Re: [time-nuts] GPS antenna in silicon/RTV encapsulation
I'd be inclined to look at radome construction. http://www.mpdigest.com/issue/articles/2008/may/mfg/default.asp The E-3 AWACS is mostly S-2 glass, but they need the strength. For a radome sitting outside, you might be able to do better. The advantage to S-2 glass is you can buy it easily, especially if you have a Tap Plastics handy. It works well with the Marine Resin they sell, so you know it will last a long time outdoors. You need to cure the resin in a vacuum, though not a particularly good vacuum. There are probably guides on the internet, but here is the basic scheme to make a fiberglass composite structure. Make a form of the final product. Cover the form in mylar. Tap Plastics sells the mylar too. The resin won't stick to the mylar. Cut the cloth to cover the form. Where you overlap, leave at least an inch. You need both the S-2 glass and the thin fiberglass mat. The mat is a very loose weave that can hold more resin than the glass. The basic construction is a sandwich of cloth, mat, then cloth. You can add more layers, but you always want mat between the cloth, and cloth on the outside. You will need more mylar to cover the last layer of cloth. This is to keep the air out. It helps to have this cut ahead of time because the resin will be hardening as you work. Mix the resin with hardener. Brush the mylar on the form with resin. The resin on the form is needed to hold the cloth onto it. Place the cloth on the form. Brush on resin. Cover with mat. Brush on more resin. Cover with the final layer. Apply more resin. Apply the mylar. Use masking tape to keep it attached. Wait two days. Note that the form has to be destructible, that is you need to pull it away from the radome. Generally you use cardboard. An alternative scheme, though I don't suggest it for a radome, is to use a foam core. You can bush directly onto the form. You need to at least a layer of mat then cloth on both sides of the form. Apply the mylar and wait two days. The form is part of the final structure, so there is nothing to remove. Generally for antennas in radome, all you do is have a weep hole at the bottom the antenna to allow air exchange. ___ 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] Measuring the accurcy of a wrist watch
Gentlemen, today I would like to propose a question that may be a bit OOT for the group but I became interested in it: Watchbuilders and juwellers use an instrument to measure the accuracy of mechanical watches. I am not aware of the correct name for this instrument in English but in German it is called a Zeitwaage and my internet translator calls it a timing maschine. For mechanical watches the timing maschine uses a microphone to detect the acustical impulses of the balance spring (correct word?) and compares it to a xtal. Some research has shown that there is an comparable instrument for ANALOG quarz watches. As far as I understand it does not try to detect the quarz frequency but detects magnetic pulses from the step motors that move the hands of the watch. Has anyone of you ever tried to do this in a time nuts laboratory? Best regards and TIA Ulrich Bangert www.ulrich-bangert.de Ortholzer Weg 1 27243 Gross Ippener ___ 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] Software for use HP 82350B gpib card.
Rui, if this card is supported by Agilent's VISA library then you can give a try to my EZGPIB tool available from: http://www.ulrich-bangert.de/html/downloads.html Best regards Ulrich -Ursprungliche Nachricht- Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im Auftrag von Rui Martins Gesendet: Montag, 14. April 2014 13:58 An: time-nuts@febo.com Betreff: [time-nuts] Software for use HP 82350B gpib card. Hi, I need any software to work with HP5335a or hp 5370B witch work with the 82350B gpib card. Timelab only works with national instruments IEEE488.2 compatible devices. Can anyone help? Rui Martins ___ 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] GPS antenna in silicon/RTV encapsulation
On 4/15/14, 1:53 AM, nuts wrote: I'd be inclined to look at radome construction. http://www.mpdigest.com/issue/articles/2008/may/mfg/default.asp The E-3 AWACS is mostly S-2 glass, but they need the strength. For a radome sitting outside, you might be able to do better. Radome design is considerably more complex than just putting something over an antenna. Typically, they make them as two face sheets separated by a honeycomb, but the dimensions and materials are chosen to minimize the reflection losses (e.g. the spacing might not be constant in the radome, depending on the angle of incidence of the radiation). A very thin face sheet is a tiny fraction of a wavelength, so the reflections from the two surfaces are almost in the same phase. For folks like time-nuts interested in parts in 1E15, this kind of thing makes a difference; not so much because of the attenuation, but because the reflected waves can cause a small phase shift in the apparent carrier phase; e.g. a 20dB reflection at 90 degrees shifts the apparent phase by about arctan(0.9)= 25 degrees. Typically in a radome, you shoot not only for low loss, but also low epsilon, so the reflection effects will be less. The advantage to S-2 glass is you can buy it easily, especially if you have a Tap Plastics handy. It works well with the Marine Resin they sell, so you know it will last a long time outdoors. What are the dielectric properties of such a composite? There's a reason why we don't build microwave circuits (in general) on G-10 or FR-4 material and use more exotic Rogers or Taconic substrates. (there's other reasons too..) Typical fiberglass uses an acrylic resin and acrylic has the spectacularly high loss tangent of 0.02 at only 1 MHz. The glass would help bring the loss down (since glass has a somewhat lower tangent, and if you have a fairly dry mix with small resin fraction, that helps) FR-4 has an epsilon of about 5 at low frequencies falling to a bit more than 4 at GHz frequencies, depending on the glass/epoxy ratio, and a loss tangent of around 0.01 at 1-2 GHz. This is quite high compared to sheet plastic of one sort or another. Take home message: I wouldn't fabricate a radome out of surfboard/boat building fiberglass unless you are very careful with the EM design. ___ 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] Measuring the accurcy of a wrist watch
In message 94A06362A4E942EE9EC49A685C099C32@athlon, Ulrich Bangert writes: Has anyone of you ever tried to do this in a time nuts laboratory? Yes. And then I threw my wrist watch away, having documented how shit it was :-) If your smartphone has a magnetometer, you can measure it that way, but you have to get pretty close to the chip in the smartphone. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS antenna in silicon/RTV encapsulation
Bert, I don't know about 1.6 GHz but I can tell you with some authority that before RTV/silicone is fully cured it is highly conductive to energy at 60 Hz. ... Martin VE3OAT Bert wrote : Am experimenting with small low cost GPS antennas and am considering as an alternative RTV/silicon. Any information on RF attenuation of RTV/silicon at 1.6 GHz ? Bert Kehren ___ 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] Measuring the accurcy of a wrist watch
Some research has shown that there is an comparable instrument for ANALOG quarz watches. As far as I understand it does not try to detect the quarz frequency but detects magnetic pulses from the step motors that move the hands of the watch. Has anyone of you ever tried to do this in a time nuts laboratory? Ulrich, Yes, this works well, for both those with seconds hands (one magnetic pulse per second) and those with only minute/hour hands (one or two steps per minute). A large coil of wire is all you need. Have a look at the watch timing tools and sensors at http://www.bmumford.com/microset.html or http://www.bmumford.com/mset/modelwatch1.html Here's an example using a magnetic sensor: http://leapsecond.com/pages/Junghans/ /tvb ___ 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] Software for use HP 82350B gpib card
You should be able to use the 82350B gpib card with labview, try installing the agilent i/o suite to do a quick test. If you don’t have access to labview, or not familiar with it, I recommend using python with pyvisa. The card is VISA compatible, so it should work with little tinkering and proper drivers. Kind regards, Mihai ___ 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] Measuring the accurcy of a wrist watch
In the United States we can buy analog quarts watches from Wal-Mart for under 15 dollars. When the battery dies you don't even bother to replace it you just buy a new watch, unless...the one you have is very good. There is a lot of variation and buying one is the luck of the draw. They can be as bad as 1 minute a month and they always seem to be gaining. Right now I have one that gains about 2 seconds a month. I fully intend to see if it is possible to replace the battery when it runs down. Counting motor pulses seems to be a little impractical because it would take 12 days to get to 1e6 accuracy. Regards. Max. K 4 O DS. Email: m...@maxsmusicplace.com Transistor site http://www.funwithtransistors.net Vacuum tube site: http://www.funwithtubes.net Woodworking site http://www.angelfire.com/electronic/funwithtubes/Woodworking/wwindex.html Music site: http://www.maxsmusicplace.com To subscribe to the fun with transistors group send an email to. funwithtransistors-subscr...@yahoogroups.com To subscribe to the fun with tubes group send an email to, funwithtubes-subscr...@yahoogroups.com To subscribe to the fun with wood group send a blank email to funwithwood-subscr...@yahoogroups.com - Original Message - From: Tom Van Baak t...@leapsecond.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Tuesday, April 15, 2014 8:52 AM Subject: Re: [time-nuts] Measuring the accurcy of a wrist watch Some research has shown that there is an comparable instrument for ANALOG quarz watches. As far as I understand it does not try to detect the quarz frequency but detects magnetic pulses from the step motors that move the hands of the watch. Has anyone of you ever tried to do this in a time nuts laboratory? Ulrich, Yes, this works well, for both those with seconds hands (one magnetic pulse per second) and those with only minute/hour hands (one or two steps per minute). A large coil of wire is all you need. Have a look at the watch timing tools and sensors at http://www.bmumford.com/microset.html or http://www.bmumford.com/mset/modelwatch1.html Here's an example using a magnetic sensor: http://leapsecond.com/pages/Junghans/ /tvb ___ 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. --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.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] Trak Systems
I have a Trak Systems time code generator/reader. This is model number 8396-2. I am looking for a service manual so that I can hook this up to display time code. An email to Trak Systems does not get an answer. Can any one help with any information on this unit?? Thanks 73 Glenn WB4UIV ___ 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] Looking for GPSDO for home use
I found this reflector after searching for GPSDO that would be suitable for individual purchase/use. Each time I found an article about GPSDO projects, that lead me to a surplus GPS module that is either no longer available, not current production, undocumented, or otherwise difficult to source. I don't mind doing my own building/integration, and am not adverse to starting with a used or suplus component, I'm not sure where to start in terms of sourcing the GPS module/antenna/etc. My main need is for something to serve as a primary frequency standard (i.e., 10 MHz output) I can use to set a voltage controlled OCXO I just installed in my (otherwise cheap chinese) frequency counter. It seems there are some modules that have/had 10 kHz output; that would work too. Even 1 PPS output seems like a workable starting point, but at the expense of a different and/or more difficult path to get to a 10 MHz reference signal I seek. Any advance or pointer to source (reasonable cost, whatever that means!) would be appreciated. Thanks! Dave wb0...@yahoo.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS antenna in silicon/RTV encapsulation
On 4/15/14, 8:13 AM, ewkeh...@aol.com wrote: Working off list on a super high performance GPSDO but low cost thanks to a time nut (sorry forgot his name) he directed me to DX.com which have ublox with antenna for lwss than $ 23. Super performance and though they are out of the one with 1 pps all you have to do is solder directly to the module. Have both versions. Attached you see what I did with the antenna but found out the hard way that when it rains the concave bottom fills with water, still works but not as good. So last night I made it flat with 3M Marine 5200 slow cure that I have extensive experience with from boating. Will take a full week to cure but if it does not work I can always remove it and start over There is a similar approach using a small display dome which is basically a round bottom beaker kind of shape designed to go on a wooden base. It can just as easily go on a big cork or stopper, or a disk cut out of a HDPE cutting board. Googling display dome will show you copious choices. or somewhere like glassdomes.com Of course, if you have a supply of canning jars or babyfood jars, then you can use those. Nothing says the jar has to be mounted with the axis vertical. You could do it sideways (like a ship in a bottle) to help solve the rain in the punt problem. ___ 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] Measuring the accurcy of a wrist watch
Here is a discussion forum page that shows a commercial quartz watch timing machine in use: http://omegaforums.net/threads/quartz-watches-some-information-some-may-find-interesting.5475/ The machine obviously measures the time of each second tick, either electrically or acoustically, because it can tell you the instantaneous rate over one second based on the time between ticks. In the example shown, the crystal is fast by 4.18 seconds/day (48 PPM) based on the period between most ticks, but every 60th tick has a longer period due to inhibition (oscillator pulse dropping), and the net rate measured over 60 seconds is 0.32 seconds/day (3.7 PPM). There is a bunch of additional information about the motor drive pulses too. The article explains what it means in some detail. It seems to me that calculating the rate information should require nothing more than capturing the leading edge of each motor pulse and time stamping it, at a rate of 1 data point per second. The motor information requires capturing several pulses (at a rate of a few kHz max.) every second. - Dave On 15/04/2014 09:52, Tom Van Baak wrote: Some research has shown that there is an comparable instrument for ANALOG quarz watches. As far as I understand it does not try to detect the quarz frequency but detects magnetic pulses from the step motors that move the hands of the watch. Has anyone of you ever tried to do this in a time nuts laboratory? Ulrich, Yes, this works well, for both those with seconds hands (one magnetic pulse per second) and those with only minute/hour hands (one or two steps per minute). A large coil of wire is all you need. Have a look at the watch timing tools and sensors at http://www.bmumford.com/microset.html or http://www.bmumford.com/mset/modelwatch1.html Here's an example using a magnetic sensor: http://leapsecond.com/pages/Junghans/ /tvb ___ 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] Measuring the accurcy of a wrist watch
You don't count the pulses, you measure the separation between the pulses. Just like with the 1PPS output on your C-Beam. -Chuck Harris Max Robinson wrote: In the United States we can buy analog quarts watches from Wal-Mart for under 15 dollars. When the battery dies you don't even bother to replace it you just buy a new watch, unless...the one you have is very good. There is a lot of variation and buying one is the luck of the draw. They can be as bad as 1 minute a month and they always seem to be gaining. Right now I have one that gains about 2 seconds a month. I fully intend to see if it is possible to replace the battery when it runs down. Counting motor pulses seems to be a little impractical because it would take 12 days to get to 1e6 accuracy. Regards. Max. K 4 O DS. ___ 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] Looking for GPSDO for home use
Dave, If you're just calibrating a frequency counter you may not need a GPSDO. A simple GPS 1PPS is all you need; just measure the time from the 1PPS to the 10 MHz, wait a minute or an hour or a day and do it again. This will show you the time drift, from which you can calculate the frequency error. Still, having a 10 MHz GPSDO available is usually more convenient, so I would not talk you out of it. If you don't want to spend time to design your own GPSDO, or to build one of the dozen homebrew projects on the web, I would recommend you get a Trimble Thunderbolt. They are as turn-key as you can get, but also allow great hacking if you so choose. I have some left over from the group buy. If you're interested contact me off-list. Thanks, /tvb - Original Message - From: David Feldman wb0...@yahoo.com To: time-nuts@febo.com Sent: Tuesday, April 15, 2014 8:27 AM Subject: [time-nuts] Looking for GPSDO for home use I found this reflector after searching for GPSDO that would be suitable for individual purchase/use. Each time I found an article about GPSDO projects, that lead me to a surplus GPS module that is either no longer available, not current production, undocumented, or otherwise difficult to source. I don't mind doing my own building/integration, and am not adverse to starting with a used or suplus component, I'm not sure where to start in terms of sourcing the GPS module/antenna/etc. My main need is for something to serve as a primary frequency standard (i.e., 10 MHz output) I can use to set a voltage controlled OCXO I just installed in my (otherwise cheap chinese) frequency counter. It seems there are some modules that have/had 10 kHz output; that would work too. Even 1 PPS output seems like a workable starting point, but at the expense of a different and/or more difficult path to get to a 10 MHz reference signal I seek. Any advance or pointer to source (reasonable cost, whatever that means!) would be appreciated. Thanks! Dave wb0...@yahoo.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS antenna in silicon/RTV encapsulation
The Gerber Baby Food Jar at Wall Mart $ 0.49 In a message dated 4/15/2014 1:03:40 P.M. Eastern Daylight Time, jim...@earthlink.net writes: On 4/15/14, 8:13 AM, ewkeh...@aol.com wrote: Working off list on a super high performance GPSDO but low cost thanks to a time nut (sorry forgot his name) he directed me to DX.com which have ublox with antenna for lwss than $ 23. Super performance and though they are out of the one with 1 pps all you have to do is solder directly to the module. Have both versions. Attached you see what I did with the antenna but found out the hard way that when it rains the concave bottom fills with water, still works but not as good. So last night I made it flat with 3M Marine 5200 slow cure that I have extensive experience with from boating. Will take a full week to cure but if it does not work I can always remove it and start over There is a similar approach using a small display dome which is basically a round bottom beaker kind of shape designed to go on a wooden base. It can just as easily go on a big cork or stopper, or a disk cut out of a HDPE cutting board. Googling display dome will show you copious choices. or somewhere like glassdomes.com Of course, if you have a supply of canning jars or babyfood jars, then you can use those. Nothing says the jar has to be mounted with the axis vertical. You could do it sideways (like a ship in a bottle) to help solve the rain in the punt problem. ___ 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] GPS antenna in silicon/RTV encapsulation
Radom for a GPS antenna. I used this for a while... Place your patch type antenna on a small round black of plastic foam packing material. Make a slit for the antenna cable so that the little antann lays flat on the disk of foam and the cable comes up from the bottom. Now find a suitable glass jar. Maybe you have finish some pickles or whatever. Clean the jar and turn it upside down then force the jar over the disk of foam. If you like to mount it to a pole or mast, cut a one inch hole in the jar lid turn the lid upside down and screw it to the a wood pole (2x4) The jar with thread onto the lid. Eventually the lib will rust and the flat bottom jar might not work in your location but is is completely weather proof for zero cost. I eventually bought a real timing GPS antenna and paced it on e 1 galvanized pipe mast. BTW I looked at some expensive GPS antenna mounting hardware intended to connect an antenna to a pipe and found it was functionally identical to a pipe flange.An inverted jar lid glued to a pipe flange would make a great radome, and then you lead the cable down the pipe. Spray paint it all white and it would even look good. On Tue, Apr 15, 2014 at 1:53 AM, nuts n...@lazygranch.com wrote: I'd be inclined to look at radome construction. http://www.mpdigest.com/issue/articles/2008/may/mfg/default.asp The E-3 AWACS is mostly S-2 glass, but they need the strength. For a radome sitting outside, you might be able to do better. The advantage to S-2 glass is you can buy it easily, especially if you have a Tap Plastics handy. It works well with the Marine Resin they sell, so you know it will last a long time outdoors. You need to cure the resin in a vacuum, though not a particularly good vacuum. There are probably guides on the internet, but here is the basic scheme to make a fiberglass composite structure. Make a form of the final product. Cover the form in mylar. Tap Plastics sells the mylar too. The resin won't stick to the mylar. Cut the cloth to cover the form. Where you overlap, leave at least an inch. You need both the S-2 glass and the thin fiberglass mat. The mat is a very loose weave that can hold more resin than the glass. The basic construction is a sandwich of cloth, mat, then cloth. You can add more layers, but you always want mat between the cloth, and cloth on the outside. You will need more mylar to cover the last layer of cloth. This is to keep the air out. It helps to have this cut ahead of time because the resin will be hardening as you work. Mix the resin with hardener. Brush the mylar on the form with resin. The resin on the form is needed to hold the cloth onto it. Place the cloth on the form. Brush on resin. Cover with mat. Brush on more resin. Cover with the final layer. Apply more resin. Apply the mylar. Use masking tape to keep it attached. Wait two days. Note that the form has to be destructible, that is you need to pull it away from the radome. Generally you use cardboard. An alternative scheme, though I don't suggest it for a radome, is to use a foam core. You can bush directly onto the form. You need to at least a layer of mat then cloth on both sides of the form. Apply the mylar and wait two days. The form is part of the final structure, so there is nothing to remove. Generally for antennas in radome, all you do is have a weep hole at the bottom the antenna to allow air exchange. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Looking for GPSDO for home use
If you are looking to build your first GPSDO. I'd go with the simplest one first. I had a goal to build and document one that did not require a custom PCB or programmed chip or any special test equipment other then a DMM and a scope with price well under $50. I've beat the price by a lot but not documentation yet. My Arduino based GPSDO is back in operation. It is literally the simplest one that can still work.It's about $8 in parts but I've disconnected one of the external chips and will try removing the remaining one. The total BOM then will be just a bare Arudion Pro Mini, three resisters and two capacitors for about $4. It is back up and running now for about 12 hours. I have the output of the simple GPSDO and the 10MHz signal from a Trimble Thunderbolt both up on my dual trace scope. The two 10MHz signals do move slowly relative tone another. It will move to the right for 20 or 30 minutes then moves back left. But it is already better than you'd need to calibrate a frequency counter. The little AVR chip inside the Adruino has all the hardware you need, a fast counter that can be captured with a raising edge of a pulse and several DACs and ADCs. That is all I'm using right now. In the past people used to have to build this using small scale ICs. (maybe 74xxx type) There are at least a half dozen ways to make this better. The goal of this project is to see which makes the most difference and order them by bang per buck On Tue, Apr 15, 2014 at 11:03 AM, Tom Van Baak t...@leapsecond.com wrote: Dave, If you're just calibrating a frequency counter you may not need a GPSDO. A simple GPS 1PPS is all you need; just measure the time from the 1PPS to the 10 MHz, wait a minute or an hour or a day and do it again. This will show you the time drift, from which you can calculate the frequency error. Still, having a 10 MHz GPSDO available is usually more convenient, so I would not talk you out of it. If you don't want to spend time to design your own GPSDO, or to build one of the dozen homebrew projects on the web, I would recommend you get a Trimble Thunderbolt. They are as turn-key as you can get, but also allow great hacking if you so choose. I have some left over from the group buy. If you're interested contact me off-list. Thanks, /tvb - Original Message - From: David Feldman wb0...@yahoo.com To: time-nuts@febo.com Sent: Tuesday, April 15, 2014 8:27 AM Subject: [time-nuts] Looking for GPSDO for home use I found this reflector after searching for GPSDO that would be suitable for individual purchase/use. Each time I found an article about GPSDO projects, that lead me to a surplus GPS module that is either no longer available, not current production, undocumented, or otherwise difficult to source. I don't mind doing my own building/integration, and am not adverse to starting with a used or suplus component, I'm not sure where to start in terms of sourcing the GPS module/antenna/etc. My main need is for something to serve as a primary frequency standard (i.e., 10 MHz output) I can use to set a voltage controlled OCXO I just installed in my (otherwise cheap chinese) frequency counter. It seems there are some modules that have/had 10 kHz output; that would work too. Even 1 PPS output seems like a workable starting point, but at the expense of a different and/or more difficult path to get to a 10 MHz reference signal I seek. Any advance or pointer to source (reasonable cost, whatever that means!) would be appreciated. Thanks! Dave wb0...@yahoo.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. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS antenna in silicon/RTV encapsulation
On 4/15/14, 11:02 AM, ewkeh...@aol.com wrote: The Gerber Baby Food Jar at Wall Mart $ 0.49 Is there a particular kind of food that works best? Perhaps strained prunes has the best regularity? ___ 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] GPS antenna in silicon/RTV encapsulation
Actually I used a home canning type wide mouth mason jar.I thought about a fish bowl but there are not threads for mounting. Then I got smarter and spend $29 on a real timing antenna and it''s been on the roof for years. The jar on a stick works but has very poor WAF. On Tue, Apr 15, 2014 at 12:05 PM, Jim Lux jim...@earthlink.net wrote: On 4/15/14, 11:02 AM, ewkeh...@aol.com wrote: The Gerber Baby Food Jar at Wall Mart $ 0.49 Is there a particular kind of food that works best? Perhaps strained prunes has the best regularity? ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/ mailman/listinfo/time-nuts and follow the instructions there. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS antenna in silicon/RTV encapsulation
Having five GPSDO's running and some for over 14 years I have a very sophisticated and expensive antenna system. This is part of a project that with the disappearance of Tbolts and other commercial GPSDO's to make available to time nuts state of the art performance at an affordable price, specifically those that have a hard time justifying large expenditures. To me the fun is in the challenge and maximum performance at minimum cost is fun. Stay tuned. Bert Kehren. In a message dated 4/15/2014 4:05:38 P.M. Eastern Daylight Time, albertson.ch...@gmail.com writes: Actually I used a home canning type wide mouth mason jar.I thought about a fish bowl but there are not threads for mounting. Then I got smarter and spend $29 on a real timing antenna and it''s been on the roof for years. The jar on a stick works but has very poor WAF. On Tue, Apr 15, 2014 at 12:05 PM, Jim Lux jim...@earthlink.net wrote: On 4/15/14, 11:02 AM, ewkeh...@aol.com wrote: The Gerber Baby Food Jar at Wall Mart $ 0.49 Is there a particular kind of food that works best? Perhaps strained prunes has the best regularity? ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/ mailman/listinfo/time-nuts and follow the instructions there. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS antenna in silicon/RTV encapsulation
Washed all three down the sink Bert Kehren In a message dated 4/15/2014 3:18:34 P.M. Eastern Daylight Time, jim...@earthlink.net writes: On 4/15/14, 11:02 AM, ewkeh...@aol.com wrote: The Gerber Baby Food Jar at Wall Mart $ 0.49 Is there a particular kind of food that works best? Perhaps strained prunes has the best regularity? ___ 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] GPS antenna in silicon/RTV encapsulation
I don't use the surf board resin. I use http://www.tapplastics.com/product/fiberglass/polyester_resins/tap_marine_vinyl_ester_resin/34 I don't have specifics on what Tap sells, but vinyl ester resins have a dielectic coeficient around 4 and dissipation of at least 0.00x. The resin is actually better than the S-2 glass.I suppose I can ask who makes their resin, but I don't know if anyone at a store has that answer. It works quite well on L-band. But to each his own. It is certainly better than the thick PVC pipe a lot of home brew antenna makers use. PVC degrades with UV unless you paint it, and if you paint it, who knows what the final result will be. The AWACS has a Al frame. Talk about reflections! The cheap arse test for a radome is you put it in the microwave with a bowl of water. See if the material gets hot. The S-2 with vinyl resin works great in that test. ___ 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.
