5mm lead pitch or whatever is reasonable. I've been prototyping a lot of late and restricting the number of through holes makes the job much much easier and quicker. No other real reason. Precluding the use of RF dams (these use arrays of plated through holes) is probably counter productive. I didn't place a limit on the lead pitch because a) I felt that limited the component selection and b) pretty much even the finest pitch can be hand assembled with care, solder wick, and 20x magnification. But if folks are very against it, it can go in the 'desired qualities' list. My only fear is the limit it might put on critical parts like a FPGA. Mechanical assy is going to be a killer. Let's start with overall form factor. Rack mount or bench format? If rack mount, 1U or more? Commercial project enclosure (ala the VNA Hammond box) or do we take an existing form factor like a disk drive as you suggest. Heck, if we go with a disk drive size, it could be built/slid into anyone's lab PC case and use ribbon cable as a back plane... 1/2 :) Inadequate shielding? I like 1U because it matches up with the rest of the test equipment on the bench and it gives it a professional feel. And there are many many surplus 1U cases out there with decent +/-12vdc,+5vdc (even some with 3.3vdc) power supplies. Linear supplies or perhaps extremely low noise/well filtered switchmode supplies will likely be necessary. Bob Bruce On Mon, Dec 20, 2010 at 6:20 PM, Bob Bownesbow...@gmail.com wrote: Well said Chris. Take a look at the initial spec in the OpenCounter Gogle group and tell me what you think with respect to your item #1. I think the core counter is going to be the really difficult part of the module list. Item #2 is going to be a tough one methinks. I love Eurocard, but, as you say, it is very expensive, if only for the connectors. In cases like this I'm a fan of either repurposing commercially available connectors (PCI and memory DIMMS are two I have used in the past) because they can be a) purchased off the shelf, b) are manufactured in enough volume to make cheap, and c) are common enough that the really cheap amongst us can get them off of scrap boards someplace for little or nothing. The N2PK VNA is built to fit into a particular HAmmond enclosure that I like but again, there are many options. My feeling is that the enclosure should not dictate any functional design decisions. #3 - I've created a group and appointed myself benevolent dictator. We can discuss things, propose designs or design criteria, call for a concensus, accept, and draft volunteers to design that section to the defined spec. If there are multiple competing designs, so much the better, as long as we all agree on the interfaces. Sound like a process? Can you tell I've done
Re: [time-nuts] Ublox GPS board
John, in a lot of cases such accuracy specs are specified (without being explicitely mentioned) for ONE sigma of the statistical distribution of the pulses. In your case this would mean that 66% of the pulses are within +/- 50 ns and 99% of the pulses are within +/- 150 ns. These numbers apply exactly only to normal distributed values but in any case give you an idea of what you may expect. Best regards Ulrich Bangert -Ursprungliche Nachricht- Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im Auftrag von John Green Gesendet: Montag, 20. Dezember 2010 17:03 An: time-nuts@febo.com Betreff: [time-nuts] Ublox GPS board I recently bought 4 older UBLOX GPS boards on eBay for $15 with free shipping. I hooked one up to my 1992 and comparing it with the Z3801, I am seeing it jump all over the place. I am using the 10 MHz output from the 3801 to start and the 1 PPS from the UBLOX to stop. I will have to bring in a TBolt just to verify the test set up. Has anyone here ever made any measurements on the UBLOX TIM-LF-0-000? These are not timing grade, by the way. The spec. sheet says the accuracy of the time pulse is 50 nSec. If that is +/- 50, then what I am seeing might be OK. ___ 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] UBLOX GPS boards
Magnus Danielson wrote:I would let the low-frequency PPS act as start and the 10 MHz as stop, unless you want to measure the PPSes directly. I tried that too. Seemed to work perhaps a little better. I ended up using the 1 PPS from the Z3801 instead of the 10 MHz. I am going to have to dig out that Tbolt just to verify that the test set up is OK. ___ 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] Form Factor
Hammond boxes are great to work with and are reasonably inexpensive. You can stack multiple boards inside, and panels are available in aluminum or plastic. Hammond will make custom lengths, just for asking. Here's a grandiose scheme I've been working on with help from Richard McCorkle that uses some 1455 boxes: http://symbiosis-foundation.org/symbiosisfoundation.html. Tom Bales KE4SYS On Tue, Dec 21, 2010 at 4:32 AM, 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: Form factor (Chris Albertson) 2. Re: Form factor (bownes) 3. Re: Form factor (Don Latham) 4. Re: Frequency counter recommendation (Bruce Griffiths) 5. Re: Ublox GPS board (Ulrich Bangert) -- Message: 1 Date: Mon, 20 Dec 2010 22:29:47 -0800 From: Chris Albertson albertson.ch...@gmail.com Subject: Re: [time-nuts] Form factor To: Discussion of precise time and frequency measurement time-nuts@febo.com Cc: Open counter opencoun...@googlegroups.com Message-ID: aanlktinmf=bkjcscj4pc9pc837y2h8eoloqwsgkpg...@mail.gmail.com Content-Type: text/plain; charset=ISO-8859-1 Eurocard has been one suggestion as a form factor. While I personally love Eurocard, the boards and connectors are expensive. Stackble connectors are a pain in assembly. Backplanes are inherently evil at high speeds. Plugging everything into one main board makes that a critical design item and that much harder to upgrade. I agree with all of the above. I think what we want is simply a mechanical standard. Something that will simply hold everything in place. What if every module was in it's own metal box? Each box has a forward or user facing panel that is tall and narrow and contains things like input jacks and status LEDs and a rear facing panel that is for power and module to module interconnect.Many of the modules, I assume would work as stand alone gadgets (a trigger is a usful device all by it self) To assemble a system you place all the boxes like books on a shelf. Maybe even some book end so they don't fall over. But you might build a wood cabinet, put a handle on top and metal bumpers on the corners. The wood cabinet would house the modules and also the power supply and the rats nest of interconnect wiresSo those who like to be neat can make nice wood cases and the rest of us can have a working system made of a half dozen boxea and cales all over the work bench Here is an example of a module box http://www.hammondmfg.com/pdf/1455L1601.pdf We would not have to specify a height or length, only the width needs to be uniform. But in our case the width becomes height when you turn them on edge. Some modules might need two PCBs and a wider box. We should make a list of connectors to be used for power and so on for the rear pannel I had previously suggested about the same thing but only to make the box the same size as a disk drive so we could use common existing racks. I'd still prefer that but maybe these hammond boxes are more popular -- = Chris Albertson Redondo Beach, California -- Message: 2 Date: Tue, 21 Dec 2010 01:48:27 -0500 From: bownes bow...@gmail.com Subject: Re: [time-nuts] Form factor To: Discussion of precise time and frequency measurement time-nuts@febo.com Cc: Open counter opencoun...@googlegroups.com,Discussion of precise time and frequency measurement time-nuts@febo.com Message-ID: e30c08a4-74fa-4cb7-9d00-d0b3a449c...@gmail.com Content-Type: text/plain; charset=us-ascii I love those Hammond boxes until I have to pay the bill. The one for my n2pk VNA was about $28. But one of those as the primary enclosure with input boards and output boards that plug into a main board would be feasable if a tad expensive. Some modules lend themselves to plugins on a main board (output modules for example) while things that need to chain like input modules ( think pre amp followed by prescaler followed by trigger sense) don't. On Dec 21, 2010, at 1:29 AM, Chris Albertson albertson.ch...@gmail.com wrote: Eurocard has been one suggestion as a form factor. While I personally love Eurocard, the boards and connectors are expensive. Stackble connectors are a pain in assembly. Backplanes are inherently evil at high speeds. Plugging everything into one main board makes that a critical design item and that much
Re: [time-nuts] Loran?
Loran c in NE US. Definitely acquired only 9007 on the austron 2100 and 2100f. The systems can lock in as little as 20 minutes at the fine time of 0300 local. But most likely after midnight to most likely 4 in the morning. Now would be the time to have the HPIB interfaces and I don't. Would be able to figure when the window is open to the US. Using the antenna in described in this thread. The signal was at 77db on both receivers. The signal to noise or noise (Have never under stood the figure in austron sense) is 637 and a bad sig is 238. Old 9960 chain Master 60 miles was 37db as a reference. Still see the noise burst signal and pretty sure its nothing within the house. Everything was pretty much off at 0300. The sky wave signal worked pretty well. The 2100f is locked to GPS through a HP 3801 consistent at -2.4 e -9 The 2100 is locked to RB reference house and -1.5 e -10. Kind of interesting that gps is not as good as the rb that I tuned when I had local loran. But clearly both are down in accuracy from what I have seen. Skywave effects? Regards Paul WB8TSL 2010/12/20 paul swed paulsw...@gmail.com Interesting Just barely I may be seeing several chains on the east coast of the US near Boston. I am using a austron 2100 and a 2100F. Definitely see it trying to lock and its does go into settle mode. But I am afraid I may have some nasty switching power supply of some sort nearby. I see a bursting noise signal semi synchronous at 100 KC. Never seen this before. I seem to see 9007 and 6731 the best. 7499 nothing and would say 7001 quite weak. May have to go to the older Austron 2000c and take a look. That gives me much more flexibility in control to confirm that I can see the signals. Antenna is a Loran preamplified antenna (No idea the model hamfest stuff) with a fiber glass whip 7' tall wound with hundreds of turns of #26 gauge wire as a single layer. Approx 6 ft off the ground. Regards Paul WB8TSL 2010/12/20 paul swed paulsw...@gmail.com Thanks Poul will do its long enough past sunset to start hunting. On Mon, Dec 20, 2010 at 5:45 PM, Poul-Henning Kamp p...@phk.freebsd.dkwrote: In message aanlkti=kyammsdn7komcpbs8igw=exzxm7nq767-+...@mail.gmail.comexzxm7nq767-%2b...@mail.gmail.com, paul swed writes: Well to be honest when I typed loran it was simply because I felt like it. It was more important to communicate the fact that I couldn't here and european stations in the northeast us. Thats all that mattered. Caps or lowercase simply no longer matters to me on the dead us service. So getting back at it I will fire up a different antenna and preamp and give it one more shot. Make sure you listen on the correct GRI's, some tables still list the long abandoned 3-digit USCG chains, rather than the 4-digit NELS chains: Eiği, GRI=9007 Lessay, GRI=6731 Sylt, GRI=7499 Værlandet, GRI=7001 For what it's worth, I have never been able to more than barely detect the 9960 chain from here in Denmark, and that was only after a major DSP exercise... Poul-Henning -- 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. ___ 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] Loran?
In message aanlktiklk32saa+c0nrhptmhe70v_otpd0xjc8fif...@mail.gmail.com, paul swed writes: Loran c in NE US. Those of you playing with Loran-C DX'ing might be interested in using this receiver design: http://phk.freebsd.dk/AducLoran/ Sparkfun.com has the ARM board for $80: http://www.sparkfun.com/products/711 In addition you need some source of 42 MHz clock, I used the TAPR PLL board, but anything goes. -- 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] LORAN C antenna thoughts from the group
In message aanlktikgjbl4yvpifgp8edfqfiracaarmxhi5jqso...@mail.gmail.com, paul swed writes: OK now that I can actually receive the 90070 chain in the US. What might be a better antenna then my whip and preamp? A big loop and preamp? A tall vertical over a ground plane. Tried 67 ft that yielded little. How might reception be improved in the US? I built a trivial loop based on a design-idea I found at vlf.it http://phk.freebsd.dk/loran-c/Antenna/ It's basically a loop with an AD797 amplifier and some power-filtering, didn't even write a schematic for it... -- 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] Form factor
Hi One source of boxes to consider is old HP equipment, some is very reasonably priced, like 37203 for small boxes and a 59401A makes an ideal housing for a Rb with clock GPS and backup power. Some times you can even use part of the guts. I even went as far as repackaging my 5062C into a HP case of that generation, heresy in the eyes of some of you Bert Kehren Miami ___ 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] what is the best way to multiply a 10 Mhz signal?
Hi everyone, I want to multiply the output from my Efratom 101 (10Mhz) to clock a DDS at 70 Mhz. Has anyone tried this? Regards, Steve G0XAR -- It is vain to do with more that which can be done with less. ___ 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] what is the best way to multiply a 10 Mhz signal?
Von: Stephen Farthing squir...@gmail.com Betreff: [time-nuts] what is the best way to multiply a 10 Mhz signal? I want to multiply the output from my Efratom 101 (10Mhz) to clock a DDS at 70 Mhz. Has anyone tried this? I did 5 MHz * 7 = 35 which is about the same, with CMOS gates and filtering. ( in the style propagated by Wenzel) This took a lot of filtering to get rid of the last spurii. Too much ado. I recommend a 70 MHz VCXO and locking this to the 10 MHz source. regrds, 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] what is the best way to multiply a 10 Mhz signal?
I'm certainly not the expert but can't you place a divide by 7 counter in the feedback loop of a phase lock loop. There is a fast version of the 4046 PPL chip that does 100Mhz and a divide by 7 is easy to rig with TTL. On Tue, Dec 21, 2010 at 8:35 AM, Stephen Farthing squir...@gmail.com wrote: I want to multiply the output from my Efratom 101 (10Mhz) to clock a DDS at 70 Mhz. Has anyone tried this? -- = Chris Albertson Redondo Beach, California ___ 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] what is the best way to multiply a 10 Mhz signal?
On 21/12/10 16:35, Stephen Farthing wrote: Hi everyone, I want to multiply the output from my Efratom 101 (10Mhz) to clock a DDS at 70 Mhz. Has anyone tried this? Regards, Steve G0XAR What is the application? What will the DDS output frequency be? Maybe you could use a 70MHz (or whatever frequency you need) VCO as the DDS clock and use the DDS as a programmable divider to produce a 10MHz output. This could be phase locked to the 10MHz output from the LPRO-101. -- Linux 2.6.35 ___ 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] what is the best way to multiply a 10 Mhz signal?
I used to be in the synthesizer business (Zeta Labs) in a previous life. I learned to ask the customers: what you are trying to accomplish as the end goal, before tackling a messy problem like multiplying by 7. Maybe you don't need to multiply by 7, but we can't tell from your question. Rick Karlquist N6RK On 12/21/2010 8:35 AM, Stephen Farthing wrote: Hi everyone, I want to multiply the output from my Efratom 101 (10Mhz) to clock a DDS at 70 Mhz. Has anyone tried this? Regards, Steve G0XAR ___ 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] Frequency counter recommendation
I'd like to input a few suggestions regarding layout and construction, namely, the PCB material and the form factor. I suggest that any circuitry processing signals over about 2-3 GHz be constructed on a PTFE or PTFE/ceramic PCB material, such as Rogers RT/Duroid (www.rogerscorp.com/). Arlon (arlon-med.com) also markets similar PCB material. The lower frequency circuitry can be made on FR4 or equivalent. As to the modularity, I suggest that modules be made so that they are stackable, but not attached to each other directly, but through a 24, 30 or 40-pin (or whatever width is necessary) ribbon cable on the rear. The cable would have IDC card-edge connectors spaced so that they could attach to all modules. Similar to the arrangement that older PCs had to interconnect floppy and hard disk drives. The modules would be stacked on top of each other, using aluminum or steel threaded spacers. That way, no card cage, intermodule interface system or back plane would be needed. Physical size could be determined at PCB layout time. Build all modules to be stacked, using the smallest size that would accommodate all modules. Any RF In/out connectors or displays could be brought out on the front edge of the modules, and extended to the front of whatever chassis the user chooses by short extension wires/cables. As to the production issue, if these boards are envisioned to be distributed in kit form, I suggest that consideration be given to the possibility of having a fab house fix the small, high pin count parts to the PCB and leave the larger, easier to solder parts for the kit builder to assemble. On the other hand, it is probably just as cheap to have the whole board stuffed and soldered than only a few ICs. That's a decision to be made by the PCB manager. I agree with the power supply approach that all supplies would be user supplied, with a STRONG recommendation that all supplies be linear. SMPS supplies could be used at the users' risk. Thanks for listening, David dgminala at mediacombb dot net ___ 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] LORAN C antenna thoughts from the group
A beverage at 100 KC must be 10-60 miles? Granted I have beverages at higher frequency. But at 100 KC it will be far from directional at any reasonable length. So I think thats a bit costly. On Tue, Dec 21, 2010 at 11:33 AM, Bill Janssen bi...@ieee.org wrote: paul swed wrote: OK now that I can actually receive the 90070 chain in the US. What might be a better antenna then my whip and preamp? A big loop and preamp? A tall vertical over a ground plane. Tried 67 ft that yielded little. How might reception be improved in the US? Thanks Paul ___ 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. Do a Google search for a Beverage Antenna. If you have room for it. Bill K7NOM ___ 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] Loran?
One quick update The reason the GPS was performing poorly was that I left the antenna off it. Was using that antenna port to troubleshoot a austron 2201a. There is a cartoon character called Bart Simpson. He would say Doa. Regards Paul On Tue, Dec 21, 2010 at 10:36 AM, Poul-Henning Kamp p...@phk.freebsd.dkwrote: In message aanlktiklk32saa+c0nrhptmhe70v_otpd0xjc8fif...@mail.gmail.com, paul swed writes: Loran c in NE US. Those of you playing with Loran-C DX'ing might be interested in using this receiver design: http://phk.freebsd.dk/AducLoran/ Sparkfun.com has the ARM board for $80: http://www.sparkfun.com/products/711 In addition you need some source of 42 MHz clock, I used the TAPR PLL board, but anything goes. -- 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. ___ 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] what is the best way to multiply a 10 Mhz signal?
Interesting. When I used to use and build DDSs back in the early 70's, we typically used 2.56 times the maximum required frequency for a clock, to get above Nyquist and allow adequate filtering stop-band rejection. At the time we could not go much higher due to limitations in device speeds, especially the D/A. Today you can easily use a much higher clock frequency which would simplify filtering and reduce gain variations. At 70 MHz clock you are only at 2.333 Nyquist. Even at 2.56 by the time you get to your desired goal of 30 MHz, you will have what looks just about like a square wave. So, filtering will be a must, and, after filtering, you will find that your amplitude output will greatly decrease with frequency. The other question is phase noise objectives. If that is not a real concern, then as suggested, maybe a simple locked VCO would be the way to go. 73 - 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 Stephen Farthing Sent: Tuesday, December 21, 2010 12:57 PM To: Richard (Rick) Karlquist; time-nuts@febo.com Subject: Re: [time-nuts] what is the best way to multiply a 10 Mhz signal? Hi Rich Thanks for the replyI have an AD9834 DDS chip I want to use for a Frequency generator with an accuracy of 1 Hz from 0-30 Mhz. . This part can be clocked at 75 Mhz - but unlike other DDS chips seems to have no internal clock multipliers. So it seems to me if I can some how generate a 70 Mhz clock signal from my rubidium standard I can solve the problem. 73s Steve On 21 December 2010 17:36, Richard (Rick) Karlquist rich...@karlquist.comwrote: I used to be in the synthesizer business (Zeta Labs) in a previous life. I learned to ask the customers: what you are trying to accomplish as the end goal, before tackling a messy problem like multiplying by 7. Maybe you don't need to multiply by 7, but we can't tell from your question. Rick Karlquist N6RK On 12/21/2010 8:35 AM, Stephen Farthing wrote: Hi everyone, I want to multiply the output from my Efratom 101 (10Mhz) to clock a DDS at 70 Mhz. Has anyone tried this? Regards, Steve G0XAR -- It is vain to do with more that which can be done with less. ___ 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] what is the best way to multiply a 10 Mhz signal?
This might explain a way to do it http://physics.eou.edu/courses/phys345/lab14_pll.pdf What this is doing is simple. It is a 70Mhz voltage controlled oscillator who's frequency is controlled such that every 7th cycle the phase matches your 10MHz reference. The example above does divide by 10 or 128 but 7 is the same thing. The way to make a divide by 7 is to have a counter feed a comparator and on match the comparator resets the counter. The reset signal is your output. It requires two 50 cent chips Can you use 80Mhz or 100Mhz. Either of these is easier and uses one less chip. On Tue, Dec 21, 2010 at 9:57 AM, Stephen Farthing squir...@gmail.com wrote: Hi Rich Thanks for the replyI have an AD9834 DDS chip I want to use for a Frequency generator with an accuracy of 1 Hz from 0-30 Mhz. . This part can be clocked at 75 Mhz - but unlike other DDS chips seems to have no internal clock multipliers. So it seems to me if I can some how generate a 70 Mhz clock signal from my rubidium standard I can solve the problem. 73s Steve On 21 December 2010 17:36, Richard (Rick) Karlquist rich...@karlquist.comwrote: I used to be in the synthesizer business (Zeta Labs) in a previous life. I learned to ask the customers: what you are trying to accomplish as the end goal, before tackling a messy problem like multiplying by 7. Maybe you don't need to multiply by 7, but we can't tell from your question. Rick Karlquist N6RK On 12/21/2010 8:35 AM, Stephen Farthing wrote: Hi everyone, I want to multiply the output from my Efratom 101 (10Mhz) to clock a DDS at 70 Mhz. Has anyone tried this? Regards, Steve G0XAR -- It is vain to do with more that which can be done with less. ___ 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 ___ 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] what is the best way to multiply a 10 Mhz signal?
You may want to check out the 10MHz locked 1GHz clock I did (using ADF4107 and a 1GHz Crystek CVCO) http://www.qslnet.de/member/on4iy/1gclock/xlock-1g.html and associated DDS to generate oddbal frequencies. http://www.qslnet.de/member/on4iy/9912.html Includes some PN measurements. Xtof. On 21/12/10 19:18, Mike Feher wrote: Interesting. When I used to use and build DDSs back in the early 70's, we typically used 2.56 times the maximum required frequency for a clock, to get above Nyquist and allow adequate filtering stop-band rejection. At the time we could not go much higher due to limitations in device speeds, especially the D/A. Today you can easily use a much higher clock frequency which would simplify filtering and reduce gain variations. At 70 MHz clock you are only at 2.333 Nyquist. Even at 2.56 by the time you get to your desired goal of 30 MHz, you will have what looks just about like a square wave. So, filtering will be a must, and, after filtering, you will find that your amplitude output will greatly decrease with frequency. The other question is phase noise objectives. If that is not a real concern, then as suggested, maybe a simple locked VCO would be the way to go. 73 - 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 Stephen Farthing Sent: Tuesday, December 21, 2010 12:57 PM To: Richard (Rick) Karlquist; time-nuts@febo.com Subject: Re: [time-nuts] what is the best way to multiply a 10 Mhz signal? Hi Rich Thanks for the replyI have an AD9834 DDS chip I want to use for a Frequency generator with an accuracy of 1 Hz from 0-30 Mhz. . This part can be clocked at 75 Mhz - but unlike other DDS chips seems to have no internal clock multipliers. So it seems to me if I can some how generate a 70 Mhz clock signal from my rubidium standard I can solve the problem. 73s Steve On 21 December 2010 17:36, Richard (Rick) Karlquist rich...@karlquist.comwrote: I used to be in the synthesizer business (Zeta Labs) in a previous life. I learned to ask the customers: what you are trying to accomplish as the end goal, before tackling a messy problem like multiplying by 7. Maybe you don't need to multiply by 7, but we can't tell from your question. Rick Karlquist N6RK On 12/21/2010 8:35 AM, Stephen Farthing wrote: Hi everyone, I want to multiply the output from my Efratom 101 (10Mhz) to clock a DDS at 70 Mhz. Has anyone tried this? Regards, Steve G0XAR Disclaimer: http://www.kuleuven.be/cwis/email_disclaimer.htm ___ 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] Hammond Boxes Available -
I have a quantity of NOS Hammond boxes available. These are model number 1598HBK. Mouser is the cheapest source for these that I found on a quick search. These are considerably larger than the hard drive enclosures previously discussed, and, these are also plastic with aluminum front and back plates. They still make excellent small project boxes. Here is the Mouser link, you can find others with better photos: http://www.mouser.com/ProductDetail/Hammond/1598HBK/?qs=3vio67wFuYpsW%252byy vIs3Bw%3D%3D My pricing is: 1 unit - $8.00 2 units - $15.00 4 units - $27.00 10 units - $60.00 Shipping will be extra, but only actual shipping cost, by your preferred method. Each box weighs 1 lb and 6 oz. Thanks Merry Christmas to all - Mike Mike B. Feher, EOZ Inc. 89 Arnold Blvd. Howell, NJ, 07731 732-886-5960 office 908-902-3831 cell ___ 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] LORAN C antenna thoughts from the group
I remember reading somewhere that the envelope of the LORAN pulses was shaped to reduce the transmitted BW. Does anybody have a reference for that, and relatedly, what does the BW of the antenna have to be? Typically, loops are about 90 KHz to 110 KHz, but can that be narrowed down? Best, -John == In message aanlktikgjbl4yvpifgp8edfqfiracaarmxhi5jqso...@mail.gmail.com, paul swed writes: OK now that I can actually receive the 90070 chain in the US. What might be a better antenna then my whip and preamp? A big loop and preamp? A tall vertical over a ground plane. Tried 67 ft that yielded little. How might reception be improved in the US? I built a trivial loop based on a design-idea I found at vlf.it http://phk.freebsd.dk/loran-c/Antenna/ It's basically a loop with an AD797 amplifier and some power-filtering, didn't even write a schematic for it... -- 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. ___ 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] Form factor
I agree about the ebay finds. Bad to design the boards form factor around old chassis. Maybe the thing is to find out from the electronic design how big the board(s) will have to be or what the electronic footprint is, then go from there? If the boards are designed so that idiosyncratic mounting is possible, we can all mount them according to our own taste? Don Chris Albertson You can't plan a project like this around eBay junk. How would you assemble 100 kits if each kit requires that you find a specific HP instrument on eBay? If cost is a big issue then I'll go back to my first idea. Make your PCB about the size os a disk drive. Then yu get a llength od 1 x 1/4 inch aluminum L and bend it into a three sided U and attach it to three sides of the PCB. The finished assembly should fit into any enclusre designed to hold SATA disk drives. A PC case could work but there are nicer looking boxes, rack mount and diesktop This trades a bit of metal working for the cost of a Hammond box. But the metal work requires only a hack say and drill. On Tue, Dec 21, 2010 at 8:35 AM, Bob Bownes bow...@gmail.com wrote: I do the same with Tek 500/500series instrumentation plugins. You can get the TM504 mainframe for $50 on ebay and scrap grade modules for $10. Plus you get a linear power supply, backplane and already RF rated enclosure. On Tue, Dec 21, 2010 at 11:12 AM, ewkeh...@aol.com wrote: Hi One source of boxes to consider is old HP equipment, some is very reasonably priced, like 37203 for small boxes and a 59401A makes an ideal housing for a Rb with clock GPS and backup power. Some times you can even use part of the guts. I even went as far as repackaging my 5062C into a HP case of that generation, heresy in the eyes of some of you Bert Kehren Miami ___ 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. -- = Chris Albertson Redondo Beach, California ___ 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. -- Neither the voice of authority nor the weight of reason and argument are as significant as experiment, for thence comes quiet to the mind. R. Bacon If you don't know what it is, don't poke it. Ghost in the Shell Dr. Don Latham AJ7LL Six Mile Systems LLP 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 www.lightningforensics.com www.sixmilesystems.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] what is the best way to multiply a 10 Mhz signal?
Christophe Huygens wrote: I'll bet your DDS will run at 80 MHz at room temp. Since this a one-off project, test it to see if it works to 80 MHz with some design margin. Now you can cascade 3 doublers. The reconstruction filter is now stop 50, pass 30 instead of stop 40 pass 30. That is WAY easier to build. Rick Karlquist N6RK ___ 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] Form factor
Another factor to consider is that ps stability requires using coax connectors that are mechanically stable to within a few microns ie no BNCs. Bruce Don Latham wrote: I agree about the ebay finds. Bad to design the boards form factor around old chassis. Maybe the thing is to find out from the electronic design how big the board(s) will have to be or what the electronic footprint is, then go from there? If the boards are designed so that idiosyncratic mounting is possible, we can all mount them according to our own taste? Don Chris Albertson You can't plan a project like this around eBay junk. How would you assemble 100 kits if each kit requires that you find a specific HP instrument on eBay? If cost is a big issue then I'll go back to my first idea. Make your PCB about the size os a disk drive. Then yu get a llength od 1 x 1/4 inch aluminum L and bend it into a three sided U and attach it to three sides of the PCB. The finished assembly should fit into any enclusre designed to hold SATA disk drives. A PC case could work but there are nicer looking boxes, rack mount and diesktop This trades a bit of metal working for the cost of a Hammond box. But the metal work requires only a hack say and drill. On Tue, Dec 21, 2010 at 8:35 AM, Bob Bownesbow...@gmail.com wrote: I do the same with Tek 500/500series instrumentation plugins. You can get the TM504 mainframe for $50 on ebay and scrap grade modules for $10. Plus you get a linear power supply, backplane and already RF rated enclosure. On Tue, Dec 21, 2010 at 11:12 AM,ewkeh...@aol.com wrote: Hi One source of boxes to consider is old HP equipment, some is very reasonably priced, like 37203 for small boxes and a 59401A makes an ideal housing for a Rb with clock GPS and backup power. Some times you can even use part of the guts. I even went as far as repackaging my 5062C into a HP case of that generation, heresy in the eyes of some of you Bert Kehren Miami ___ 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. -- = Chris Albertson Redondo Beach, California ___ 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] What is the best way to multiply a 10 Mhz
It would seem the most jitter free way to do it would be to simply multiply it up like we used to do. Some reasonably Hi-Q LC circuits could make a nice flywheel and filter out other signals at the same time. Once you have it to the desired signal frequency you could condition it to clock your DDS. Am I missing something here? Wouldn't be the first time, ya know! Burt, K6OQK Subject: Re: [time-nuts] what is the best way to multiply a 10 Mhz signal? On 21/12/10 16:35, Stephen Farthing wrote: Hi everyone, I want to multiply the output from my Efratom 101 (10Mhz) to clock a DDS at 70 Mhz. Has anyone tried this? Regards, Steve G0XAR From: Eamon Skelton nos...@oceanfree.net What is the application? What will the DDS output frequency be? Maybe you could use a 70MHz (or whatever frequency you need) VCO as the DDS clock and use the DDS as a programmable divider to produce a 10MHz output. This could be phase locked to the 10MHz output from the LPRO-101. 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] Form factor
That would all depend upon the interconnect strategy, which hasn't reached consensus either. Based on the early module list, a bus probably isn't necessary, and individual ribbon cable and/or coax will do if speeds stay low. On Dec 21, 2010, at 2:34 PM, Bruce Griffiths bruce.griffi...@xtra.co.nz wrote: Another factor to consider is that ps stability requires using coax connectors that are mechanically stable to within a few microns ie no BNCs. Bruce Don Latham wrote: I agree about the ebay finds. Bad to design the boards form factor around old chassis. Maybe the thing is to find out from the electronic design how big the board(s) will have to be or what the electronic footprint is, then go from there? If the boards are designed so that idiosyncratic mounting is possible, we can all mount them according to our own taste? Don Chris Albertson You can't plan a project like this around eBay junk. How would you assemble 100 kits if each kit requires that you find a specific HP instrument on eBay? If cost is a big issue then I'll go back to my first idea. Make your PCB about the size os a disk drive. Then yu get a llength od 1 x 1/4 inch aluminum L and bend it into a three sided U and attach it to three sides of the PCB. The finished assembly should fit into any enclusre designed to hold SATA disk drives. A PC case could work but there are nicer looking boxes, rack mount and diesktop This trades a bit of metal working for the cost of a Hammond box. But the metal work requires only a hack say and drill. On Tue, Dec 21, 2010 at 8:35 AM, Bob Bownesbow...@gmail.com wrote: I do the same with Tek 500/500series instrumentation plugins. You can get the TM504 mainframe for $50 on ebay and scrap grade modules for $10. Plus you get a linear power supply, backplane and already RF rated enclosure. On Tue, Dec 21, 2010 at 11:12 AM,ewkeh...@aol.com wrote: Hi One source of boxes to consider is old HP equipment, some is very reasonably priced, like 37203 for small boxes and a 59401A makes an ideal housing for a Rb with clock GPS and backup power. Some times you can even use part of the guts. I even went as far as repackaging my 5062C into a HP case of that generation, heresy in the eyes of some of you Bert Kehren Miami ___ 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. -- = Chris Albertson Redondo Beach, California ___ 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] What is the best way to multiply a 10 Mhz
So, two doublers for 40 MHz and a tripler for 30 and then mix to get 70? What happens to phase noise when you do that? Is it as bad as a PLL? Seems like you ought to get adequate harmonic rejection. What about six mixers to get 20, 30, 40, 50, 60, and 70 MHz? Chips and tank coils are cheap, no? Bill Hawkins -Original Message- From: Burt I. Weiner Sent: Tuesday, December 21, 2010 1:39 PM It would seem the most jitter free way to do it would be to simply multiply it up like we used to do. Some reasonably Hi-Q LC circuits could make a nice flywheel and filter out other signals at the same time. Once you have it to the desired signal frequency you could condition it to clock your DDS. Am I missing something here? Wouldn't be the first time, ya know! Burt, K6OQK Subject: Re: [time-nuts] what is the best way to multiply a 10 Mhz signal? On 21/12/10 16:35, Stephen Farthing wrote: Hi everyone, I want to multiply the output from my Efratom 101 (10Mhz) to clock a DDS at 70 Mhz. Has anyone tried this? Regards, Steve G0XAR ___ 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] LORAN C antenna thoughts from the group
In message 53187.12.6.201.2.1292957970.squir...@popaccts.quikus.com, J. Fors ter writes: I remember reading somewhere that the envelope of the LORAN pulses was shaped to reduce the transmitted BW. The envelope is designed for two things: sensible BW and ease of production. There is some math musing about it in the Radiation Lab book. Does anybody have a reference for that, and relatedly, what does the BW of the antenna have to be? Typically, loops are about 90 KHz to 110 KHz, but can that be narrowed down? In principle you can make it as narrow as you want, and compensate for the resulting pulse-shape distortion in your receiver. Going much wider than 30kHz (85-115kHz) usually results in more interference from CW signals than improvement to the loran signal. You can see a typical power spectrum at the bottom of this page: http://phk.freebsd.dk/loran-c/Antenna/ Poul-Henning -- 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] What is the best way to multiply a 10 Mhz
Burt I. Weiner wrote: It would seem the most jitter free way to do it would be to simply multiply it up like we used to do. Some reasonably Hi-Q LC circuits could make a nice flywheel and filter out other signals at the same time. Once you have it to the desired signal frequency you could condition it to clock your DDS. Some experience here. At Zeta Labs, we made a lot of money building such multipliers. It is surprisingly hard to do it correctly and get low phase noise. At HP, the X6 multiplier to 60 MHz in the 5065 and the X9 multipler in the 5060/1 were full employment plans for production engineers, especially if they were operating under the Peter Principle. HP definitely knew less than Zeta about these things. The two examples of doing it right at HP were the 8662A and 5071A which had doubler chains. I never heard a peep from the production engineers about the 5071A doubler chain that I designed. It just worked. Period. The doubling was accomplished by wiring the LO and RF ports of an ASK-1 mixer in series and driving it with a very well filtered low distortion sine wave (important) at about 10 mW. The output filtering was just a ladder of parallel resonant tanks in shunt and series resonant tanks in series. The Q of the tanks was fairly low. I used a fair number of them to get enough filtering. Not a few high Q tanks as you typically see. There were no (zero) adjustments. Rick Karlquist N6RK ___ 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] LORAN C antenna thoughts from the group
I was more interested in reducing the BW, rather than increasing it. Years ago, I bought up some of the resuidual of Appelco, a New Hampshire LORAN company that made units for Raytheon. Included were a bunch of active tunable filters, designed to tune out interference. However, there is no documentation. I was just toying with the idea that a good shielded (possibly active) loop, the tunable filters, and an Austron 2100F might still be usable on the east coast. FWIW, -John In message 53187.12.6.201.2.1292957970.squir...@popaccts.quikus.com, J. Fors ter writes: I remember reading somewhere that the envelope of the LORAN pulses was shaped to reduce the transmitted BW. The envelope is designed for two things: sensible BW and ease of production. There is some math musing about it in the Radiation Lab book. Does anybody have a reference for that, and relatedly, what does the BW of the antenna have to be? Typically, loops are about 90 KHz to 110 KHz, but can that be narrowed down? In principle you can make it as narrow as you want, and compensate for the resulting pulse-shape distortion in your receiver. Going much wider than 30kHz (85-115kHz) usually results in more interference from CW signals than improvement to the loran signal. You can see a typical power spectrum at the bottom of this page: http://phk.freebsd.dk/loran-c/Antenna/ Poul-Henning -- 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] What is the best way to multiply a 10 Mhz
The 6 mixer scheme was my first thought for lowest PN. That way you do not get 20logN, but you just get the RMS sum of the noise power each time. That would be 3 dB to get to 20 MHz, and, each time the sum becomes less than 3 dB, as the highest frequency dominates. It would only degrade approximately a total of 10 dB vs. the 17 dB from a regular times 7. Regards - 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 Bill Hawkins Sent: Tuesday, December 21, 2010 2:55 PM To: 'Discussion of precise time and frequency measurement' Subject: Re: [time-nuts] What is the best way to multiply a 10 Mhz So, two doublers for 40 MHz and a tripler for 30 and then mix to get 70? What happens to phase noise when you do that? Is it as bad as a PLL? Seems like you ought to get adequate harmonic rejection. What about six mixers to get 20, 30, 40, 50, 60, and 70 MHz? Chips and tank coils are cheap, no? Bill Hawkins -Original Message- From: Burt I. Weiner Sent: Tuesday, December 21, 2010 1:39 PM It would seem the most jitter free way to do it would be to simply multiply it up like we used to do. Some reasonably Hi-Q LC circuits could make a nice flywheel and filter out other signals at the same time. Once you have it to the desired signal frequency you could condition it to clock your DDS. Am I missing something here? Wouldn't be the first time, ya know! Burt, K6OQK Subject: Re: [time-nuts] what is the best way to multiply a 10 Mhz signal? On 21/12/10 16:35, Stephen Farthing wrote: Hi everyone, I want to multiply the output from my Efratom 101 (10Mhz) to clock a DDS at 70 Mhz. Has anyone tried this? Regards, Steve G0XAR ___ 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] Form factor
Hi all, You might also consider these Hammond Like cabinets... http://www.rfsupplier.com/index.php?cpath=103 I've used one for a project, very nice. regards Tim -- VK2XTT :: QF56if :: BMARC :: WIA :: AMSAT-VK :: AMSAT ___ 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] What is the best way to multiply a 10 Mhz
Mike Feher wrote: The 6 mixer scheme was my first thought for lowest PN. That way you do not get 20logN, but you just get the RMS sum of the noise power each time. That No, this is a fallacy because phase noise adds coherently, so that each doubler adds 6 dB and each tripler adds 9.54 dB. There is no way to get around 20 LOG N, no matter how you implement the multiplier even if you add a tripler output to a quadrupler output, where phase noise also adds coherently. Rick Karlquist N6RK ___ 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] West coast LORAN
Has anybody on the west coast tried to pick up LORAN stations from north west Pacific? Does anybody have any idea of how long those transmitters are likely to keep running? -- These are my opinions, not necessarily my employer's. I hate spam. ___ 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] UBLOX GPS board testing
I tried substituting the 1 PPS output from the Z3801 and comparing it to its own 10 MHz output and find the same jumpy behavior as I get with the UBLOX boards. Well, not exactly the same but pretty much. Now I am confused. I expected the 1 PPS to be in lock step with the 10 MHz. ___ 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] LORAN C antenna thoughts from the group
John I believe that it is usable certainly from the pre-amplified whip that I picked up 90070 last night on. The downside is you have to be awake at 0300. One of those nights. As I mentioned my GPS comparison was not very good because I forgot to rehook the gps antenna up to the hp3801. Do. Explains that pretty well. Is there a real advantage to a 4 or 6 foot big loop compared to a small loop? I use a 3 foot loop on wwvb/preamp and that works well. One other point on the wavefrom on loran c. It was constructed to minimize the impact of skywave influence on the receiver. Essentially making it easier for the receiver to distinguish between the two. Thast what I hadread in the loran docs. Regards Paul. PS I thought the bw was +/- 10KC and even wider. On Tue, Dec 21, 2010 at 3:11 PM, J. Forster j...@quik.com wrote: I was more interested in reducing the BW, rather than increasing it. Years ago, I bought up some of the resuidual of Appelco, a New Hampshire LORAN company that made units for Raytheon. Included were a bunch of active tunable filters, designed to tune out interference. However, there is no documentation. I was just toying with the idea that a good shielded (possibly active) loop, the tunable filters, and an Austron 2100F might still be usable on the east coast. FWIW, -John In message 53187.12.6.201.2.1292957970.squir...@popaccts.quikus.com, J. Fors ter writes: I remember reading somewhere that the envelope of the LORAN pulses was shaped to reduce the transmitted BW. The envelope is designed for two things: sensible BW and ease of production. There is some math musing about it in the Radiation Lab book. Does anybody have a reference for that, and relatedly, what does the BW of the antenna have to be? Typically, loops are about 90 KHz to 110 KHz, but can that be narrowed down? In principle you can make it as narrow as you want, and compensate for the resulting pulse-shape distortion in your receiver. Going much wider than 30kHz (85-115kHz) usually results in more interference from CW signals than improvement to the loran signal. You can see a typical power spectrum at the bottom of this page: http://phk.freebsd.dk/loran-c/Antenna/ Poul-Henning -- 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. ___ 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] LORAN C antenna thoughts from the group
In message aanlktimsqshe+yehhhydw2v2edj855sszt78mpqch...@mail.gmail.com, paul swed writes: Is there a real advantage to a 4 or 6 foot big loop compared to a small loop? I use a 3 foot loop on wwvb/preamp and that works well. There is a very good and simple explanation of the theory behind loops here: http://www.vlf.it/octoloop/rlt-n4ywk.htm Sensitivity rises with the area of your loop, so doubling the diameter gives you four times the signal, which may or may not be a relevant low number of dB. One other point on the wavefrom on loran c. It was constructed to minimize the impact of skywave influence on the receiver. Essentially making it easier for the receiver to distinguish between the two. Thast what I hadread in the loran docs. Yes, this is why you should always zoom in on the 3rd positive zero-crossing. Inside the announced service areas, the skywave will never arrive early enough to disturb the groundwave at that point. PS I thought the bw was +/- 10KC and even wider. Yes, it is, but the amount of actual energy once you get past +/- 10kHz or 15kHz is very very limited. The perfect bandwidth is where the S/N of the loran-C signal is 1:1, but I have never found a good way to determine that automatically. -- 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] West coast LORAN
No idea at all. I am a east coaster. On Tue, Dec 21, 2010 at 4:00 PM, Hal Murray hmur...@megapathdsl.net wrote: Has anybody on the west coast tried to pick up LORAN stations from north west Pacific? Does anybody have any idea of how long those transmitters are likely to keep running? -- These are my opinions, not necessarily my employer's. I hate spam. ___ 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] UBLOX GPS board testing
Don't be burting my trust bubble here. I would have thought they would be the same. Now you are making me think. On Tue, Dec 21, 2010 at 4:26 PM, John Green wpxs...@gmail.com wrote: I tried substituting the 1 PPS output from the Z3801 and comparing it to its own 10 MHz output and find the same jumpy behavior as I get with the UBLOX boards. Well, not exactly the same but pretty much. Now I am confused. I expected the 1 PPS to be in lock step with the 10 MHz. ___ 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] LORAN C antenna thoughts from the group
Thanks will read the link. Think I have in the past but did not have a need. I might guess 4 db would be quite helpful in this effort. I still have some garbage I am seeing that I will need to hunt down. But its not within the house so that really makes things interesting. On Tue, Dec 21, 2010 at 5:14 PM, Poul-Henning Kamp p...@phk.freebsd.dkwrote: In message aanlktimsqshe+yehhhydw2v2edj855sszt78mpqch...@mail.gmail.comaanlktimsqshe%2byehhhydw2v2edj855sszt78mpqch...@mail.gmail.com, paul swed writes: Is there a real advantage to a 4 or 6 foot big loop compared to a small loop? I use a 3 foot loop on wwvb/preamp and that works well. There is a very good and simple explanation of the theory behind loops here: http://www.vlf.it/octoloop/rlt-n4ywk.htm Sensitivity rises with the area of your loop, so doubling the diameter gives you four times the signal, which may or may not be a relevant low number of dB. One other point on the wavefrom on loran c. It was constructed to minimize the impact of skywave influence on the receiver. Essentially making it easier for the receiver to distinguish between the two. Thast what I hadread in the loran docs. Yes, this is why you should always zoom in on the 3rd positive zero-crossing. Inside the announced service areas, the skywave will never arrive early enough to disturb the groundwave at that point. PS I thought the bw was +/- 10KC and even wider. Yes, it is, but the amount of actual energy once you get past +/- 10kHz or 15kHz is very very limited. The perfect bandwidth is where the S/N of the loran-C signal is 1:1, but I have never found a good way to determine that automatically. -- 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] What is the best way to multiply a 10 Mhz
Am 21.12.2010 21:41, schrieb Rick Karlquist: No, this is a fallacy because phase noise adds coherently, so that each doubler adds 6 dB and each tripler adds 9.54 dB. There is no way to get around 20 LOG N, no matter how you implement the multiplier even if you add a tripler output to a quadrupler output, where phase noise also adds coherently. Yes, it adds coherently because it stems from the same source. It is easier to see in the time domain: 1ps of jitter on a 10 MHz carrier, when multiplied to 100 MHz is still 1 ps of jitter, just look at the zero crossings. But at 100 MHz, the jitter percentage of 1 ps to the 360° is 10 times as bad, because the 360 degrees/s have shrunk. So, a phase detector will give 10 times the output voltage or 20 dB more power. No way around this. Gerhard, dk4xp ___ 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] UBLOX 1pps vs Z3801A
John, The Z3801A 1pps is based on the mean UTC/GPS time, but regenerated from the local (very stable) 10MHz reference, so has little jitter. The UBLOX GPS module 1pps output is more or less instantaneous, so has jitter resulting from each individual position solution. If you provide it with a known position, the jitter will be reduced, but still not as good as the regenerated 1pps from the Z3801A. The jitter is much greater if 'Selective Availability' is on. One of the important factors in designing and building your own GPSDO is to shield your stable OCXO from this timing jitter. The aim is to have the going rate of the OCXO follow UTC/GPS, not the jitter, SA, fix solution or diurnal satellite variations. Murray ZL1BPU -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of time-nuts-requ...@febo.com Sent: Wednesday, 22 December 2010 11:47 a.m. To: time-nuts@febo.com Subject: time-nuts Digest, Vol 77, Issue 97 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. West coast LORAN (Hal Murray) 2. Re: UBLOX GPS board testing (John Green) 3. Re: LORAN C antenna thoughts from the group (paul swed) 4. Re: LORAN C antenna thoughts from the group (Poul-Henning Kamp) 5. Re: West coast LORAN (paul swed) 6. Re: UBLOX GPS board testing (paul swed) 7. Re: LORAN C antenna thoughts from the group (paul swed) 8. Re: What is the best way to multiply a 10 Mhz (Gerhard Hoffmann) -- Message: 1 Date: Tue, 21 Dec 2010 13:00:55 -0800 From: Hal Murray hmur...@megapathdsl.net Subject: [time-nuts] West coast LORAN To: time-nuts@febo.com Message-ID: 20101221210055.66c18800...@ip-64-139-1-69.sjc.megapath.net Content-Type: text/plain; charset=us-ascii Has anybody on the west coast tried to pick up LORAN stations from north west Pacific? Does anybody have any idea of how long those transmitters are likely to keep running? -- These are my opinions, not necessarily my employer's. I hate spam. -- Message: 2 Date: Tue, 21 Dec 2010 15:26:54 -0600 From: John Green wpxs...@gmail.com Subject: Re: [time-nuts] UBLOX GPS board testing To: time-nuts@febo.com Message-ID: aanlkti=9ae5k216qmopzq+ve0w9v5w8-2evgvdi2g...@mail.gmail.com Content-Type: text/plain; charset=ISO-8859-1 I tried substituting the 1 PPS output from the Z3801 and comparing it to its own 10 MHz output and find the same jumpy behavior as I get with the UBLOX boards. Well, not exactly the same but pretty much. Now I am confused. I expected the 1 PPS to be in lock step with the 10 MHz. -- Message: 3 Date: Tue, 21 Dec 2010 17:09:10 -0500 From: paul swed paulsw...@gmail.com Subject: Re: [time-nuts] LORAN C antenna thoughts from the group To: j...@quik.com, Discussion of precise time and frequency measurement time-nuts@febo.com Message-ID: aanlktimsqshe+yehhhydw2v2edj855sszt78mpqch...@mail.gmail.com Content-Type: text/plain; charset=ISO-8859-1 John I believe that it is usable certainly from the pre-amplified whip that I picked up 90070 last night on. The downside is you have to be awake at 0300. One of those nights. As I mentioned my GPS comparison was not very good because I forgot to rehook the gps antenna up to the hp3801. Do. Explains that pretty well. Is there a real advantage to a 4 or 6 foot big loop compared to a small loop? I use a 3 foot loop on wwvb/preamp and that works well. One other point on the wavefrom on loran c. It was constructed to minimize the impact of skywave influence on the receiver. Essentially making it easier for the receiver to distinguish between the two. Thast what I hadread in the loran docs. Regards Paul. PS I thought the bw was +/- 10KC and even wider. On Tue, Dec 21, 2010 at 3:11 PM, J. Forster j...@quik.com wrote: I was more interested in reducing the BW, rather than increasing it. Years ago, I bought up some of the resuidual of Appelco, a New Hampshire LORAN company that made units for Raytheon. Included were a bunch of active tunable filters, designed to tune out interference. However, there is no documentation. I was just toying with the idea that a good shielded (possibly active) loop, the tunable filters, and an Austron 2100F might still be usable on the east coast. FWIW, -John In message 53187.12.6.201.2.1292957970.squir...@popaccts.quikus.com, J. Fors ter writes: I remember reading
Re: [time-nuts] UBLOX GPS board testing
On 12/21/2010 10:26 PM, John Green wrote: I tried substituting the 1 PPS output from the Z3801 and comparing it to its own 10 MHz output and find the same jumpy behavior as I get with the UBLOX boards. Well, not exactly the same but pretty much. Now I am confused. I expected the 1 PPS to be in lock step with the 10 MHz. Sometimes counters has a problem when the start and stop signals occur too tight in time after each other. Running the Stop signal through some extra cable avoid the trigger issue and out pops stable readings. Since each meter of coax adds 5 ns of delay, it is a pretty handy method of getting out of trouble. Do measure the PPS to Clock property of your GPS. If your counter needs it, use the cable trick above to get stable measurements. A month ago Björn and I did some experiments together, found in my posting of 20 Nov titled PPS and 5/10 MHz GPSDO time relationship: 8--- Fellow time-nuts, Björn and I have been having some fun during our get-together in his basement time-lab. I pulled with me some gear (CNT-90 and SR620) for him to play with, so a good warmup exercise was to measure the offset between the PPS and the clock output (5 MHz or 10 MHz). The results was uhm... spread out... so we felt like sending you guys a report. First out was a RAPCO 1804M which has a HCD 66 SC 5 MHz oven diciplined by an old Trimble SV6+ (?) GPS receiver. We popped the lid for other purposes... :) It had the 5 MHz rising edge 32,17 ns behind the PPS rising edge, with 100 ps RMS jitter. Quite noticeable offset but fair jitter. The good old RAPCO was jumperable to be on OSC or GPS on the mysterious jumper LK9 and it was stuck hard on the OSC setting, but some physical exercise later we got it into GPS setting and it had a about 200 ns peak to peak sawtooth... nice and pedagogical exercise. We then had a look at the Brandywine GPS-4 (mine on loan to Björn) and found it had fairly nice numbers... until we discovered it has a periodically reoccuring glitch of unknown system-source. Natually we hooked in to Björns Thunderbolt and found the offset so tight that we ran into trigger-problems, but offsetting the clock by about 8 ns of coax cable we had a about 4 ns in average and 6 ns peak-to-peak. The PPS thus jumped between two distinct offsets with their respective gaussian distribution around them. Not all that neat, and the RAPCO was the quietest in this shoot-out. Over and out, Magnus and Björn ---8 Once you know how your favorite GPSDO behaves, you should know if you can use the PPS directly as a quiet source or if you only should use it as an external ARM to trigger measurements and then use the clock for Start (Channel A) and DUT for Stop signal (Channel B). Going for the PPS-arming directly avoids the issue somewhat. When comparing a different frequency than 10 MHz I insert a generator which locks to the 10 MHz and produces the nominal frequency onto which I will do my measurements. Don't forget to optimize trigger jitter and verify it separately for the Start and Stop signals. Don't forget to let your DUT warmup. Cheers, Magnus ___ 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] Form factor
I wrote some more ideas, I'm trying here to write what might later, after some edits become a consensous document. that captures what most people want. Edit away, maybe some of this will make it to the web site... ++ Here is an idea for the top of the web page: How is the Open Counter project open. 1) The basic design of the counter is open to the addition of new modules and new technology. New modules can be pllugged in or replac older modules. The interface between modules is published, anyone is open to design or build a module 2) The design of each module is open for all to see. Anyone can provide kits or parts or make PCBs. (There may be some restrictions on commercial sales.) 3) The designs are publishing using open file formats that are industry standads 4) the design tools, compilers, schematic captures, word processors, used to read and modify the design files are available to all wit at the most a very modest fee or preferable are Open Source tools 5) the hardware is designed such that it can be physiclly built by anyone with amateur level skills. the parts can be build by an open group +++ Form Factor: One more idea. I think there is a way to have all of the above Let's say we agree to make all PCBs the same size as a 160-3U Eurocard but with four holes in the corners too. A real Eurocard system is expensive but I'm just saying to use the same size rectangle but no back plane. If you do this they will (mechanically, not electrically) fit in a Euro card cage they will also fit in those Hammond boxes and with four holes people can stack them on threaded rods with spacers or mount them in 1U chassis on standoffs. They could also by mounted with standoffs to a disk sled and then go into a computer or file server chassis. The spec is easy to write and understand too: Cards shall be 100mm x 160mm, less than 2mm thick and have 5mm holes in each corner spaced 5mm from each edge. These cards would fit perfectly into a Hammond 1455P2201 box or as I said above mounted just about any way that has so far been suggested. + The next thing to work on is the rear facing edge of the card. We really need to minimize the number of different connectors and signal levels. The smaller the set the better. I'll take a stabe at it below and This is for the REAR edge: 1) power: four pins on 0.1 inch centers for +12, -12, +5 and ground 2) frequency reference can be 1Hz, 10MHz or ?? as required but will use SMA connector 3) Data, for command and setup and digital output wiil use a shared 100Kbps i2c bus (also called two wire) Each card is to have two connectors so the multiple cards can be diasy chained. cards shall NOT allow there internal components to be visible on this external i2c bus. 4) Many cards such as a trigger or pre-scaeler will produce output signals that need to to sent point to point to the rear edge of other cards I'll suggest SMA for this (I hope this covers everything. unless we might need digitized signals and these can be very high bandwidth) The FRONT edage of each card is reserved entirely for signals that the user would directly interact with, such as input jacks or status/power LED or a data connectors for a computer or network The next level of interface design is the format of the data to go over the I2C bus. Some ideas. 1) Each card type (trigger, counter, Interface,...) will have it's own unique number. Each physial card will have it's own instance number So if two cards of the same type are in the system each is numbered 0, 1, 2,.. Cards in an Open Counter are identified by combining the two numbers. There are many options but all allow for over 100 cards in one system. 2) As a minimum each card must implement one command, that would be Identify yourself. The card must respond with at least a one bit status saying present. By this mmeans any card can find out what other cards are present. ++ At some point we need to say what is and what is not an Open Counter Open Counter System requirements. 1) An Open Counter system will always require a minimum of two cards with one being an Interface card and the other some kind of signal handing card. An Interface card connects the data in the 12c system bus to a computer, network or to a human operator via a display or status LEDs. 2) Notwithstanding the above, single cards must be usable devices when used by themselves. cards may poll the (disconnected) i2c bus to find that they are isolated and then must default to standalone mode. 3) Cards must allow that multiple instance of their own type may be connected on the same system i2c bus, that is, all output data shall include the card's instance number. (This allows for a multi channel Open Counter) This requirement applies to
[time-nuts] My Garmin 18x, Ver 3.50, currently 1 second slow to UTC
Calling any Garmin 18x users, I noticed this morning that my Garmin 18x was giving the time 1 second slow to UTC - it has been running in sync with UTC for about 2 years now. Garmin has recently ( 13th Dec 2010 ) changed the 18x firmware from 3.30 to 3.50, so I updated my GPS sensor just now to the new version 3.50 - and it is still 1 second slow to UTC. I tried two of my older Garmin 18 (no x) modules, and they are in sync with UTC. All three Garmins are showing (on the $PGRMF sentence) that the delta between GPS time and UTC is 15 seconds (which is correct). I guess it is that time of the year when pending leap seconds can apply (although Dec 31 2010 is NOT going to be a leap second year). So I wondered, any other folk out there with a Garmin 18x - is it 1 second slow to UTC ? Regards, Kiwi Geoff (Christchurch, New Zealand). ___ 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] UBLOX GPS board testing
On Tue, 21 Dec 2010 15:26:54 -0600, John Green wrote: I tried substituting the 1 PPS output from the Z3801 and comparing it to its own 10 MHz output and find the same jumpy behavior as I get with the UBLOX boards. Well, not exactly the same but pretty much. Now I am confused. I expected the 1 PPS to be in lock step with the 10 MHz. With a Z3815A (Furuno receiver, E1938A oscillator) I noticed the PPS to jump up and down by 2 ns pk-pk in average. On a plot of phase difference to a more stable 10 MHz source, the upper and lower values formed two lines, leading to the assumption of it being quantization steps. (The time interval measurement resolution was significantly better, using a HP 5370B.) I have since dropped the idea of using this PPS for stability measurements by feeding it to the TIC and will use a PPS externally divided down from 10 MHz instead. -- Neu: GMX De-Mail - Einfach wie E-Mail, sicher wie ein Brief! Jetzt De-Mail-Adresse reservieren: http://portal.gmx.net/de/go/demail ___ 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] Editing, nitpicking, and graciousness
List, I, and I suspect many others, archive this list on a word processor to save its information for projects and learning. That said, there are a number on this list who do not edit their replies to a thread so we end up with pages upon pages of previous postings. If one or more people do this, besides violating the lists protocol, It makes it extremely difficult to follow the postings. So in essence by not editing the effectiveness of the responses are greatly diminished. Some seem to delight in nitpicking minutia details. Look at the whole message. Does it really have to be absolutely 100 percent accurate to be valid? Come on give it a break. For most of us this is a hobby and we don’t have advanced science degrees. All have some or a great deal of expertise in one or more areas but no one has great expertise in ALL areas. This leads nicely into my last comment on civility. All of us are wrong or mis-guided at times. A helpful private email correction is appreciated. Being sarcastic to the poster in public isn’t. I try to remember this wise adage: Be Careful Of The Toes You Step On Today As They May Be Attached To The Butt You Have To Kiss Tomorrow. Regards, Perrier ___ 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] My Garmin 18x, Ver 3.50, currently 1 second slow to UTC
I noticed this morning that my Garmin 18x was giving the time 1 second slow to UTC - it has been running in sync with UTC for about 2 years now. I assume it was working correctly previously. If not... At least one GPS receiver I've used is off by a second. There is an ambiguity as to whether the time applies to the previous or next PPS. I assume that's why they got it wrong, but maybe they are just off by one for some other reason. So I wondered, any other folk out there with a Garmin 18x - is it 1 second slow to UTC ? I've seen Garmin 18s (probably no x) be off by a second, but that was only for a transient. I haven't chased it. I assumed it was when recovering from not-enough satellites. (I'm running them inside, poor signal.) -- These are my opinions, not necessarily my employer's. I hate spam. ___ 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] What is the best way to multiply a 10 Mhz
It is easier to see in the time domain: 1ps of jitter on a 10 MHz carrier, when multiplied to 100 MHz is still 1 ps of jitter, just look at the zero crossings. But at 100 MHz, the jitter percentage of 1 ps to the 360° is 10 times as bad, because the 360 degrees/s have shrunk. So, a phase detector will give 10 times the output voltage or 20 dB more power. No way around this. I'm interested too because I have several of the same DDS chip that I will want to drive from a 10Mhz GPSDO. First off let's look at what the DDS chips needs. It wants a square wave input an exact 50% duty cycle is not required. We do want very low jitter in the clock. OK I see how the above applies if you just look at one cycle of the 10MHz but my simple plan was to use a PLL with divide by 10 in the filter but I figure you do better than you describe because there is a low pass filter on the voltage that controls the 100Mhz VCO. So in effect the controlling voltage is the running average of many phase detection errors. My plan was this... 1) A 100 Mhz voltage controlled crystal oscillator will drive the DDS chip 2) this same 100MHz is also divided by 10 and sent to phase detector in PLL chip 3) error signal from chip goes to low pass filter them to the 100Mhz VCXO. I think this is 100% classic PLL multiplier design that goes back decades. As I understand it this can work well if my VCXO is stable over a period of 30 minutes or so. I think al thesmarts is in picking the time constant for the low pass filter. -- = Chris Albertson Redondo Beach, California ___ 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] Form Factor
Tom wrote: Hammond boxes are great to work with and are reasonably inexpensive. You can stack multiple boards inside, and panels are available in aluminum or plastic. Hammond will make custom lengths, just for asking. I'm still using similar extrusions left over from a project we did years ago. The extrusions we used do not have one slide-off side as the Hammond boxes do, so to access the circuitry you have to pull the card(s) out. However, they provide better RF shielding. I don't remember who we got the extrusions from, but they were stock items and there were a number of suppliers. Starting with raw extrusions brings the cost per box down considerably, even if you have them finished (we had ours grained and anodized). Best regards, Charles ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] LORAN C is good again tonight 90070
OK getting a bit more information I can acquire and track the 90070 chain in the North East US. First settle occurred at 1900 local and tracking at 2000. Austron terms. The 2100f seems to grab the signal quickly the 2100 seems to have a far harder time. Signal strength is 80 db and noise is 1200. I have not tried the Austron 2000c yet or the SRS FS700 yet. Still using a preamplified whip. Good news is that GPS is rolling down nicely. Currently -2.8 e10. Given numbers of hours think it will do better. Thus making Europe a viable LORAN C frequency reference. Kind of amazing actually considering it must be 3000 miles and only skywave. Regards Paul WB8TSL ___ 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] Question on GPS and reference standards
A good question for the group... /tvb Hi: I have both a GPS Frequency standard (Trimble Thunder Bolt) which outputs the 10 MHz reference and also the 1 PPS signal. In addition, I have a Collins AEU unit which has a 10 MHz Rubidium reference inside. Both units work well and produce a very accurate reference signal for the units that require a 10 MHz reference. The challenge is that I am looking for a source of a 10:1 frequency divider so I can create a 1 MHz reference for my Rockwell Collins HF-80 system. Can you suggest a source of a high quality frequency divider that outputs a (nearly) sine wave signal? We only need two units - one for production and one for our development lab. The object is to provide a very accurate source of 1 MHz and 10 MHz to the various radio systems used in our disaster and humanitarian relief radio network. When you send data, you need to be exactly on frequency. Any help would be great. Just need to be pointed in the right direction. While we could try to design something to meet this objective, I am sure that someone has already done this. Thank you. Kevin ___ 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] Question on GPS and reference standards
A conjugate regenerative divider will have asinewave output. It only requires a mixer an amplifier or two and a couple of bandpass filters. It will have lower phase noise than all(?) alternative techniques. Bruce Tom Van Baak wrote: A good question for the group... /tvb Hi: I have both a GPS Frequency standard (Trimble Thunder Bolt) which outputs the 10 MHz reference and also the 1 PPS signal. In addition, I have a Collins AEU unit which has a 10 MHz Rubidium reference inside. Both units work well and produce a very accurate reference signal for the units that require a 10 MHz reference. The challenge is that I am looking for a source of a 10:1 frequency divider so I can create a 1 MHz reference for my Rockwell Collins HF-80 system. Can you suggest a source of a high quality frequency divider that outputs a (nearly) sine wave signal? We only need two units - one for production and one for our development lab. The object is to provide a very accurate source of 1 MHz and 10 MHz to the various radio systems used in our disaster and humanitarian relief radio network. When you send data, you need to be exactly on frequency. Any help would be great. Just need to be pointed in the right direction. While we could try to design something to meet this objective, I am sure that someone has already done this. Thank you. Kevin ___ 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] Question on GPS and reference standards
Not knowing all the particulars and requirements, I may be off base, but instead of spending money trying to frequency stabilize a 20+ year old radio (HF-80), wouldn't it make more sense to spend it on a modern, inexpensive HF rig? You can even get a TCXO option for some rigs. This should be stable enough for most common HF data protocols. I assume that this is for Amateur use? If not, then my comments may not apply. Joe Gray W5JG On Tue, Dec 21, 2010 at 9:48 PM, Bruce Griffiths bruce.griffi...@xtra.co.nz wrote: A conjugate regenerative divider will have asinewave output. It only requires a mixer an amplifier or two and a couple of bandpass filters. It will have lower phase noise than all(?) alternative techniques. Bruce Tom Van Baak wrote: A good question for the group... /tvb Hi: I have both a GPS Frequency standard (Trimble Thunder Bolt) which outputs the 10 MHz reference and also the 1 PPS signal. In addition, I have a Collins AEU unit which has a 10 MHz Rubidium reference inside. Both units work well and produce a very accurate reference signal for the units that require a 10 MHz reference. The challenge is that I am looking for a source of a 10:1 frequency divider so I can create a 1 MHz reference for my Rockwell Collins HF-80 system. Can you suggest a source of a high quality frequency divider that outputs a (nearly) sine wave signal? We only need two units - one for production and one for our development lab. The object is to provide a very accurate source of 1 MHz and 10 MHz to the various radio systems used in our disaster and humanitarian relief radio network. When you send data, you need to be exactly on frequency. Any help would be great. Just need to be pointed in the right direction. While we could try to design something to meet this objective, I am sure that someone has already done this. Thank you. Kevin ___ 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.
