Re: [time-nuts] Different Survey Results
Peter, My TB is running continuously during months. It draws about 7 W using the black PWR-supply proposed by Tom (TvB). In the room at about 22 °C it does show 32.43 °C, I never passed 37 °C. So I would propose to net go beyond the 40 °C internal temp. reading. I will manufacture a wooden box with thick walls to stabilize the temp. Wood does of course not shield, but because the high thermal capacitance together with its isolation (moderate)it should result in a long thermal constant. Of course the temperature will come up, hopefully not surpassing 42 °C. Low temperature = longer lifetime. Your osc. Adev values are similar to mine, that should be ok (good). I can confirm the experience by Warren. I use 490 s,0.68 damp factor and a gain of -3.55 Hz/V actually resulting to PPS ADEV @ 1 tau 5.096E-11, @ 100 tau 3.05E-11, @ 500 tau 6.43E-12 @ 1000 tau 2.92E-12 Osc. ADEV @ 1 tau 3.39E-09, @ 100 tau 3.45E-11, @ 500 tau 7.05E-12 @ 1000 tau 3.32E-12 read by Lady Heather, which does not mean that these values are exact! This with the original OCXO, perhaps with an external oscillator one could get better results, but I had no luck yet. The PPS does very seldom exceed +- 5 ns, normally it does move just around +- 2 to 3 ns. The DAC-Voltage changes are in the range of +- 3 steps of around 25µV (a step presesents close to 8 µV) These are my observations, I hope it does help you. regards, Arnold Am 19.08.2010 23:59, schrieb Peter Krengel: To John WA4WDL: The coordinates out of my current (fixed) position calculated by the SirF GPS and the tbold during a 48h survey are different. On a map this differences makes up a shift of up to 100m around my true qth. With other words if I would (and could) use the tbold as a mobile GPS I would come off road at once ;) To ws: Thanks for the interesting answer and tips for modifying factory settings. My tbold works in a good stable (temperature) environment. I tried out to put it in a temp-isolated box but Osc temperature went up to about 50°C (not too hot?). Secondly I tried it without a box at normal 20°C room temperature (varying a little bit) and it showed OSC 41.75°C. What is the better choice? It also got fine antenna conditions (mostly 8 sats are recognized having signals between 38 and 48dBc) by using a roof top ceramic chip antenna (it has a inner preamp) followed by a 20dB wideband amp and about 20m coax. As I am located on a hill top it sees a 360° free sky down to 0° elevation. I got the following results using factory settings after cold start and 10 hours running with my true (are they really my true coords?) qth coordinates saved after self-survey: OSC ADEV 1tau 2.7E-09 1 tau 7.0E-13 My intension (of cause..) is to get the best out of the tbold in short and long term stability. The tbold isnt modified in any way running the original oscillator. What do you think ? To Mark: I too got a LPRO rubidium but it I'm not very satisfied because of the need of long time warm up after power fail and the need of a heat sink. In addition the tube wont last for ever and is used for 10(?) years... Anyway I would like to compare both tbold and Lpro if the tbold is setup best as possible. Thanks and regards Peter DG4EK ___ ___ 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] Phase noise measurement (was - no subject)
Mark You've come to the right place - well, that is if you want to devote a significant amount of your life in the pursuit of ever-more accurate time and frequency measurements If you've only got one source then you need to use the frequency discriminator method (aka delay line method) of phase noise measurement. Basically you take the output of the source, split it in two, delay one of the signals, re-combine the two and then measure the resultant signal on a base-band spectrum analyser. There are loads of references to this on the web, which describe the method in more detail, including :- The Art of phase noise measurement - Dieter Scherer and HP Application Note AN270-2 both available from John Miles web site www.thegleam.com/ke5fx/gpib/pn.htm The references at the end of these articles, especially the HP ones, are particularly useful. The operating manual for the HP 11729B or 11729C Carrier Noise Test Set is also highly recommended. Yes, there's some maths, you need to understand the relationship between phase and frequency measurements, but you don't necessarily need ALL the theory that most of the papers give - don't give up just because of a few differential equations :) The limitation of the frequency discriminator method is that the noise floor of the measurement system is often worse than the DUT, especially if your DUT is very good, and it's even worse if you're trying to measure close-in noise. The Sherer article gives a good graph illustrating this. If you're trying to measure the phase noise of the oscillator inside a Tbolt then I don't think that a frequency discriminator will be sensitive enough, although I might be wrong. Despite what you said, you might want to consider buying an HP 10811 oscillator or similar which you could use in a phase detector measurement system which is likely to give superior results. Hope that helps regards Grant Mark wrote :- My new GPSDO leaves me with the question of how do I measure the phase noise of what is by far the best oscillator I own... without buying a better one to compare it to. That question is what brought me to time-nuts. I'm starting to read some papers on oscillator characterization that are collected together in a technical note from NIST that a co-worker pointed me towards, but some of them are giving me a math-induced headache. ___ 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] Different Survey Results
Hi The TBolt is rated to 70 C. You probably are ok running them at 50 C. The OCXO does not mind the heat and there's nothing else in there that has any noticeable heat rise. If you text search for pool of mercury in the archives you will hit a thread that goes into the details (and impracticality) of very long thermal time constants. The wood box with foam is a good way to go. Past that active control makes sense. Bob On Aug 20, 2010, at 3:23 AM, Arnold Tibus arnold.ti...@gmx.de wrote: Peter, My TB is running continuously during months. It draws about 7 W using the black PWR-supply proposed by Tom (TvB). In the room at about 22 °C it does show 32.43 °C, I never passed 37 °C. So I would propose to net go beyond the 40 °C internal temp. reading. I will manufacture a wooden box with thick walls to stabilize the temp. Wood does of course not shield, but because the high thermal capacitance together with its isolation (moderate)it should result in a long thermal constant. Of course the temperature will come up, hopefully not surpassing 42 °C. Low temperature = longer lifetime. Your osc. Adev values are similar to mine, that should be ok (good). I can confirm the experience by Warren. I use 490 s,0.68 damp factor and a gain of -3.55 Hz/V actually resulting to PPS ADEV @ 1 tau 5.096E-11, @ 100 tau 3.05E-11, @ 500 tau 6.43E-12 @ 1000 tau 2.92E-12 Osc. ADEV @ 1 tau 3.39E-09, @ 100 tau 3.45E-11, @ 500 tau 7.05E-12 @ 1000 tau 3.32E-12 read by Lady Heather, which does not mean that these values are exact! This with the original OCXO, perhaps with an external oscillator one could get better results, but I had no luck yet. The PPS does very seldom exceed +- 5 ns, normally it does move just around +- 2 to 3 ns. The DAC-Voltage changes are in the range of +- 3 steps of around 25µV (a step presesents close to 8 µV) These are my observations, I hope it does help you. regards, Arnold Am 19.08.2010 23:59, schrieb Peter Krengel: To John WA4WDL: The coordinates out of my current (fixed) position calculated by the SirF GPS and the tbold during a 48h survey are different. On a map this differences makes up a shift of up to 100m around my true qth. With other words if I would (and could) use the tbold as a mobile GPS I would come off road at once ;) To ws: Thanks for the interesting answer and tips for modifying factory settings. My tbold works in a good stable (temperature) environment. I tried out to put it in a temp-isolated box but Osc temperature went up to about 50°C (not too hot?). Secondly I tried it without a box at normal 20°C room temperature (varying a little bit) and it showed OSC 41.75°C. What is the better choice? It also got fine antenna conditions (mostly 8 sats are recognized having signals between 38 and 48dBc) by using a roof top ceramic chip antenna (it has a inner preamp) followed by a 20dB wideband amp and about 20m coax. As I am located on a hill top it sees a 360° free sky down to 0° elevation. I got the following results using factory settings after cold start and 10 hours running with my true (are they really my true coords?) qth coordinates saved after self-survey: OSC ADEV 1tau 2.7E-09 1 tau 7.0E-13 My intension (of cause..) is to get the best out of the tbold in short and long term stability. The tbold isnt modified in any way running the original oscillator. What do you think ? To Mark: I too got a LPRO rubidium but it I'm not very satisfied because of the need of long time warm up after power fail and the need of a heat sink. In addition the tube wont last for ever and is used for 10(?) years... Anyway I would like to compare both tbold and Lpro if the tbold is setup best as possible. Thanks and regards Peter DG4EK ___ ___ 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] (no subject)
Hi The TBolt OCXO does have good noise characteristics. Unfortunately you have to pull it out of the unit to figure that out. Bob On Aug 19, 2010, at 10:31 PM, Mark J. Blair n...@nf6x.net wrote: On Aug 19, 2010, at 7:13 PM, Bob Camp wrote: Hopefully they will keep GPS running long enough for me to find something to compare it to. My new GPSDO leaves me with the question of how do I measure the phase noise of what is by far the best oscillator I own... without buying a better one to compare it to. That question is what brought me to time-nuts. I'm starting to read some papers on oscillator characterization that are collected together in a technical note from NIST that a co-worker pointed me towards, but some of them are giving me a math-induced headache. :) -- Mark J. Blair, NF6X n...@nf6x.net Web page: http://www.nf6x.net/ GnuPG public key available from my web page. ___ 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 pcb IDs??
-Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Alan Melia Sent: Thursday, 19. August 2010 12:44 To: did...@cox.net; Discussion of precise time and frequency measurement Subject: Re: [time-nuts] GPS pcb IDs?? Hi Didier, the Trimble is a Resolution T (3.3v)user manual at the URL quoted by Stanley (Thanks again Stanley) The Synergy is Motorola UT+ Oncore (5v) and I am sure the manual for those is around somewhere but not had time to chase that yet. Alan, on the gpsd website you can find the Motorola Oncore Documentation: http://gpsd.berlios.de/vendor-docs/motorola/ Christian Please feel free to add these to your gallery...I may have some more when I get round to taking some photos Thanks and Best Wishes Alan G3NYK - Original Message - From: Didier Juges did...@cox.net To: Time-Nuts time-nuts@febo.com Sent: Thursday, August 19, 2010 12:43 AM Subject: Re: [time-nuts] GPS pcb IDs?? Alan, You may want to compare to those: http://www.ko4bb.com/Timing/GPS_Pics/ If they do not match and you eventually find out what they are, please let me know and I will add them to my collection. That goes for anybody who has identified, clear pictures of GPS receiver boards, both sides preferably. Thanks in advance, Didier KO4BB Sent from my BlackBerry Wireless thingy while I do other things... -Original Message- From: Alan Melia alan.me...@btinternet.com Sender: time-nuts-boun...@febo.com Date: Thu, 19 Aug 2010 00:07:20 To: Time-Nuts measurementtime-nuts@febo.com Reply-To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: [time-nuts] GPS pcb IDs?? Hi I have just acquired a couple of GPS receiver pcbs, ex Telcoms equipment. I know a lot of htese poards were discussed so time ago on the group. Does anyone recognise what they are and could point me at some intrormations please. I am afraid the flash has washed the the pics out a bit but hopefully there is enough detail to be recognised http://www.alan.melia.btinternet.co.uk/GPS/Trimble_top.JPG http://www.alan.melia.btinternet.co.uk/GPS/Trimble_lower.JPG http://www.alan.melia.btinternet.co.uk/GPS/Synergy_top.JPG http://www.alan.melia.btinternet.co.uk/GPS/Synergy_lower.JPG The Trimble pcb is 2.6 by 1.25in., and the Synergy is 3.15 by 1.6 in. Thanks Alan G3NYK ___ 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] OT: Service manual for Tektronix Type 130 L-C Meter
Folks, If any of you have a service manual for the Type 130 L-C meter do contact me. I am trying to get one going for my collection. Cheers -- Raj, VU2ZAP Bangalore, India. ___ 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 pcb IDs??
Thanks Christian, I have that doc but although I think it is probably relevant the outline of the pcb is totally different to the pcb I have though more like a number of M12 Oncores I have. Thank you for your interest, and help. Best Wishes Alan G3NYK - Original Message - From: Christian Riesch christian.rie...@omicron.at To: 'Discussion of precise time and frequency measurement' time-nuts@febo.com Sent: Friday, August 20, 2010 1:13 PM Subject: Re: [time-nuts] GPS pcb IDs?? -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Alan Melia Sent: Thursday, 19. August 2010 12:44 To: did...@cox.net; Discussion of precise time and frequency measurement Subject: Re: [time-nuts] GPS pcb IDs?? Hi Didier, the Trimble is a Resolution T (3.3v)user manual at the URL quoted by Stanley (Thanks again Stanley) The Synergy is Motorola UT+ Oncore (5v) and I am sure the manual for those is around somewhere but not had time to chase that yet. Alan, on the gpsd website you can find the Motorola Oncore Documentation: http://gpsd.berlios.de/vendor-docs/motorola/ Christian Please feel free to add these to your gallery...I may have some more when I get round to taking some photos Thanks and Best Wishes Alan G3NYK - Original Message - From: Didier Juges did...@cox.net To: Time-Nuts time-nuts@febo.com Sent: Thursday, August 19, 2010 12:43 AM Subject: Re: [time-nuts] GPS pcb IDs?? Alan, You may want to compare to those: http://www.ko4bb.com/Timing/GPS_Pics/ If they do not match and you eventually find out what they are, please let me know and I will add them to my collection. That goes for anybody who has identified, clear pictures of GPS receiver boards, both sides preferably. Thanks in advance, Didier KO4BB Sent from my BlackBerry Wireless thingy while I do other things... -Original Message- From: Alan Melia alan.me...@btinternet.com Sender: time-nuts-boun...@febo.com Date: Thu, 19 Aug 2010 00:07:20 To: Time-Nuts measurementtime-nuts@febo.com Reply-To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: [time-nuts] GPS pcb IDs?? Hi I have just acquired a couple of GPS receiver pcbs, ex Telcoms equipment. I know a lot of htese poards were discussed so time ago on the group. Does anyone recognise what they are and could point me at some intrormations please. I am afraid the flash has washed the the pics out a bit but hopefully there is enough detail to be recognised http://www.alan.melia.btinternet.co.uk/GPS/Trimble_top.JPG http://www.alan.melia.btinternet.co.uk/GPS/Trimble_lower.JPG http://www.alan.melia.btinternet.co.uk/GPS/Synergy_top.JPG http://www.alan.melia.btinternet.co.uk/GPS/Synergy_lower.JPG The Trimble pcb is 2.6 by 1.25in., and the Synergy is 3.15 by 1.6 in. Thanks Alan G3NYK ___ 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] Phase noise measurement (was - no subject)
Mark, you have the following options: - HP (Agilent) E5052A/B or RS FSUP Signal Source Analyzer (works for a single DUT, though limited to 1 Hz offset, normally useful for 10 Hz up to 40 MHz). - Compare two identical DUT's with a HP 3048A or similar PN test system and subtract 3 dB, assuming that the PN characteristic of both DUT's is identical. - Compare 3 similar DUT's with a HP 3048A and calculate the individual PN using the three cornerd hat method. - set up a cross correlation PN measurement system similar to the E5052A and have fun. You will however need two - as good as possible, but preferaby not more than 10 dB worse than what you want to measure - VCXO's like HP 10811A's... - you may build your own HP 3048A alike system, but be prepared to invest serious money and time, and much more time than you thought in the beginning... (if that is what you're after, you'll have the most fun you can). - find someone who has one of the above and talk him into measuring yours. - search the web for published PN data of the model you have and take these as a reference (give or take a few dB). Btw. do not assume that the phase noise of a disciplined VCXO is the same as the VCXO alone. Also keep the power supply contribution into account that can be surprisingly high. And, the PN of most frequency standards is significantly lower than what you can measure with any spectrum analyzer with PN measurement software (except for the RS FSUP of course). Adrian Grant Hodgson schrieb: Mark You've come to the right place - well, that is if you want to devote a significant amount of your life in the pursuit of ever-more accurate time and frequency measurements If you've only got one source then you need to use the frequency discriminator method (aka delay line method) of phase noise measurement. Basically you take the output of the source, split it in two, delay one of the signals, re-combine the two and then measure the resultant signal on a base-band spectrum analyser. There are loads of references to this on the web, which describe the method in more detail, including :- The Art of phase noise measurement - Dieter Scherer and HP Application Note AN270-2 both available from John Miles web site www.thegleam.com/ke5fx/gpib/pn.htm The references at the end of these articles, especially the HP ones, are particularly useful. The operating manual for the HP 11729B or 11729C Carrier Noise Test Set is also highly recommended. Yes, there's some maths, you need to understand the relationship between phase and frequency measurements, but you don't necessarily need ALL the theory that most of the papers give - don't give up just because of a few differential equations :) The limitation of the frequency discriminator method is that the noise floor of the measurement system is often worse than the DUT, especially if your DUT is very good, and it's even worse if you're trying to measure close-in noise. The Sherer article gives a good graph illustrating this. If you're trying to measure the phase noise of the oscillator inside a Tbolt then I don't think that a frequency discriminator will be sensitive enough, although I might be wrong. Despite what you said, you might want to consider buying an HP 10811 oscillator or similar which you could use in a phase detector measurement system which is likely to give superior results. Hope that helps regards Grant Mark wrote :- My new GPSDO leaves me with the question of how do I measure the phase noise of what is by far the best oscillator I own... without buying a better one to compare it to. That question is what brought me to time-nuts. I'm starting to read some papers on oscillator characterization that are collected together in a technical note from NIST that a co-worker pointed me towards, but some of them are giving me a math-induced headache. ___ 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] Phase noise measurement (was - no subject)
Hi You can make a pretty good front end (mixer / amp / lock) for under $100. That will let you measure phase noise with an audio spectrum analyzer. Bob On Aug 20, 2010, at 10:40 AM, Adrian rfn...@arcor.de wrote: Mark, you have the following options: - HP (Agilent) E5052A/B or RS FSUP Signal Source Analyzer (works for a single DUT, though limited to 1 Hz offset, normally useful for 10 Hz up to 40 MHz). - Compare two identical DUT's with a HP 3048A or similar PN test system and subtract 3 dB, assuming that the PN characteristic of both DUT's is identical. - Compare 3 similar DUT's with a HP 3048A and calculate the individual PN using the three cornerd hat method. - set up a cross correlation PN measurement system similar to the E5052A and have fun. You will however need two - as good as possible, but preferaby not more than 10 dB worse than what you want to measure - VCXO's like HP 10811A's... - you may build your own HP 3048A alike system, but be prepared to invest serious money and time, and much more time than you thought in the beginning... (if that is what you're after, you'll have the most fun you can). - find someone who has one of the above and talk him into measuring yours. - search the web for published PN data of the model you have and take these as a reference (give or take a few dB). Btw. do not assume that the phase noise of a disciplined VCXO is the same as the VCXO alone. Also keep the power supply contribution into account that can be surprisingly high. And, the PN of most frequency standards is significantly lower than what you can measure with any spectrum analyzer with PN measurement software (except for the RS FSUP of course). Adrian Grant Hodgson schrieb: Mark You've come to the right place - well, that is if you want to devote a significant amount of your life in the pursuit of ever-more accurate time and frequency measurements If you've only got one source then you need to use the frequency discriminator method (aka delay line method) of phase noise measurement. Basically you take the output of the source, split it in two, delay one of the signals, re-combine the two and then measure the resultant signal on a base-band spectrum analyser. There are loads of references to this on the web, which describe the method in more detail, including :- The Art of phase noise measurement - Dieter Scherer and HP Application Note AN270-2 both available from John Miles web site www.thegleam.com/ke5fx/gpib/pn.htm The references at the end of these articles, especially the HP ones, are particularly useful. The operating manual for the HP 11729B or 11729C Carrier Noise Test Set is also highly recommended. Yes, there's some maths, you need to understand the relationship between phase and frequency measurements, but you don't necessarily need ALL the theory that most of the papers give - don't give up just because of a few differential equations :) The limitation of the frequency discriminator method is that the noise floor of the measurement system is often worse than the DUT, especially if your DUT is very good, and it's even worse if you're trying to measure close-in noise. The Sherer article gives a good graph illustrating this. If you're trying to measure the phase noise of the oscillator inside a Tbolt then I don't think that a frequency discriminator will be sensitive enough, although I might be wrong. Despite what you said, you might want to consider buying an HP 10811 oscillator or similar which you could use in a phase detector measurement system which is likely to give superior results. Hope that helps regards Grant Mark wrote :- My new GPSDO leaves me with the question of how do I measure the phase noise of what is by far the best oscillator I own... without buying a better one to compare it to. That question is what brought me to time-nuts. I'm starting to read some papers on oscillator characterization that are collected together in a technical note from NIST that a co-worker pointed me towards, but some of them are giving me a math-induced headache. ___ 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] OT: Service manual for Tektronix Type 130 L-C Meter
Have you tried BAMA? -John === Folks, If any of you have a service manual for the Type 130 L-C meter do contact me. I am trying to get one going for my collection. Cheers -- Raj, VU2ZAP Bangalore, India. ___ 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] OT: Service manual for Tektronix Type 130 L-C Meter
On 08/20/2010 06:26 PM, J. Forster wrote: Have you tried BAMA? I have: http://bama.edebris.com/manuals/tek/130/ 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] OT: Service manual for Tektronix Type 130 L-C Meter
Thanks Guys, I Googled and nothing worthwhile turned up. BAMA.. I did not check. Now I've got it. Cheers Raj At 20-08-2010, you wrote: Have you tried BAMA? -John === Folks, If any of you have a service manual for the Type 130 L-C meter do contact me. I am trying to get one going for my collection. Cheers -- Raj, VU2ZAP Bangalore, India. ___ 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. -- Raj, VU2ZAP Bangalore, India. ___ 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] Symmetricom 58535A GPS antenna splitters FS
Hi Mike, Do you still have any of these splitters available by any chance? Thanks! Henry On Fri, Mar 26, 2010 at 4:29 PM, Mike Feher mfe...@eozinc.com wrote: I have the same items available in original sealed bags, for $35 each for one, $65 for two, and $120 for 4, plus actual priority shipping. So for one that is about $6, and for 2 or 4 it is about $11. Sorry to advertise on here, but, I know I am not setting a precedent. PayPal or checks welcome. I am now in Atlanta, but will be home tomorrow. Regards - Mike Mike B. Feher, N4FS 89 Arnold Blvd. Howell, NJ, 07731 732-886-5960 -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of J. L. Trantham, M. D. Sent: Friday, March 26, 2010 6:55 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] GPS antenna splitters I have used one of these (ePay item 370265750113) and it works well. Joe ___ 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. -- Henry Hallam Sent from my Laptop ___ 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] Symmetricom 58535A GPS antenna splitters FS
Hi...We purchased one of these from mike a year ago, and it really works well. Thanks Thank You Kiss-Electronics Ms Ashley Hall 183 N 5th Avenue Cornelius, Oregon 97113 W7DUZ www.kiss-electronics.com -Original Message- From: Henry Hallam he...@pericynthion.org To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Fri, Aug 20, 2010 9:48 am Subject: Re: [time-nuts] Symmetricom 58535A GPS antenna splitters FS Hi Mike, o you still have any of these splitters available by any chance? Thanks! enry On Fri, Mar 26, 2010 at 4:29 PM, Mike Feher mfe...@eozinc.com wrote: I have the same items available in original sealed bags, for $35 each for one, $65 for two, and $120 for 4, plus actual priority shipping. So for one that is about $6, and for 2 or 4 it is about $11. Sorry to advertise on here, but, I know I am not setting a precedent. PayPal or checks welcome. I am now in Atlanta, but will be home tomorrow. Regards - Mike Mike B. Feher, N4FS 89 Arnold Blvd. Howell, NJ, 07731 732-886-5960 -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of J. L. Trantham, M. D. Sent: Friday, March 26, 2010 6:55 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] GPS antenna splitters I have used one of these (ePay item 370265750113) and it works well. Joe ___ 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. -- enry Hallam Sent from my Laptop ___ ime-nuts mailing list -- time-nuts@febo.com o unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts nd 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] (no subject)
On Aug 20, 2010, at 5:07 AM, Bob Camp wrote: The TBolt OCXO does have good noise characteristics. Unfortunately you have to pull it out of the unit to figure that out. Is its phase noise substantially worse when it's in the unit? I.e., is the rest of the TBolt adding a lot of phase noise to its output via its power and/or tuning voltages? I'm powering my TBolt with an HP 6236B bench supply rather than the cheap open-frame switcher that came with it. Based on what I read, powering the TBolt with a switcher adds a lot of noise/spurs to the OCXO spectrum. My unit has the Trimble-marked OCXO, which I gather is supposed to be a lot better than the Piezo-marked one. My TBolt is presently just screwed onto the top cover of the 6236B, which is probably far from optimal. I have the whole setup installed in a closet, so at least it doesn't get nailed with a blast of cold air every time the air conditioner turns on. -- Mark J. Blair, NF6X n...@nf6x.net Web page: http://www.nf6x.net/ GnuPG public key available from my web page. ___ 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] Phase noise measurement (was - no subject)
On Aug 20, 2010, at 4:56 AM, Grant Hodgson wrote: You've come to the right place - well, that is if you want to devote a significant amount of your life in the pursuit of ever-more accurate time and frequency measurements :) If you've only got one source then you need to use the frequency discriminator method (aka delay line method) of phase noise measurement. Basically you take the output of the source, split it in two, delay one of the signals, re-combine the two and then measure the resultant signal on a base-band spectrum analyser. [...] The limitation of the frequency discriminator method is that the noise floor of the measurement system is often worse than the DUT, especially if your DUT is very good, and it's even worse if you're trying to measure close-in noise. The Sherer article gives a good graph illustrating this. If you're trying to measure the phase noise of the oscillator inside a Tbolt then I don't think that a frequency discriminator will be sensitive enough, although I might be wrong. I got the impression that for good OCXOs like the HP 10811 or (supposedly) the OCXO in my TBolt, the delay line method wouldn't provide enough sensitivity for measuring close-in phase noise. Despite what you said, you might want to consider buying an HP 10811 oscillator or similar which you could use in a phase detector measurement system which is likely to give superior results. I might need 2 or 3 of them so I can weed out the under-performers! :) I had originally considered getting one of the surplus HP/Agilent GPSDOs with HP 10811 OCXOs, but I settled on the TBolt since it appeared to be almost as good (in terms of phase noise), a bit cheaper, and a bit easier to power than one of the HPs that need 48VDC. Well, I bought another power supply for the TBolt, anyway, but at least it would be easier to build a power supply that operates from +12VDC, a voltage that's always available in a ham shack. -- Mark J. Blair, NF6X n...@nf6x.net Web page: http://www.nf6x.net/ GnuPG public key available from my web page. ___ 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] Phase noise measurement (was - no subject)
On Aug 20, 2010, at 7:40 AM, Adrian wrote: - you may build your own HP 3048A alike system, but be prepared to invest serious money and time, and much more time than you thought in the beginning... (if that is what you're after, you'll have the most fun you can). I did a quick survey of surplus phase noise measurement system prices on eBay, and was shocked by how cheap they apparently aren't. I'll set up some searches to warn me when any of the instruments you mentioned appear, since it may be a while before the right one shows up at the right price. - Compare 3 similar DUT's with a HP 3048A and calculate the individual PN using the three cornerd hat method. That sounds like a method I'll want to learn about, since I'll necessarily be building up my testbench with surplus equipment of unknown condition, and the things I'd want to characterize initially would likely be the best oscillators I can get my hands on (except for the ones that no longer perform to spec, which I'd want to weed out). Once I have the bugs worked out of my test system, I could then use it to characterize other oscillators (probably far inferior to the Trimble/HP OCXOs) in practical applications. Btw. do not assume that the phase noise of a disciplined VCXO is the same as the VCXO alone. Also keep the power supply contribution into account that can be surprisingly high. In the case of my TBolt OCXO, I'll be interested in characterizing it while it's in the TBolt, with its regular power supply, and under discipline, since that's the way I'd be using it as a frequency reference on my bench. And, the PN of most frequency standards is significantly lower than what you can measure with any spectrum analyzer with PN measurement software (except for the RS FSUP of course). Yup, the phase noise plots I've seen of the HP and TBolt OCXOs show close-in phase noise very far beyond the dynamic range of any spectrum analyzers I'm familiar with. I wandered through the labs at work in hope of finding something I could use to look at the phase noise of my new toys (I'm in the GPS industry, and have access to some nice spectrum and network analyzers), but it looks like I'm on my own. -- Mark J. Blair, NF6X n...@nf6x.net Web page: http://www.nf6x.net/ GnuPG public key available from my web page. ___ 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] Phase noise measurement (was - no subject)
On Aug 20, 2010, at 8:30 AM, Bob Camp wrote: You can make a pretty good front end (mixer / amp / lock) for under $100. That will let you measure phase noise with an audio spectrum analyzer. I am intrigued by your ideas, and I would like to subscribe to your newsletter. Oh, wait, I've already subscribed to your newsletter. :-) -- Mark J. Blair, NF6X n...@nf6x.net Web page: http://www.nf6x.net/ GnuPG public key available from my web page. ___ 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 counters
Hi guys, I want to find a frequency counter that will read to 1 hz precision up to a minimum of 30 Mhz that I can clock using the output from my Efratom 101 Rb frequency standard. I am quite happy to make one if there is a suitable design out there. Any suggestions? 72/3 de Steve G0XAR -- It is vain to do with more that which can be done with less. ___ 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] Frequency counters
Virtually any HP counter made after 1975 will do that. You might also look at a Tektronix TM-500 counter (DC503, ...) and mainframe. -John == Hi guys, I want to find a frequency counter that will read to 1 hz precision up to a minimum of 30 Mhz that I can clock using the output from my Efratom 101 Rb frequency standard. I am quite happy to make one if there is a suitable design out there. Any suggestions? 72/3 de Steve G0XAR -- It is vain to do with more that which can be done with less. ___ 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] Frequency counters
On Aug 20, 2010, at 10:35 AM, Stephen Farthing wrote: I want to find a frequency counter that will read to 1 hz precision up to a minimum of 30 Mhz that I can clock using the output from my Efratom 101 Rb frequency standard. I am quite happy to make one if there is a suitable design out there. Any suggestions? I'm also beginning to look for a counter with very similar requirements. Studying eBay the other day, I came to the conclusion that an HP 5384A would be a good option, combining small size (compared to older rackmount counters), adequate resolution, an external reference input, and availability at fairly low prices. I decided that I probably don't need to hold out for one with the TCXO or OCXO options, since I'd generally only use it on my bench with my TBolt's OCXO as a reference, and it simply switches between its built-in reference and the external one rather than phase-locking its own reference (so I wouldn't be using its internal reference, and thus its performance wouldn't matter). -- Mark J. Blair, NF6X n...@nf6x.net Web page: http://www.nf6x.net/ GnuPG public key available from my web page. ___ 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] Frequency counters
On 08/20/2010 07:39 PM, J. Forster wrote: Virtually any HP counter made after 1975 will do that. You might also look at a Tektronix TM-500 counter (DC503, ...) and mainframe. A HP5335A or HP5334A should be good value for the money in that category, just to get you started in finding something. 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] Phase noise measurement (was - no subject)
Mark J. Blair wrote: oscillator inside a Tbolt then I don't think that a frequency discriminator will be sensitive enough, although I might be wrong. I got the impression that for good OCXOs like the HP 10811 or (supposedly) the OCXO in my TBolt, the delay line method wouldn't provide enough sensitivity for measuring close-in phase noise. Right, the delay line method is a non-starter. Despite what you said, you might want to consider buying an HP 10811 oscillator or similar which you could use in a phase detector measurement system which is likely to give superior results. On the 10811 production line, they would use Anzac AMC-123 amplifiers to drive a +17 dBm mixer, and then amplify the IF output with a low noise current amplifier like the Linear LT1028. You can easily homebrew this setup. You will need to have a DC coupled connection to the IF output to make a narrow PLL that drives the EFC of one of the oscillators. You can use a PC based audio spectrum analyzer program to look at the phase noise output. You can break the PLL to get a beat note to calibrate the system. The AMC-123 can also be homebrewed by reading the patent, which is listed on the data sheet. No need at all to get a 3048, etc. Rick Karlquist N6RK ___ 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] Symmetricom 58535A GPS antenna splitters FS
Henry - Yes I do. How many would you like. Thanks - Mike Mike B. Feher, N4FS 89 Arnold Blvd. Howell, NJ, 07731 732-886-5960 -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Henry Hallam Sent: Friday, August 20, 2010 12:49 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Symmetricom 58535A GPS antenna splitters FS Hi Mike, Do you still have any of these splitters available by any chance? Thanks! Henry On Fri, Mar 26, 2010 at 4:29 PM, Mike Feher mfe...@eozinc.com wrote: I have the same items available in original sealed bags, for $35 each for one, $65 for two, and $120 for 4, plus actual priority shipping. So for one that is about $6, and for 2 or 4 it is about $11. Sorry to advertise on here, but, I know I am not setting a precedent. PayPal or checks welcome. I am now in Atlanta, but will be home tomorrow. Regards - Mike Mike B. Feher, N4FS 89 Arnold Blvd. Howell, NJ, 07731 732-886-5960 -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of J. L. Trantham, M. D. Sent: Friday, March 26, 2010 6:55 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] GPS antenna splitters I have used one of these (ePay item 370265750113) and it works well. Joe ___ 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. -- Henry Hallam Sent from my Laptop ___ 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] Phase noise measurement (was - no subject)
On Aug 20, 2010, at 11:17 AM, Rick Karlquist wrote: On the 10811 production line, they would use Anzac AMC-123 amplifiers to drive a +17 dBm mixer, and then amplify the IF output with a low noise current amplifier like the Linear LT1028. You can easily homebrew this setup. You will need to have a DC coupled connection to the IF output to make a narrow PLL that drives the EFC of one of the oscillators. You can use a PC based audio spectrum analyzer program to look at the phase noise output. You can break the PLL to get a beat note to calibrate the system. The AMC-123 can also be homebrewed by reading the patent, which is listed on the data sheet. No need at all to get a 3048, etc. Interesting. I'm also the proud new owner of an Ettus Research USRP with a nice selection of RF front end boards, so maybe I could press that into service for spectrum analysis as long as I'm looking at things that will fall within its dynamic range and noise floor. I have a lot of learning to do... ;) -- Mark J. Blair, NF6X n...@nf6x.net Web page: http://www.nf6x.net/ GnuPG public key available from my web page. ___ 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] Phase noise measurement (was - no subject)
Hi Sounds like that's less than $100 on a home brew basis. There are several variations you could try. None of them break the bank. All do a quadrature test on a pair of OCXO's. Bob On Aug 20, 2010, at 2:17 PM, Rick Karlquist rich...@karlquist.com wrote: Mark J. Blair wrote: oscillator inside a Tbolt then I don't think that a frequency discriminator will be sensitive enough, although I might be wrong. I got the impression that for good OCXOs like the HP 10811 or (supposedly) the OCXO in my TBolt, the delay line method wouldn't provide enough sensitivity for measuring close-in phase noise. Right, the delay line method is a non-starter. Despite what you said, you might want to consider buying an HP 10811 oscillator or similar which you could use in a phase detector measurement system which is likely to give superior results. On the 10811 production line, they would use Anzac AMC-123 amplifiers to drive a +17 dBm mixer, and then amplify the IF output with a low noise current amplifier like the Linear LT1028. You can easily homebrew this setup. You will need to have a DC coupled connection to the IF output to make a narrow PLL that drives the EFC of one of the oscillators. You can use a PC based audio spectrum analyzer program to look at the phase noise output. You can break the PLL to get a beat note to calibrate the system. The AMC-123 can also be homebrewed by reading the patent, which is listed on the data sheet. No need at all to get a 3048, etc. Rick Karlquist N6RK ___ 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] Frequency counters
I'm also beginning to look for a counter with very similar requirements. Studying eBay the other day, I came to the conclusion that an HP 5384A would be a good option, combining small size (compared to older rackmount counters), adequate resolution, an external reference input, and availability at fairly low prices. One thing to add to your checklist... Does it have a (noisy) fan? I suspect anything that is low cost won't have a lot of parts it in so won't make much heat and won't need a fan. But you might find a good deal on a fancy/noisy unit. -- These are my opinions, not necessarily my employer's. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] (no subject)
Hi It's not that the TBolt is noisy, it's that good phase noise is a whole lot of db down. If you look at the posted plots, there is a lot of digital crud in them even with a good supply. The TBolt innards are the most likely source. Bob On Aug 20, 2010, at 1:00 PM, Mark J. Blair n...@nf6x.net wrote: On Aug 20, 2010, at 5:07 AM, Bob Camp wrote: The TBolt OCXO does have good noise characteristics. Unfortunately you have to pull it out of the unit to figure that out. Is its phase noise substantially worse when it's in the unit? I.e., is the rest of the TBolt adding a lot of phase noise to its output via its power and/or tuning voltages? I'm powering my TBolt with an HP 6236B bench supply rather than the cheap open-frame switcher that came with it. Based on what I read, powering the TBolt with a switcher adds a lot of noise/spurs to the OCXO spectrum. My unit has the Trimble-marked OCXO, which I gather is supposed to be a lot better than the Piezo-marked one. My TBolt is presently just screwed onto the top cover of the 6236B, which is probably far from optimal. I have the whole setup installed in a closet, so at least it doesn't get nailed with a blast of cold air every time the air conditioner turns on. -- Mark J. Blair, NF6X n...@nf6x.net Web page: http://www.nf6x.net/ GnuPG public key available from my web page. ___ 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] Frequency counters
Hi I never liked the display on the 5384. The LED's on the 5335 or 5334 always seemed easier to read. Bob On Aug 20, 2010, at 2:44 PM, Hal Murray hmur...@megapathdsl.net wrote: I'm also beginning to look for a counter with very similar requirements. Studying eBay the other day, I came to the conclusion that an HP 5384A would be a good option, combining small size (compared to older rackmount counters), adequate resolution, an external reference input, and availability at fairly low prices. One thing to add to your checklist... Does it have a (noisy) fan? I suspect anything that is low cost won't have a lot of parts it in so won't make much heat and won't need a fan. But you might find a good deal on a fancy/noisy unit. -- These are my opinions, not necessarily my employer's. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ 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] Frequency counters
Almost any counter with a 10 sec (hz) resolution time is fine. Doesn't even need to have provisions for an external clock , ( you can wire that in), as long as it has a 10mhz time base. You're going to drive it with an external 10mhz disciplined anyhow. Thank You Kiss-Electronics Ms Ashley Hall 183 N 5th Avenue Cornelius, Oregon 97113 W7DUZ www.kiss-electronics.com -Original Message- From: Hal Murray hmur...@megapathdsl.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Fri, Aug 20, 2010 11:44 am Subject: Re: [time-nuts] Frequency counters I'm also beginning to look for a counter with very similar requirements. Studying eBay the other day, I came to the conclusion that an HP 5384A would be a good option, combining small size (compared to older rackmount counters), adequate resolution, an external reference input, and availability at fairly low prices. One thing to add to your checklist... Does it have a (noisy) fan? I suspect anything that is low cost won't have a lot of parts it in so won't ake much heat and won't need a fan. But you might find a good deal on a ancy/noisy unit. -- hese are my opinions, not necessarily my employer's. I hate spam. __ ime-nuts mailing list -- time-nuts@febo.com o unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts nd 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] Re Frequency counters
Hi guys, A little research has revealed :- http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItemitem=150444654388_trksid=p2759.l1259#ht_1131wt_783 http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItemitem=150444654388_trksid=p2759.l1259#ht_1131wt_783which points to a guy selling a PIC based module which is clocked at 10 Mhz. I guess it should be possible to take the crystal out and clock it from the Rb standard. I have asked him a couple of questions about the module and will report back. and http://homepage.eircom.net/~ei9gq/counter.html http://homepage.eircom.net/~ei9gq/counter.htmlalso a pic based design. I would really love one of the HP counters but they are expensive over here. If I make Dayton next year I will see if I can get one at the fleamarket. 72/3 de Steve G0XAR -- It is vain to do with more that which can be done with less. ___ 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] Frequency counters
Hi Stephen, I assume from the callsign that you are in the UK. You could do worse than to buy a used HP 5316A for £75 from Stewart of Reading http://www.stewart-of-reading.co.uk/Frequency%20Counters.htm A quality compact universal counter with reciprical counting, external reference input and HPIB. I've no association with Stewarts apart from being a happy customer personally and for work for nearly 30 years! Regards, Robert G8RPI. --- On Fri, 20/8/10, Stephen Farthing squir...@gmail.com wrote: From: Stephen Farthing squir...@gmail.com Subject: [time-nuts] Frequency counters To: time-nuts@febo.com Date: Friday, 20 August, 2010, 18:35 Hi guys, I want to find a frequency counter that will read to 1 hz precision up to a minimum of 30 Mhz that I can clock using the output from my Efratom 101 Rb frequency standard. I am quite happy to make one if there is a suitable design out there. Any suggestions? 72/3 de Steve G0XAR -- It is vain to do with more that which can be done with less. ___ 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 pcb IDs??
Gentlemen, What you have is a Motorola SL Oncore navigation receiver, R6 series model number, with timing firmware installed. These 8 channel receivers, slightly smaller than the UT+ but larger than the M12x receivers, were flashed with UT+ timing firmware and shipped to various telecom companies between 1999 and 2003. Unlike the Motorola VP, GT/GT+ and UT/UT+ receivers, the SL Oncore receivers are characterized by an RF Dam PC trace in place of the full metal shield covering the RF components. Most of the SL Oncore receivers we shipped were mounted in a full, shielded enclosure to operate in higher EMI environments encountered in telecom installations. An SL Oncore Engineering Notes document outlines the physical, electrical and environmental characteristics of this GPS receiver. A separate User's Guide for the SL was not published. The navigation firmware load is like the older GT+ and the timing firmware load is like the UT+. Therefore, the UT+ command/reply messages outlined in the GT+/UT+ User's Guide can serve as a reference to the timing messages available in the SL Oncore. Because of continuing requests, we will be updating our web site to include information on Motorola's legacy GPS receivers. In the interim, please let me know where I can e-mail the SL Engineering Notes so that anyone with interest can make reference to them. Engineering notes in electronic form are also available for the Basic Oncore, VP Oncore, GT+ UT+ Oncore and the M12 Oncore (but not M12+) - Thanks! Art Sepin Synergy Systems, LLC San Diego T (858) 566-0666 F (858) 566-0768 a...@synergy-gps.com -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Alan Melia Sent: Friday, August 20, 2010 6:37 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] GPS pcb IDs?? Thanks Christian, I have that doc but although I think it is probably relevant the outline of the pcb is totally different to the pcb I have though more like a number of M12 Oncores I have. Thank you for your interest, and help. Best Wishes Alan G3NYK - Original Message - From: Christian Riesch christian.rie...@omicron.at To: 'Discussion of precise time and frequency measurement' time-nuts@febo.com Sent: Friday, August 20, 2010 1:13 PM Subject: Re: [time-nuts] GPS pcb IDs?? -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Alan Melia Sent: Thursday, 19. August 2010 12:44 To: did...@cox.net; Discussion of precise time and frequency measurement Subject: Re: [time-nuts] GPS pcb IDs?? Hi Didier, the Trimble is a Resolution T (3.3v)user manual at the URL quoted by Stanley (Thanks again Stanley) The Synergy is Motorola UT+ Oncore (5v) and I am sure the manual for those is around somewhere but not had time to chase that yet. Alan, on the gpsd website you can find the Motorola Oncore Documentation: http://gpsd.berlios.de/vendor-docs/motorola/ Christian Please feel free to add these to your gallery...I may have some more when I get round to taking some photos Thanks and Best Wishes Alan G3NYK - Original Message - From: Didier Juges did...@cox.net To: Time-Nuts time-nuts@febo.com Sent: Thursday, August 19, 2010 12:43 AM Subject: Re: [time-nuts] GPS pcb IDs?? Alan, You may want to compare to those: http://www.ko4bb.com/Timing/GPS_Pics/ If they do not match and you eventually find out what they are, please let me know and I will add them to my collection. That goes for anybody who has identified, clear pictures of GPS receiver boards, both sides preferably. Thanks in advance, Didier KO4BB Sent from my BlackBerry Wireless thingy while I do other things... -Original Message- From: Alan Melia alan.me...@btinternet.com Sender: time-nuts-boun...@febo.com Date: Thu, 19 Aug 2010 00:07:20 To: Time-Nuts measurementtime-nuts@febo.com Reply-To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: [time-nuts] GPS pcb IDs?? Hi I have just acquired a couple of GPS receiver pcbs, ex Telcoms equipment. I know a lot of htese poards were discussed so time ago on the group. Does anyone recognise what they are and could point me at some intrormations please. I am afraid the flash has washed the the pics out a bit but hopefully there is enough detail to be recognised http://www.alan.melia.btinternet.co.uk/GPS/Trimble_top.JPG http://www.alan.melia.btinternet.co.uk/GPS/Trimble_lower.JPG http://www.alan.melia.btinternet.co.uk/GPS/Synergy_top.JPG http://www.alan.melia.btinternet.co.uk/GPS/Synergy_lower.JPG The Trimble pcb is 2.6 by 1.25in., and the Synergy is 3.15 by 1.6 in. Thanks Alan G3NYK ___ time-nuts mailing
Re: [time-nuts] Frequency counters
I want to find a frequency counter that will read to 1 hz precision up to a minimum of 30 Mhz that I can clock using the output from my Efratom 101 Rb frequency standard. I am quite happy to make one if there is a suitable design out there. Any suggestions? Do you want to read the answer with your eyes, or get it into a computer? Most of the older HP counters have HP-IB/GP-IB. I think you could build everything you need in a small FPGA. I'm thinking of something like this: Assuming a reference clock, generate a pulse every second. Count cycles on your unknown clock. On each second pulse, copy the cycle-counter to another register and reset the counter. That gives you the number of cycles in the previous second. If you count in decimal rather than binary, it's simple to send out the digits as ASCII. With a bit more work, you could feed them to a small LCD display. One complication is avoiding metastability. My straw man would be to run the internal logic at 100 MHz (derived from the 10 MHz reference) and just run the input signal through a classic pair of FFs. I pulled 100 MHz out of the air. It's a nice round number. It might be too fast for a simple design with 8 digits in the counter chain. This whole problem is easily pipelined so you can run it at close to the max toggle rate in your chip, but that adds complexity. In the simplest version of the synchronizer, the receiving clock has to run at over 2X the sending clock. Then the receiving logic just looks for rising edges in the input data stream. You can gain a factor of 2 if you divide the sending clock by 2 and look for either rising or falling edges. That would let you run the main clock at 40 MHz which might be slow enough to avoid having to think about pipelines. You can probably to do the whole thing in software if you pick a chip with the right counter/timer blocks. I'd have to check the fine print on the data sheet carefully to see how fast the counter/timers will go. Some of them have prescalers so the counter can watch a fast signal, but if you divide the input signal too much you won't be able to get your 1 Hz resolution. But maybe you can count for several seconds... -- These are my opinions, not necessarily my employer's. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS pcb IDs??
Thanks Art that describes it faithfully and explains the differences. I am sure one of the guys will offer to host the information for the group. Thanks and Best Wishes Alan G3NYK - Original Message - From: Art Sepin a...@synergy-gps.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Friday, August 20, 2010 9:27 PM Subject: Re: [time-nuts] GPS pcb IDs?? Gentlemen, What you have is a Motorola SL Oncore navigation receiver, R6 series model number, with timing firmware installed. These 8 channel receivers, slightly smaller than the UT+ but larger than the M12x receivers, were flashed with UT+ timing firmware and shipped to various telecom companies between 1999 and 2003. Unlike the Motorola VP, GT/GT+ and UT/UT+ receivers, the SL Oncore receivers are characterized by an RF Dam PC trace in place of the full metal shield covering the RF components. Most of the SL Oncore receivers we shipped were mounted in a full, shielded enclosure to operate in higher EMI environments encountered in telecom installations. An SL Oncore Engineering Notes document outlines the physical, electrical and environmental characteristics of this GPS receiver. A separate User's Guide for the SL was not published. The navigation firmware load is like the older GT+ and the timing firmware load is like the UT+. Therefore, the UT+ command/reply messages outlined in the GT+/UT+ User's Guide can serve as a reference to the timing messages available in the SL Oncore. Because of continuing requests, we will be updating our web site to include information on Motorola's legacy GPS receivers. In the interim, please let me know where I can e-mail the SL Engineering Notes so that anyone with interest can make reference to them. Engineering notes in electronic form are also available for the Basic Oncore, VP Oncore, GT+ UT+ Oncore and the M12 Oncore (but not M12+) - Thanks! Art Sepin Synergy Systems, LLC San Diego T (858) 566-0666 F (858) 566-0768 a...@synergy-gps.com -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Alan Melia Sent: Friday, August 20, 2010 6:37 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] GPS pcb IDs?? Thanks Christian, I have that doc but although I think it is probably relevant the outline of the pcb is totally different to the pcb I have though more like a number of M12 Oncores I have. Thank you for your interest, and help. Best Wishes Alan G3NYK - Original Message - From: Christian Riesch christian.rie...@omicron.at To: 'Discussion of precise time and frequency measurement' time-nuts@febo.com Sent: Friday, August 20, 2010 1:13 PM Subject: Re: [time-nuts] GPS pcb IDs?? -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Alan Melia Sent: Thursday, 19. August 2010 12:44 To: did...@cox.net; Discussion of precise time and frequency measurement Subject: Re: [time-nuts] GPS pcb IDs?? Hi Didier, the Trimble is a Resolution T (3.3v)user manual at the URL quoted by Stanley (Thanks again Stanley) The Synergy is Motorola UT+ Oncore (5v) and I am sure the manual for those is around somewhere but not had time to chase that yet. Alan, on the gpsd website you can find the Motorola Oncore Documentation: http://gpsd.berlios.de/vendor-docs/motorola/ Christian Please feel free to add these to your gallery...I may have some more when I get round to taking some photos Thanks and Best Wishes Alan G3NYK - Original Message - From: Didier Juges did...@cox.net To: Time-Nuts time-nuts@febo.com Sent: Thursday, August 19, 2010 12:43 AM Subject: Re: [time-nuts] GPS pcb IDs?? Alan, You may want to compare to those: http://www.ko4bb.com/Timing/GPS_Pics/ If they do not match and you eventually find out what they are, please let me know and I will add them to my collection. That goes for anybody who has identified, clear pictures of GPS receiver boards, both sides preferably. Thanks in advance, Didier KO4BB Sent from my BlackBerry Wireless thingy while I do other things... -Original Message- From: Alan Melia alan.me...@btinternet.com Sender: time-nuts-boun...@febo.com Date: Thu, 19 Aug 2010 00:07:20 To: Time-Nuts measurementtime-nuts@febo.com Reply-To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: [time-nuts] GPS pcb IDs?? Hi I have just acquired a couple of GPS receiver pcbs, ex Telcoms equipment. I know a lot of htese poards were discussed so time ago on the group. Does anyone recognise what they are and could point me at some intrormations please. I am afraid the
Re: [time-nuts] Phase noise measurement (was - no subject)
On Aug 20, 2010, at 11:17 AM, Rick Karlquist wrote: On the 10811 production line, they would use Anzac AMC-123 amplifiers How does this amplifier look for this application? http://minicircuits.com/pdfs/ZFL-500LN.pdf If I understand the specifications properly, the noise figure is better and it has higher reverse isolation and higher gain, but a lower output intercept point. -- Mark J. Blair, NF6X n...@nf6x.net Web page: http://www.nf6x.net/ GnuPG public key available from my web page. ___ 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] Phase noise measurement (was - no subject)
It is good that you asked this FAQ. Basically, what is magic about the AMC-123 is that it has certifiably low phase noise, guaranteed by design and characterization, although not specified by Anzac. The other 99.9% of amplifiers that seem plausible, like this one, do not have the sophisticated negative feedback scheme of the AMC-123, and likely do NOT have good enough phase noise. In any event, we have zero information about the phase noise of this Mini-Circuits amplifier. Having a low noise figure is necessary but not sufficient to have good phase noise. Of course you could always get lucky. But then you have to also build an amplifier phase noise measurement system, which generally entails a line stretcher. Again, thank you for asking this question. It comes up often. Would anyone else like to suggest a known good low phase noise buffer amplifier? Maybe something from a Fred Walls paper? Rick Karlquist N6RK Mark J. Blair wrote: On Aug 20, 2010, at 11:17 AM, Rick Karlquist wrote: On the 10811 production line, they would use Anzac AMC-123 amplifiers How does this amplifier look for this application? http://minicircuits.com/pdfs/ZFL-500LN.pdf If I understand the specifications properly, the noise figure is better and it has higher reverse isolation and higher gain, but a lower output intercept point. -- Mark J. Blair, NF6X n...@nf6x.net Web page: http://www.nf6x.net/ GnuPG public key available from my web page. ___ 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] Phase noise measurement (was - no subject)
On Aug 20, 2010, at 2:19 PM, Rick Karlquist wrote: It is good that you asked this FAQ. Basically, what is magic about the AMC-123 is that it has certifiably low phase noise, guaranteed by design and characterization, although not specified by Anzac. [...] Having a low noise figure is necessary but not sufficient to have good phase noise. Ah, I see. Is the AMC-123 or an equivalent still in production, or was homebrewing brought up as an option because it's not? -- Mark J. Blair, NF6X n...@nf6x.net Web page: http://www.nf6x.net/ GnuPG public key available from my web page. ___ 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] Phase noise measurement (was - no subject)
to drive a +17 dBm mixer, and then amplify the IF output with a low noise current amplifier like the Linear LT1028. You can easily homebrew low noise _voltage_ ? 73, Gerhard dk4xp ___ 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] Phase noise measurement (was - no subject)
Rick, thank you again for having pointed me to the AMC123 that were just available when you mentioned them. Part of the magic is the 10 dB gain and typical +23 dBm output. So, you don't saturate it with a 10811, which would be bad in terms of phase noise, and, on the other hand, if you overdrive it accidentally, there is no risk to damage the +23 dBm mixer (phase detector) in the 11848A test set. There are some other interesting Anzac models featuring the lossless feedback design, but this one fits best. I was lucky to find some Q-Bit anps (QBH-137 and 138) that are based on an almost identical patent but, with 12 to 15 dB, have more gain and maybe slightly higher PN. Anzac patent: 3,624,536 which is the original David E. Norton patent from 1971. Q-Bit patent: 4,042,667 from 1977 http://www.freepatentsonline.com/4042887.pdf To comment on the Mini Circuits amp, for my needs it has way too much gain and +5 dBm 1 dB compression makes it completely useless for PN measurement purposes. Adrian Rick Karlquist schrieb: It is good that you asked this FAQ. Basically, what is magic about the AMC-123 is that it has certifiably low phase noise, guaranteed by design and characterization, although not specified by Anzac. The other 99.9% of amplifiers that seem plausible, like this one, do not have the sophisticated negative feedback scheme of the AMC-123, and likely do NOT have good enough phase noise. In any event, we have zero information about the phase noise of this Mini-Circuits amplifier. Having a low noise figure is necessary but not sufficient to have good phase noise. Of course you could always get lucky. But then you have to also build an amplifier phase noise measurement system, which generally entails a line stretcher. Again, thank you for asking this question. It comes up often. Would anyone else like to suggest a known good low phase noise buffer amplifier? Maybe something from a Fred Walls paper? Rick Karlquist N6RK Mark J. Blair wrote: On Aug 20, 2010, at 11:17 AM, Rick Karlquist wrote: On the 10811 production line, they would use Anzac AMC-123 amplifiers How does this amplifier look for this application? http://minicircuits.com/pdfs/ZFL-500LN.pdf If I understand the specifications properly, the noise figure is better and it has higher reverse isolation and higher gain, but a lower output intercept point. -- Mark J. Blair, NF6Xn...@nf6x.net Web page: http://www.nf6x.net/ GnuPG public key available from my web page. ___ 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] Frequency counters
+1 on the 5315 / 5316A/B. 5316's come with HPIB. Both can be surprisingly cheap, and, they have no fan. Adrian Robert Atkinson schrieb: Hi Stephen, I assume from the callsign that you are in the UK. You could do worse than to buy a used HP 5316A for £75 from Stewart of Reading http://www.stewart-of-reading.co.uk/Frequency%20Counters.htm A quality compact universal counter with reciprical counting, external reference input and HPIB. I've no association with Stewarts apart from being a happy customer personally and for work for nearly 30 years! Regards, Robert G8RPI. --- On Fri, 20/8/10, Stephen Farthingsquir...@gmail.com wrote: From: Stephen Farthingsquir...@gmail.com Subject: [time-nuts] Frequency counters To: time-nuts@febo.com Date: Friday, 20 August, 2010, 18:35 Hi guys, I want to find a frequency counter that will read to 1 hz precision up to a minimum of 30 Mhz that I can clock using the output from my Efratom 101 Rb frequency standard. I am quite happy to make one if there is a suitable design out there. Any suggestions? 72/3 de Steve G0XAR ___ 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 frequency counters
Guys, My needs are pretty simple, i need to put the output frequency of my qrss beacons into a 100 hz sub band within my chosen band of operation - mostly 30 meters. The beacon puts out a morse id in the form of a 4 Hz square wave with a dot length of 3 secs or more. With a calibrated frequency counter accurate to 1 Hz this is a breeze. So a simple eyeball check is ok...though a simple logging capability would be handy so I can see how the output frequency varies with temperature. I am pretty sure I can do it all with a simple microcontroller and an LCD display plus a prescaler. Time to break out the Arduino..and cut some code... FWIW QRSS is a weak signal mode, it is possible for signals 100 mW to be received globally. My beacon uses a mere 3 transistors and a crystal plus a handful of passive components. It puts out 100 mW. 72/3 de Steve g0xar -- It is vain to do with more that which can be done with less. ___ 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] Phase noise measurement (was - no subject)
dk...@arcor.de wrote: to drive a +17 dBm mixer, and then amplify the IF output with a low noise current amplifier like the Linear LT1028. You can easily homebrew low noise _voltage_ ? 73, Gerhard dk4xp Oh yes, low noise voltage. The noise current of the LT1028 is actually quite high, but that's OK because the source impedance is low. Rick N6RK ___ 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] Phase noise measurement (was - no subject)
Mark J. Blair wrote: On Aug 20, 2010, at 2:19 PM, Rick Karlquist wrote: It is good that you asked this FAQ. Basically, what is magic about the AMC-123 is that it has certifiably low phase noise, guaranteed by design and characterization, although not specified by Anzac. [...] Having a low noise figure is necessary but not sufficient to have good phase noise. Ah, I see. Is the AMC-123 or an equivalent still in production, or was homebrewing brought up as an option because it's not? -- Mark J. Blair, NF6X n...@nf6x.net Web page: http://www.nf6x.net/ GnuPG public key available from my web page. It might still be available through Tyco/MAcom. They have continued to make selected Anzac components. There was also an AM-123, which was a TO-something can version. Rick N6RK ___ 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] Phase noise measurement (was - no subject)
Would anyone else like to suggest a known good low phase noise buffer amplifier? Maybe something from a Fred Walls paper? You can always build HF isolation amps by rigging MMICs and attenuators together, but this will not reliably get you below -160 dBc/Hz. Bruce G. has given some good advice in this regard, with some circuit designs at http://www.ko4bb.com/~bruce/IsolationAmplifiers.html and elsewhere. I'm a fan of this version (also from Bruce): http://www.ke5fx.com/norton.htm This one has the advantage of simplicity. No weird parts, nothing that is likely to be out of production or hard to find, and dirt cheap. I've measured the broadband floor at near -170 dBc/Hz at 10 MHz, and its noise contribution at 100 Hz is below what the 3048A can see. These figures are adequate to measure any 10811-class OCXOs. A practical PN measurement system for 10811-class oscillators can be made by building two of those amplifiers and using them to drive pretty much any random double-balanced mixer found on eBay with +10 dBm LO specs or more. Both ports should be driven strongly to reject AM artifacts and avoid degrading the excellent noise floor offered by the amps. I'd hit the LO port with +10 to +12 dBm and the RF port with at least 0 dBm. Then, see the Wenzel app note here ( http://www.wenzel.com/documents/measuringphasenoise.htm ) to lock the two oscillators in quadrature and amplify the resulting baseband output. Any of several sound-card FFT programs can be used to generate an output graph, although if you want absolute calibration in dBc/Hz you need to be prepared to sweep the actual test setup from mixer output to FFT input to watch for various sources of flatness error. A combination of an AD7760-EVAL board and a Digilent Nexys2 can be used to construct an excellent baseband digitizer for the DC-1 MHz spectrum, but most of the time a good-quality 192-kHz sound card is fine for this sort of work. Most good crystal oscillators reach their broadband floor by 10 kHz, so there's no real need to go out to 1 MHz or more. -- john, KE5FX ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Phase noise measurement (was - no subject)
you have the following options: - HP (Agilent) E5052A/B or RS FSUP Signal Source Analyzer (works for a single DUT, though limited to 1 Hz offset, normally useful for 10 Hz up to 40 MHz). - Compare two identical DUT's with a HP 3048A or similar PN test system and subtract 3 dB, assuming that the PN characteristic of both DUT's is identical. - Compare 3 similar DUT's with a HP 3048A and calculate the individual PN using the three cornerd hat method. - set up a cross correlation PN measurement system similar to the E5052A and have fun. You will however need two - as good as possible, but preferaby not more than 10 dB worse than what you want to measure - VCXO's like HP 10811A's... - you may build your own HP 3048A alike system, but be prepared to invest serious money and time, and much more time than you thought in the beginning... (if that is what you're after, you'll have the most fun you can). - find someone who has one of the above and talk him into measuring yours. Also, it looks like you (Mark) are only about an hour from Cerritos, where the MUD ( http://www.microwaveupdate.org ) conference will be held at the end of October. This could be one option for you. As part of the $35 registration cost, you get access to a test lab set up to help attendees measure noise figure, PN, etc. on any homebrew or commercial gear they wish to bring. Microwave communication nuts are especially concerned with reference-oscillator PN because they end up multiplying it by 1000x or more. Last year Agilent provided an E5052B, and I imagine they will this year, too. If not I'll probably bring my prototype cross-correlation analyzer, so one way or another you would be able to get some PN readings at the conference. -- john, KE5FX ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
