On 3/15/2014 5:17 PM, Martin Brown wrote:> On 15/03/2014 02:59, Jasen Betts wrote: >> On 2014-03-14, Frnak McKenney <frnak@far.from.the.madding.crowd.com> >> wrote: >> >>>> I used a multi-turn 8" loop antenna encased in 1/2" copper pipe >>>> (with a fiber joint to avoid a shorted turn. >>> >>> Square/rectangular, yes? Or is there some easy way to bend Cu pipe >>> into a nice, pretty circle? <grin!> >> >> anneal it first. (get it red-hot with a propane torch) >> then when it cools it'll be soft and can be formed by hand. > > ISTR You have to drop it in a bucket of water whilst red hot to make > copper stay soft (and avoid the jet of steam and boiling water). >Quenching usually makes metals hard and brittle. You can also just get Type K copper tubing. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net
Methods for improving 60kHz RF signal (WWVB)?
Started by ●March 13, 2014
Reply by ●March 15, 20142014-03-15
Reply by ●March 15, 20142014-03-15
On Sat, 15 Mar 2014 18:16:57 -0400, Phil Hobbs <hobbs@electrooptical.net> wrote:>On 3/15/2014 2:04 PM, Jim Thompson wrote: >> On Sat, 15 Mar 2014 10:45:47 -0700, Jeff Liebermann <jeffl@cruzio.com> >> wrote: >> >>> On Thu, 13 Mar 2014 09:51:15 -0500, Frnak McKenney >>> <frnak@far.from.the.madding.crowd.com> wrote: >>> >>>> I have two "atomic clocks": one is a La Crosse LCD unit, the other an >>>> "analog" wall clock whose hands are driven by a WWVB-sync 1xAA-powered >>>> mechanism. Following the recent "let's screw with everybody's clocks" >>>> cycle neither of my "atomic clocks" caught it, and I was reminded that >>>> I was Going To Fix This Problem last time. And the time before... >>>> <grin!> >>> >>> That was in late 2012 that WWVB added phase modulation and broke many >>> WWVB receivers. If that's your problem, there are a few fixes, but I >>> suspect they're only useful for higher end receivers. >>> <http://www.maxmcarter.com/rubidium/2012_mod/> >>> >> [snip] >> >> Aha! I didn't know about that phase modulation addition. Reading >> here.... >> >> <http://www.nist.gov/pml/div688/grp40/wwvb.cfm> >> >> the way they did it will raise havoc with the synchronous AGC AM >> detection schemes used in most old clocks, and in my old chip >> design... >> >> <http://www.analog-innovations.com/SED/WWVB-Schematic+Data.pdf> >> >> I'll have to muse over that and see if there's a solution. >> >> ...Jim Thompson >> > >A Costas loop, or failing that, a squaring loop as in the article. > >Cheers > >Phil HobbsOr a Thompson magical loop ;-) ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
Reply by ●March 15, 20142014-03-15
On 3/15/2014 8:59 PM, Jim Thompson wrote:> On Sat, 15 Mar 2014 18:16:57 -0400, Phil Hobbs > <hobbs@electrooptical.net> wrote: > >> On 3/15/2014 2:04 PM, Jim Thompson wrote: >>> On Sat, 15 Mar 2014 10:45:47 -0700, Jeff Liebermann <jeffl@cruzio.com> >>> wrote: >>> >>>> On Thu, 13 Mar 2014 09:51:15 -0500, Frnak McKenney >>>> <frnak@far.from.the.madding.crowd.com> wrote: >>>> >>>>> I have two "atomic clocks": one is a La Crosse LCD unit, the other an >>>>> "analog" wall clock whose hands are driven by a WWVB-sync 1xAA-powered >>>>> mechanism. Following the recent "let's screw with everybody's clocks" >>>>> cycle neither of my "atomic clocks" caught it, and I was reminded that >>>>> I was Going To Fix This Problem last time. And the time before... >>>>> <grin!> >>>> >>>> That was in late 2012 that WWVB added phase modulation and broke many >>>> WWVB receivers. If that's your problem, there are a few fixes, but I >>>> suspect they're only useful for higher end receivers. >>>> <http://www.maxmcarter.com/rubidium/2012_mod/> >>>> >>> [snip] >>> >>> Aha! I didn't know about that phase modulation addition. Reading >>> here.... >>> >>> <http://www.nist.gov/pml/div688/grp40/wwvb.cfm> >>> >>> the way they did it will raise havoc with the synchronous AGC AM >>> detection schemes used in most old clocks, and in my old chip >>> design... >>> >>> <http://www.analog-innovations.com/SED/WWVB-Schematic+Data.pdf> >>> >>> I'll have to muse over that and see if there's a solution. >>> >>> ...Jim Thompson >>> >> >> A Costas loop, or failing that, a squaring loop as in the article. >> >> Cheers >> >> Phil Hobbs > > Or a Thompson magical loop ;-) > > ...Jim Thompson >I think that was first invented by Dr. Fred M'Bogo. http://www.answers.com/topic/dr-fred-mbogo-computer-jargon Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net
Reply by ●March 16, 20142014-03-16
"Phil Hobbs" <hobbs@electrooptical.net> wrote in message news:5324F143.5010807@electrooptical.net...>>>> Square/rectangular, yes? Or is there some easy way to bend Cu pipe >>>> into a nice, pretty circle? <grin!> >>> >>> anneal it first. (get it red-hot with a propane torch) >>> then when it cools it'll be soft and can be formed by hand. >> >> ISTR You have to drop it in a bucket of water whilst red hot to make >> copper stay soft (and avoid the jet of steam and boiling water).My understanding is, it's veeeeeeeeery slightly softer (like a percent or a few) quenched, but it basically doesn't matter.>> > > Quenching usually makes metals hard and brittle.If "usually" is by tonnage, that's about right. A36 is the most common grade I think, and ranges from ~1020 to "floor sweepings". More than a few blacksmiths have been burned by that. IIRC, only martensitic type systems (Fe-C being the most important) are prone to quench hardening, which by the periodic table, aren't very common I think. Of course, the rest of the periodic table is too reactive or soft or low melting to be of structural value (e.g., cerium, lead, sodium..), or just too damn rare and expensive (there are probably some awesome scandium alloys yet to be discovered, but..).> You can also just get Type K copper tubing.Bend the bendable stuff? You must be joking! :-) It even comes in a coil, so open the box, stretch it out and you've got one hell of an RFC for that megawatt vacuum tube final you always wanted. Tim -- Seven Transistor Labs Electrical Engineering Consultation Website: http://seventransistorlabs.com
Reply by ●March 16, 20142014-03-16
On Sat, 15 Mar 2014 12:47:39 -0700, Jeff Liebermann <jeffl@cruzio.com> wrote:>On Sat, 15 Mar 2014 12:05:27 -0700, Jeff Liebermann <jeffl@cruzio.com> >wrote: > >>I don't think battery operation will help much. At the low power >>requirements for a WWVB front end, a simple analog power supply should >>be adequate. If you're worried about conducted emissions from the >>power lines, then there are various power line filters and ferrite >>beads that should help.The problem these days is that a house is surrounded by electric "smog" due to all active electronics such as VFDs. If you are used some small untuned whip antenna close to the house as in many pictures in that article and links, you are going to have a 1-10 pF connection from the in-house wiring to that whip and hence have a strong connection interference from the mains to the whip. Typically a simple active is just not much more a high input resistance FET drain follower that probes the voltage in the whip and drives the 50 ohm coax with significant current gain. Since the short antenna is highly reactive (some pF capacitance from the "ether" to the whip) there is going to be a capacitive voltage divider to ground, either through the FET gate-source capacitance or a huge attenuation due to the coaxial cable capacitance, if such short antenna is connected directly to a coax to avoid indoor noise pickup. Since some of the link were broken, I don't know if this whip was actually tuned, i.e. used some kind of loading coil to make the antenna look like a resistive source to the amplifier ? In my experiments I have used a few meters of wire suspended into some trees in the garden, connected to a LC tank top through a 10 pF capacitor. The inductance consisted of several coils in series and selected by the band and the voltage at the lowest coil (relatively low impedance), went through a darlington voltage follower to a short 50 ohm coax. The capacitance was tunable with mechanical multi section capacitor. The short coax was required to avoid spurious radiation from the receiver synthesizer to the antenna :-). The whole setup was operated from a 12 V car battery. With this setup, the 16 kHz Rugby UK station (nearly 2000 km away) could heard with good SNR even during summer days. Of course this setup with mechanical variable capacitors made sense only during warm summer days :-). Running an mains extension cord across the garden without connecting the charger, increased the noise level.> >A bit more on power line emissions and WWVB: ><http://www.prc68.com/I/LF-Ant.shtml> >The whip antenna is tunable and run from an AC power supply. However, >the conducted junk from the power line made 60 KHz reception rather >problematic, until the author added additional RF filtering and >bypassing. > >Some performance reports with a Spectracom 8206 antenna, which is a >shielded ferrite rod type: ><http://www.febo.com/time-freq/wwvb/sig-strength/wwvb-spectracom.html> >Note that at some times of the day, the SNR is near zero making AM >demodulation impossible.Small magnetic loop antennas have some advantage compared to small electric (capacitive) antennas in the near field due to the cube/square relationship.
Reply by ●March 16, 20142014-03-16
In article <5324F143.5010807@electrooptical.net>, Phil Hobbs <hobbs@electrooptical.net> wrote:> On 3/15/2014 5:17 PM, Martin Brown wrote: > > On 15/03/2014 02:59, Jasen Betts wrote: > >> On 2014-03-14, Frnak McKenney <frnak@far.from.the.madding.crowd.com> > >> wrote: > >> > >>>> I used a multi-turn 8" loop antenna encased in 1/2" copper pipe > >>>> (with a fiber joint to avoid a shorted turn. > >>> > >>> Square/rectangular, yes? Or is there some easy way to bend Cu pipe > >>> into a nice, pretty circle? <grin!> > >> > >> anneal it first. (get it red-hot with a propane torch) > >> then when it cools it'll be soft and can be formed by hand. > > > > ISTR You have to drop it in a bucket of water whilst red hot to make > > copper stay soft (and avoid the jet of steam and boiling water). > > > > Quenching usually makes metals hard and brittle.For ferrous metals, yes. The size of the quenching effect varies with specific alloy. For instance, steel containing 1% carbon gets very hard, while steel containing 0.18% carbon is not much affected by quenching. For non-ferrous metals, no, it anneals them. Copper alloys have variations in quenching effect, but I don't offhand know which is which. Likewise, silver - I first heard the quench- to- anneal story when taking jewelry making class in the 1970s. We would combine quenching with firescale (oxide) and flux removal by quenching in a dilute mineral acid after hard soldering.> You can also just get Type K copper tubing.Yes, but that's cheating. You should be drawing your own tubing from billet. Joe Gwinn
Reply by ●March 18, 20142014-03-18
On Sat, 15 Mar 2014 14:11:29 -0700, Jeff Liebermann <jeffl@cruzio.com> wrote:> On Sat, 15 Mar 2014 15:05:27 -0500, Frnak McKenney ><frnak@far.from.the.madding.crowd.com> wrote: > >>Good thought. Unfortunately, I've had WWV/WWVB reception problems as >>long as I've lived here. > > Find a spectrum analyzer and look at what you're actually receiving > from the antenna. I spent a day troubleshooting a WWVB receiver > before I discovered that I had an oscillating RF amplifier in the > remote antenna section.Ouch!>>I finally build a 1m dia tuned loop so my >>Heath Most Accurate Clock could reliably receive WWV 10MHz. > > Nice. I have a GC-1000 Most Accurate Clock that I'm slowly > rebuilding. The original builder was seriously lacking in mechanical > ability and made a nice mess.Ouch! again. Did you get a manual with it? ( Hm. I'd better make sure I can locate _mine_ before I make any offers. <grin!> )>>Good thought. As in, "make sure you're solving the right problem". > > Yep. In general, if you have at least 10dB SNR, you should be able to > demodulate WWVB. If you look at the plots at: ><http://www.febo.com/time-freq/wwvb/sig-strength/wwvb-spectracom.html> > The >10dB SNR is typically about 20 hrs per day. Avoid working around > sunset and you'll probably be ok. > > Most people spend their time trying to maximize the antenna gain. Bad > idea as that increases both the signal and the noise equally. What's > needed is a way to improve the SNR by reducing the noise pickup. > That's the real problem.>>My analog clock has a WWVB-sync'ed movement like this one: >> http://www.amazon.com/Atomic-Clock-Movement-Shaft-Length/dp/B007KA54RW/ >> >>and there isn't room inside it for much of an antenna. One might >>guess that the LaCrosse WS-8418 has a slightly larger antenna, but it >>would be a guess; I haven't had an excuse to take it apart (yet). > > Well, it's probably larger than the tiny loopstick used in the wrist > watches. Here's a possible dissection of a similar clock movement: ><http://www.amug.org/~jthomas/wwvbmod.html> > Looks like a reasonable size ferrite rod and coil winding. No > shielding, which is typical.Thanks. Now I can find a replacement movement if I need one. Oh, and if any of our readers are interested in making their own 3"-tall nixie-ish displays from EL wire: http://hackaday.com/2014/02/24/el-wire-nixie-tube-is-in-your-reach/>>><http://www.c-max-time.com/tech/antenna.php> >> >>Thank you for the pointer. I've filed it for future reference. ( Do >>the Aerial Connection diagrams a-d look mislabeled to you? ) > > You have good eyes. They should be labeled: > a) single ended b) single ended something strange > c) balanced center d) balanced center > tap coil tap resistorsOkay. Thanks for the reassurance -- I thought I was going crazy. ( Okay, crazier. <grin> )>>Agreed. I don't forsee ever needing instant mid-day updates, though. > > To save battery power, most such clocks play dead during the day and > only wake up when a strong signal might be expected. Typical for the > chip is only a few updates per night with a 1 to 24 hr delay after > each successful update. If battery operated, they do NOT listen > continuously. This is all settable in the chip at the whim of the > designer. See the flow chart at: ><http://www.c-max-time.com/tech/software6005.php>Another page I hadn't noticed the last time I visited c-max. Thanks>>> Build a 60 KHz sniffer and see if they really are a problem. My bet >>> is that if you have interference problems, it's local. >> >>Good suggestion, but I think I was trying to say that I didn't want >>any signal amplifier I built to cause problems for my neighbors. > > Unless it decides to oscillate and become a transmitter, I wouldn't > expect any problems. However, hanging a large loop antenna on the > fence line might produce some paranoia on the part of the neighbors. I > suggest threading some vines through it as natural camouflage.Vines... vines... how about that adorable plant named Audrey II from "Little Shop of Horrors"?>>Well, if I build a 60Hz "sniffer" I should be able to find one if I >>have it. > > Ummm... that's 60 KHz, not Hz. ...A-hum. I knew that... it's my spelling checker's fault! <grin!>> ... It's difficult to tell what you're > looking at with a scope. A portable spectrum analyzer would be > better, if you can find something that works at 60 Khz. A high end > 192 KHz sound cards should work. Probably already been done.... yep: ><http://www.geocities.jp/bitalemon3000/english.html> ><https://www.youtube.com/user/pobox22cpo> ><http://www.qsl.net/dl4yhf/spectra1.html> > More on VLF reception using Spectrum Lab software: ><http://abelian.org/vlfrx/> > Note the graphs with the noise plot. 60 KHz looks ugly and note the > comments on buzz from the 12 KV lines.Thanks. I've been looking at USB audio interfaces that would (a) work with Ubuntu Linux and (b) sample at greater than 2x60kHz, and while there are a lot of inexpensive ones out there, it's really hard to tell what their spec's are. Punchline? I finally got around to checking the specifications on my laptop's built-in audio... and found that Dell dropped an STAC9205 into this D630... and that chip says it can deliver 24-bit samples at 192kHz. ( Now I have to verify that the Linux drivers can reliably deliver this. That should not be taken as a jab at Linux, merely an exposure of my own inexperience. <grin!> ) Sounds like a good time for lunch. Thanks again. It'll probably be a few weeks before I have any progress, but I'll post something back when I have results. Frank -- How much easier it is to do things yourself than to teach other people to do them! ...throughout my foolish life, there has been that inner something or other that compelled me to teach people how to do things, no matter how eccentric or unorthodox -- a sense of some great event ahead that would need every talent I could develop in all who came under my influence. That strange urge was behind every decision of policy in our medical work, in our nurses' training; behind acceptance of duties for which I was poorly trained: an urge to learn first, how to do the thing myself, and then to find someone whom I could teach to do it for me. -- Gordon S. Seagrave / Burma Surgeon -- Frank McKenney, McKenney Associates Richmond, Virginia / (804) 320-4887 Munged E-mail: frank uscore mckenney aatt mindspring ddoott com
Reply by ●March 18, 20142014-03-18
On 3/18/2014 9:51 AM, Frnak McKenney wrote:> On Sat, 15 Mar 2014 14:11:29 -0700, Jeff Liebermann <jeffl@cruzio.com> wrote: >> On Sat, 15 Mar 2014 15:05:27 -0500, Frnak McKenney >> <frnak@far.from.the.madding.crowd.com> wrote: >> >>> Good thought. Unfortunately, I've had WWV/WWVB reception problems as >>> long as I've lived here. >> >> Find a spectrum analyzer and look at what you're actually receiving >> from the antenna. I spent a day troubleshooting a WWVB receiver >> before I discovered that I had an oscillating RF amplifier in the >> remote antenna section. > > Ouch! > >>> I finally build a 1m dia tuned loop so my >>> Heath Most Accurate Clock could reliably receive WWV 10MHz. >> >> Nice. I have a GC-1000 Most Accurate Clock that I'm slowly >> rebuilding. The original builder was seriously lacking in mechanical >> ability and made a nice mess. > > Ouch! again. Did you get a manual with it? ( Hm. I'd better make > sure I can locate _mine_ before I make any offers. <grin!> ) > >>> Good thought. As in, "make sure you're solving the right problem". >> >> Yep. In general, if you have at least 10dB SNR, you should be able to >> demodulate WWVB. If you look at the plots at: >> <http://www.febo.com/time-freq/wwvb/sig-strength/wwvb-spectracom.html> >> The >10dB SNR is typically about 20 hrs per day. Avoid working around >> sunset and you'll probably be ok. >> >> Most people spend their time trying to maximize the antenna gain. Bad >> idea as that increases both the signal and the noise equally. What's >> needed is a way to improve the SNR by reducing the noise pickup. >> That's the real problem. > > >>> My analog clock has a WWVB-sync'ed movement like this one: >>> http://www.amazon.com/Atomic-Clock-Movement-Shaft-Length/dp/B007KA54RW/ >>> >>> and there isn't room inside it for much of an antenna. One might >>> guess that the LaCrosse WS-8418 has a slightly larger antenna, but it >>> would be a guess; I haven't had an excuse to take it apart (yet). >> >> Well, it's probably larger than the tiny loopstick used in the wrist >> watches. Here's a possible dissection of a similar clock movement: >> <http://www.amug.org/~jthomas/wwvbmod.html> >> Looks like a reasonable size ferrite rod and coil winding. No >> shielding, which is typical. > > Thanks. Now I can find a replacement movement if I need one. > > Oh, and if any of our readers are interested in making their own > 3"-tall nixie-ish displays from EL wire: > > http://hackaday.com/2014/02/24/el-wire-nixie-tube-is-in-your-reach/ > >>>> <http://www.c-max-time.com/tech/antenna.php> >>> >>> Thank you for the pointer. I've filed it for future reference. ( Do >>> the Aerial Connection diagrams a-d look mislabeled to you? ) >> >> You have good eyes. They should be labeled: >> a) single ended b) single ended something strange >> c) balanced center d) balanced center >> tap coil tap resistors > > Okay. Thanks for the reassurance -- I thought I was going crazy. > ( Okay, crazier. <grin> ) > >>> Agreed. I don't forsee ever needing instant mid-day updates, though. >> >> To save battery power, most such clocks play dead during the day and >> only wake up when a strong signal might be expected. Typical for the >> chip is only a few updates per night with a 1 to 24 hr delay after >> each successful update. If battery operated, they do NOT listen >> continuously. This is all settable in the chip at the whim of the >> designer. See the flow chart at: >> <http://www.c-max-time.com/tech/software6005.php> > > Another page I hadn't noticed the last time I visited c-max. Thanks > >>>> Build a 60 KHz sniffer and see if they really are a problem. My bet >>>> is that if you have interference problems, it's local. >>> >>> Good suggestion, but I think I was trying to say that I didn't want >>> any signal amplifier I built to cause problems for my neighbors. >> >> Unless it decides to oscillate and become a transmitter, I wouldn't >> expect any problems. However, hanging a large loop antenna on the >> fence line might produce some paranoia on the part of the neighbors. I >> suggest threading some vines through it as natural camouflage. > > Vines... vines... how about that adorable plant named Audrey II from > "Little Shop of Horrors"? > >>> Well, if I build a 60Hz "sniffer" I should be able to find one if I >>> have it. >> >> Ummm... that's 60 KHz, not Hz. ... > > A-hum. I knew that... it's my spelling checker's fault! <grin!> > >> ... It's difficult to tell what you're >> looking at with a scope. A portable spectrum analyzer would be >> better, if you can find something that works at 60 Khz. A high end >> 192 KHz sound cards should work. Probably already been done.... yep: >> <http://www.geocities.jp/bitalemon3000/english.html> >> <https://www.youtube.com/user/pobox22cpo> >> <http://www.qsl.net/dl4yhf/spectra1.html> >> More on VLF reception using Spectrum Lab software: >> <http://abelian.org/vlfrx/> >> Note the graphs with the noise plot. 60 KHz looks ugly and note the >> comments on buzz from the 12 KV lines. > > Thanks. I've been looking at USB audio interfaces that would (a) work > with Ubuntu Linux and (b) sample at greater than 2x60kHz, and while > there are a lot of inexpensive ones out there, it's really hard to > tell what their spec's are. Punchline? I finally got around to > checking the specifications on my laptop's built-in audio... and found > that Dell dropped an STAC9205 into this D630... and that chip says it > can deliver 24-bit samples at 192kHz. ( Now I have to verify that the > Linux drivers can reliably deliver this. That should not be taken as > a jab at Linux, merely an exposure of my own inexperience. <grin!> ) > > Sounds like a good time for lunch. > > Thanks again. It'll probably be a few weeks before I have any > progress, but I'll post something back when I have results. > > > Frank >WWVB recently added a whole new modulation method that should stunningly improve their reception reliability. Unfortunately, the new chips are half a year overdue and appear to be stuck in the pipe. See http://www.nist.gov/pml/div688/grp40/upload/NIST-Enhanced-WWVB-Broadcast-Format-2012-12-07-3.pdf -- Many thanks, Don Lancaster voice phone: (928)428-4073 Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552 rss: http://www.tinaja.com/whtnu.xml email: don@tinaja.com Please visit my GURU's LAIR web site at http://www.tinaja.com
Reply by ●March 18, 20142014-03-18
On Tue, 18 Mar 2014 11:51:15 -0500, Frnak McKenney <frnak@far.from.the.madding.crowd.com> wrote:>> Nice. I have a GC-1000 Most Accurate Clock that I'm slowly >> rebuilding. The original builder was seriously lacking in mechanical >> ability and made a nice mess. > >Ouch! again. Did you get a manual with it? ( Hm. I'd better make >sure I can locate _mine_ before I make any offers. <grin!> )Thanks, but I have both the printed and scanned manuals. What I lack is time and incentive.> http://hackaday.com/2014/02/24/el-wire-nixie-tube-is-in-your-reach/Yech. That's ugly. With real Nixie tubes, you can read all the digits instead of just the one up front. However, if you're using real Nixie tubes with a 60KHz receiver, you're going to have RFI problems from the usual switching high voltage power supply. I've seen it done, but it required lots of shielding and ferrite filters.>Thanks. I've been looking at USB audio interfaces that would (a) work >with Ubuntu Linux and (b) sample at greater than 2x60kHz, and while >there are a lot of inexpensive ones out there, it's really hard to >tell what their spec's are.There are quite a few that offer 192KHz sampling rate. The problem is that the audio sections usually roll off at about 20KHz. I've found cards that will allegedly go to 90KHz, but they're expe$ive. For example: <http://www.asus.com/Sound_Cards_and_DigitaltoAnalog_Converters/Xonar_Essence_STX/#specifications> I have yet to find a USB version that does above 20KHz, but suspect that once can be found which might be modified. (Yet another project).>Punchline? I finally got around to >checking the specifications on my laptop's built-in audio... and found >that Dell dropped an STAC9205 into this D630... and that chip says it >can deliver 24-bit samples at 192kHz.No, that's NOT the spec. The 192KHz is the sampling rate not the frequency response. If you want to go up to the Shannon limit, you theoretically can get about 80Khz for the upper frequency. You'll need to butcher the audio amplifier section of the sound card to do that. My guess(tm) is that's easier to add a mixer and downconvert the 60KHz RF to a lower frequency that's more easily digested by a sound card. That's the way DRM broadcasting is done from the 455KHz IF frequency of a receiver. <http://www.radiomuseum.hu/radiomuseum/rajzok/drmvevo.pdf> With a working bandwidth of only about 5Hz, this should be easy (famous last words). Good luck. -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
Reply by ●March 18, 20142014-03-18
On Tue, 18 Mar 2014 10:24:22 -0700, Don Lancaster <don@tinaja.com> wrote:>WWVB recently added a whole new modulation method that should stunningly >improve their reception reliability.Yep.>Unfortunately, the new chips are half a year overdue and appear to be >stuck in the pipe.See: <http://www.xtendwave.com/atomictimekeeping.html> <http://www.xtendwave.com/xtendwavefirstshipment.html> <http://www.xtendwave.com/WhitePaper_Everset_Technology_Receivers_%202013.pdf> I'm still waiting for samples from last year. No data sheets or tech info to be found. I'm wondering if the chip is for real. Xtendwave did most of the work on the new WWVB system for the NIST. I don't know anything about the status of their licenses to other chip vendors. I suspect they want to make their own chips before licensing the IP to anyone else: <http://news.thomasnet.com/companystory/Xtendwave-Selects-EnSilica-s-eSi-3200-Processor-for-the-Receiver-IC-Implementing-NIST-s-Next-Generation-WWVB-Atomic-Timekeeping-Signal-616104> Patents and applications: <https://www.google.com/patents/US20130121397> <https://www.google.com/patents/US8270465> <https://www.google.com/patents/US20120082008> <https://www.google.com/patents/WO2013074789A3> and a whole bunch more patents and applications: <https://www.google.com/search?tbm=pts&q=xtendwave> Hmmm... Looks like ownership is now in the hands of Grindstone Capital. Click "Legal Events" on most of the patents. -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
