Re: [time-nuts] Thunderbolt mounting
I mounted mine in a cabinet along with a power line filter and power supply. Pics at www.omen.com/wa7kgx.ham.html The filter is important if you are a ham or SWL. The temp hangs around 35C. The cat likes to sit on it as it is slightly warm. The Rb oscillator and its 15 volt power supply have been removed. -- Chuck Forsberg WA7KGX N2469R c...@omen.com www.omen.com Developer of Industrial ZMODEM(Tm) for Embedded Applications Omen Technology Inc The High Reliability Software 10255 NW Old Cornelius Pass Portland OR 97231 503-614-0430 ___ 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] Thunderbolt mounting
When I had my Tbolt running full time, I just had it sitting in the bottom corner of a bookcase that was hard to get to (Tek 7104 on a cart packed with other gear too was in the way, along with piles of other things). No drafts, so the temp stayed pretty constant. It was taken out of full service when I got a Z3801. I want to build a home for it and my two Rb units in a temp controlled box, but haven't gotten there yet. -Dave - Original Message - From: Gary Fiber gfi...@comcast.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Wednesday, July 11, 2012 4:12:04 PM Subject: Re: [time-nuts] Thunderbolt mounting I have mine in a nice case along with the switcher supply. Am debating on the need of including a small fan. I made a shelf from 2 sided PCB material and mounted the Thunderbolt onto that shelf. The switching power supply sits below the Thunderbolt mounted to the case bottom. Gary Fiber K8IZ Sent from my iPad On Jul 11, 2012, at 10:28 AM, Peter Gottlieb n...@verizon.net wrote: I would like to put my Thunderbolt into a chassis with power supply and would like to have the most favorable thermal environment since the unit is somewhat temperature dependent. I was thinking of mounting the unit in insulating material, but am worried it will get too hot to the point the temp control loop won't work properly. Has anyone experimented with this and found the best solution? I would like to remove the strong dependence on room temperature that I have currently. Peter On Jul 11, 2012, at 11:18 AM, Gary Fiber gfi...@comcast.net wrote: I purchased a Trimble Thunderbolt. Is there a web page or does someone have a set of written steps to set up the Thunderbolt? There are quite a few adjustments available for it and it makes sense to me not to reinvent the wheel. I have googled and got some results using Tboltmon. Have tried Lady Heather, but have to figure out just how to utilize that program. Have the Thunderbolt, a Mean Well 60 watt supply, have I hope is a decent antenna arriving Friday. Am intending on using the 19 MHz output for a time base for my HP-8935A and HP-8656B. Gary Fiber K8IZ Sent from my iPad ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Thunderbolt mounting
Just thinking outside of the Styrofoam box, wouldn't an analog controller on the fan be better? That is use a DC fan and adjust the current to change the speed. On 7/11/2012 8:54 PM, Chris Albertson wrote: On Wed, Jul 11, 2012 at 6:55 PM, Mark Spencer mspencer12...@yahoo.cawrote: I tried putting my thunderbolt in a styrofoam box. It got hotter than I liked and didn't seem to perform any better than when I left it in a cardboard box. I worry about the long term implications for component life as the temperature goes up. The advantage of the insulation comes in when you build the fan controller. Mine uses a temperature sensor and an IC comparator that drives a transistor that drives a 12V fan. The fan does on when the set point is reached then goes off. If you set the operating point a little higher then the inside of yur house then the fan cycles and keeps the inside of the box and roughly, more or less constant. The parts to build a fan controller are about $5 If you don't have a temperature controlled fan then the next best thing is a well vented cardboard box whose only purpose is to keep air currents off the unit. Insulation without an active temperature controller is only going to make it hotter, not more stable Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Thunderbolt mounting
On 07/12/2012 05:54 AM, Chris Albertson wrote: On Wed, Jul 11, 2012 at 6:55 PM, Mark Spencermspencer12...@yahoo.cawrote: I tried putting my thunderbolt in a styrofoam box. It got hotter than I liked and didn't seem to perform any better than when I left it in a cardboard box. I worry about the long term implications for component life as the temperature goes up. The advantage of the insulation comes in when you build the fan controller. Mine uses a temperature sensor and an IC comparator that drives a transistor that drives a 12V fan. The fan does on when the set point is reached then goes off. If you set the operating point a little higher then the inside of yur house then the fan cycles and keeps the inside of the box and roughly, more or less constant. The parts to build a fan controller are about $5 You *really* don't want an on/off regulation scheme. The OCXO gets dynamic thermal stress from it which causes it to go off in frequency as the heat wave (or cooling wave) comes in and has a rate faster than the oven can steer. The oven gain will be much less than for slow semi-static temperature changes. Old ovens used on/off schemes, but it was dropped as electronics allowed for continuous feedback loops. You will see a bump in your ADEV at about the cycling period of your fan. If you have quick cycling period, it will affect your close in phase noise and ADEV, but you might suppress your room/house AC/heating loop. If you run continuous, there will be a much quieter response. Another side-effect of cycling power for an OCXO is that it will for each cycle shifts its phase. The OCXO control will return it to temperature as fast as it can, which should return it to frequency. What happens is that the curve around the balancing point isn't completely symmetric, but the heat-up/cool-off temperature profile certainly isn't. The end result becomes that the frequency error under the curve isn't 0 over such a cycle, and that integrated over time will become phase. So, this unstable phase creep will keep the control loop active to fight it back, until you reach holdover, when the error will be exposed completely. I've learned this the hard way, from observing frequency and phase fluctuations and fighting them. If you don't have a temperature controlled fan then the next best thing is a well vented cardboard box whose only purpose is to keep air currents off the unit. Insulation without an active temperature controller is only going to make it hotter, not more stable Using a cardboard box or other wall around the oscillator will as a passive oven work well, if the unit is still allowed to dissipate it's excess heat to the surrounding. The effect is really great and helps the control loop as temperature shifts occurs more gradually such that the control loop can track it within it's bandwidth. Long term temperature shifts like the bang-bang regulator of the building AC/heating will still eat into the box. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Proper setup of a Trimble Thunderbolt
I think that the only action is to wipe out any old setup present (use the TBolt monitor program), especially a previous position hold setting. You know, timing receivers have the position hold capability and it is mandatory to restart the survey for your location. I have 2 TBolts but (what a shame for me) never tried to start them up so I cannot be more practical like go there, click that, check this and so on. I use an HP Z3815A as a reference and have yet to prepare a good linear power supply for the TBolts. On Thu, Jul 12, 2012 at 1:09 AM, Gary Fiber gfi...@comcast.net wrote: Yes it was a typo meant 10 MHz. I've got the readme for Lady Heather and will go through it. I was hopeful someone had any needed basic settings for the Thunderbolt otherwise I will leave it as it came out of the box from the seller. Gary Fiber K8IZ Sent from my iPad On Jul 11, 2012, at 10:36 AM, Azelio Boriani azelio.bori...@screen.it wrote: 10MHz output you mean, not 19MHz, surely it was a typo. Yes, best to use LadyHeather: learn how to use and you will have the best monitoring utility for the TBolt. On Wed, Jul 11, 2012 at 5:18 PM, Gary Fiber gfi...@comcast.net wrote: I purchased a Trimble Thunderbolt. Is there a web page or does someone have a set of written steps to set up the Thunderbolt? There are quite a few adjustments available for it and it makes sense to me not to reinvent the wheel. I have googled and got some results using Tboltmon. Have tried Lady Heather, but have to figure out just how to utilize that program. Have the Thunderbolt, a Mean Well 60 watt supply, have I hope is a decent antenna arriving Friday. Am intending on using the 19 MHz output for a time base for my HP-8935A and HP-8656B. Gary Fiber K8IZ Sent from my iPad ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Thunderbolt mounting
On 7/11/12 7:00 PM, Mike S wrote: On 7/11/2012 8:15 PM, Chris Wilson wrote: Does anyone know if there's a means to log max and min temps for these things? I was going to make a crude box for mine out of 2 inch cavity wall insulation hard foam, The TB reports it's own temperature. Lady Heather will track it. I'm surprised no one has mounted one to a Peltier cooler, and stabilized the temp with PID control, based on the self-reported temp. Why not run it cooler than ambient? I'd assume a simple microcontroller could handle the task, but don't have any deep PID control knowledge myself. PID controller code for Arduinos and the like is readily available.. However, as to why not run it cooler? The internal oven tries to keep the crystal at the temperature where the frequency vs temp curve has the lowest slope. If you cool the outside, then you just burn more power in the internal oven. ___ 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] Thunderbolt mounting
On 07/12/2012 03:22 PM, Jim Lux wrote: On 7/11/12 7:00 PM, Mike S wrote: On 7/11/2012 8:15 PM, Chris Wilson wrote: Does anyone know if there's a means to log max and min temps for these things? I was going to make a crude box for mine out of 2 inch cavity wall insulation hard foam, The TB reports it's own temperature. Lady Heather will track it. I'm surprised no one has mounted one to a Peltier cooler, and stabilized the temp with PID control, based on the self-reported temp. Why not run it cooler than ambient? I'd assume a simple microcontroller could handle the task, but don't have any deep PID control knowledge myself. PID controller code for Arduinos and the like is readily available.. However, as to why not run it cooler? The internal oven tries to keep the crystal at the temperature where the frequency vs temp curve has the lowest slope. If you cool the outside, then you just burn more power in the internal oven. You can run it at higher temperature if you maintain that actively. There is a balance between elevated temperature and shorting of life that way and elevated oven current and shorting of life that way. Whatever cooling mechanism used (and a PID controller is a good start) a linear control is recommended. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[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] Temperature control/isolation of T-bolts...
mp...@clanbaker.org said: 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 Did you have anything else in the box to increase thermal mass? Water? Bricks? Cast iron? -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Thunderbolt Fan mounting
fan designed for variable speed plus finned heatsink plus temp sensor (sometimes) in a neat package from any old computer cpu cooler... Don WarrenS Mark Although Lady Heather's temperature controller can hold the temp at the TBolt's sensor constant to delta 0.000x deg over 72 hrs, this does not hold the temperature at the oscillator close enough to maintain an exact constant frequency because the TBolt's sensor location is not at the OCXO. The change of the Oscillator's open loop freq vs. room temp can be seen when the room temp is also plotted and compared to the DAC voltage in an extended length LH plot. What Lady Heater does is plenty good enough for most, but if you want to be even more nuts (and who wouldn't), there are still further improvements possible that can eliminate all of the TBolt's OCXO sensitivity to small room temperature changes. 1) One way to improve LH's temp control, which is not very practical and not recommended, is to reposition the TB's temp sensor. :( 2) There are several ways that Lady Heather could be modified, to change the control loop set point a little as a function of room temp. 3) The simple mechanical way that I use to minimize any remaining variation due to room temperature changes when using LH's temperature control loop is to adjust the position the LH controlled fan to compensate for the difference between the TB's sensor and it's oscillator. Shown in the attachment, I placed the stock Tbolt in a tight fitting foam lined small box where only the top case of the TBolt's is exposed. This minimizes temperature gradients on the case and causes the TB's temperature to rise a safe amount. I use a small 12v, 1W fan loosely mounted to the top to a 1/4 inch sheet of aluminum plate that sits on top of the TBolt. For course adjustment, I change the position of the aluminum plate on the TB. For fine adjustment, I change the location of the fan a little so that it is blowing air at a different spot on the plate. Not shown in the attachment, is a small insulator / deflector that only allows fan air to blow on the aluminum plate, not on the TBolt's exposed upper case. This insulator and the foam forces most all of TBolt cooling to go thru the 1/4 inch aluminum heat sink plate. I can then adjust the fan position so that there is no visible effect on the TBolt's OCXO due to small daily room temperature changes. The power supply I'm using is stable enough that I have not seen any TBolt changes when the PS is heated with a hair dryer or the line voltage is changed by large amounts with a variac. ws ** Mark posted: I tried putting a Tbolt in a small (six-pack sized) Coleman cooler. The temperature rose above the alarm temperature... it does not take much insulation to cause problems. Lady Heather's built in temperature PID controller works very well. When properly set it up, short term variations can be well under 20 millidegrees. Long term RMS temperature error can be a few microdegrees or less. Attached is a screen dump showing a 0 microdegree RMS temp error over 72 hours! Besides the TT command to set the desired setpoint temperature, there are some built in PID parameter commands (KW sets a slow pid,KM sets a fast pid, KA attempts a PID autotune... you can also tweak the various PID parameters individually... see the routine edit_pid_value() in heathui.cpp for some idea of the available parameters). For best performance, it helps to have the power supply in the temperature controlled box. This will minimize the effects of temperature variation on the supply, which can be a third of the overall system temperature sensitivity. It is also a good idea to not have the box so well sealed that the unit overheats if the computer/PID/fan shuts down. You probably don't want a flammable box in case your cheapo Chinese power supply bursts into flame. For best operation of a new Tbolt, you should first run the 48 hour precision survey, then execute the a auto-tune command. Autotune sets the oscillator parameters, elevation mask, and signal level mask to time-nutty values. Before running a, first set the elevation mask to a low value and collect data for a couple of hours. This lets the program find the satellite elevation angle where the signal starts to degrade. Note that it can take several weeks for an old, unused oscillator to fully stabilize and age in. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Neither the voice of authority nor the weight of reason and argument are as significant as experiment, for thence comes quiet to the mind. R. Bacon If you don't know what it is, don't poke it. Ghost in the Shell Dr. Don Latham AJ7LL Six Mile Systems LLP 17850 Six Mile Road
Re: [time-nuts] Thunderbolt mounting
Sorry about the bad URL. I corrected it below. On 07/12/2012 12:22 AM, Chuck Forsberg WA7KGX N2469R wrote: I mounted mine in a cabinet along with a power line filter and power supply. Pics at www.omen.com/wa7kgx/ham.html The filter is important if you are a ham or SWL. The temp hangs around 35C. The cat likes to sit on it as it is slightly warm. The Rb oscillator and its 15 volt power supply have been removed. The Tbolt in its cabinet currently sits atop my office computer, next to a south facing window. Putting it in a dark corner would doubtlessly improve its temperature stability but the cat would be disappointed. -- Chuck Forsberg WA7KGX N2469R c...@omen.com www.omen.com Developer of Industrial ZMODEM(Tm) for Embedded Applications Omen Technology Inc The High Reliability Software 10255 NW Old Cornelius Pass Portland OR 97231 503-614-0430 attachment: tbolt.gif___ 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] Thunderbolt mounting
Sorry guys, but using a fan on a thunderbolt is nuts. Not time nuts. First you get ADEV humps as discussed here. Then the fan vibrations will show up as massive spurs in the phase noise plots. Then the fan's commutator emi will go everywhere. Then the fan may modulate the supply voltage going into the thunderbolt if the same supply is used -not good. Get a better docxo and replace the thunderbolt oven, done. If you need the best thermal stability. Shield it from airflow as best as possible. That should do it. Bye, Said Sent from my iPad On Jul 12, 2012, at 12:05, Chuck Forsberg WA7KGX N2469R c...@omen.com wrote: Sorry about the bad URL. I corrected it below. On 07/12/2012 12:22 AM, Chuck Forsberg WA7KGX N2469R wrote: I mounted mine in a cabinet along with a power line filter and power supply. Pics at www.omen.com/wa7kgx/ham.html The filter is important if you are a ham or SWL. The temp hangs around 35C. The cat likes to sit on it as it is slightly warm. The Rb oscillator and its 15 volt power supply have been removed. The Tbolt in its cabinet currently sits atop my office computer, next to a south facing window. Putting it in a dark corner would doubtlessly improve its temperature stability but the cat would be disappointed. -- Chuck Forsberg WA7KGX N2469R c...@omen.com www.omen.com Developer of Industrial ZMODEM(Tm) for Embedded Applications Omen Technology Inc The High Reliability Software 10255 NW Old Cornelius Pass Portland OR 97231 503-614-0430 tbolt.gif ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Thunderbolt mounting
Nope, if implemented properly it works VERY well. No ADEV humps, no vibration induced spurs, no commutator EMI, no power supply garbage. Lady Heather's PID PWMs the fan to control the speed. It is not a bang-bang controller. You should baffle the air flow so that it does not impinge directly on the unit. I have the tbolt sitting on a piece of waffle foam in the box... gives very good vibration isolation, but even without it I saw no fan related noise/spurs. Proper power supply filtering for the fan power might be useful, but I see no coupling on mine. As the Wise Man said... one experiment is worth 1000 opinions. - Sorry guys, but using a fan on a thunderbolt is nuts. Not time nuts. ___ 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] Thunderbolt mounting
On Thu, Jul 12, 2012 at 6:56 PM, Said Jackson saidj...@aol.com wrote: Sorry guys, but using a fan on a thunderbolt is nuts. Not time nuts. First you get ADEV humps as discussed here. Then the fan vibrations will show up as massive spurs in the phase noise plots. Then the fan's commutator emi will go everywhere. Then the fan may modulate the supply voltage going into the thunderbolt if the same supply is used -not good. Have you actually tried using a fan and measured EMI and the supply voltage modulation. I'm curious how much the fan pulled down the power supply. Those things could happen but at what level? Is the effect even measurable? I think it might be like standing of a single sheet of paper so you are taller and can see farther. Yes in theory it works but the effect is small. Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
