[time-nuts] Mark-- LH Milliseconds Display
Hello, Mark-- OOPS!! My bad!! --I misunderstood what the "milliseconds" display was indicating. It says: /TSZ = *"- toggle show digital clock with milliseconds" I took this literally to mean that the digital clock would display hours, minutes, seconds and milliseconds but that the "milliseconds" meant a running, incrementing, millisecond-by-millisecond display of the time and not the difference in the time of arrival of the RX time message. *Thanks for the correction info! Mike Baker Micanopy, FL * ___ 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 about Lady Heather millisecond display
Hello, Time-Nutters I recently updated an old version of Lady Heather that has been running well 24/7/365 for a number of years (except during prolonged power grid outages !). V5.0 is now installed and running. Getting it to display full-screen takes a bit of fiddling with different commands but otherwise seems to be running OK. I do have a number of questions about V5.0 but one I am focusing on at the moment is the command to enable the millisecond digits for the time display. The info I have says this is done by entering the /TSZ command. However, when entering this command the three millisecond digits do appear but only alternate back and forth every several seconds between "052" and "053". What might I be doing wrong? Any suggestions on how to make the millisecond digits count and sequence correctly? Thanks for any suggestions on resolving this issue !! Mike Baker Micanopy, FL * ___ 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] A Lady Heather question...
Hello, Time-Nutters-- I have been trying to figure out how to tell LH to display the GPS birds signal strength vs EL and AZ. I have a note that says the command for this is SAS but when I enter / followed by SAS, the ADEV lists go away but after a few seconds, the ADEV list starts back up again. I do not see the command SAS listed anywhere, so I have no idea who passed that on to me or where it came from. A year or so ago I managed to get the signal strength vs AZ/EL display running but have lost track of how to do it. What am I doing wrong? Where is the command SAS listed? Thanks! Mike Baker --- -- “The duty of a Patriot is to protect his country from its government.” – Thomas Paine ___ 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 command question
Thank you Azelio, for your response to my question regarding how to get Lady Heather to display the signal-strengths vs AZ and EL. I have been trying to figure out how to get LH to display the signal strength diagram. I have been entering 'SAS' ret into the command line. LH responds by clearing off the ADEV lists but then starts the ADEV lists all over again. Where do the SAS, SAD, SAE, SAA, SAW, SAC commands and their function explanation appear? I do not see them listed anywhere. What is the correct procedure for entering the commands? Are you saying I should enter ' SAS/SAD/SAE/SAA ' (ret)...? In other words, enter all the commands in sequence separated by the forward slash (/)...? Thanks-- Mike Baker ** Azelio Boriani said: Use: S A S signal S A D data S A E elevation S A A azimuth S A W S A C to clear the view -- “The duty of a Patriot is to protect his country from its government.” – Thomas Paine ___ 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] FCC politics vs their engineers...
Time-Nutters-- Jim wrote: snip That's why the FCC granted a conditional waiver of the rules. It was politically expedient, and I would imagine that the engineers at the FCC thought there's no way they'll be able to demonstrate no interference Charles wrote: snip The Commission not only thought LS would demonstrate non-interference, it put its thumb on the scale until the public outcry became too loud to ignore (the GPS interests took forever to wake up -- that didn't happen until all of the comment periods were long closed). It just didn't matter what the staff engineers thought -- which is business as usual at the FCC. A friend of mine was one of the FCC lead supervisory engineers that was involved in the LS fiasco. He tells me that there were technical reports, evaluation summaries and strong opinions offered by the engineering staff that provided a number of reasons why the LS project should be denied. He tells me that most of these engineering studies got buried and ignored. He tells me with some bitterness that politics triumphed over all of the objections of the engineering staff to LS and that this is not the first time that this has happened. Mike Baker Gainesville, FL USA ___ 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] DIY GPS antenna...
Time-nutters-- Somewhere I have seen a commercial ( Symmetricon--?) GPS antenna that was made with the active elements mounted over a rather large diameter (30 or 40 cm ??) flat plane surface fabricated from some sort of material that absorbed and attenuated all GPS reflected signals. If this technique is effective, it might be worth home-brewing to investigate the results...? Mike Baker Gainesville, FL USA -- ___ 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 on a Laptop
Hi, All-- I have dedicated an ancient Windows 95 laptop to sitting on a shelf in my workshop running Lady Heather. It's CPU speed is only 400 MHz and it only has a very small hard-drive and almost no memory but it seems to handle LH well. Except for some of the frequent power outages we see around here, it has been running LH 24/7 for the last 3 years, maybe a little longer. The screen is on continually and is somewhat dimmer than when I installed it but it is still quite useable. Mike Baker - ___ 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] 100 watt higher LED power supply...
Time-Nutters-- OK-- So flicker would be objectionable running off a rectified 110VAC line.My thinking was to find a way around needing a current limiter that would waste energy as heat. Rectifying (and some filtering) of the 110AC line seemed to be one approach. I am thinking of building a several hundred watt LED light for over my workbench by mounting the LEDs on an existing frame for a 4-lamp (long-tube) fluorescent lamp fixture and using the large surface area of the metal frame as a heat sink. The 100 watt LEDS are on eBay but I have not seen the current-limiting drivers for them on eBay. Mike Baker ___ 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] Hi Power LED Light power supply...
Time-Nutters-- I was wondering, after seeing some 100 watt LED series wired assemblies that were listed at 30-34 VDC @ 2.9A if a number of LEDs could be wired in series and powered directly from a rectified 110 VAC power source. If enough LEDs are wired in series such that the peak DC voltage from the rectified 110 AC line does not exceed the max current rating of the LEDs this should eliminate any excess current from flowing. Obviously, this does not provide for any safety isolation from the line. Hm Maybe if an 1:1 isolation transformer is used except that it would be too heavy and large Mike Baker -- ___ 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] Bullet Chronograph
Hi, Paul-- I have several different ballistic chronographs-- only one of the ones I have interfaces to a laptop (Oehler Ballistic Laboratory model). There are inexpensive chronographs available for a little over $100. Some models do provide interface to a laptop as well as a LOT of built-in functions such as this one: http://www.midwayusa.com/product/773378/ced-millennium-2-chronograph-system CED Millennium 2 Chronograph System Over 1000 shot capacity with up to 500 string permanent memory Records velocities from 50 fps to 7,000 fps High, Low, Average, Hi-Average velocity readings Extreme Spread Standard Deviation Edit Omit functions Built-in Calculator IPSC / IDPA Power Factor computation Function New Data Collector Software program included Meter or feet recording 10X Mode - records slower velocities in decimeters Voice Chip technology - Results can be heard as well as seen On / Off control, with no-memory loss Auto-Shut Down mode PC Downloads - USB interface for fast, software downloads of stored data Data Collector Software program included Low battery warning indicator Back-up battery storage Operating Temperature range (0°C to 50°C) -- Mike Baker ___ 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] Seeing/monitoring very short pulses
Time-nutters-- I have had several instances where I needed to monitor the continuous presence of pulses too short or too spaced out to check on conveniently, even with a scope. My solution was a one-shot monostable IC driving an LED. Example--: a uS (or whatever length) pulse triggers the one-shot which turns the LED on brightly for 1/10 second. I have incorporated this feature into several PC board projects over the years. I am anally-compulsive about installing ways to monitor different functions in the circuitry of my projects. On a couple of occasions I have gone so far as to build a sub-panel with a collection of monitoring indicators. These have been huge time savers for quickly zeroing-in on the cause of many problems occurring long after I have forgotten the working details of a projects circuitry. Mike Baker ___ 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] Femto-second photography exposures...
Timenutters-- Highspeed (slowmotion) photography in femto-seconds...?? Yikes!! http://www.wimp.com/trillionframes/ Mike Baker ___ 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] My T-bolt died...
Time-nutters-- Aaaarrrghhh! My T-bolt died. I have the version with the built-in power supply that requires only a +24 input. The power supply is putting out +12, -12 and +5. At least I see these voltages on the upper board on the pins of the 6-pin connector that supplies power to the main board. What puzzles me is that the main board acts as if it is not getting *any* power; the OCXO stays cold and none of the multi-pin chips on the main board seem to be getting any power as they do not show any sign of getting even the slightest bit warm. The main board is a multi- layer PC board which makes it nearly impossible to trace how the power supply voltages get to anywhere on the board. Fortunately, I have a back-up T-bolt I picked up on flea-bay and it works... at least it puts out 10 MHz and clock pulses. What is the correct Lady Heather procedure for setting up a T-bolt for best performance? I powered it up and told it to do a survey. Two displays came up; one that plots fixes on a horiz and vert axis in different colors and one that shows the tracks of all the birds passing overhead. However-- all of the color dots showing fix points are waaa off at the top of the little display box. After doing fixes for a few hours it appears that most of the fixes are off screen outside the upper side of the display. It appears that I have not gone through the correct procedure to do the proper set-up to put the T-bolt into service at a new location. Any suggestions on the proper sequence of Lady Heather commands? Thanks!! Mike Baker WA4HFR Gainesville/Micanopy, Florida USA -- ___ 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] Orbital time-delayed angular momentum phasing....???!!
Time-nutters-- Didier Juges asked: What does that do to the focussing properties of the dish? I have seen several descriptions of how the dish needs to be shaped in order to develop the orbital time-delayed angular momentum signal and still achieve an integral focus point. I am not sure that I can describe it, but as I understand it, the dish is not just split and bent into a cork-screw, but that the surface of the dish is also continuously shaped so as to provide a good focus It is just that the signal striking parts of the dish which are increasingly displaced along the axis of the bore-sight are time delayed more or less with respect to other surfaces of the dish. The only way I can see for this to work is for the dish surface to deviate from a true parabolic shape incrementally as each particular area is displaced closer or further away from the focal point. It is a little hard to visualize and a lot harder to find the right words to adequately describe! Mike Baker --- ___ 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] Orbital time-delayed angular momentum phasing....???!!
Timenutters-- Along the lines of splitting time into small increments, there is an interesting article in the May 2012 issue of the IEEE Spectrum Journal. It describes experiments with what I am calling cork-screw time-shift phasing modulation or orbital time-delayed angular momentum phasing for lack of a better description of the process. This is not the same as circular-polarization of a radiated signal. Visualize a 4-ft dia parabolic reflector which has been cut (sliced) in a straight line from any arbitrary point on its outer edge to its center.Then, at the outer lip of the reflector surface, pull one side of the cut about a foot forward of the other side of the cut. The separation is greatest at the edge of the dish, gradually becoming less and less as the cut approaches the center of the dish. The concept is that RF energy from the feed progressively strikes different areas of the dish slightly ahead (time-wise) from RF energy that strikes other parts of the dish. Because the surface of the dish resembles a cork-screw the signal from the dish has elements that are time-delayed with respect to other parts. Accordingly, data elements can be incorporated into the signal which have sightly different time-delay angular momentum properties. Again, the folks working on this insist that this is not the same as circular polarity of the radiated signal such as is obtained with a helix antenna. At the receive end, the process is reversed, producing a signal which when demodulated can contain extra levels of data modulation superimposed on it. The article points out that there are skeptics of the process who say that this same modulation procedure can be done with other methods although the modulation and demodulation process would be much more complex. The orbital angular momentum of photons in the optical realm has been extensively studied, although applying these principles to RF is something new. Mike Baker -- ___ 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] Temperature control/isolation of T-bolts...
Time-Nutters-- Some years ago I ran some experiments trying to improve on the temperature control of a circuit board with a reference oscillator and other heat producing items on it. I quickly discovered that enclosing it in a small Styrofoam container jacked the temperature up wy to high.Eventually, I tried putting it in a large picnic sized Styrofoam container. This worked much better. The inside temperature did go up, but not so much as to be a problem. At some point the size of the container provided enough heat loss so as not to overheat the circuitry but also provided a lot of thermal isolation from ambient room temperature changes. I monitored the inside temperature of the Styrofoam box with an HP-Agilent precision lab-grade quartz thermometer borrowed from the physics lab at the Univ of Flori-DUH. Mike Baker -- ___ 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] Procom GPS4 quadrifilar antenna...
Time-nutters-- The Procom website lists the noise-figure of their quadrifilar LNA as: GAIN 30 dB NOISE FIGURE 3 dB (incl. input filter). Typ. approx. 3 dB I am a little surprised at this relatively high NF for a product in this price category. Even most low-end mass-produced consumer grade GPS antennas are spec'd at 1.5 to 2.0 dB NF. Mike Baker -- ___ 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] Those helix antennas in the photos...
Time-Nutters-- What I saw in the photos of the helix antennas that I found interesting was: A) The tapered cone-shaped cup that some of the helix antennas sat in. What does this do? Most helix antennas seem to sit over a flat ground plane but these are different. B) Some of the helix antennas are tapered in diameter very gradually from the base to the top-end. Why? C) Some of the helix antennas that are tapered gradually along their entire length have an abrupt taper at the end. Why? And lastly; what is the material that is used for winding the helix elements onto? I have some large sheets of copper foil with an adhesive backing that would be ideal for fabricating helix antennas similar to the ones seen in the photos. I tried building a 3-turn helix to feed my 1.8 meter, 0.39 F/d dish on 1.7 GHz for downlinking the NOAA HRPT digital imagery. After several iterations I finally only got mediocre performance. I think this was due to poor illumination of the dish. I then tried to build a circular polarity patch feed by scaling the dimensions for a 2.4 GHz patch feed but this was a dismal failure as I never could get the circular polarity right. I finally wound up with a coffee-can style feed which works OK. Not wonderfully well, but just OK.Here is a DropBox link to a recent image: http://dl.dropbox.com/u/60102282/FLA%201130-3May12.JPG The HRPT imagery is pretty neat but now a group of us are working on figuring out how to demodulate/decode and display the much higher resolution (and far more natural looking) imagery from the AQUA and TERRA birds. These birds imaging telemetry comes down at 8.2 GHz at 15 Mbps in a Staggered Quadrature Phase Shift (SQPSK) format. I am currently trying to come up with an efficient 8.2 GHz feed and LNA or LNC for my dish. Should be a fun project! Here is a DropBox link to a sample TERRA image from the NASA archives: http://dl.dropbox.com/u/60102282/Web%20Terra-Aqua%20Sample.jpg Mike Baker - ___ 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] T-bolt steering an LPRO...?
Time-nutters-- Some time ago I queried the list for info on how to connect and steer an LPRO-101 Rb oscillator with a T-bolt. Now that I am ready to start on that project I can't find the responses I got from the list. I apologize for this repeat of my original query but it is not my fault-- Mice sneak in at night and mess with my computer and lose my saved files (that's my story and I am sticking with it!). Thanks (again) for any feedback on this!! Mike Baker - ___ 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] Re-radiating a GPS signal...??
Time-nutters-- So-- How do GPS signal re-radiators work? How do you place a GPS antenna on top of a building, pick up the signal with an LNA, amplify it to re-transmit on an inside antenna without the amplified re-transmitted signal getting back into the roof-top receiving antenna? I can see circumstances where a huge metal building (aircraft hangar?) might provide enough isolation to prevent problems, but in many cases I wonder about it... As an aside note-- I recall seeing, many years ago, a totally passive TV signal repeater on top of a tall hill in mountainous territory relaying a TV station signal to some homes in a valley just below. The passive repeater consisted of an array of high-gain UHF yagis pointing to the 40 mile distant TV station tower. The yagi array was coupled to another set of high-gain yagi antennas pointing down to the homesites in the valley. I was told that it worked pretty well. Mike Baker -- ___ 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] Thoughts on lightning protection measures....
Time-nutters-- Around here (N. Central Flori-DUH) it is not uncommon for near-by lightning strikes to damage underground cables and wiring. This is why buried wiring to things like driveway gate-openers are often placed in conduit rather than done with direct-burial wiring so that if lightning damages the wiring a new cable can be pulled through the conduit without having to re-dig the burial trench. Some years ago I had occasion to hold some long discussions with Martin Uman, one of the worlds most distinguished and eminent lightning researchers. He commented that even with the most extraordinary and costly efforts to install protection measures, that-- sooner or later-- there was a good chance that lightning would find a way to damage things. His lightning research laboratory was located here in N.Central Florida because it is in the heart of the most dense strike area in N. America. Mike Baker ___ 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] Best location for a GPS antenna...?
Time-Nutters-- My workshop is surrounded by tall trees (70 to 80 ft). There is no easy way to place my T-Bolt antenna above the tree-top foliage. Since choke-ring antennas do not provide much benefit for dealing with multi-path that originates from directly above the antenna I have considered putting the antenna on a 10-ft pole and mounting the pole in the top of the nearby trees so as to have the antenna just above the tree-top foliage. However, here in north-central Florida lightning is a serious problem. In the 12 years we have lived here, 3 trees have been hit within 75 meters of my workshop building behind my house. Here is a DropBox link to a map of lightning-strike-days in USA locations: http://dl.dropbox.com/u/60102282/Lightning%20Isokeraunic%20map.JPG I have a number of VHF and UHF antennas mounted on my workshop building but when not in use, they are kept disconnected where they enter the building. I have thought about finding some way to bring the GPS RF signal into my workshop via an optical fiber interface and sacrifice the RF to optical fiber interface if lightning strikes it in a treetop but have not found a way to implement this idea. Two years ago lightning struck a neighbor's TV antenna mounted on a pole attached to the side of his house and started a fire in one of their 2nd floor bedrooms which did a lot of damage before it was put out. The tower was well grounded and the coax leading into the room was fed through a grounded lightning protector but none of these precautions prevented the fire from the lightning strike. Any list folks have ideas on this? Mike Baker WA4HFR Gainesville/Micanopy, Fla ___ 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] OP-Amps for 10MHz distribution...?
Hello, Time-Nutters-- Here is a link to a TI app note on using op-amps for RF. It occurred to me that this might work OK for distribution of the ref freq from a GPSDO... http://www.ti.com/lit/an/slyt102/slyt102.pdf Mike Baker --- ___ 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] 15 Seconds error...??
Hello, TimeNutters-- Can anyone shed some light on why there is a 15 sec difference between the large digit time display on my Lady Heather display and WWV...? I have been accused of living on another planet-- maybe it is true after all and that is why there is such a time difference...?? Thanks-- Mike Baker ___ 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] Seen this? Clock generator IC....
Hello, Time-Nutters-- Seen SiLabs new clock generator chip? I have no idea of its pros and cons but it looks like it would be interesting to check into... Mike Baker --- Silicon Labs' new Si5335 web-customizable clock generator/buffer IC http://mkto-a0231.com/track?type=clickenid=bWFpbGluZ2lkPXNpbGFic0JldGFjdXN0LTE2MTgtNjc3My0yLTk2MC1wcm9kLTE3MzAmbWVzc2FnZWlkPTAmZGF0YWJhc2VpZD0xNzMwJnNlcmlhbD0xMjYwNTI1NjgwJmVtYWlsaWQ9bXBiNDVAY2xhbmJha2VyLm9yZyZ1c2VyaWQ9OTkwMDczJmV4dHJhPSYmJg==http://www.silabs.com/products/clocksoscillators/clock-generators-and-buffers/Pages/pci-express-clocks.aspx?mkt_tok=3RkMMJWWfF9wsRonva3BZKXonjHpfsXx4uwtXqSg38431UFwdcjKPmjr1YoHTNQhcOuuEwcWGog80wVUG%2BKG is the industry's easiest to customize clocking solution for addressing complex timing challenges in PCIe- and FPGA-based applications. Through its easy-to-use ClockBuilder^(TM) utility, web-customized, pin-controlled Si5335 devices are available in two weeks (no minimum ordering quantity). - Eliminates need for multiple clock generators/buffers (up to three unique device configurations can be specifie for a single part number) - Simplifies multi-chip clocking challenges by supporting any combination of differential formats (LVPECL, LVDS, CML, LVCMOS, etc.) - Exceeds performance requirements of PCIe, Ethernet and mass storage industry standards - Generates up to eight output clocks at up to four unique frequencies to 350 MHz with sub-picosecond jitter Build your custom clock: ClockBuilder^(TM) Web-Configuration Utility http://mkto-a0231.com/track?type=clickenid=bWFpbGluZ2lkPXNpbGFic0JldGFjdXN0LTE2MTgtNjc3My0yLTk2MC1wcm9kLTE3MzAmbWVzc2FnZWlkPTAmZGF0YWJhc2VpZD0xNzMwJnNlcmlhbD0xMjYwNTI1NjgwJmVtYWlsaWQ9bXBiNDVAY2xhbmJha2VyLm9yZyZ1c2VyaWQ9OTkwMDczJmV4dHJhPSYmJg==http://www.silabs.com/products/clocksoscillators/Pages/Utilityintro.aspx?mkt_tok=3RkMMJWWfF9wsRonva3BZKXonjHpfsXx4uwtXqSg38431UFwdcjKPmjr1YoHTNQhcOuuEwcWGog80wVUG%2BKG Get the data sheet: Si5335 Web-Customizable, Any-Frequency, Any-Output Quad Clock Generator/Buffer http://mkto-a0231.com/track?type=clickenid=bWFpbGluZ2lkPXNpbGFic0JldGFjdXN0LTE2MTgtNjc3My0yLTk2MC1wcm9kLTE3MzAmbWVzc2FnZWlkPTAmZGF0YWJhc2VpZD0xNzMwJnNlcmlhbD0xMjYwNTI1NjgwJmVtYWlsaWQ9bXBiNDVAY2xhbmJha2VyLm9yZyZ1c2VyaWQ9OTkwMDczJmV4dHJhPSYmJg==http://www.silabs.com/Support%20Documents/TechnicalDocs/Si5335.pdf?mkt_tok=3RkMMJWWfF9wsRonva3BZKXonjHpfsXx4uwtXqSg38431UFwdcjKPmjr1YoHTNQhcOuuEwcWGog80wVUG%2BKG - Silicon Labs 400 West Cesar Chavez Austin, Texas 78701 USA + 512.416.8600 customeri...@silabs.com http://mkto-a0231.com/track?type=clickenid=bWFpbGluZ2lkPXNpbGFic0JldGFjdXN0LTE2MTgtNjc3My0yLTk2MC1wcm9kLTE3MzAmbWVzc2FnZWlkPTAmZGF0YWJhc2VpZD0xNzMwJnNlcmlhbD0xMjYwNTI1NjgwJmVtYWlsaWQ9bXBiNDVAY2xhbmJha2VyLm9yZyZ1c2VyaWQ9OTkwMDczJmV4dHJhPSYmJg==mailto:customeri...@silabs.com?mkt_tok=3RkMMJWWfF9wsRonva3BZKXonjHpfsXx4uwtXqSg38431UFwdcjKPmjr1YoHTNQhcOuuEwcWGog80wVUG%2BKG www.silabs.com http://mkto-a0231.com/track?type=clickenid=bWFpbGluZ2lkPXNpbGFic0JldGFjdXN0LTE2MTgtNjc3My0yLTk2MC1wcm9kLTE3MzAmbWVzc2FnZWlkPTAmZGF0YWJhc2VpZD0xNzMwJnNlcmlhbD0xMjYwNTI1NjgwJmVtYWlsaWQ9bXBiNDVAY2xhbmJha2VyLm9yZyZ1c2VyaWQ9OTkwMDczJmV4dHJhPSYmJg==http://www.silabs.com?mkt_tok=3RkMMJWWfF9wsRonva3BZKXonjHpfsXx4uwtXqSg38431UFwdcjKPmjr1YoHTNQhcOuuEwcWGog80wVUG%2BKG www.silabs.com/twitter http://mkto-a0231.com/track?type=clickenid=bWFpbGluZ2lkPXNpbGFic0JldGFjdXN0LTE2MTgtNjc3My0yLTk2MC1wcm9kLTE3MzAmbWVzc2FnZWlkPTAmZGF0YWJhc2VpZD0xNzMwJnNlcmlhbD0xMjYwNTI1NjgwJmVtYWlsaWQ9bXBiNDVAY2xhbmJha2VyLm9yZyZ1c2VyaWQ9OTkwMDczJmV4dHJhPSYmJg==http://www.silabs.com/twitter?mkt_tok=3RkMMJWWfF9wsRonva3BZKXonjHpfsXx4uwtXqSg38431UFwdcjKPmjr1YoHTNQhcOuuEwcWGog80wVUG%2BKG www.silabs.com/facebook http://mkto-a0231.com/track?type=clickenid=bWFpbGluZ2lkPXNpbGFic0JldGFjdXN0LTE2MTgtNjc3My0yLTk2MC1wcm9kLTE3MzAmbWVzc2FnZWlkPTAmZGF0YWJhc2VpZD0xNzMwJnNlcmlhbD0xMjYwNTI1NjgwJmVtYWlsaWQ9bXBiNDVAY2xhbmJha2VyLm9yZyZ1c2VyaWQ9OTkwMDczJmV4dHJhPSYmJg==http://www.silabs.com/facebook?mkt_tok=3RkMMJWWfF9wsRonva3BZKXonjHpfsXx4uwtXqSg38431UFwdcjKPmjr1YoHTNQhcOuuEwcWGog80wVUG%2BKG www.silabs.com/youtube http://mkto-a0231.com/track?type=clickenid=bWFpbGluZ2lkPXNpbGFic0JldGFjdXN0LTE2MTgtNjc3My0yLTk2MC1wcm9kLTE3MzAmbWVzc2FnZWlkPTAmZGF0YWJhc2VpZD0xNzMwJnNlcmlhbD0xMjYwNTI1NjgwJmVtYWlsaWQ9bXBiNDVAY2xhbmJha2VyLm9yZyZ1c2VyaWQ9OTkwMDczJmV4dHJhPSYmJg==http://www.silabs.com/youtube?mkt_tok=3RkMMJWWfF9wsRonva3BZKXonjHpfsXx4uwtXqSg38431UFwdcjKPmjr1YoHTNQhcOuuEwcWGog80wVUG%2BKG www.silabs.com/linkedin http://mkto-a0231.com/track?type=clickenid=bWFpbGluZ2lkPXNpbGFic0JldGFjdXN0LTE2MTgtNjc3My0yLTk2MC1wcm9kLTE3MzAmbWVzc2FnZWlkPTAmZGF0YWJhc2VpZD0xNzMwJnNlcmlhbD0xMjYwNTI1NjgwJmVtYWlsaWQ9bXBiNDVAY2xhbmJha2VyLm9yZyZ1c2VyaWQ9OTkwMDczJmV4dHJhPSYmJg==http://www.silabs.com/linkedin?mkt_tok=3RkMMJWWfF9wsRonva3BZKXonjHpfsXx4uwtXqSg38431UFwdcjKPmjr1YoHTNQhcOuuEwcWGog80wVUG%2BKG ___ time-nuts mailing list --
[time-nuts] Unplug T-bolt before booting up...??
Hello, TimeNutters-- I have heard of the problem of needing to unplug a T-bolt before booting up the (Windows) computer but I have never seen that problem myself. I have had a T-bolt running on several different desktops and laptops and never experienced it. I do recall that there was a fix for this problem but have no idea what it is. Mike Baker ___ 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] Tongue Testing battery charge levels....
Hello, TimeNutters-- I have used the tip-of-the-tongue test for determining the state of charge of batteries for many years when my bench meters are elsewhere. The strength of the bitter taste is proportional to the voltage and I have gotten pretty good at estimating the charge condition of the ubiquitus little 9 volt batteries as well as a few others to within +/- one volt or two. I recommend not using this procedure for anything over a 12 volt battery as above that level the bitter taste turns into an unpleasant bite. Mike Baker - ___ 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] Time-code for film and/or video...
Hello, Timenutters-- I have seen time-code generators for both film and video occasionally show up on eBay, sometimes at low-end surplus prices... Mike Baker -- ___ 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] T-Bolt sig-stringth vs AZ-EL display...?
Hello TimeNutters-- Can someone tell me what the required keystroke entries are to display the LH Signal Strength vs. AZ-EL display? Thanks!! Mike Baker WA4HFR --- ___ 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] Lady Heather Help...
'Allo TimeNutters-- I have seen an LH display depicting the signal strength and paths of GPS birds in its antenna view over a period of hours. I do not see any command for invoking this display feature. Can anyone help with this? Thanks-- Mike Baker WA4HFR Gainesville/Micanopy, Fla -- ___ 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] USGS Benchmark accuracy...?
Hello, Timenutters-- There is a USGS survey benchmark on the side of the road just a half-mile from my house. Any guess as to how accurate these are? I parked my pickup truck over the benchmark with the LH box and antenna ( a 10 year-old Trimble surveyors antenna). I only let LH run for an hour-- I am not sure how I could leave a LH box out there for a long survey period without running the risk of theft. The survey marker is about 20 feet off the side of the road in a grassy area and marked only by a 4-foot-tall plastic USGS geodetic pole next to the buried concrete post. The head of the marker post with the brass plate on the top is flush with the surface, but covered with grass. I had to scratch around to find it. There is also a second concrete post in the ground about 30-40 feet away-- apparently you line up the two concrete markers to give you a true cardinal direction. Mike Baker -- ___ 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] Another LH question....
Hello, Timenutters-- Somewhere I saw a LH display screen showing an AZ-EL display of signal strength. Looking through the help files, I do not see where to call this display up. I made a screen-capture of it if anyone would like to see it. I think that feature would tell a lot about what the sky/satellite view really looks like from any given window or roof vantage point of the antenna. I also see the various LH operating parameters all spaced out neatly. I know that there are commands to change the vertical scale of things being displayed but I have never been able to make any of this work. Several other folks who were interested in the LH display looked at this and had no better luck than I did altering certain aspects of the LH display. If anyone ever creates an addendum to the help files that gives examples such as: This is what your character string should look like to do this or that I would like to see it! Thanks-- Mike Baker ___ 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] National Geodetic Survey Bench Mark
Hello, TimeNutters-- Majdi asked about details on the USGS benchmark located about 1/2 mile from my house out here in the boonies. Below is what I have in my file on it. Some of this means nothing to me-- my only interest in the benchmark was knowing (roughly) how accurately it is located for comparing to my GPS and GPSDO receivers. Mike Baker --- N 29d 32m 31.00741s(which is 31s plus 0.75ft) W 082d 21m 04.77943s(which is 04s plus 68.84ft) Parked truck immediately beside the (apparent) marker location and got the following readings: N 29d32.519m (translates to: 32m 31.14s or 31s plus 14.12ft) W 82d21.078m (translates to: 21m 04.92s or 04s plus 60.06ft) At this location, each sec north = 100.83ft each sec west = 88.33ft Look for a cap and nail (small disk) on the centerline of the road, or some sort of marker post by the southwest side of the road. If you find the marker post, the benchmark is 7.5 feet south of it, and pretty much next to the cap and nail in the road centerline. It will be between the driveways for 1926 SE Wacahoota Road and 2010 SE Wacahoota Road. THE STATION IS A STANDARD AC GIS DISK STAMPED---STATION A107---, SET IN THE GROUND 15 FT TO REFUSAL (6 IN PVC SLEEVE) 9.83 METERS (32.24 FT) SOUTHWEST FROM A NAIL CAP (NO 3765) SET IN CENTERLINE OF ACR 18, 51.17 METERS (167.87 FT) NORTHWEST FROM A NAIL CAP (NO 3765) SET IN POWER POLE, 2.3 METERS (7.5 FT) SOUTH OF CARSONITE POST SET, 31.82 METERS (104.40 FT) SOUTHEAST FROM A NAIL CAP (NO 3765) SET IN A POWER POLE, 7.96 METERS (26.13 FT) NORTHEAST FROM A REBAR CAP (NO 3765) SET. --- AZIMUTH MARK NO. 1 IS A STANDARD AC GIS DISK STAMPED---AZIMUTH A108---, SET INTO GROUND 10.5 FT TO REFUSAL (6 IN PVC SLEEVE) 5.95 METERS (19.52 FT) NORTHWEST FROM A NAIL CAP (NO 3765) SET IN POWER POLE, 9.58 METERS (31.43 FT) SOUTH FROM A NAIL CAP (NO 3765) SET IN CENTERLINE OF ACR 18. TO REACH THE AZIMUTH FROM THE STATION, GO NORTHWEST FOR 0.5 KM (0.3 MI) ON ACR 18 TO AZIMUTH MARK ON THE SOUTH SIDE OF ROAD. STATION RECOVERY (2002) RECOVERY NOTE BY FL DEPT OF ENV PRO 2002 (BPJ) THE MARK IS ABOUT 4.6 MI NORTHWEST OF MICANOPY, IN SECTION 18, TOWNSHIP 11 SOUTH, RANGE 20 EAST. A DISC METAL ROD COMBINATION RECESSED 0.3 FT BELOW THE LEVEL OF THE GROUND AND LEVEL WITH SOUTHEAST WACAHOOTA ROAD. LOCATED 122.0 FT EAST-SOUTHEAST OF THE EXTENDED APPROXIMATE CENTERLINE OF A DIRT DRIVEWAY AT 2010 SOUTHEAST WACAHOOTA ROAD, 108.0 FT WEST-NORTHWEST OF THE EXTENDED APPROXIMATE CENTERLINE OF A DIRT DRIVEWAY AT 1926 SOUTHEAST WACAHOOTA ROAD, 32.3 FT SOUTH-SOUTHWEST OF THE APPROXIMATE CENTERLINE OF SOUTHEAST WACAHOOTA ROAD, 7.8 FT SOUTH-SOUTHWEST OF A BARB WIRE FENCE 7.7 FT SOUTH-SOUTHWEST OF A CARSONITE WITNESS POST. NOTE A BAR MAGNET WAS EMBEDDED IN THE MONUMENT. NOTE 6-INCH PVC SLEEVE AROUND THE DISC IS DAMAGED BUT DISC IS IN GOOD CONDITION. The NGS Data Sheet See file dsdata.txt for more information about the datasheet. DATABASE = ,PROGRAM = datasheet, VERSION = 7.61 1National Geodetic Survey, Retrieval Date = SEPTEMBER 4, 2008 AR1764 *** AR1764 DESIGNATION - A 107 AR1764 PID - AR1764 AR1764 STATE/COUNTY- FL/ALACHUA AR1764 USGS QUAD - MICANOPY (1988) AR1764 AR1764 *CURRENT SURVEY CONTROL AR1764 ___ AR1764* NAD 83(2007)- 29 32 31.00741(N)082 21 04.77943(W) ADJUSTED AR1764* NAVD 88 -29.117 (meters) 95.53 (feet) ADJUSTED AR1764 ___ AR1764 EPOCH DATE -2002.00 AR1764 X - 739,157.689 (meters) COMP AR1764 Y - -5,504,058.842 (meters) COMP AR1764 Z - 3,126,301.264 (meters) COMP AR1764 LAPLACE CORR- -0.46 (seconds) DEFLEC99 AR1764 ELLIP HEIGHT- 1.257 (meters) (02/10/07) ADJUSTED AR1764 GEOID HEIGHT- -27.78 (meters) GEOID03 AR1764 DYNAMIC HT - 29.077 (meters) 95.40 (feet) COMP AR1764 AR1764 --- Accuracy Estimates (at 95% Confidence Level in cm) AR1764 TypePIDDesignation North East Ellip AR1764 --- AR1764 NETWORK AR1764 A 107 2.12 1.43 4.21 AR1764 --- AR1764 MODELED GRAV- 979,275.5 (mgal)
[time-nuts] GPSDO + X72...??
Hello, TimeNutters-- I understand that I will get less output jitter with a high quality GPSDO than a Rb oscillator, but, even so, having a Rb unit locked and disciplined by a GPS receiver appeals to me. The one thing that I noted about the X72 is that the factory has provided for a convenient way to GPS steer it. Hm.. Maybe, if I could find an X72 for a decent price and feed it into a Nixie-tube time-clock display, it would make a neat curiosity conversation object for the living room fireplace shelf. So far, the cheapest eBay X72 units I have seen were around $300 and no bargain... Mike Baker Micanopy, FL -- ___ 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] LVPECL logic for dummies (that would be Moi)
Hello, TimeNutters-- Part deux of the continuing saga of the SiLabs oscillator chip that has no output I did not realize that LVPECL chips were such a hassle... Next time, I am going insure that such devices I use are CMOS and not LVPECL. This particular SiLabs Si595 chip has complementary LVPECL output. As you may recall, I wired up dead-bug legs on the 110MHz Si595 VCXO and hooked the circuit up on a breadboard and got no output. Sadly, the chip behaved as if it were dead. (Sniff) Poking around (in-between bouts of sniffling) I came across the following in an app note by another manufacturer of LVPECL logic chips: Why can't I get any output from an ECL Output Connector, and how should I measure it? It has been shown that that ECL outputs are open emitters. Without pull-down resistors, the outputs are turned off and therefore, there is no output voltage. Even if the output has an internal pull-down resistor, it may still not be possible to measure the true output signal either, unless the measurement device is impedance-matched to the ECL output structure. The reason for this problem is that the internal connection between the output ECL device pin and the output connector is most likely a long line, and neither the scope probe nor the high impedance scope input represents an impedance match to the ECL output structure. If one was to connect the ECL output directly to a 50 Ohm oscilloscope input, there would no output either, because the output emitter will be turned off by the ground-referenced 50 Ohm input, even if the output has a 200 Ohm pull-down resistor. However, AC coupling an ECL output with an internal 200 Ohm pull-down resistor to a 50 Ohm input instrument is OK So much for not being able to measure an ECL signal, now we shall show how it can be measured using an ECL Terminator. ECL/PECL output circuits are designed to drive 50 Ohm loads terminated into a terminating voltage V[TT]= V[CC]-2 V. For ECL, V[CC] = 0 V, and V[TT] = -2 V. For PECL, V[TT] = +3 V. If the input of a measurement instrument is made to look just like a 50 Ohm/V[TT] termination, then all should be well. In fact, that is exactly what an ECL or PECL Terminator is. An ECL Terminator is basically a biased 50 Ohm microwave attenuator. The input has an equivalent 50 Ohm/-2 V termination, and the output is suitable for driving a ground referenced 50 Ohm input instrument. Similarly, the input of a PECL Terminator has an equivalent 50 Ohm/3 V termination. In order to protect sensitive instruments, however, a properly designed ECL/PECL terminator should have a near ground level output For measuring a differential ECL output either an instrument with a differential input and the proper termination or a differential to single-ended converter is required. Caution! Do not connect the output of a PECL device to an ECL terminator or to a ground-referenced 50 Ohm input instrument. This could spell instant disaster for the PECL device or the instrument Although connecting an ECL output to a PECL Terminator may not destroy the ECL device, it could cause gradual degradation of the output emitter follower, due to possible excessive reverse bias voltage developed across the base to emitter junction. It is also shown that the collectors of the ECL output emitter followers are connected to V[CC]. When V[CC] is ground, shorting the emitter to ground merely turns off the emitter follower and no damage will occur. This is not the case when V[CC] is = +5 V. The transistor output current is limited only by b times its base current, which is supplied by R[1] or R[2] connected to V[CC]. In most cases, the device is destroyed instantly. In fact, connecting a PECL output device to a ground-referenced 50 Ohm load often destroys the device instantly as well. --- Now-- back to the breadboard to see if I can get this ornery LVPECL oscillator to show me some output... (next time, I am going to make sure such chips I use are CMOS !!) Mike Baker Micanopy, FL USA ___ 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] Silicon Labs series of oscillators...
Hello, TimeNutters- Silicon Labs [1]http://www.silabs.com/products/clocksoscillators/pages/default.aspx offers a large assortment of various types of oscillator chips: XO, VCXO, programmable XO, clock generators, clock distribution chips, Jitter Attenuators, Clock cleaners, etc, etc I have a need for a 110 MHz VCXO in a 1.8GHz to 7.5GHz tracking generator I am building for my Tek 494 spectrum analyzer. I bought a pair of Silicon Labs 110 MHz VCXO chips for less than $25 for the pair from Cramer Distributors. The Si595 VCXO chips are in an industry standard 5mm X 7mm surface-mount package. Yikes! I knew I was going to have trouble (for lack of thru-hole leads) breadboarding this chip. However, I managed (using a magnifier-loupe and a v-e-r-r-r-y tiny soldering iron tip) to get some legs soldered onto the surface-mount pads. Great... I inserted the critter into the socket-strips of my breadboard, hooked up the required 3.3vdc Vdd and ground and checked to see what it's output looks like. No joy. Drat. It has a set of complementary output pins. One sits at around 50% of Vdd and the other is low. When I pull the Output Enable pin high, the 50% output pin goes low. The other (complementary) pin just stays low. If I pull the Output Enable pin low, neither output pin changes. Drat. I must have destroyed the little critter during the leg soldering process. These chips are supposed to be pretty static from normal handling and-- here in humid Flori-DUH, handling problems from static build-up is almost a non-existent problem. Even so, I do all my breadboarding on a 3-foot X 2-foot static-drain pad. So I used the utmost care in soldering legs to the second chip. The surface-mount pads are gold-plated and it is super easy to just momentarily tap them with the soldering iron tip and leave a very teensy blob of solder on each one. Using pre-tinned gold-plated legs stripped from some surplus 1/8 Watt resistors, I fastened the legs on the chip with only the briefest time of soldering-iron tip contact; less than one second, I am guessing. Same result with the second chip; the outputs appear to be dead. I guess this sad saga boils down to my question for the Time-Nutters List: How do you deal with breadboarding when it comes to parts that are ONLY available in surface-mount configuration (and are just at the size limit for hand soldering? Thanks for any input on this! Mike Baker Micanopy, FL References 1. http://www.silabs.com/products/clocksoscillators/pages/default.aspx ___ 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] T-Bolts object to being dropped.....
Hello, Time Nutters Last week I was rearranging gear on a shelf over my workbench. I managed to knock my T-bolt off the shelf and onto the top of the workbench, about a 20-inch fall. After I finished calling myself a $...@$%*#@ idiot, I hooked it back up and, just as I feared, there was a BAD OSCILLATOR warning and something about an OSCILLATOR AGE warning. There was no oscillator output. ggg Taking it apart to see what I could find, I noted that the OCXO WAS running, but apparently so far off that no lock occurred. Thinking I had nothing to lose, I considered removing the access screw over the oscillator tweaking adjustment and seeing if I could resurrect it, but decided I had done enough damage for the day and went back into the house whimpering over the demise of my T-bolt. However, the next day, it had recovered all on its own, at least enough that there was normal output, although the steering voltage was nearly at its limit. Over the following week, it slowly recovered and appears now to be back to normal with all parameters right where they used to be. No permanent damage seems to have been done Mike Baker ___ 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] Help!! Trimble T-Bolt serial port interface problem...
Hello, Time Nutters-- I just installed Lady Heather on my Dell D-610 laptop. When I booted it up with the T-bolt plugged into the serial port on the laptop, it screwed up the pointer and touch-pad. The pointer functions erratically and is generally uncontrollable. As I recall, this is a common problem when plugging T-bolts into serial ports. I know that there is a procedure to cure this problem-- but I forgot what it is. Sometimes I think I am getting senile and getting forgetful... The laptop has Windows-7 Eternity OS on it but I think the fix procedure is the same as Win-XP. Can any Time-Nutters on the list help me out with this...?? Many thanks!! Mike Baker Micanopy, FL -- ___ 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] Why .30 cal holes can't be seen at 800 yds...
Timenutters-- The question was asked-- Why can't a large aperture high-resolution optic be used to locate bullet holes in a target at 800 yards? Consider this--: I often shoot at targets on the 600 yard berm at the Manatee Range (near Bradenton, FL). Typically, by 11AM the atmospheric shimmering mirage distortion makes even the 4 target hard to see. By 1PM the use of any rifle scope magnification greater than around 10X is an exercise in futility. Often, the mirage is severe enough that even the 12 steel plates are hard to find through a 10X scope. .30 holes in a target...? No way. - Other questions that were asked: To what degree of accuracy can the 800 yard distance be measured? I have a laser range-finder which has been verified to be within +/- 20 inches out to 1000 yards (the U of F college of Engineering has a series of distance marker posts set up for some research they were doing). What kind of accuracy is expected for measuring bullet velocity at the shooting bench and downrange? I have a set of Oehler Research sky-screen chronographs that use a 10MHz crystal for clocking the counting registers. The projectiles start out at roughly between 2750 FPS and 3100 fps and end up downrange not slower than around 1800 fps. Assume sky-screen clocking ambiguities of only a couple of clock pulses. As an aside, projectiles whose velocity drops to sub-sonic at 800 yds are of no interest to me. The transition from super-sonic to sub-sonic generally includes conditions that create inaccuracy. I am VERY grateful for the feedback on this topic! A couple of innovative suggestions from list members have given me food for thought and I am going to pursue looking into them. My first chore is to investigate what kind of pulse rise-times I get from a selection of inexpensive ultrasonic sensors when a supersonic bullet passes within a couple of feet from them. I have a Tek 2252 scope that I can place downrange to look at the sensors with but storing the waveform for examination may be a problem (no one seems to have volunteered to stand downrange monitoring the scope screen!) The Tek 2252 has a Centronix screen-capture printer output but it is an Epson FX format and I have no idea if any current printers at the local Office Mart are compatible with the Epson FX data format. Anyone on the TimeNuts list have any thoughts on this? The 2252 scope also has a GPIB port but I don't know if it outputs the printer data. I have a Sparkfun GPIB/USB dongle but that may not be of any use if there is no printer data on the GPIB port. Mike Baker --- ___ 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] A real world project need for timing accuracy...
Timenutters-- I appreciate the feedback for implementing my ballistic field measurement project but I think there is some misunderstanding of what the goal is. For instance, it is not practical to find 800 meters of coax and trench it in out to the downrange target. This system needs to be relatively portable so it can be set up at any given shooting range. I need to determine: A) down-range velocity of the still super-sonic projectile, B) time of flight and C) shot-group size. Measuring down-range shot-group size with an array of ultrasonic sensors is pretty straightforward. I can do all the computation with a $6 microprocessor and send the X/Y coordinates back to the laptop at the shooting bench with a simple RF link. Down-range velocity is easily determined with a set of sky-screens and the results also sent back via an RF link. Time-of-flight is much more problematic to determine but the plan is to determine the elapsed time between the moment the projectile passes over the muzzle skyscreen and the moment of passing over the downrange skyscreen. This means syncing the 10 MHz clocks at both ends together. I guess the crux of my question to the time-nuts gang is what is the easiest (cheapest!!) way to do this. For a number of years I have been using an ultrasonic shot-group size measurement system made by Oehler Research. It can resolve individual shot placement to within 1 cm. Some less expensive systems that use fewer sensors can only resolve to +/- 2 cm. The Oehler Research system also determines time of flight. The problem is that these systems all use a cable to connect back to the equipment at the shooting bench. I am trying to find a way to synchronize/coordinate a downrange 10 MHz clock to the master 10 MHz system clock at the shooting bench without spending hundreds of $$ doing it. It is not too big a problem to process all of the signals from the downrange skyscreens and the ultrasonic shot-group sensors and telemeter the results back to the shooting bench. However, time-of-flight info (via an RF link requires that I sync the 10MHz clocks at both ends together. Use of GPS receivers seems to be the most likely way to do this but how do I keep the cost and complexity down? Thanks in advance for any feedback on the matter! Mike Baker - ___ 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] A real-world precision timing need....
Hello, Time-Nutters-- A real-world precision timing need: As a dedicated long-range rifle shooter and ballistics enthusiast, I am in the early stages of a project I am getting started on... The object is to measure the velocity of a rifle bullet both at the muzzle and downrange at various distances up to 800 yards/meters or so. Conventional optical sky-screens will will be used for measuring the velocity at both ends. However, I also need time-of-flight and this requires knowing the timing relationship between the time the bullet crosses the muzzle sky-screen and the downrange sky-screen. Bullet muzzle velocities will be between 1900 to 3200 feet-per-second. Additionally, I will be using the output from an array of 4 ultrasonic sensors located on the corners of a 4-foot PVC pipe square to determine the size of the shot group at the far end and telemeter this info back to a laptop at the shooting bench. I can use a 10-MHz crystal for the sky-screen clocks and the for the 4 ultrasonic bullet shot location sensors. However, determining the time-of-flight is a more difficult task as this requires syncing clocks together at both ends to a moderate degree of accuracy. Out to 100 yards I can send the time-of-flight far-end pulse back by wire and compare it to the muzzle-end sky-screen pulse but this is not practical to do by wire out at 800 yards. This project is on a tight budget-- namely, MY wallet, so cost is a major concern. Suggestions will be most welcome!! Thanks!! Mike Baker Gainesville, Florida, USA - ___ 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] Interesting time interval measuring chip....
Hello, Time-Nutters-- A friend pointed me to an interesting chip for time interval measurement and related time and temperature measurement functions: A general purpose TDC: The TDC-GP2 I think the chip is around $20 in single-unit quantity. www.acam.de Measurement range 3.5 ns to 1.8 us 2 channels with resolution of 50 ps 4 events can be measured against each other 15 ns pulse-pair resolution - It also has a temperature measurement function: 2 or 4 sensors 16 bit resolution 0.004 Deg C resolution for platinum sensors --- Mike Baker ___ 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] ROHN 9H50 34 Foot Telescopic TV Wireless Antenna Push Up Mast
Hello, Time-Nutters-- RE: ROHN 9H50 34 Foot Telescopic Antenna Push Up Mast Some years ago, before we moved out here in the boonies on a 6 acre lot, we lived in a home in a small suburban lot surrounded by tall trees and no room to put up a guyed tower. I installed a heavy-duty guyed 40' telescoping push-up pole on top of the roof. It had four guys that ran down to the corners of the roof where I had installed reinforcing buttresses to take the strain of the guy wires in heavy winds. We live in N. Central Flori-DUH and it stayed up for 12 years and survived numerous high-wind thunderstorms and one moderately close pass-by of a hurricane. I bought the push-up pole at a county surplus equipment sale and have no idea who made it, but it was vastly more heavy-duty than the el-cheapo/crapo push-up poles sold by Radio Shack. I had two small beam antennas and a small rotor mounted on it. Mike Baker Gainesville/Micanopy FL ___ 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] Glonassgps receiver board on eBay
Hello, Time-Nutters-- See below-- Mike Baker Gainesville/Micanopy FL -- 20ns timing glonass/gps receiver eBay Item number:300287488541$59 High accuracy 20ns timing glonass/gps receiver| 2X 1PPS Item condition:Used Quantity: 10 available Price:US $59.99Buy It NowBuy It NowBuy It Now or Best Offer:Make OfferMake OfferMake Offer Shipping:$8.00 Standard Flat Rate Shipping Service Item number:300287488541 Item location:China, China ___ 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] Traceable to NIST...??
Hello, Time Nutters-- Traceable to NIST...? All you need is this LPRO Rb osc being disciplined by a GPSDO and you can claim NIST traceability? Not the way I understand the rules http://www.tenmhz.com/GPSDO.htm What say the list? Mike Baker -- Today’s communication devices and protocols often require an accurate timebase. Leveraging the best technology of yesterday and today, we are proud to bring you the world's first rubidium GPSDO under $500! The LPRO-101 by Efratom® /Symmetricom®, stabilized by a high-sensitivity GPS system, provides affordable, traceable precision. Watch our DEMO * Features: Guaranteed Accurate to 5x10-11, Traceable to NIST when LED is green * Typical accuracy is even better → Typical Accuracy Charted * Low phase noise 10 MHz, 50Ω BNC output at +7 dBm * Includes power supply and high-gain GPS antenna * Phase Locked for absolute accuracy over long time intervals ___ 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] GPS External (mag-mount) antenna with a bazillion dB gain.....
Time Nutters-- See: http://tinyurl.com/25rrlnb http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItemitem=120378309245ssPageName=STRK:MEWAX:IT for a GPS mag-mount antenna that claims to have all manner of marvelous qualities, not to mention some 53dB of gain I would love to hear some feedback on what the list thinks of some of these claims!! Mike Baker --- ___ 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] Which voltage regulator chips offer good performance...?
Hello, Time-Nutters-- Bob Camp said: snip ...stability is not the only issue. Crud on the power supply is an issue as well. Some of the ultra low drop out regulators are not real good crud blockers. --- So... This would seem to bring up the question of which 3-terminal regulators ARE good (if not good then which are the best?) providing both stability -AND- clean, crud free output? How about old standby regulators such as the 723? Problem there is that the stand-alone chip is only good for really low current. For years I have been using general purpose 3-terminal regulators sometimes with carefully selected low impedance capacitance on the output. In some cases I have found that a high-gain transistor in the output configured as a capacitance multiplier serves to handle current load spikes but is only a nominal help in cleaning up crud on the output. Comments? Suggestions? Mike Baker - ___ 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] Lady Heather function/control mysteries....
Hello, Time Nutters-- Mark Sims said: An easy solution is to use a Thunderbolt and the beta 3.0 version of Lady Heather. It has both analog (watch style) and digital time displays. You can zoom those displays to a full screen. --- Mark-- How do you zoom those displays to full screen? How do you go back to a normal display In trying to figure out how to get LH to display the SV sky position and the fix distribution display I have managed to get it into a mode where it says: DISCIPLINE OFF -and- Discipline Mode: DISABLED I have been unable to figure out how to get the discipline mode turned back on. Any suggestions will be most welcome!! Speaking of LH function/control mysteries, if anyone has been able to identify any of the mystery function commands please share what you have learned by posting their description on the list. For instance, I can display the OSC graph, but it obscures all the other graphs-- how can I reduce its amplitude and/or shift it vertically so as not to cover up the other graphs? Thanks for any help you can offer!! Mike Baker --- ___ 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] Days of buying crystals numbered...??
Hello, Time-Nutters-- I am in need of a 110 MHz VCXO for a mixer input to provide the needed offset for a tracking generator I am building for my Tek 494P Spectrum Analyzer. The 110 MHz VCXO only needs to be pullable/pushable by +/- 100KHz in order to center the tracking gen signal in the passband of the spectrum analyzer. So-- here is the question: Can programmable oscillators such as the Silicon Labs Si570/571 be configured to be pullable/pushable so as to serve as a stand-alone VCXO...? It would appear that phase noise requirements are very loose for this particular application. Any thoughts on this? Thanks!! Mike Baker -- ___ 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] Lady Heather CPU Usage...?
Fellow Time-Nutters-- I note that Lady Heather keeps my CPU usage up at around 40%-45% as long as it is running. When I close LH my CPU usage falls to around 1% to 3%. What are other LH users on the List seeing...? Thanks! Mike Baker -- ___ 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] Weird T-Bolt elevation readings...
Hello, TimeNutters-- While we are on a thread about Trimble T-bolts, perhaps someone might expand on why my T-bolt does not ever come up with altitude readings that are even close. After a long fix, the Lat-Lon coordinates are pretty close, but the altitude is always given as around 2 meters. We are pretty low here in Flori-DUH, but not THAT low. My ground elevation here is 28M ABMSL and my GPS antenna is another 8M above that on top of my fireplace chimney. I have roughly 50 ft of RG-59 cable on the antenna, but altering the cable length value does not seem to have any effect. I get these same very low altitude readings with TBOLTMON and Lady Heather v3 beta. Since I know my altitude well withing one meter, should I enter that manually? What is the procedure for doing that? Suggestions...?? Thanks!! Mike Baker --- ___ 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] HP-428B What I really meant....
Hello, TimeNutters-- Oops!! I goofed-- I meant to say HP/Agilent 428B Sensitive Clip-On DC Milliammeter. Only the latest revision model with a serial number prefix of 995-x is worth having. In their last revision, HP retained a couple of tubes in functions where they felt early 80's transistors would be less reliable. However, most of the circuitry is solid state and is all on a very nice printed circuit board. The unit went out of production in 1984. The probes are extremely fragile and if dropped or exposed to excessive heat for long periods of time the ferrite cores or the Mu metal shields will be degraded. The manual warns against storing the probe on top of any hot instrument top. My 428B has been an invaluable and frequently used test instrument on my work bench. Alignment was a little tricky but once done, my unit has been in use for over 10 years with no problems. It is very handy for measuring low current drains of circuits down around the 1 to 10 milliamp range. Actually, on the lowest scale (0 to 1mA) you can accurately measure currents down to 0.1mA. Mike Baker ___ 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] Analog Devices precision voltage source
Hello, TimeNutters-- I used the Analog Devices AD588 chip http://www.analog.com/static/imported-files/data_sheets/AD588.pdf to build a precision current reference for an older model HP-628B clamp-on current meter. I used the precision 10VDC to feed a 0.1% 1K resister for a 10mA reference. I brought a loop of wire in series with the 10K resistor out to the front panel for access by the probe. The meter's full-scale meter ranges are: 1mA - 3mA - 10mA - 30mA - 100mA - 300mA - 1A - 10A The HP628B clamp-on current meter has been a very useful item on my work bench and the precision 10mA current reference to check the meter calibration has been very handy. Mike Baker ___ 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] Speaking of valves and tubes....
Hello, Time Nutters Back in the 70's on a visit to the office of a fellow broadcast station Chief Engineer, I saw, on his desk, a cute novelty item created as a promotional sales gift by the General Electric company for its tube (valve?) marketing efforts. The item consisted of several 9-pin miniature glass tube (valve?) envelopes mounted on a wooden base. Inside one tube was a very tiny hand-cranked rotary egg-beater. The label under the tube read Mixer Tube. The next tube had a tiny swinging gate patterned after the likes of which might be found on a vegetable garden fence and it was labeled Gate Tube. There were four tube functions represented, but I forget what the other two were. I thought it very clever... Mike Baker - ___ 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] I like Nixie tubes!!
Hello, Time-Nuts-- Paul Swed said: For whatever reason I have resurrected a 1967 HP 5245L counter. Indeed I have many newer units. But there is something about that nixie tube glow. Indeed. I have an old HP-5245L counter that I keep running on the shelf over my bench just because the Nixie tubes rippling through their count sequence is so... well, so cool and appealing. I also have an old HP selective level meter that tunes up to around 20 MHz or so that has a Nixie tube display and I often turn it on just for the effect that the Nixie tube display has. If all the digits are cleanly and evenly lit and there is no extraneous glow visible in the tube to damage the contrast of the digits, Nixie displays really appeal to me! Mike Baker WA4HFR Gainesville (Micanopy) FL USA ___ 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] Thanks for the screen captures and a question...
Hello, Time Nuts-- My thanks to those couple of you who have sent screen captures of your LH 3.0 beta display to eddikate me. Any other screen captures pending will be most welcome. Part of my quest in this is to see how others have configured their displays so as to display the most information but not have the display so cluttered with overlaid graphs as to be unreadable. My computer-fu is not very strong and it helps to have other people's examples to compare to what I see! My first stumbling attempts to set LH 3.0 beta up have brought up a couple of questions, one of which is why, after commanding it to do a 4 hour fix, it came up with a Lat and Lon reading that is very much in error? After the precision fix the Lat/Lon/Alt reads: Lat 47.x N Lon 122.xx W Alt -9.xxx M However, my actual Florida/USA location is: Lat 29 N Lon 82 W Alt 27m AMSL. What am I doing wrong to wind up with this wrong Lat/Lon ?? As for tips for configuring LH 3.0 beta, Mark's suggestion to set the signal level mask to a low value (like AMU=1.0) and the satellite elevation mask to a high value (like 25 degrees) is much appreciated. My antenna location (on top of the fireplace chimney cap 6 feet above the house roof) is surrounded by tall trees and most of the sky below 20 degrees is blocked by foliage. Mike Baker - ___ 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] Why they call it Flori-DUH...!!
Hello, Time Nuts-- Now you know why they started calling this far southeast corner of the nation Flori-DUH...!! Somewhere along in the process of installing LH v3.00 beta I managed to get John Miles on-line T-Bolt unit mis-labeled. In my struggle to figure out the confusing command line structure, I did not understand why it seemed to be behaving so weirdly!! DUH!! I think I will fix myself a stiff egg-nog and start all over again!! Thanks for all the patience extended to me by the several who offered help and suggestions!! Mike Baker WA4HFR Micanopy, Flori-DUH, USA ___ 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] Lady Heather screen-capture request...
Fellow Time-Nuts-- Mark Sims posted a screen capture of his Lady Heather screen display. In the interest of comparing my LH screen display to what others see, could I impose on some other list members to send me a screen capture of their LH screen display? Or-- if you are using the LH v3.0 beta, send me a screen capture of that as well? There are several anomalies I see from time to time that I am not sure if are normal or not and comparing to other LH users would be a big help!! Send screen captures (.gif is OK) to me at mpb45 (at) clanbaker (dot) org Thanks!! Mike Baker Micanopy, FL --- ___ 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] Sending me Lady Heather screen-captures....
Hello, Time-Nuts-- Many thanks to Warren S for sending me over 20 Lady Heather screen-captures showing different configurations!! I really appreciate seeing these and welcome anyone else on the list sending me their screen captures. John Miles commented that individual screenshots may not be very useful without specifying the timescale, filters, and graphs you're looking for. This is true, but I am not even sure what I am looking for,--and some of the filter configurations mean nothing to me!! At this stage, I am like the little boy on the sidewalk looking into the toy store window and saying, WOW!! How COOL!! Look at that, and that, and that!! Now I have some studying to do of the graphs of all the different filters and configurations-- this will take me a while as I am not really sure what I am looking at with some of the graphs. Thanks again Warren!! My Thunderbolt sits next to my desktop computer in the shop and I have made no attempt to thermally isolate it from ambient temperature excursions due to routine air-conditioner cycles in the summer and heat-pump cycles in the winter so I expect to see some regular variation of the temperature graph. I mainly use it's outputs to reference and lock my spectrum analyzer and frequency counters with. One mystery is that once or twice daily, the temperature graph exhibits a sharp, almost perfectly vertical spike which recovers over a period of a few minutes. The temperature cannot possibly change that rapidly so there is something else going on. LH often indicates that the blue PPS ADEV and the red OSC ADEV are both in the high E-13 zone for several hours and then invariably, both will drop back to the mid E-12 zone and sometimes stay there for many hours. Periodically, the violet PPS graph and the green DAC graph will go off scale for 10-15 minutes and I cannot find a reason for this-- it does not seem to be either temperature related or have anything to do with how strong the signals from the birds are or where the birds are relative to any tall tree foliage blocking the antenna sky view. Mike Baker --- ___ 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] Temperature stabilization of a Thunderbolt
Hello, Time-Nutters-- Mike Naruta's AA8K comments about his experiments to temperature stabilize a Thunderbolt brought to mind my own initial TB temperature stabilization experiments. I placed the TB inside a small 6-pack Styrofoam drink cooler. I left the power supply outside and ran the wires into the TB via a small hole through the inch-thick wall of the insulated container. Initially, I used a laboratory grade quartz thermometer probe to monitor the temperature and once the internal temperature stabilized it stayed fixed to well within a couple of tenths of a degree C. I suppose that one could refine this technique by purchasing a thick-wall Styrofoam cooler for a couple of dollars and cutting small pieces from it to fabricate a small custom sized insulated box just big enough to fit the TB inside of. Mike Baker WA4HFR Gainesville, FL. USA ___ 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] New Thunderbolt firmware v 3.0...?
Hello, TimeNutters-- Apparently, more recent Thunderbolt releases have been encountered with a V 3.0 firmware upgrade. Does anyone have any info on what benefits this might offer...? Thanks-- Mike Baker --- ___ 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] Lady Heather Display Question....
Hello, Time-Nutters A question about possible software modifications to the Lady Heather display: Looking at the LH display, I see a large empty (black background) area on the left side of the screen, between the top of the graph area and the bottom of the list of satellites being tracked. When the cursor is placed in the graph area, a line appears in that large empty space that indicates the time where the cursor is sitting. Other than that, it is just a large empty space in the display. Is this space being used (or reserved) for something I don't know about? Is there some reason why a running time display with, say-- inch-high digits, could not be placed in that area? Something that could be clearly read from across the room? Thanks-- Mike Baker --- ___ 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] Glass is not a liquid but has some similar molecular similarities
Hello, Time Nuts-- For those of you following the thread on glass properties, see: Dual personality of glass explained at last Mike Baker --- See the entire article at: [1]http://tinyurl.com/mqsrjo [2]http://www.newscientist.com/ * 18:00 22 June 2008 by Colin Barras snip Although glass feels like a solid, its molecules cannot quite settle into a regular 3D lattice, instead taking on the disordered arrangement of a liquid. Quite why glass behaves like this has been unclear. snip This geometry is incapable of slotting together, or tessellating, to form the regular 3D lattice characteristic of a solid. But equally they cannot move around freely because they are larger than the original particles. snip Royall thinks that the molecules of real glass takes on the same icosahedral structure, leaving it unable to crystallise into a solid, but not free enough to have liquid-like properties. 'Metallic glass' snip For a long time, no-one has really shown what the structure of glass is, Royall says, but we have been able to show how the structure of a glass differs from that of a liquid. References 1. http://tinyurl.com/mqsrjo 2. http://www.newscientist.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] Weird Lady Heather behavior observed...??
Hello, Time-Nutters-- Is there any possibility that opening and closing the Lady Heather display inflicts some sort of temporary disturbance to the T-bolt it is monitoring? If I run the Lady Heather display on my Dell Dimension 9200 desktop screen and let it run undisturbed for 8 or 10 hours, it tells me that my T-bolt has settled down nicely; PPS staying within +/- 2ns to 4ns and Osc never straying outside of roughly +0.01ppb to -0.01ppb. The PPS OADEV gets down to the 4e-13 category and the OSC OADEV to around the 3e-13 category. The green DAC graph stays well centered within one division over or under (@ 100uV/div) and the violet PPS graph also stays well centered within +/- one division (100uV/div). The yellow temp line stays centered inside one division. Everything looks great right...?? As long as I do not minimize or close and then re-open the LH display, this situation will continue for many hours. HOWEVER-- if I close the LH display and open it back up shortly thereafter, all my T-bolt running parameters start fluctuating wildly and going off-scale. Even the yellow temp line goes off scale and PPS OADEV and OSC OADEV both drop back to a high e-12. It takes about 90 minutes for everything to settle back down, after which everything runs tightly for many hours until the next time I minimize or close and re-open the LH display. If this is just a coincidence, it sure has happened with consistent regularity over the last week or so since I first noticed this behavior. Is this just a coincidence? Has anyone else noticed anything like this? I can send anyone a before and after screen capture of what I am describing. Mike Baker WA4HFR Gainesville (Micanopy) Florida USA - ___ 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] Lady Heather command line modification question...
Hello, John-- Every now and then, LH says my T-bolt PPS and DAC are experiencing wide excursions. The PPS OADEV and the OSC OADEV both stay down around 6 X e-13 but PPS and DAC both get hinky for an hour or two and then things settle back down for a few hours. This process seems to repeat itself 2X or 3X per day. It may be due to all the tall trees around my place and my less than ideal sky view. In any event, every few hours the violet PPS line and the green DAC line go off chart and it would be nice to be able to expand the scale just a bit to better see what is happening. I am trying to change the scale for the PPS graph from 2ns/div to 5ns/div and the DAC from 50uv/div to 100uv/div I have been unsuccessful at entering the appropriate command line modifiers-- I right-click on the Lady Heather desktop icon and select PROPERTIES. In the PROPERTIES box I see the Target address which is: C:\Program Files\Heather\heather.exe I put a space after the .exe and enter /mp[=5] and close the quote I enter OK and then get an error message that says: The name 'C:Program Files\Heather\heather.exe /mp[=5]' specified in the Target box is not valid. Make sure the path and file name are correct. What am I doing wrong? Maybe I am not clear where to enter spaces? I have tried different combinations, but no joy... Is this not the correct place to enter the /mp=5 suffix? Thanks, Mike Baker - ___ 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] Lady Heather display is GREAT!!!
Hello, John and Mark-- The display is beautiful and tells a great deal more from a quick glance than the Trimble factory supplied software. You guys did a great job with it!! The display looks really good when I do an ALT / ENTER to run the display full screen. This display is the cat's meow and I will likely dedicate an old laptop I have sitting around to running it and leave it running full time on the shelf in my shop. Thanks again for all your work on this-- You and Mark have done all us T-Bolt users a great favor!! I am wondering about the big empty space on the lower left center of the display Is this for some sort of future embellishment? Hmm. How about a very large clock ticking away in that space or some other sort of running information? Mike Baker ___ 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 E vs Lady Heather open space....
Time-Nutters-- RE: Utilizing the large open space in the Lady Heather display for a (large) running clock or other application... Mark said: If you happen to have a Thunderbolt-E four of the lines in that space would be taken up by the four additional satellites that the Thunderbolt-E can track... True, but it appears that that there would still be a rather large open space under the Cursor GPS Time indicator... Mike Baker WA4HFR Gainesville (Micanopy) Florida, USA ___ 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] LPRO-101 Heatsinking
Hello, Timenutters-- I only have experience with four different LPRO-101 units, but with respect to heatsinking, all 4 behaved identically during my testing of them. It appears that the LPRO-101 units do not require much heatsinking. I experimented with a variety of heatsinks and discovered that just bolting them down to a 1/8 thick flat sheet of aluminum roughly 8 x 10 (no fins, just a flat sheet) kept the case of the unit and the aluminum sheet below 105 deg F. That is relatively quite cool as far as electronic circuitry is concerned-- only slightly warm to the touch. The 4 units I tested were powered by a regulated 24VDC supply and the aluminum sheet was kept vertical and had good air flow around it. I also experimented with a heat sink that is very nearly the same size as the base plate of the LPRO units but only has ten 1/2 tall fins that are quite wide spaced on it. With that particular very minimal heatsink the highest temp reached after 4 hours was only 97 deg F. I put a teeny 12 volt CPU fan about 2 from the fins and ran it on 6 volts DC to keep the blade speed waaay down (and essentially silent). After two hours had elapsed, the heat sink and case were still only ever so slightly above room temperature. Bottom line seems to be that the LPRO units must have at least some minimal heatsinking but they do not require much. The four units I tested came to me with their base plates covered with a very thin layer of some sort of a pale green heat transfer material so I did not need to apply any of the typical messy white moose-poop zinc-oxide and silicone grease heat transfer paste. Mike Baker WA4HFR Gainesville (Micanopy) Florida --- ___ 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] Leap-second happens when...??
Hello, Time-Nutters-- I must have missed something... I have known about the coming leap-second for months, but have not heard when it was going to be inserted. When will the leap-second take place? Will it hurt? Am I going to need a band-aid? Or just another rum-laced egg-nog...?? Thanks!! Mike Baker WA4HFR Gainesville, FL -- ___ 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] How good is my T-bolt...??
Hello, Time-Nutters-- Bruce said: A statement of accuracy is of little value unless you also give: 1) An estimate of the accuracy of standard used for comparison. 2) An estimate of the random and systematic errors in the comparison 3) Some details of the comparison method. 4) Averaging time and other pertinent info. -- Mike asked: What frequency reference did they use at the university standards lab to measure the T-Bolt frequency? And how did they measure its frequency? How did they do the comparison to your TBolt? If it was a counter, what kind was it? You mentioned the error was better than 1e-12 90% of the time. What was the average error? -- Hi, Bruce, Mike, et al-- Your points are all well taken! However, all I wanted to know (and all I asked the standards lab) was: How much ballpark error will I have when using my T-bolt as a reference to confirm the frequency of my 10GHz ham transmitter? Yes, from a Time-Nuts perspective, my question is crude and unsophisticated, but I simply did not have any interest in knowing anything about the T-bolt except how good it is when used as a reference for checking the frequency output of my 10GHz transmitter. I really did not care about ADEV, MDEV, XYZDEV or any other alphabet soup criteria, and yes, I know that this confirms that I am a primitive knuckle-dragging troglodyte with respect to the subtle nuances of time and frequency standards... It's kinda like looking at the speedometer on my pickup truck as I drive down the Interstate highway: My only interest is that it be accurate enough to use for my particular application. Same goes for my T-bolt... Can I trust it to get me within 10Hz at 10GHz?+/- 100Hz?+/- 1KHz? As for what the lab used to make the measurements, all I can say is that the lab has several time/frequency references, one I saw was about the size of a refrigerator called a CH1-75 Active Hydrogen Maser. Big-- looked expensive, blinking lights, pretty colors... impressed me. I'll go back to my cave, now... Cheers!! Mike Baker WA4HFR Gainesville, Florida, USA ___ 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] He is a Time-Nut Troublemaker....
Hello, TimeNutters-- Mike Monett said: It is refreshing to see such sweet innocence. For most of us, those days are gone forever. Your problem is you only have one clock. As soon as you get two, you ask a very simple question: which one is right? But that only makes things worse. That question leads you over the edge and down the slippery slope that brings most of us to this forum. The same thing happened to Tom, and look at how many clocks he has now. Right now, you don't have enough clocks. The only real solution to your problem, is to get another TBolt:) -- Just ducked out of my cave to let you know that you are a troublemaker. Get another T-bolt... Right. --Just what I need... another techno-addiction. As far as sweet innocence is concerned, I lost all I ever had when I jumped head-first into bench-rest rifle competition 15 years ago. You have your addiction-- I already have mine in the never ending search to find the magic combination of details that produce the holy-grail of a 10-shot half-inch group at 400 yards... For what it is worth, I am up to my kiester in the pursuit of long-range bench-rest rifle accuracy. I spend most of my free time trying to come up with subtle ways to better last week's tight shot-group I got with my bench-rest rifle with the diamond-lapped, air-gaged Krieger barrel. I weigh and sort each boat-tailed projectile to the nearest 0.1 grain, I check every handloaded cartridge case for neck concentricity and runout error. I weigh and match all my cartridge cases, I weigh each boat-tailed Berger benchrest grade bullet. I weigh each powder charge to the nearest 0.1 grain. Every primer pocket is cleaned and inspected and every primer flash hole is swaged for uniformity. I set my wind flags out and carefully analyze the vagaries of every little zephyr that wafts over the 400 yard space between me and my target. After all of this, I am only half way down the list of details I pay careful attention to, but you get the idea Hey-- do I look like the kind of guy that would get sucked down the slippery slope of paying attention to any kind of activity that would require attention to microscopic subtle technical details of some arcane art in order to advance my capabilities by one-half of one percent (such as paying attention to ADEV, MDEV or close-in phase noise??) Not me... Now, if you will excuse me, I need to prepare for next weeks shoot by spinning each of these projectiles on my ultrasonic testing instrument and testing for uniform concentric jacket thickness... Cheers!! Mike Baker WA4HFR Gainesville, FL ___ 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 accuracy...??
Hello, TimeNutters-- John Miles, KE5FX wrote: Well, sure, it's more accurate than the undisciplined OCXO in the counter, that's the idea behind the Thunderbolt. :) n3...@aol.com wrote: I just wanted to ask the group if the Thunderbolt would be more accurate than the internal reference? I want to think it is but my link to the thunderbolt spec sheet is no longer valid. - Some time ago, I took my T-bolt over to the Metrology and Standards Lab at the University of Florida and set it up to run overnight and let it do its full survey process. In spite of the fact that the antenna was in a rather poor location it locked up quickly and seemed to run flawlessly. The monitoring was only intended to look at the frequency accuracy of the 10 MHz output-- other timing characteristics so dear to Time-Nuts hearts were ignored. After its overnight warm-up and survey process was done, we found (over a period of 48 hours) that the 10MHz output was never worse than 1.0 X E-12 and was generally better than that by a considerable margin about 90% of the time. Mike Baker WA4HFR Gainesville, FL ___ 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] Old nixie tube displays
Hello, Time-Nutters-- Jim Lux wrote: To those tinkering at home, though, this cycling through is great.. If you're willing to fix it yourself, and maybe have a hangar queen or princess for parts, or you don't need ALL the functions to work (never needed that knob anyway..), then you too get really nice gear to work with. (and, besides there's something really satisfying about that orange glow of the Nixies... It impresses people who see your garage, because its redolent of Atomic Age science fiction movies of the 60s and 70s.) For what it is worth, I keep a couple of vintage HP counters, sweepers and timers operational in my shop simply because they are so, well... kuel. Besides, the flickering of the nixie tubes impresses the natives. You gotta admit, an old 10 digit HP frequency counter cycling away on its internal reference just oozes panache Mike Baker --- ___ 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 self-survey results...
Hello, All-- My Thunderbolt seems to be able to determine its Lat and Lon location coordinates with reasonable accuracy. However, after completing its self-survey it thinks its elevation is 11.2 meters when the actual elevation of its antenna (on my house roof) is 28.4 meters. I arrived at this value by looking at the USGS topo map of my property, noting the elevation ABMSL where my house is located and adding the distance from the ground to the GPS antenna on my roof and coming up with 28.4 meters. Should I store this value into POSITION/ALTITUDE? If I enter this value into ALTITUDE, then what? Should I then SAVE SEGMENT? SET ACCURATE POSITION? Thanks, Mike Baker WA4HFR Micanopy, FL ___ 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] GPS receivers and poor sky visibility.....
Hello, All-- Jim Robbins reported poor GPS performance because his GPS antenna has a limited clear view of the sky. Hmm Jim-- might you have some sort of antenna or feed line problem? My house is in the middle of a relatively small yard in the center of a VERY HEAVILY wooded 6 acre lot. My Thunderbolt antenna has an extremely limited clear view of the open sky and at no direction is it better than 40 degrees above the horizon. My T-bolt typically indicates good signals from at least 6 or 7 birds with signal levels of 8.0 to over 12.0. As an experiment, I switched it over to an antenna INSIDE my house and while the signal levels all dropped to between 5.0 to 8.0, indicated performance as reported by T-bolt Mon is still solid. Mike Baker ___ 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] Whispering Gallery-Mode....??
Hello, Time-Nuts-- I have skimmed through a very interesting review publication of whispering gallery-mode oscillators http://tinyurl.com/6qsr5k but I do not see any concise explanation of why they are referred to with the rather strange name of whispering gallery-mode Can anyone give me a simplified explanation of this term? Thanks-- Mike Baker WA4HFR Micanopy, FL USA ___ 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] T-bolt elevation error...
Hello, All-- Darrell Robinson said: My guess is that at least some of the difference that you see in your altitude is from the propagation delay in the cable between your antenna and the GPS module. Guessing still further, I would think that the position as reported would be some distance immediately below the antenna. How long is your cable? Just for the sake of illustration, lets suppose that the antenna is on my roof 20 feet above the ground but that it took 150 feet of cable to get to the receiver. Presumably, with no other information, the determined altitude would be offset by the delay in the cable giving a 130 foot error? It would seem natural that the receiver would be (should be?) able to be told how long the antenna cable is so that it could factor out the delay. However, I do not see any place in any of the control panels to input a cable length correction. Mike Baker WA4HFR Micanopy, FL ___ 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] Another Trimble Tbolt question....
Hello, All-- Thanks to the collective savvy of this list and the patient assistance of Ken Winterling wa2lbi I was finally able to get my Tbolt to stop requiring me to configure the COM-4 channel every time I ran the monitoring software. So-- I had such good luck with that question, I'm going to pester the group with one more Tbolt question: In the Position area of the Tbolt monitoring display my altitude is given as 1.4 meters. The USGS topo map and a recent survey both say that the ground level at my house is 84 feet above MSL. The antenna for the T-bolt is on the top of my house 19 feet above the ground. If I open SETUP / POSITION and SET ACCURATE POSITION to, say: 28 meters and enter that value, the indicated altitude changes to 28 meters, but the next day or so, I always find that it has reverted to 1.4 meters. Admittedly, having a (relatively) accurate altitude display is of minor importance to me since my primary reason for having the Tbolt is for a decent 10MHz reference. However, as a matter of principle it would be nice to have the altitude display be a little closer! Any suggestions as to how to get the Tbolt to display a more correct altitude? Thanks! Mike Baker WA4HFR Micanopy, FL - ___ 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] Tboltmon Serial Port Selection...??
Hello, All-- Can anyone tell me why, when I click on the Tboltmon icon associated with my Trimble Thunderbolt, that a little Serial Port Selecton window pops up and why does my T-bolt only run after selecting COM-4? Why can't this be selected once and then forgotten about? It seems like an un-necessary step. Thanks!! Mike Baker WA4HFR Micanopy, FL ___ 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] 100MHz VCTCXO...???
Matt Ettus asked if anyone knew of a source for a 100MHz VCTCXO. I am not sure what that term means, but I happen to be looking for a source myself for a 110MHz VCXO with 150 to 200ppm pullability, I came across Mtron-PTI who offer TCXO's, TCVCXO's, VCTCXO's and VCXO's. Some of their units come in tiny hermetically sealed metal containers with a footprint about the size of a 14-pin DIP IC. See: http://www.mtronpti.com/products/index.php?category=TCXO%2FTCVCXO%2FVCTCXO I have no idea how much Mtron PTI will want for a unit with a crystal on your particular frequency (or mine on 110MHz, either-- I need to call them and find out, I suppose...) eBay has a source selling one of the Mtron PTI units set up with a crystal up for 105MHz for under $15. I bought a sample to see what it would take to swap out the crystal. I removed the metal case and managed to swap out the crystal for one I had on 121MHz just to see if it could be done. Now I need to find a source for ordering a crystal on the proper frequency and see if I can get it to work with the unit. Matt-- if you would like some photos of the unit now that I have the case removed, I can send some. It's a cute little critter! If anyone has other suggested sources for (relatively) inexpensive VCXO's please let me know too!! Mike Baker WA4HFR Micanopy, FL ___ 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] GPS PRN vs SV...??
Hello, All-- Tom Van Baak [EMAIL PROTECTED] asked: Which time-nut will be the first to see PRN 32 on Feb 19? I wonder what old GPS receivers won't be able to see it? - So-- Is PRN the same as SV as given for each GPS bird being tracked by my Trimble T-Bolt? Thanks!! Mike Baker Micanopy, FL - ___ 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] Best choice for house 10MHz reference...??
Hello, All-- RE: Tom Van Baak's comments on his preference for a CNS-II for long-term, high -accuracy UTC measurements (against Cs or maser) included the statement: I don't use a GPSDO. Instead I use a plain, non-disciplined OEM GPS board or something like a CNS II (http://www.cnssys.com/cnsclock/CNSClockII.html). High-end, short-term, or low phase noise, you always use quartz; long-term you always used GPS. The cool thing about a GPSDO is that you get (almost) the best of both in one box. -- This got me to wondering.: My primary need for a GPSDO is as a 10MHz house frequency reference to externally lock my spectrum analyzer up with. I currently have a Trimble Thunderbolt running and it seems to be working OK-- Is this a good choice for a 10MHz long-term frequency reference that does not require hocking my wife's car to pay for...? (she might notice if I did that...) I will be a happy camper if I can reliably measure up to the upper frequency limits of my Tek 497P/494P (21GHz) to within +/- a few hundred Hz... Any feedback on this will be most appreciated!! Mike Baker WA4HFR Micanopy, Florida ___ 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] Wenzel, Inc article on low-noise oscillators
Hello All-- I suppose that most on this list already know all about this, but as a newbie to considerations about low noise oscillators, I found the Wenzel, Inc article on design notes for ultra-low noise oscillators interesting-- Just in case anyone on the list has not seen it: http://www.wenzel.com/pdffiles1/pdfs/RFDesign1.pdf Mike Baker --- ___ 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] Choke-Ring Antennas for GPSDO use?
Hello, All-- Over the past couple of years I have seen several references indicating that the reason all GPS units intended for precision survey applications use a choke-ring antenna is that a properly designed GPS choke ring antenna will cut multi-path reception down very significantly. Other references I have seen indicate that using a choke-ring antenna results in a moderate improvement in GPSDO performance. Can any list members comment on this? If a choke-ring antenna does improve GPSDO performance, what degree of improvement can be expected? Enough to be worthwhile? Would switching to a properly designed choke-ring antenna on my Trimble Thunderbolt GPSDO be worthwhile? My house is surrounded by large trees and my roof-top GPS antenna does not have a foliage free view of the sky until about 40-degrees above the horizon. I have set a horizon elevation mask of 30 degrees in my T-bolt software but have wondered if multipath through the remaining tree-tops may still be a slight problem. Only very rarely do used GPS choke-ring antennas show up on eBay and they typically ask around $600 to $800. My good friend Bob Johnson, WB4JZM, tracked down some references to GPS choke-ring antennas which he sent to me (Thanks, Bob!!) and I have taken the liberty of appending some of his post below: --- Bob said: It looks like this article describes an antenna that is easier to design and manufacture than a choke-ring antenna, with similar performance: http://mwrf.com/Articles/Index.cfm?Ad=1ArticleID=5490 The standard choke-ring design comes from JPL, and may be public domain in the U.S. Certainly there must be a published patent somewhere that will give enough detail to build one (otherwise, it isn't a valid patent). They are normally milled from a solid aluminum billet, but you could use other fabrication methods and make your own. And you seem to have enough test equipment to test it... An article on choke-ring theory: http://javad.com/jns/index.html?/jns/technology/Choke%20Ring%20Theory.html and improvements on the JPL design from the same company: http://javad.com/jns/index.html?/jns/technology/Single-Depth%20Low-Multipath%20Choke%20Ring.html A choke-ring design with improved reception of low-elevation signals: http://www.novatel.com/Documents/Papers/3D_choke_ring.pdf This looks like an excellent article. Of interest in this article are the photos of different choke rings they evaluated: it appears that the critical factor is the depth of the grooves, and there is some disagreement about the optimum depth, so obviously that isn't critical either! In other words, build your own, it will almost certainly provide some benefit, possibly more than an expensive commercial unit. A patent that appears to have enough detail to build your own: http://www.freepatentsonline.com/6278407.html Possibly the greatest difficulty in building your own is the actual GPS antenna: for best results, you need to know the phase center of the antenna, and mount it at the center of the choke ring (for that matter, the antenna needs to have a single phase center: but real-world designs have different phase centers in different dimensions). And the choke ring should be designed for a specific antenna: you can't just buy a choke ring off eBay and stick any old antenna on it and get optimum results (although it is likely to be an improvement over the same antenna without a choke ring if you mount it correctly). Discussion of phase center and precision GPS work: http://www.ngs.noaa.gov/ANTCAL/images/summary.html So-- can any list members shed any light on the efficacy of switching to a choke-ring antenna on a GPSDO unit? Mike Baker WA4HFR Gainesville, Florida ___ 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] GIMP VS PhotoShop
Time-Nuts-- John De Armond said: RE: Gimp. I wouldn't foist that crap off on my worst enemy. Whomever conceived that user interface had to be stoned. Bad stoned. --- Someone has written a revised menu structure for GIMP that matches the user interface in Photoshop... It is called Gimpshop and is supposed to make it much easier for PhotoShop users to transition to The Gimp (and easier for Gimp users to follow PhotoShop tutorials). http://www.gimpshop.com/ According to the description on the website: GIMPshop is a modification of the free/open source GNU Image Manipulation Program (GIMP), intended to replicate the feel of Adobe Photoshop. Its primary purpose is to make users of Photoshop feel comfortable using GIMP. It shares all GIMP's advantages, including the long feature list and customisability, while addressing some common criticisms regarding the program's interface: GIMPshop modifies the menu structure to closely match Photoshop's, adjusts the program's terminology to match Adobe's, and, in the Windows version, uses a plugin called 'Deweirdifier' to combine the application's numerous windows in a similar manner to the MDI system used by most Windows graphics packages. While GIMPshop does not support Photoshop plugins, all GIMP's own plugins, filters, brushes, etc. remain available. Due to the changes to the interface, many Photoshop tutorials can be followed in GIMPshop unchanged, and most others can be adapted for GIMPshop users with minimal effort. - I have installed Gimpshop, but not had a chance to try it out to see how well it compares to Photoshop CS3 which is currently my most used image processor software. Mike Baker ___ 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] Super stable BVA Quartz resonators... BVA??
Hello, All-- In doing some reading to educate myself on the relative short and long-term stability characteristics of the best grade quartz resonators, I find that BVA cut resonators are on the leading edge of quartz crystal technology. I have found out how a BVA resonator is fabricated, but I have not discovered what the acronym BVA stands for. I suspect that the B in BVA may refer to Raymond Besson the discoverer of the BVA quartz resonator, but I have not been able to confirm that. Can anyone on the list shed some light on this? Mike Baker -- ___ 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] Frequency trimming of Seiko wristwatches
Max Robinson wished for a way to open up wrist-watches and adjust the crystal trimmer. I have owned at least two Seiko wrist watches which had a simple to open screw-on back. I opened the back and tweaked the trimmer capacitor on both of them using the ticks from WWV as a reference. After watching for a month to see which way the drift was, I re-tweaked several times. Ultimately, the best I could achieve was around +/- a few seconds per month. The problem appeared to be one of temperature compensation-- seconds gained or lost per month were different in the winter months as opposed to the summer months. These particular Seiko wristwatches had a tiny o-ring to seal them against moisture and I had no problems with leakage. Mike Baker Micanopy, FL USA --- ___ 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] Plus-minus 1sec per century wristwatches coming...??
Jeff Mock posted the URL of an article on the history of quartz oscillators in wristwatches which I found quite fascinating. Here is its Tiny-URL: http://tinyurl.com/35nsct Following the recent announcement of super-tiny atomic clocks no larger than a grain of rice I am anxiously anticipating the introduction of wristwatches capable of +/- a few seconds per century. See the NIST announcement here: -- From: http://www.nist.gov/public_affairs/releases/miniclock.htm The heart of a minuscule atomic clock —believed to be 100 times smaller than any other atomic clock— has been demonstrated by scientists at the Commerce Department’s National Institute of Standards and Technology (NIST), opening the door to atomically precise timekeeping in portable, battery-powered devices for secure wireless communications, more precise navigation and other applications. Described in the Aug. 30, 2004, issue of Applied Physics Letters, the clock’s inner workings are about the size of a grain of rice (1.5 millimeters on a side and 4 millimeters high), consume less than 75 thousandths of a watt (enabling the clock to be operated on batteries) and are stable to one part in 10 billion, equivalent to gaining or losing just one second every 300 years. In addition, this “physics package” could be fabricated and assembled on semiconductor wafers using existing techniques for making micro-electro-mechanical systems (MEMS), offering the potential for low-cost mass production of an atomic clock about the size of a computer chip and permitting easy integration with other electronics. Eventually, the physics package will be integrated with an external oscillator and control circuitry into a finished clock about 1 cubic centimeter in size. -- Mike Baker -- ___ 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.
