Re: [time-nuts] GPS with 10KHz output
albertson.ch...@gmail.com said: If you ned the 10KHz, Jupiter is one that has been used. I think a 10KHz GPS will make your GPSDO converge quickly ... Does the 10KHz signal change smoothly or does it jump to a new value once per second? Has anybody looked at the fine print? What sort of ADEV is there on the 10 KHz signal? -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS with 10KHz output
Hal Murray wrote: albertson.ch...@gmail.com said: If you ned the 10KHz, Jupiter is one that has been used. I think a 10KHz GPS will make your GPSDO converge quickly ... Does the 10KHz signal change smoothly or does it jump to a new value once per second? Has anybody looked at the fine print? What sort of ADEV is there on the 10 KHz signal? It jumps. We discussed this several months/years ago. Bruce ___ 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 with 10KHz output
On 9/19/2013 5:33 AM, Chris Albertson wrote: But 10KHz does allow a simpler design for the GPSDO that can be done 100% analog A very simple, full analog, GPSDO that exploits the 10 kHz from a Jupiter GPS receiver can be found here : http://gpsdo.i2phd.com/ 73 Alberto I2PHD ___ 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 with 10KHz output
Hi It's not the best thing to use. Since the 10 KHz jumps once a second, it's not really very useful. The GPS it's self is not as well optimized for timing applications as a UT or a LEA-(any number) T. At auction prices, the GPS isn't going to be the major cost item in your GPSDO. Better to get a good one. Bob On Sep 18, 2013, at 10:21 PM, Bill Reed br...@otelco.net wrote: Hi, Does anyone know the suitability of this module for GPSDO ? I am new to the group. Thanks, Bill R http://www.ebay.com/itm/Navman-jupiter-T-Tu60-GPS-Kit-1pps-10khz-GPS-Module-/260790984470?pt=US_Ham_Radio_Amplifiershash=item3cb85a9f16 ___ 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] New NTBW50AA
HI What can be said with reasonable confidence: 1) The unit isn't broken and it does not need to go back to RDR under their 30 day return policy. 2) The OCXO isn't broken and it does not need to be replaced. 3) The unit is functioning ok, but probably not as good as it could. 4) Without comparison to an independent standard, there's no way to know how well it is or isn't doing. Bob On Sep 18, 2013, at 10:44 PM, Charles Steinmetz csteinm...@yandex.com wrote: Dave wrote: You didn't say, but I get the feeling maybe I should be getting smaller ppt numbers? When you say noisy, is high ppt generally a result of excess noise (front end NF)? Hard to say about the ppt numbers -- my TBolts give somewhat lower numbers than you are getting, but they use different OCXOs with different phaselocking circuitry, so I can't say what would be considered normal for the model you have. Also, as several have said already, the GPSDO is measuring itself with itself (no independent reference), so its proclamations need to be taken with more than some caution. Excess noise on the GPS signals (from whatever cause) causes timing errors in the GPS, which makes the GPS think the oscillator needs correction, which leads to DAC adjustments that aren't necessary. But if you are seeing at least some numbers in the 50 dBc and higer range, there is nothing further you can do in this regard. (Well, if the model you have supports it, you can set a signal level mask that will exclude satellites with signals below a dBc threshold of your choice. As with the elevation mask, if you get too aggressive you may force the unit into holdover when there are a few OK but not great signals.) As we all have said repeatedly, you need a good, accurate survey. Also, it is the nature of crystal oscillators that when they are disturbed (turned off and back on, frequency adjusted, handling/moving, fast temperature changes, etc., etc.) that they take time to settle back down -- often months. Now that you have a permanent antenna location, do a precision survey, SAVE IT, then let the unit sit undisturbed for several months and see where you are. You are certainly in the ballpark -- there are clearly no gross problems. Bob presumably knows more than I do about non-TBolt Trimbles (since I know nothing about them). If he says you can't adjust the TC and gain I'd be inclined to believe him. (And if you can't adjust the gain, there is no point in measuring the EFC characteristics of the OCXO, except for curiosity.) The antenna is a Lucent PCTEL GPS-TMG-HR-26N, High Rejection 26dB With Enhanced Narrow Band Filtering, apparently for high RF environments, only one I've got or tried You may have read on another thread about narrow bandpass filters tending to have rising group delay at the passband edges. An antenna with Enhanced Narrow Band Filtering very likely has more group delay error than one with more gentle filtering, so it is possible that satellites with high doppler shifts are causing the GPS timing solution to shift around more than it would with a different antenna. The one you have is presumably good enough for cell timing, since that is what it was designed for. The question is whether the lower group delay of an antenna without Enhanced Narrow Band Filtering would be enough better that you could tell. Without measuring the filters, we can't really predict what to expect. You might ask the seller if he would exchange your antenna for one that doesn't have the extra filtering. You almost certainly don't need it in your rural location, and an antenna without it would at least not be any worse, all else equal. Best regards, Charles ___ 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 with 10KHz output
Bob, please have a look to the flwng link. about the stability.. http://www.jrmiller.demon.co.uk/projects/ministd/stab.htm Rgds Ernie. -Original Message- From: Bob Camp li...@rtty.us To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thu, Sep 19, 2013 1:21 pm Subject: Re: [time-nuts] GPS with 10KHz output Hi It's not the best thing to use. Since the 10 KHz jumps once a second, it's not eally very useful. The GPS it's self is not as well optimized for timing pplications as a UT or a LEA-(any number) T. At auction prices, the GPS isn't oing to be the major cost item in your GPSDO. Better to get a good one. Bob On Sep 18, 2013, at 10:21 PM, Bill Reed br...@otelco.net wrote: Hi, Does anyone know the suitability of this module for GPSDO ? I am new to the group. Thanks, Bill R http://www.ebay.com/itm/Navman-jupiter-T-Tu60-GPS-Kit-1pps-10khz-GPS-Module-/260790984470?pt=US_Ham_Radio_Amplifiershash=item3cb85a9f16 ___ 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. ___ 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] New NTBW50AA
Thanks Bob, Charles, Well, here's my plan. Get a single piece of RG-11 direct burial. Get a more stable post for the antenna and perhaps a bit taller. Keep my eye out for a different antenna, right now they seem to be going for $50 and up for the 26 dB versions, I could contact RDR, but I didn't see anything on his site about other antennas. Yes, this is no high RF area except when maybe I turn on the 170 W 2M brick and that's nothing, I saw that thread about filters in the antenna. Finish this 48 hour survey and get these other things done and then do a 72 hour survey. Let it run for months and see where we are. Get a smaller switching type power supply. I figured nothing was broken or not working right. Bob, are you saying playing with the masks TC, gain and other stuff in LH does nothing to the NTBW50AA? It just affects how LH looks on my computer screen and I'm really not changing anything of how the Nortel works? Thanks, Dave - Original Message - From: Bob Camp To: Discussion of precise time and frequency measurement Sent: Thursday, September 19, 2013 7:23 AM Subject: Re: [time-nuts] New NTBW50AA HI What can be said with reasonable confidence: 1) The unit isn't broken and it does not need to go back to RDR under their 30 day return policy. 2) The OCXO isn't broken and it does not need to be replaced. 3) The unit is functioning ok, but probably not as good as it could. 4) Without comparison to an independent standard, there's no way to know how well it is or isn't doing. Bob ___ 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] Doppler and FMT
I was playing with SpecLab and my TS-2000 just to see how accurately I could measure frequencies in the HF region. I notice when I set the rx on cw and listen to the 750 Hz output of WWV at 15 or 20 MHz with SL, I get like 2 and sometimes more tracks about 2 Hz apart constantly shifting around. I assume this is Doppler going in and out? If that's so, how can anyone reasonably expect to measure any ionospheric HF signal in the mHz range? Dave N3DT ___ 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] Doppler and FMT
I knew it was not that easy. I didn't think about WWVB, and yes, I hear them quite often on 20. So it's just a matter of averaging what you can measure and assuming that the average will be close? I can imagine the shift can be all one way or the other for extended periods and how would anyone know which way? I'll have to check another signal that I know is not a double and see what I see. With SpecLab, it's easy to see mHz, but it's constantly changing so I guess one needs to log the data and use the spreadsheet to average it and hope it's close. The other thing is the 2000 wanders around especially when the fan goes on, so I've got a circuit to lock the MO to a GPS. XRef-VS, there are others for other radios too. We'll see what happens when I get the XRef installed and working. When I saw the WWV/B? signals I figured it was just how lucky you were. If I'm seeing 2 Hz spread how can anything be measured with precision? You can get close to anything once, it's doing it all the time that counts. Dave N3DT - Original Message - From: Dan Rae To: Discussion of precise time and frequency measurement Sent: Thursday, September 19, 2013 10:07 AM Subject: Re: [time-nuts] Doppler and FMT On 9/19/2013 6:48 AM, quartz55 wrote: I was playing with SpecLab and my TS-2000 just to see how accurately I could measure frequencies in the HF region. I notice when I set the rx on cw and listen to the 750 Hz output of WWV at 15 or 20 MHz with SL, I get like 2 and sometimes more tracks about 2 Hz apart constantly shifting around. I assume this is Doppler going in and out? If that's so, how can anyone reasonably expect to measure any ionospheric HF signal in the mHz range? Dave, it's not that easy. I did the ARRL FMTs a few years back when they were transmitting from the other side of the States and thought I was doing well to get within 0.1 Hz. The phase shifts on 7 and 14 MHz I was seeing due to Doppler were up to 360 degrees, and quite rapid. Mind you I was using non computer techniques [1], so averaging by eyeball was possible. Also if you are using WWV / WWVH, here at least, you often get both signals at similar strength, so you might well be seeing two different offsets. Dan ac6ao [1] looking at the 100 kHz IF output of the receiver on a scope, both scope trigger and Rx reference driven by homebrew GPS unit. ___ 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. - No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1432 / Virus Database: 3222/6180 - Release Date: 09/19/13 ___ 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] Doppler and FMT
On 9/19/2013 6:48 AM, quartz55 wrote: I was playing with SpecLab and my TS-2000 just to see how accurately I could measure frequencies in the HF region. I notice when I set the rx on cw and listen to the 750 Hz output of WWV at 15 or 20 MHz with SL, I get like 2 and sometimes more tracks about 2 Hz apart constantly shifting around. I assume this is Doppler going in and out? If that's so, how can anyone reasonably expect to measure any ionospheric HF signal in the mHz range? Dave, it's not that easy. I did the ARRL FMTs a few years back when they were transmitting from the other side of the States and thought I was doing well to get within 0.1 Hz. The phase shifts on 7 and 14 MHz I was seeing due to Doppler were up to 360 degrees, and quite rapid. Mind you I was using non computer techniques [1], so averaging by eyeball was possible. Also if you are using WWV / WWVH, here at least, you often get both signals at similar strength, so you might well be seeing two different offsets. Dan ac6ao [1] looking at the 100 kHz IF output of the receiver on a scope, both scope trigger and Rx reference driven by homebrew GPS unit. ___ 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 Thunderbolt 10 MHZ GPSDO units
We are building a VHF radio system that we intend to be simulcast when completed; we need 2 or 3 more of the (used to be!) low cost used Thunderbolt GPSDO units to get our sites on the same frequency using this as a standard. We already have the Larsen antennas ready; now just hunting like 3 more of the Thunderbolt receivers; anyone got some to sell? Call me! Robert L. Bob Burchett WB6SLC 22826 Mariposa Ave. Torrance CA 90502 Direct line: 310.534.4456 Website: www.EEonTheWeb.com QCWA ARRL RCA ___ 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] Doppler and FMT
You shouldn't be seeing a 2Hz spread. It can happen but in my experience that is big. Check gain control and make sure you aren't seeing artifacts. There is an fmt-nuts on yahoo which may be more appropriate for this. Doc Sent from mobile On Sep 19, 2013, at 10:32 AM, quartz55 quart...@hughes.net wrote: I knew it was not that easy. I didn't think about WWVB, and yes, I hear them quite often on 20. So it's just a matter of averaging what you can measure and assuming that the average will be close? I can imagine the shift can be all one way or the other for extended periods and how would anyone know which way? I'll have to check another signal that I know is not a double and see what I see. With SpecLab, it's easy to see mHz, but it's constantly changing so I guess one needs to log the data and use the spreadsheet to average it and hope it's close. The other thing is the 2000 wanders around especially when the fan goes on, so I've got a circuit to lock the MO to a GPS. XRef-VS, there are others for other radios too. We'll see what happens when I get the XRef installed and working. When I saw the WWV/B? signals I figured it was just how lucky you were. If I'm seeing 2 Hz spread how can anything be measured with precision? You can get close to anything once, it's doing it all the time that counts. Dave N3DT - Original Message - From: Dan Rae To: Discussion of precise time and frequency measurement Sent: Thursday, September 19, 2013 10:07 AM Subject: Re: [time-nuts] Doppler and FMT On 9/19/2013 6:48 AM, quartz55 wrote: I was playing with SpecLab and my TS-2000 just to see how accurately I could measure frequencies in the HF region. I notice when I set the rx on cw and listen to the 750 Hz output of WWV at 15 or 20 MHz with SL, I get like 2 and sometimes more tracks about 2 Hz apart constantly shifting around. I assume this is Doppler going in and out? If that's so, how can anyone reasonably expect to measure any ionospheric HF signal in the mHz range? Dave, it's not that easy. I did the ARRL FMTs a few years back when they were transmitting from the other side of the States and thought I was doing well to get within 0.1 Hz. The phase shifts on 7 and 14 MHz I was seeing due to Doppler were up to 360 degrees, and quite rapid. Mind you I was using non computer techniques [1], so averaging by eyeball was possible. Also if you are using WWV / WWVH, here at least, you often get both signals at similar strength, so you might well be seeing two different offsets. Dan ac6ao [1] looking at the 100 kHz IF output of the receiver on a scope, both scope trigger and Rx reference driven by homebrew GPS unit. ___ 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. - No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1432 / Virus Database: 3222/6180 - Release Date: 09/19/13 ___ 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] Varian 921-0062 ion pump supply question
Hi, I'm working on a Varian 921-0062 ion pump controller for the pumps used in a Maser. I just got it in and it is wired for 240 VAC and I want 120VAC. My manual and the ones I can find on line show a power TX with 4 input terminals which they show how to strap for 240 or 120 VAC. My unit has TX has 6 terminals 1/2/3/4/8/9. Does anyone know how to wire this TX for 120 VAC? Thanks, Corby Dawson ___ 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] Varian 921-0062 ion pump supply question
Hi Corby, How's it wired now? Basically it should be two windings in series, say line to 1, 2 linked to 3 and neutral to 4. To set to 120V leave line and neutral were they are and link 2 to 4 and 3 to 1. As a double check for phasing when you lift the link between 2 and 3 check for winding resistance between 1 and 2 and separately 3 and 4. They should benear identical resistance values. Change tag numbers to suit your original wiring. HTH, Robert G8RPI. From: cdel...@juno.com cdel...@juno.com To: time-nuts@febo.com Sent: Thursday, 19 September 2013, 20:43 Subject: [time-nuts] Varian 921-0062 ion pump supply question Hi, I'm working on a Varian 921-0062 ion pump controller for the pumps used in a Maser. I just got it in and it is wired for 240 VAC and I want 120VAC. My manual and the ones I can find on line show a power TX with 4 input terminals which they show how to strap for 240 or 120 VAC. My unit has TX has 6 terminals 1/2/3/4/8/9. Does anyone know how to wire this TX for 120 VAC? Thanks, Corby Dawson ___ 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] picosecond baking
So, Magnus, what does a baked picosecond taste like? How many to make a mouthful? Just an attempt to raise the humor level on this list :) Bill Hawkins -Original Message- From: Magnus Danielson Sent: Thursday, September 19, 2013 3:14 PM Fellow time-nuts, Every once in a while, you find that a felliow time-nut is in town. That's when food and beer is supplemented with optimal baking methods and picosecond precision timing and well, fun. I do hope Joe and his wife found their way back in the dark yesterday :) Just wanted to share some of the social aspects of this list :) Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] picosecond baking
Fellow time-nuts, Every once in a while, you find that a felliow time-nut is in town. That's when food and beer is supplemented with optimal baking methods and picosecond precision timing and well, fun. I do hope Joe and his wife found their way back in the dark yesterday :) Just wanted to share some of the social aspects of this list :) Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Does any one have a manual on RS Cesium Frequency standard XSC
Just got a XSC and a spare module, works great but would like to get a manual/ Any help will be appreciated. Thanks 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] Varian 921-0062 ion pump supply question
Try a Google search on it, you will find the manual. 73, Dick, W1KSZ On 9/19/2013 12:43 PM, cdel...@juno.com wrote: Varian 921-0062 ion pump controlle ___ 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 with 10KHz output
Hi, I may have missed something back then, but I don't recall any description of exactly how it was generated - more a discussion of what the manuals/datasheets meant. Angus From: Bruce Griffiths To: Discussion of precise time and frequency measurement Sent: September 19, 2013 8:22 AM Subject: Re: [time-nuts] GPS with 10KHz output Hal Murray wrote: albertson.ch...@gmail.com said: If you ned the 10KHz, Jupiter is one that has been used. I think a 10KHz GPS will make your GPSDO converge quickly ... Does the 10KHz signal change smoothly or does it jump to a new value once per second? Has anybody looked at the fine print? What sort of ADEV is there on the 10 KHz signal? It jumps. We discussed this several months/years ago. Bruce ___ 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] New NTBW50AA
Hi With a Trimble TBolt, when you do an auto-cal it comes up with a sensitivity of the OCXO, and modifies the filter (as in the PID control loop filter) coefficients. You can then save them to the eeprom / flash in the TBolt. The settings persist across multiple reboots. The settings do impact the way the TBolt functions. This allows you to use OCXO's with different sensitivities (and even control polarity) in the TBolt. In the Trimble NTBW50 (and Trimble made clones) you can run the auto cal via LH. The sensitivity is calculated and may appear to change. The settings can not be saved in flash / eeprom. They do not persist across multiple reboots. There is no evidence that the NTBW50 actually uses the changed settings. Switching elevation masks, changing AMU limits, works with both units. These changes do save to flash / eeprom on both units. They persist across multiple reboots on both. The do impact the way both units function. - My guess is that the antenna you have is virtually identical to the Lucent 26 db gain device. I doubt that the cost of getting one is worth the money. If you want a better antenna, go for one of the $300 - $500 choke ring antennas. You will also need a bias Tee (they mostly run on 12 volts), but it's often included. Enjoy! Bob On Sep 19, 2013, at 9:40 AM, quartz55 quart...@hughes.net wrote: Thanks Bob, Charles, Well, here's my plan. Get a single piece of RG-11 direct burial. Get a more stable post for the antenna and perhaps a bit taller. Keep my eye out for a different antenna, right now they seem to be going for $50 and up for the 26 dB versions, I could contact RDR, but I didn't see anything on his site about other antennas. Yes, this is no high RF area except when maybe I turn on the 170 W 2M brick and that's nothing, I saw that thread about filters in the antenna. Finish this 48 hour survey and get these other things done and then do a 72 hour survey. Let it run for months and see where we are. Get a smaller switching type power supply. I figured nothing was broken or not working right. Bob, are you saying playing with the masks TC, gain and other stuff in LH does nothing to the NTBW50AA? It just affects how LH looks on my computer screen and I'm really not changing anything of how the Nortel works? Thanks, Dave - Original Message - From: Bob Camp To: Discussion of precise time and frequency measurement Sent: Thursday, September 19, 2013 7:23 AM Subject: Re: [time-nuts] New NTBW50AA HI What can be said with reasonable confidence: 1) The unit isn't broken and it does not need to go back to RDR under their 30 day return policy. 2) The OCXO isn't broken and it does not need to be replaced. 3) The unit is functioning ok, but probably not as good as it could. 4) Without comparison to an independent standard, there's no way to know how well it is or isn't doing. Bob ___ 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] Varian 921-0062 ion pump supply question
Here is the deal. The 4 terminal TX wiring is pretty obvious. (I have a unit with the 4 terminal to compare with) The 6 terminal I have ohmed out and it is not obvious! Pins 1 to 3 and 2 to 4 (.5 Ohms) appear to be the 120VAC windings and hooking them in parallel should do the trick. As wired for 240 VAC 1 to 3 and 2 to 4 are in series which makes sense. However when the 4 terminal is wired for 240VAC a wire comes off the input center tap to provide 120VAC to some circuits in the unit. The 6 terminal when wired for 240VAC has an extra wire connected to pin 8. Pin 8 to 1 and pin 9 to 2 show .2 Ohms so they look like maybe taps for a different input voltage slightly different from 120VAC. The problem there is that the wire to pin 8 which would logically go to the center tap as above goes to this pin 8 tap which makes no sense! Of course it could have been miswired when I got it! All the manuals I can find by Goggling show the 4 pin TX! Was hoping someone might have a unit with the 6 pin TX wired for 120VAC so they could advise me! Thanks, Corby ___ 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 with 10KHz output
Hi Based on the plot shown, the GPS is doing about 2x10^-12 at 1,000 seconds. That translates to roughly 2 ns at one second. The newer timing receivers can get down to about 4 to 5X better than that. Bob On Sep 19, 2013, at 8:02 AM, Erno Peres erniepe...@aol.com wrote: Bob, please have a look to the flwng link. about the stability.. http://www.jrmiller.demon.co.uk/projects/ministd/stab.htm Rgds Ernie. -Original Message- From: Bob Camp li...@rtty.us To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thu, Sep 19, 2013 1:21 pm Subject: Re: [time-nuts] GPS with 10KHz output Hi It's not the best thing to use. Since the 10 KHz jumps once a second, it's not eally very useful. The GPS it's self is not as well optimized for timing pplications as a UT or a LEA-(any number) T. At auction prices, the GPS isn't oing to be the major cost item in your GPSDO. Better to get a good one. Bob On Sep 18, 2013, at 10:21 PM, Bill Reed br...@otelco.net wrote: Hi, Does anyone know the suitability of this module for GPSDO ? I am new to the group. Thanks, Bill R http://www.ebay.com/itm/Navman-jupiter-T-Tu60-GPS-Kit-1pps-10khz-GPS-Module-/260790984470?pt=US_Ham_Radio_Amplifiershash=item3cb85a9f16 ___ 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. ___ 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 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] Doppler and FMT
Hi Remember - there's more than one station on 5, 10, 15 and 20 MHz. You may be picking up the modulation from one of them. Ionospheric shift can easily give you a few Hz on HF. Back when I was doing FMT stuff there was no ionosphere involved. I was within ground wave of Newington …. Bob On Sep 19, 2013, at 9:48 AM, quartz55 quart...@hughes.net wrote: I was playing with SpecLab and my TS-2000 just to see how accurately I could measure frequencies in the HF region. I notice when I set the rx on cw and listen to the 750 Hz output of WWV at 15 or 20 MHz with SL, I get like 2 and sometimes more tracks about 2 Hz apart constantly shifting around. I assume this is Doppler going in and out? If that's so, how can anyone reasonably expect to measure any ionospheric HF signal in the mHz range? Dave N3DT ___ 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] Doppler and FMT
So it's just a matter of averaging what you can measure and assuming that the average will be close? Two quick comments. 1) A gradual phase drift over time is identical (by definition) to a frequency offset. 2) In general, averaging a moving target gets you *less* accuracy, not more. We learned in school that averaging enhances accuracy. This is true in textbook cases where the mean is constant and where the distribution of error about the mean is symmetrical. But when working with clocks (time, frequency, stability measurements) this assumption often not true and it's helpful to think of averaging more as a disease than a cure. /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] Doppler and FMT
Hi As with most complex questions the real answer is that depends … Blind averaging will indeed get you in trouble. Curve fitting (a straight line is a simple one) often is the better approach to phase data. You can get an averaging like improvement (square root of the number of samples). You need to use a technique that fits the data and the noise you have on the data. Bob On Sep 19, 2013, at 8:17 PM, Tom Van Baak t...@leapsecond.com wrote: So it's just a matter of averaging what you can measure and assuming that the average will be close? Two quick comments. 1) A gradual phase drift over time is identical (by definition) to a frequency offset. 2) In general, averaging a moving target gets you *less* accuracy, not more. We learned in school that averaging enhances accuracy. This is true in textbook cases where the mean is constant and where the distribution of error about the mean is symmetrical. But when working with clocks (time, frequency, stability measurements) this assumption often not true and it's helpful to think of averaging more as a disease than a cure. /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] GPS with 10KHz output
Hi Bill, I have a number of these modules purchased from the particular eBay source you gave a link for. They work well but I never found a way to keep their data output as NMEA as they seem to revert to Binary on power down. However if it is just the 10KHz output you want from them or their Binary data stream they should be fine in my humble opinion. I have a small batch file that commands them into NMEA once powered up but nothing to save this setting. Merv VK6BMT ___ 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 with 10KHz output
Hi Merv, Thanks. I will try one. This is a great group! Bill -Original Message- From: Merv Thomas Sent: Thursday, September 19, 2013 9:01 PM To: time-nuts@febo.com Subject: Re: [time-nuts] GPS with 10KHz output Hi Bill, I have a number of these modules purchased from the particular eBay source you gave a link for. They work well but I never found a way to keep their data output as NMEA as they seem to revert to Binary on power down. However if it is just the 10KHz output you want from them or their Binary data stream they should be fine in my humble opinion. I have a small batch file that commands them into NMEA once powered up but nothing to save this setting. Merv VK6BMT ___ 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] New NTBW50AA
In the Trimble NTBW50 (and Trimble made clones) you can run the auto cal via LH. The sensitivity is calculated and may appear to change. The settings can not be saved in flash / eeprom. They do not persist across multiple reboots. There is no evidence that the NTBW50 actually uses the changed settings. Switching elevation masks, changing AMU limits, works with both units. These changes do save to flash / eeprom on both units. They persist across multiple reboots on both. The do impact the way both units function. Bob, I suppose you came across this by experimentation, not by any instruction booklet? I guess we're on our own here with the Nortel units. How about Mark's (I think) suggestion to set the EL mask to a low value (F E 0), clear the signal data (S A C) let the unit run for a day or so, then do the osc autotune (A). This will set the elevation mask to a level that matches what your antenna can see. Or you can check the elevation plot (S A E) and see where the tick mark shows the signal level dropping off and enter that value manually. My guess is that the antenna you have is virtually identical to the Lucent 26 db gain device. I doubt that the cost of getting one is worth the money. If you want a better antenna, go for one of the $300 - $500 choke ring antennas. You will also need a bias Tee (they mostly run on 12 volts), but it's often included. Well, that's not going to happen, the $3-500 anyhow. I was also thinking about the filter, aren't all the L1 sats on the same freq, so there shouldn't be any phase difference with respect to the sats, but I may be way off base here. I found a nice 15' locust log today that's about 6-8 dia. that I can strap to one of the fence posts and get rid of the 3/4 EMT. Wife likes it too because it looks 'rustic'. Cool. Thanks, Dave ___ 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] Doppler and FMT
But when working with clocks (time, frequency, stability measurements) this assumption often not true and it's helpful to think of averaging more as a disease than a cure. /tvb I can understand that. Dave ___ 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] picosecond baking
Mmmm femtoseconds ... And if you manage to eat just a half you can travel in time! -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Bill Hawkins Sent: Friday, 20 September 2013 7:32 AM To: 'Discussion of precise time and frequency measurement' Subject: Re: [time-nuts] picosecond baking So, Magnus, what does a baked picosecond taste like? How many to make a mouthful? Just an attempt to raise the humor level on this list :) Bill Hawkins -Original Message- From: Magnus Danielson Sent: Thursday, September 19, 2013 3:14 PM Fellow time-nuts, Every once in a while, you find that a felliow time-nut is in town. That's when food and beer is supplemented with optimal baking methods and picosecond precision timing and well, fun. I do hope Joe and his wife found their way back in the dark yesterday :) Just wanted to share some of the social aspects of this list :) Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts 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] JL LC_XO Performance
Hello All, I just spoke with JL - I should have one of the Jackson Labs' LC_XO's in my hands soon (TCXO option) - I was wondering if any of you have had a chance to look at it - and what your opinion is of the unit? If you have taken any detailed measurements you would like to share - that will be appreciated too. Also - if you have also taken a look at their GPSTCXO (TXCO option too) - how does it compare? Thanks In Advance, John Westmoreland ___ 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.
