Re: [time-nuts] ADF4002 phase noise - in FireFly-IIA-100MHz
from my limited understanding of things I would have guessed that the ADF4001/2 PFD's ability to produce very short pulses in the locked condition puts a lot of energy into higher harmonics of the PFD's output, making it more easy for the loop filter to remove them. In contrast to that the simple rectangle from an XOR has most of its energy in the lower harmonics. That is why I have believed AD's claims to have a real low noise PFD in these devices. Is the theory all that wrong or do you expect other factors to be responsible for the not superiour performance? My guess is that the ratio of the loop bandwidth to the comparison frequency is so dramatic in these cases -- on the order of 100,000:1 -- and the VC(X)O has such low tuning sensitivity, that there are unlikely to be any observable effects related to the PD output waveform. These typically show up as comparison-frequency sidebands rather than as broadband noise, in any event. I have actually never built a loop with an XOR gate; I've always used PFDs of one stripe or another. Let me put forward the question in another way: Had you to lock a 100 MHz VCXO to a 10 MHz reference, what other chip had you used that you believe is the better performer? Please no injection locking or even stranger, just plain PLL. I don't think there are any magic chips that will deliver state-of-the-art performance in this application, unfortunately. If I really wanted to tweak a multiplier like that to the max, I'd be tempted to multiply the 10 MHz signal to 100 MHz with a tuned multiplier chain, and then use the OCXO to 'filter' it, using a mixer as the phase detector and no digital dividers at all. By the same token, a regenerative divider to bring the OCXO down to 10 MHz would also work well. Careful construction and a lot of tweaking would be needed, either way. In practice I'm OK with an inband noise floor of around -115 dBc/Hz as delivered by the ADF4002, as long as it falls off steeply beyond the loop BW (which it does, reaching ~-150 dBc/Hz by 1 kHz and well under -160 dBc/Hz by 10 kHz). Most DDS or ADC chips that I'm likely to drive with such a source will see little if any degradation beyond their residual specs. I am in the state of constructiong a 10 to 100 MHz multiplier and your advice is highly appreciated, until now I have been thinking the ADF4002 could be an improvement against my usual AD9901 cover design in an FPGA or CPLD. More experiments need to be done, certainly. There have been a number of FPGA/CPLD reflock modules designed by various people over the years, but I haven't seen any really good measurements of what they can do. With the ADF chips, the last few dBc/Hz of inband performance always seem to come down to the amount of care you take with the input signal conditioning, and I don't think the FPGA/CPLD phase detector would be very different in that regard. -- john, KE5FX ___ 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] nubie querie
Concerning my query about what's good enough to count as a contact... We've done Moonbounce with 3mW (Hobart - Dwingeloo) in JT65 - but a 26m and a 25m dish is stretching 'amateur' a bit again. Googling for JT65 finds a nice paper: http://www.arrl.org/FandES/field/regulations/techchar/18JT65.pdf The JT65 Communications Protocol Joe Taylor, K1JT It's a fun read. 17 pages. The basic idea seems to be that amateurs (hams) have to exchange station IDs. That's more than a few bits, but not a huge number. JT65 is a compact protocol for doing that in a (very) weak signal environment. Their packet format is 72 bits expanded to 378 by forward error correcting. On top of that, they use half of the time for a synchronizing signal so the receiver can find the transmitter's time and frequency. Each 72 bit packet takes 1 minute to send. Their modulation scheme is 1 of 65 tones. 6 bits per baud. The extra tone is the synchronizing 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] nubie querie (Earth Venus Earth, done!)
Sorry, it's already been done I believe. http://freenet-homepage.de/dl4yhf/speclab/earth_venus_earth.htm Some years ago, like nearly 20, I helped some friends and built a 224 element broadside colinear aray for EME. It (eventualy) worked realy well. Echoes could be heard under good conditions with 5W I seem to recall (and no computer driven DSP tools then.) We also did so far (as we know) the only mobile EME contact, between G8MBI/m and W5UN. As a result, I think my Land Rover holds the world 2m mobile DX record (regardless how you calculate it.) Also the World EME land speed record (45MPH). http://www.rfham.com/g8mbi/mbi.htm and scroll down about 3/4 down the page. 73. Dave G0WBX. Not sure about being a fully qualified Time Nut, but a Nut none the less! The sticker on the back door of the Landie these days also confims it. This vehicle may contain nuts -Original Message- Date: Wed, 10 Mar 2010 14:32:33 -0700 From: David Forbes dfor...@dakotacom.net Subject: Re: [time-nuts] nubie querie To: Discussion of precise time and frequency measurement time-nuts@febo.com Message-ID: 4b980ff1.7040...@dakotacom.net Content-Type: text/plain; charset=ISO-8859-1; format=flowed Hal Murray wrote: This, and similar impressive accomplishments, has prompted some lunchtime discussion at work (JPL).. One of us (N5BF) has been contemplating what it would take to do an amateur EarthVenusEarth (after some of his experiments doing EME with 5 watts).. Perhaps a better question is: What is the bandwidth? What sort of signal do I have to receive in order to claim contact? Is one bit/blob of energy at the right time/frequency good enough, or do I have to demodulate the signal and extract a few bits of data? Marconi claimed credit for the first transatlantic communication by sending the letter S in Morse code. That sounds like a fine standard - one byte of data. It's statistically significant. With regard to the restoration and use of a derelict radio telescope for amateur radio, that's a fine example of amateurs putting themselves to a big task and succeeding. I work on radio telescopes, so I know how big a task that is. --David Forbes -- ___ 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] nubie querie
Hal Murray wrote: Concerning my query about what's good enough to count as a contact... We've done Moonbounce with 3mW (Hobart - Dwingeloo) in JT65 - but a 26m and a 25m dish is stretching 'amateur' a bit again. Googling for JT65 finds a nice paper: http://www.arrl.org/FandES/field/regulations/techchar/18JT65.pdf The JT65 Communications Protocol Joe Taylor, K1JT It's a fun read. 17 pages. The basic idea seems to be that amateurs (hams) have to exchange station IDs. That's more than a few bits, but not a huge number. JT65 is a compact protocol for doing that in a (very) weak signal environment. Their packet format is 72 bits expanded to 378 by forward error correcting. On top of that, they use half of the time for a synchronizing signal so the receiver can find the transmitter's time and frequency. Each 72 bit packet takes 1 minute to send. Their modulation scheme is 1 of 65 tones. 6 bits per baud. The extra tone is the synchronizing signal. 6 bits per symbol. 1 baud is 1 symbol per second. Happy to see someone using baud, just unhappy about seeing it being used incorrectly. An amusing error was found in one of our early datasheets. For some reason they wanted to tell the signal rate, so they said 1,0625 GBaud/s. I found that very amusing to have symbol acceleration... it gets faster every second!!! Just keep a fixed bit/symbol ratio and you have a hell of a product. Later in life it will transport all of universe into a black hole. 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] nubie querie
mag...@rubidium.dyndns.org said: Their modulation scheme is 1 of 65 tones. 6 bits per baud. The extra tone is the synchronizing signal. 6 bits per symbol. 1 baud is 1 symbol per second. Happy to see someone using baud, just unhappy about seeing it being used incorrectly. Thanks for correcting my screwup. -- 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] nubie querie
Hal Murray wrote: mag...@rubidium.dyndns.org said: Their modulation scheme is 1 of 65 tones. 6 bits per baud. The extra tone is the synchronizing signal. 6 bits per symbol. 1 baud is 1 symbol per second. Happy to see someone using baud, just unhappy about seeing it being used incorrectly. Thanks for correcting my screwup. No worries, I am sure you will return the favour when I screw up. I still wonder when people will limit themselves to using bandwidth only for denoting a frequency range. 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] Thermal time constant
Most building insulation foam sold here in UK has an Alu foil cladding on both sides ... Dave ___ 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] Thermal time constant
Predrag Dukic wrote: How well depleted it really is? DU has about 1/3 the U235 of natural U, of which less than 1% is U235. All the isotopes are radioactive, but I don't recall what the relative activities are. I think U238 has a half live of 4E9 years or more, so not very many atoms spontaneously disintegrate every second. Uranium separation is not perfect. Some radioactivity is still left. Not much.. you'd have more trouble if you lived on granite or lived in a brick/stone house. It's an alpha emitter, too, so painting it would provide shielding. It's the fact that it's a heavy metal that's more of an issue for toxicity. Don't know about the neutrons from the spontaneous fission. I don't think it is healthy to have it beside You for a long time. Certainly not 8 pounds :)) At 05:35 11.3.2010, you wrote: Bob Camp wrote: Hi The gotcha is that you are interested in the amount of heat per cubic foot rather than the amount of heat per pound. You need to take the standard heat per weight numbers and convert them to heat per volume numbers. Of the things you can easily get, copper is good. Steel is not as good as copper, but better than aluminum. Bob Gold is your friend. Mercury has convective losses because it's a liquid. Platinum or Osmium would also be ok. You might want something that is dense but lower conductivity.. lead? Depleted Uranium? (DU is available very cheaply if you can take 80,000 pound lots) ___ 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. __ Information from ESET NOD32 Antivirus, version of virus signature database 4933 (20100310) __ The message was checked by ESET NOD32 Antivirus. http://www.eset.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Thermal time constant
Hi Bob: How about just wrapping the aluminum block in aluminum foil with the shiny side out. Then wrap the Styrofoam cube with the shiny side in before putting it in the aluminum box? Have Fun, Brooke Clarke http://www.PRC68.com Bob Camp wrote: Hi Since styrofoam is being rated as a building insulation, it's reasonable to believe that the material on both sides is up around 1. I highly doubt that somebody tossing styrofoam in walls is going to add a radiation factor ... In our application we're talking about a metal block inside a metal enclosure, polishing the surfaces could drop the emissivity by10X. If the budget allows, you could gold plate the surfaces in addition to polishing them . Bob On Mar 10, 2010, at 8:01 PM, Bruce Griffiths wrote: Oops forgot a factor of 4 Radiative heat transfer for surface with an emissivity of 1 at 300K is about 612uW/square cm/degree C which is equivalent to about 25mm of styrofoam. Which raises the question what's the emissivity of the isothermal surface used when measuring the thermal resistance of a slab of styrofoam? Bruce Bruce Griffiths wrote: Radiative heat transfer (for a surface with an emissivity of 1) is around 150uW/square cm /degreeC at 300K. That's equivalent to about 10cm of styrofoam. It seems unlikely that the radiative heat transfer component is included in the thermal resistance rating for Styrofoam. The radiative component is independent of insulation thickness where the insulation doesnt absorb in the 10-30um infrared region. Adding carbon black to the foam appears to increase the thermal resistance of 25mm thick foam by about 10%. Bruce Bob Camp wrote: Hi That raises the interesting question of weather radiant transfer is already included in the rated thermal resistance. My guess is that the 8 of foam is enough to cover any radiation issues and still get you above 20 C / W. Since you are probably starting with 1 or 2 slabs, including the aluminum foil would be pretty easy. It can't hurt and it might help. Bob On Mar 10, 2010, at 7:29 PM, Neville Michie wrote: I have been wondering about achieving the rated thermal resistance from plastic foam, the problem being that radiant transmission may be very strong through the foam. What happens if you interleave concentric sheets of foam plastic with aluminium foil? (taking care to keep the foil on isothermal surfaces) Will this stop the radiant transfer and leave only the thermal conduction of the plastic foam? cheers, Neville Michie ___ 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/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] Lady Heather software help
Hi John, Thank You for taking the time, I am relatively New at this and would like to knows if I am interpreting the reading correctly. Best regards, Sal C. Cornacchia Electronic RF Microwave Engineer (Ret.) From: John Miles jmi...@pop.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thu, March 11, 2010 2:42:01 AM Subject: Re: [time-nuts] Lady Heather software help That's a common question; rest assured you are not alone in your confusion. One of us -- Mark or myself or some other doughty volunteer -- *will* eventually write a user guide of some sort... but the software itself is still undergoing too many tweaks. It's a bit too soon to nail down the UI by writing documentation for it. I usually run the 3.00 beta with the /ga /go /gm /x=100 switches, to help keep the graph area uncluttered and bring up the PPI-style satellite view. -- john, KE5FX -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on Behalf Of SAL CORNACCHIA Sent: Wednesday, March 10, 2010 10:54 AM To: time-nuts@febo.com Subject: [time-nuts] Lady Heather software help Hello Group members, I need some help interpreting Lady Heather software results like the colours and chart results for My Tbold GPS Receiver, any help would be appreciated as I am new at this. Best regards, Sal C. Cornacchia Electronic RF Microwave Engineer (Ret.) ___ 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] Thermal time constant
Hi Sounds cheaper than gold plating. I'd put a couple layers of foil in the 8 of foam as well. Maybe a layer every 2. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Brooke Clarke Sent: Thursday, March 11, 2010 9:48 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Thermal time constant Hi Bob: How about just wrapping the aluminum block in aluminum foil with the shiny side out. Then wrap the Styrofoam cube with the shiny side in before putting it in the aluminum box? Have Fun, Brooke Clarke http://www.PRC68.com Bob Camp wrote: Hi Since styrofoam is being rated as a building insulation, it's reasonable to believe that the material on both sides is up around 1. I highly doubt that somebody tossing styrofoam in walls is going to add a radiation factor ... In our application we're talking about a metal block inside a metal enclosure, polishing the surfaces could drop the emissivity by10X. If the budget allows, you could gold plate the surfaces in addition to polishing them . Bob On Mar 10, 2010, at 8:01 PM, Bruce Griffiths wrote: Oops forgot a factor of 4 Radiative heat transfer for surface with an emissivity of 1 at 300K is about 612uW/square cm/degree C which is equivalent to about 25mm of styrofoam. Which raises the question what's the emissivity of the isothermal surface used when measuring the thermal resistance of a slab of styrofoam? Bruce Bruce Griffiths wrote: Radiative heat transfer (for a surface with an emissivity of 1) is around 150uW/square cm /degreeC at 300K. That's equivalent to about 10cm of styrofoam. It seems unlikely that the radiative heat transfer component is included in the thermal resistance rating for Styrofoam. The radiative component is independent of insulation thickness where the insulation doesnt absorb in the 10-30um infrared region. Adding carbon black to the foam appears to increase the thermal resistance of 25mm thick foam by about 10%. Bruce Bob Camp wrote: Hi That raises the interesting question of weather radiant transfer is already included in the rated thermal resistance. My guess is that the 8 of foam is enough to cover any radiation issues and still get you above 20 C / W. Since you are probably starting with 1 or 2 slabs, including the aluminum foil would be pretty easy. It can't hurt and it might help. Bob On Mar 10, 2010, at 7:29 PM, Neville Michie wrote: I have been wondering about achieving the rated thermal resistance from plastic foam, the problem being that radiant transmission may be very strong through the foam. What happens if you interleave concentric sheets of foam plastic with aluminium foil? (taking care to keep the foil on isothermal surfaces) Will this stop the radiant transfer and leave only the thermal conduction of the plastic foam? cheers, Neville Michie ___ 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/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] HP10811 taxonomy?
It is entirely possible that a 10544 could have excellent aging and beat a 10811. The SC cut doesn't improve aging. The other disadvantages of the 10544 in terms of electronics also don't affect aging. The main advantage of the 10811 is that it is much better from a cold start in an instrument. Not something that affects time-nuts users. Rick Karlquist N6RK Robert Atkinson wrote: Hi Charles, See http://www.leapsecond.com/museum/10811a/90027-1.pdf for details of the 10811D/E versions and options. It's been appended to this copy of the A/B manual http://www.hparchive.com/Manuals/HP-10811AB-Manual.pdf Hope this helps. Robert G8RPI. --- On Thu, 11/3/10, Charles P. Steinmetz charles_steinm...@lavabit.com wrote: From: Charles P. Steinmetz charles_steinm...@lavabit.com Subject: [time-nuts] HP10811 taxonomy? To: Discussion of precise time and frequency measurement time-nuts@febo.com Date: Thursday, 11 March, 2010, 4:07 Has anyone compiled a taxonomy of the apparently numerous variants of 10811 OXOs? (Distinguishing features, rated performance, used in what instruments, etc.) Also, I found Mark's observation that 10544s may drift less than 10811s interesting. I own several 10544As and have experience with perhaps several dozen others, and think very highly of them, but haven't seen enough 10811s for a meaningful comparison (meaningful being a relative term, when the sample sizes are as low as dozens). What have others observed? 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 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] HP10811 taxonomy?
Hi A couple of possibilities: The 10544 has a bigger lump of quartz (BT is thicker) in it = good for aging. The 10544 could have been on power a lot longer = good for aging. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Richard (Rick) Karlquist Sent: Thursday, March 11, 2010 10:53 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] HP10811 taxonomy? It is entirely possible that a 10544 could have excellent aging and beat a 10811. The SC cut doesn't improve aging. The other disadvantages of the 10544 in terms of electronics also don't affect aging. The main advantage of the 10811 is that it is much better from a cold start in an instrument. Not something that affects time-nuts users. Rick Karlquist N6RK Robert Atkinson wrote: Hi Charles, See http://www.leapsecond.com/museum/10811a/90027-1.pdf for details of the 10811D/E versions and options. It's been appended to this copy of the A/B manual http://www.hparchive.com/Manuals/HP-10811AB-Manual.pdf Hope this helps. Robert G8RPI. --- On Thu, 11/3/10, Charles P. Steinmetz charles_steinm...@lavabit.com wrote: From: Charles P. Steinmetz charles_steinm...@lavabit.com Subject: [time-nuts] HP10811 taxonomy? To: Discussion of precise time and frequency measurement time-nuts@febo.com Date: Thursday, 11 March, 2010, 4:07 Has anyone compiled a taxonomy of the apparently numerous variants of 10811 OXOs? (Distinguishing features, rated performance, used in what instruments, etc.) Also, I found Mark's observation that 10544s may drift less than 10811s interesting. I own several 10544As and have experience with perhaps several dozen others, and think very highly of them, but haven't seen enough 10811s for a meaningful comparison (meaningful being a relative term, when the sample sizes are as low as dozens). What have others observed? 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 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] Thermal time constant
Hi Also true here in the US, but not for Styrofoam. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of David C. Partridge Sent: Thursday, March 11, 2010 8:53 AM To: 'Discussion of precise time and frequency measurement' Subject: Re: [time-nuts] Thermal time constant Most building insulation foam sold here in UK has an Alu foil cladding on both sides ... Dave ___ 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] nubie querie (Earth Venus Earth, done!)
I think the Dutch have done EVE; seems something passed by on Moon-Net in the past year... Don Dave Baxter Sorry, it's already been done I believe. http://freenet-homepage.de/dl4yhf/speclab/earth_venus_earth.htm Some years ago, like nearly 20, I helped some friends and built a 224 element broadside colinear aray for EME. It (eventualy) worked realy well. Echoes could be heard under good conditions with 5W I seem to recall (and no computer driven DSP tools then.) We also did so far (as we know) the only mobile EME contact, between G8MBI/m and W5UN. As a result, I think my Land Rover holds the world 2m mobile DX record (regardless how you calculate it.) Also the World EME land speed record (45MPH). http://www.rfham.com/g8mbi/mbi.htm and scroll down about 3/4 down the page. 73. Dave G0WBX. Not sure about being a fully qualified Time Nut, but a Nut none the less! The sticker on the back door of the Landie these days also confims it. This vehicle may contain nuts -Original Message- Date: Wed, 10 Mar 2010 14:32:33 -0700 From: David Forbes dfor...@dakotacom.net Subject: Re: [time-nuts] nubie querie To: Discussion of precise time and frequency measurement time-nuts@febo.com Message-ID: 4b980ff1.7040...@dakotacom.net Content-Type: text/plain; charset=ISO-8859-1; format=flowed Hal Murray wrote: This, and similar impressive accomplishments, has prompted some lunchtime discussion at work (JPL).. One of us (N5BF) has been contemplating what it would take to do an amateur EarthVenusEarth (after some of his experiments doing EME with 5 watts).. Perhaps a better question is: What is the bandwidth? What sort of signal do I have to receive in order to claim contact? Is one bit/blob of energy at the right time/frequency good enough, or do I have to demodulate the signal and extract a few bits of data? Marconi claimed credit for the first transatlantic communication by sending the letter S in Morse code. That sounds like a fine standard - one byte of data. It's statistically significant. With regard to the restoration and use of a derelict radio telescope for amateur radio, that's a fine example of amateurs putting themselves to a big task and succeeding. I work on radio telescopes, so I know how big a task that is. --David Forbes -- ___ 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. -- 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] nubie querie (Earth Venus Earth, done!)
At 20.33 11/03/2010, you wrote: I think the Dutch have done EVE; seems something passed by on Moon-Net in the past year... Don AMSAT DL, one year ago, using 6kW CW (injection locked magnetron) on 13 cm and a big parabolic reflector. See http://www.arrl.org/news/stories/2009/03/31/10738/?nc=1 73 - Marco IK1ODO ___ 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] ADF4002 phase noise - in FireFly-IIA-100MHz
Hi, In order to avoid a dead zone in a phase detector there is a current pulse in both the up and the down source. The net result when locked is zero but the noise is still there. Therefor the moved charge in lock should be as low as possible. The up and down currents must be as short as possible. Therefor a well designed PFD will out perform a EXOR. I allways designed for the shortest pulses. For the nmos current source I used 100ps but the pmos dictated to go to 300ps. Henk Op 10 mrt 2010, om 19:36 heeft saidj...@aol.com het volgende geschreven: Hi Ulrich, I think in our design the spec is limited by the ~-100dBc noise at 100Hz offset of the 100MHz VCXO. Please note that the ADF4002 actually improves that noise by about 15dB from the datasheet spec (or the unit we tested was that much better than the one shown in the datasheet). Also, the ADF4002 allows different Current settings for the PFD, this affects phase noise as well. Fine-tuning of these settings and the loop filter reduced the noise further. We use a 10MHz PFD output, so that should be optimal for phase noise. So in short, we improve the inherent close-in PN performance of the VCXO significantly. Would an Exor gate have resulted in better performance? Maybe. But the 10MHz spur on the VCXO EFC pin from the EXOR output may cause much higher spur levels at 10, 20, 30MHz etc on the VCXO output. And you would have to contend with counter noise (10:1 divider), and there would not have been flexibility in frequency, as well as a PLL Lock indicator.. bye, Said In a message dated 3/10/2010 07:19:14 Pacific Standard Time, df...@ulrich-bangert.de writes: Let me put forward the question in another way: Had you to lock a 100 MHz VCXO to a 10 MHz reference, what other chip had you used that you believe is the better performer? Please no injection locking or even stranger, just plain PLL. ___ 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] ADF4002 phase noise - in FireFly-IIA-100MHz
Thats only true when the current source noise dominates. When switching jitter on the pulse eges dominates the pulse width has no effect (to first order) on the noise. Since the supply rails are relatively noisy in an FPGA the current source noise will usually dominate in a CMOS XOR implemented in an FPGA. If the XOR supply noise can be made very low then its possible that the switching jitter noise contribution dominates. One example being the classical diode ring mixer with both IF and LO ports saturated. Bruce Henk wrote: Hi, In order to avoid a dead zone in a phase detector there is a current pulse in both the up and the down source. The net result when locked is zero but the noise is still there. Therefor the moved charge in lock should be as low as possible. The up and down currents must be as short as possible. Therefor a well designed PFD will out perform a EXOR. I allways designed for the shortest pulses. For the nmos current source I used 100ps but the pmos dictated to go to 300ps. Henk Op 10 mrt 2010, om 19:36 heeft saidj...@aol.com het volgende geschreven: Hi Ulrich, I think in our design the spec is limited by the ~-100dBc noise at 100Hz offset of the 100MHz VCXO. Please note that the ADF4002 actually improves that noise by about 15dB from the datasheet spec (or the unit we tested was that much better than the one shown in the datasheet). Also, the ADF4002 allows different Current settings for the PFD, this affects phase noise as well. Fine-tuning of these settings and the loop filter reduced the noise further. We use a 10MHz PFD output, so that should be optimal for phase noise. So in short, we improve the inherent close-in PN performance of the VCXO significantly. Would an Exor gate have resulted in better performance? Maybe. But the 10MHz spur on the VCXO EFC pin from the EXOR output may cause much higher spur levels at 10, 20, 30MHz etc on the VCXO output. And you would have to contend with counter noise (10:1 divider), and there would not have been flexibility in frequency, as well as a PLL Lock indicator.. bye, Said In a message dated 3/10/2010 07:19:14 Pacific Standard Time, df...@ulrich-bangert.de writes: Let me put forward the question in another way: Had you to lock a 100 MHz VCXO to a 10 MHz reference, what other chip had you used that you believe is the better performer? Please no injection locking or even stranger, just plain PLL. ___ 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] ADF4002 phase noise - in FireFly-IIA-100MHz
Hi If you are running a synthesizer with a 1 KHz reference frequency and trying to use a 900 MHz VCO for the output, reference spurs are going to be a major issue. If you are going straight from 10 MHz to 100 MHz with a crystal oscillator at 100 MHz, reference spurs should not be a significant problem. Different issues in different designs. Bob On Mar 11, 2010, at 4:56 PM, Bruce Griffiths wrote: Thats only true when the current source noise dominates. When switching jitter on the pulse eges dominates the pulse width has no effect (to first order) on the noise. Since the supply rails are relatively noisy in an FPGA the current source noise will usually dominate in a CMOS XOR implemented in an FPGA. If the XOR supply noise can be made very low then its possible that the switching jitter noise contribution dominates. One example being the classical diode ring mixer with both IF and LO ports saturated. Bruce Henk wrote: Hi, In order to avoid a dead zone in a phase detector there is a current pulse in both the up and the down source. The net result when locked is zero but the noise is still there. Therefor the moved charge in lock should be as low as possible. The up and down currents must be as short as possible. Therefor a well designed PFD will out perform a EXOR. I allways designed for the shortest pulses. For the nmos current source I used 100ps but the pmos dictated to go to 300ps. Henk Op 10 mrt 2010, om 19:36 heeft saidj...@aol.com het volgende geschreven: Hi Ulrich, I think in our design the spec is limited by the ~-100dBc noise at 100Hz offset of the 100MHz VCXO. Please note that the ADF4002 actually improves that noise by about 15dB from the datasheet spec (or the unit we tested was that much better than the one shown in the datasheet). Also, the ADF4002 allows different Current settings for the PFD, this affects phase noise as well. Fine-tuning of these settings and the loop filter reduced the noise further. We use a 10MHz PFD output, so that should be optimal for phase noise. So in short, we improve the inherent close-in PN performance of the VCXO significantly. Would an Exor gate have resulted in better performance? Maybe. But the 10MHz spur on the VCXO EFC pin from the EXOR output may cause much higher spur levels at 10, 20, 30MHz etc on the VCXO output. And you would have to contend with counter noise (10:1 divider), and there would not have been flexibility in frequency, as well as a PLL Lock indicator.. bye, Said In a message dated 3/10/2010 07:19:14 Pacific Standard Time, df...@ulrich-bangert.de writes: Let me put forward the question in another way: Had you to lock a 100 MHz VCXO to a 10 MHz reference, what other chip had you used that you believe is the better performer? Please no injection locking or even stranger, just plain PLL. ___ 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] 5370B OCXO
Hi The OCXO in the 5370B is a 10811-60111. The only added spec on it is a 1x10^-11 ADEV spec at 1 second. By modern standards that's not a real tight spec. There are other 10811's with tighter specs on them at 1 second. My guess is that it was not a real tight spec for the 10811 to hit. The short term would appear to contribute to the total error on the counter. Why not put a better oscillator in it? Bob ___ 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] 5370B OCXO
Many if not most 5370-based measurements are based on differential timing between the START and STOP channels, and wouldn't benefit from a better 10 MHz reference. If a customer did need something better, they probably already had a house standard to pipe in the back... and if not, HP would have been able to sell them one. It made more sense to keep the cost down by not including a high-end OCXO that would have gone unappreciated by most users. The 5370's jitter+resolution floor doesn't allow it to reach 1E-11 at t=1s in any event, so the -60111 wouldn't have been the limiting factor in the short term. One valid question, though, is why they bothered to put the nicer 10811-60109 OCXOs in the post-2120 series 5065A models, where its short-term performance is hosed by tying it to the rubidium reference with a ~1 Hz loop. Those 5065As would have been OK with a -60111, at least in the pre-2632 serial #s with the original integrator board. I'd be curious to know if they lowered the loop BW when they respun the integrator PCB. -- john, KE5FX -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on Behalf Of Bob Camp Sent: Thursday, March 11, 2010 7:11 PM To: Discussion of precise time and frequency measurement Subject: [time-nuts] 5370B OCXO Hi The OCXO in the 5370B is a 10811-60111. The only added spec on it is a 1x10^-11 ADEV spec at 1 second. By modern standards that's not a real tight spec. There are other 10811's with tighter specs on them at 1 second. My guess is that it was not a real tight spec for the 10811 to hit. The short term would appear to contribute to the total error on the counter. Why not put a better oscillator in it? Bob ___ 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] Thermal time constant
Jack Smith at Clifton Laboratories built a replacement for the 1502 chart recorders. An early prototype can be seen here: http://www.cliftonlaboratories.com/mar_2007.htm On Thu, 11 Mar 2010 04:51:00 +, Mark Sims hol...@hotmail.com wrote: Gawd, tell me about it... I just got through rebuilding the drive roller in half a dozen Tektronix YT-1 and YT-1S chart recorders for the 1502B/1520C/1503B/1503C TDR's -- kc0ukk at msosborn dot com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Thunderbolt antenna?
Hello, I'm looking for a decent outdoor antenna for my Thunderbolt... I need to graduate beyond the puck-antenna in the window sill. Any recommendations and/or sources (the lower cost, the better of course!)? Thanks, Dave ___ 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] Thunderbolt antenna?
It doesn't get any better than Ebay item 270262189976... I've tested a couple dozen antennas and nothing comes close to what it does... It's big. It's pricey (but FAR less than the $2000+ original cost). It's good. --- I'm looking for a decent outdoor antenna for my Thunderbolt... I need to graduate beyond the puck-antenna in the window sill. _ Hotmail: Trusted email with Microsoft’s powerful SPAM protection. http://clk.atdmt.com/GBL/go/201469226/direct/01/ ___ 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] Thermal time constant
That's the 1502/1503 chart recorder that uses a hot stylus and paper roll with a punched timing track. Paper is available at $25-$36 a roll (min purchase 10 rolls). I have a mod that lets you use $1-$2 a roll ECG paper. The 1502B/1503B/1502C/1503C are a different animal. Their chart recorders use a plain paper roll and a thermal bar printhead. And that horrid print roller and a paper feed mechanism that really sucks. Once you load a new roll in you have to print at least 4 charts to get it to feed properly. And if it doesn't you can spend the rest of eternity getting it properly adjusted. -- Jack Smith at Clifton Laboratories built a replacement for the 1502 chart recorders. An early prototype can be seen here: _ Hotmail: Powerful Free email with security by Microsoft. http://clk.atdmt.com/GBL/go/201469230/direct/01/ ___ 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] [FS] New Gigatronics 2408AL 10MHz - 8GHz signal generator
Hello, folks. I have a Giga-tronics 20408AL signal generator for sale. It does 10MHz - 8GHz. I believe it to be new and uninstalled. It is in immaculate physical condition. It was originally sold in 2007 and has a factory cal sticker from May 17, 2007. It is packed in the factory box with software and original docs. Specs can be seen here: http://www.rootscomm.com/products/tms/files/2400.pdf If you are interested, please contact me off list for pics, etc. Thanks. -Pete ___ 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.
