Re: [time-nuts] OCXO sensitive to gravitational effects
Perhaps not the van that went to the crusher, but the returns from shipping accidents. I once had a 100 pound item shipped to me in a light cardboard box for paper towels, filled with peanuts. The carton was ripped, the peanuts were gone, and a large corner of the chassis looked like it had been mashed by a heavier box. Wasn't replaceable. Ya gotta love eBay - anybody can participate. Bill Hawkins -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Ed Palmer Sent: Friday, September 04, 2009 3:13 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] OCXO sensitive to gravitational effects Peter Putnam wrote: >You have all been a bit stingy with your gravitational inputs on the hp >18011 oscillator... one G this way... two Gs the other way... >Here you can see the result of some serious Gs, all applied at the same >time... >e*.* auction item:160360186935 >Add only $56.55 to your bid to ship the carcass. > Here's a matching generator to go with the counter. It might need a bit of a tuneup: 160349277602 "Some assembly required" :-) I wonder if they were both left in the van that was sent to the crusher. Ed ___ 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] HP 5372a error 160
Francesco Ledda wrote: It is easy to do. Indeed. I had this problem with my 5372A when I got it. Replacing the battery, doing the calibration procedure and it has been happy since. So, don't be afraid. :) 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] GPS Antenna Voltage-Dropping
Thanks to all for your comments and suggestions. In a private message James Miller advised that while constructing a splitter, he discovered tubular ceramic capacitors have significant self-inductance at 1.5 GHz. Then Warren ’s suggestion that the VSWR meter (PRD 2919) might not like unbiased diodes caused me to re-measure the adapter with a bias-T and forward bias. The VSWR dropped to about 1.9. It appears the self-inductance of the capacitor is causing part of the RF current to flow through the diodes. With forward biased diodes, the capacitor may be unnecessary. The remaining VSWR is likely caused by the coaxial line impedance of the internal parts being other than 50 ohms. I will try the antenna with the adapter. If it fails to work, and the antenna can be readily opened, Bert’s suggestion of putting the diodes in there (past the bias-T) sounds good, as does the eBay lead for an inexpensive external bias-T. Bruce Hunter ___ 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] More Z3801/Tbolt comparisons
> -Original Message- > From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On > Behalf Of Stan, W1LE > Sent: Friday, September 04, 2009 10:27 AM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] More Z3801/Tbolt comparisons > > If I see the rack mounting ears on a piece of test equipment I assume > that it was rack mounted > and acoustically sheltered from the user. I assess my bid to include a > new fan, usually 30-50$. > > Yes, rack mounted test equipment was usually from a fixed location, and > has no "road rash". > > Stan, W1LE > I don't know about that. I've got a fair amount of "gear with ears" that looks beat up. Here at JPL, when you get something from the loan pool it may or may not have ears, and may or may not have been slid across the bench or floor a few times. At least you know that it probably works. ___ 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] More Z3801/Tbolt comparisons
If I see the rack mounting ears on a piece of test equipment I assume that it was rack mounted and acoustically sheltered from the user. I assess my bid to include a new fan, usually 30-50$. Yes, rack mounted test equipment was usually from a fixed location, and has no "road rash". Stan, W1LE Roy Phillips wrote: Nigel I must say that much of what you have stated is right, I have a 53131A counter and the basic time-base is a joke, but agreed, we mostly use a common external reference with our instruments. There are some exceptions, as I am finding with a very recently purchased HP 8657A Sig. Gen. that has the option 001 oven oscillator. This is a 1998 production (made in the US), the TCXO would seem to be a very stable device with coarse and fine adjustment - after running for 48 hours its holding 10 Mhz to ^10. In fact it would seem to be somewhat better than the TCXO in my Marconi 2024 Sig. Gen. - - hence my singing the praises of HP. The large number of Racal 199# on the UK market in recent times are I would suggest, ex UK military issue and as portable instruments have probably had a rough life, and have frequently been stored for ten years in somewhat poor environments. I would suggest that buying equipment that has come from a commercial origin, and has been part of a rack test set-up, have been better cared for and sometimes have had very little use. What do you others think about this theory ? Roy - Original Message - From: To: Sent: Friday, September 04, 2009 12:36 PM Subject: Re: [time-nuts] More Z3801/Tbolt comparisons In a message dated 04/09/2009 11:18:07 GMT Daylight Time, phill...@btinternet.com writes: Racal 19## Counters are something else - - I got rid of mine some years back, not only the ongoing problems with the key-pad, but I don't think they put much cost into the oven osc. Perhaps you should consider moving on to an HP or other quality counter, "you deserve it" -- Even the best counters can sometimes suffer from poor internal oscillators. The basic onboard oscillator in the HP53132A for example has no practical use whatsoever, other than to demonstrate that the counter is functional, but I suspect most, if not all, list members will generally be operating counters with external references anyway Whilst I wouldn't even consider swapping my 53132A for a 199x I must be a glutton for punishment as I've just bought another 1991 after also selling my previous one some time ago. Aside from the reported key pad problems, which haven't affected me so far, and the lesser resolution, it's a good solid workhorse and, something not to be sneezed at, this one in very good condition cost me at least 80% less than I'd expect to pay for a similar condition 53132A:-) Earlier 19xx counters also strike me as being underrated these days. Although it's lacking in resolution for most of my current needs I've still got a 1905 I bought new in the late 70s/early 80s and that has served me very well as a general purpose counter. I'd suggest that too as an excellent workhorse and more than adequate for such things as transmitter or receiver adjustment etc and, at the give-away prices the 1904 and 1905 often seem to fetch on Ebay, they can be quite a bargain. regards Nigel GM8PZR ___ 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] HP 5372a error 160
It is easy to do. -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on Behalf Of Norman J McSweyn Sent: Friday, September 04, 2009 8:53 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] HP 5372a error 160 Francesco, I saw in the troubleshooting section that a weak internal battery could be the cause. HA!!! Just found the procedure in the manual!! Looks deceptively easy. Thanks, Norm n3ykf Francesco Ledda wrote: > You need to replace the internal battery (3.6) and calibrate the inputs; the > procedure is simple. > > -Original Message- > From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on > Behalf Of Norman J McSweyn > Sent: Friday, September 04, 2009 8:16 AM > To: Discussion of precise time and frequency measurement > Subject: [time-nuts] HP 5372a error 160 > > > Hi all!! > Bid on and got an HP 5372a. Supposed to be tested, working. Powers up to > error 160 out of sensitivity calibration. Did download the svc man from > Agilent. Spent a few minutes looking through the manual. Not sure what > to make of it. > It's not obvious whether a complete cal needs to be done. > Questions, comments cheerfully received. > Will be on a boat trip for our holiday (US) from 10z Saturday until > Tuesday 10z or so. > Thanks, > Norm n3ykf > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] More Z3801/Tbolt comparisons
In a message dated 04/09/2009 16:32:09 GMT Daylight Time, phill...@btinternet.com writes: I must say that much of what you have stated is right, I have a 53131A counter and the basic time-base is a joke, but agreed, we mostly use a common external reference with our instruments. There are some exceptions, as I am finding with a very recently purchased HP 8657A Sig. Gen. that has the option 001 oven oscillator. This is a 1998 production (made in the US), the TCXO would seem to be a very stable device with coarse and fine adjustment - after running for 48 hours its holding 10 Mhz to ^10. In fact it would seem to be somewhat better than the TCXO in my Marconi 2024 Sig. Gen. - - hence my singing the praises of HP. - Hi Roy I suspect the 8657A option 001 is likely to be a 10811B, which also appears in quite a lot of other HP kit and is also the better of the options for the 53131A and 53132A. They are certainly very nice oscillators. -- The large number of Racal 199# on the UK market in recent times are I would suggest, ex UK military issue and as portable instruments have probably had a rough life, and have frequently been stored for ten years in somewhat poor environments. I would suggest that buying equipment that has come from a commercial origin, and has been part of a rack test set-up, have been better cared for and sometimes have had very little use. What do you others think about this theory ? You're quite right that the majority of 199x counters available in recent times are ex-mil but that doesn't always mean a hard life, although I agree there can be an element of risk involved when buying them. My first 1991, bought a few years ago, was ex-mil but had never been issued and was still new in its original box, having been taken out just once since original calibration to check it was still "serviceable". The one just bought is also ex-mil, this one has been used but looks to have been very well treated. It carries a label indicating the warranty ran out in 2001, so I assume it was manufactured in 2000, with last calibration expiring in April 2009. Although it's fitted with the manual pouch for portable use it doesn't show any signs that it's actually been used portable, the case and front and rear panels are unmarked, so I suspect it may have just seen bench use. There's no obvious problems with the front panel switches either, which is another good sign, although, of course, that could change tomorrow:-) It's very likely that there's a lot more of all sorts of test gear, on Ebay at least, that's ex-mil rather than ex-commercial so it's really quite difficult to avoid unless prepared to always buy from dealers who are able to guarantee previous ownership, and also prepared to pay their much higher prices. regards Nigel GM8PZR ___ 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] OCXO sensitive to gravitational effects
You should have seen the Tek CG5011 cal generator that I got from him (bought it for the optical encoder to repair another one). Half the ceramic ECL chips were decapitated... it's only a flesh wound... cleanup on 6, bring a scooper. _ Windows Live: Keep your friends up to date with what you do online. http://windowslive.com/Campaign/SocialNetworking?ocid=PID23285::T:WLMTAGL:ON:WL:en-US:SI_SB_online:082009 ___ 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] More Z3801/Tbolt comparisons
Nigel I must say that much of what you have stated is right, I have a 53131A counter and the basic time-base is a joke, but agreed, we mostly use a common external reference with our instruments. There are some exceptions, as I am finding with a very recently purchased HP 8657A Sig. Gen. that has the option 001 oven oscillator. This is a 1998 production (made in the US), the TCXO would seem to be a very stable device with coarse and fine adjustment - after running for 48 hours its holding 10 Mhz to ^10. In fact it would seem to be somewhat better than the TCXO in my Marconi 2024 Sig. Gen. - - hence my singing the praises of HP. The large number of Racal 199# on the UK market in recent times are I would suggest, ex UK military issue and as portable instruments have probably had a rough life, and have frequently been stored for ten years in somewhat poor environments. I would suggest that buying equipment that has come from a commercial origin, and has been part of a rack test set-up, have been better cared for and sometimes have had very little use. What do you others think about this theory ? Roy - Original Message - From: To: Sent: Friday, September 04, 2009 12:36 PM Subject: Re: [time-nuts] More Z3801/Tbolt comparisons In a message dated 04/09/2009 11:18:07 GMT Daylight Time, phill...@btinternet.com writes: Racal 19## Counters are something else - - I got rid of mine some years back, not only the ongoing problems with the key-pad, but I don't think they put much cost into the oven osc. Perhaps you should consider moving on to an HP or other quality counter, "you deserve it" -- Even the best counters can sometimes suffer from poor internal oscillators. The basic onboard oscillator in the HP53132A for example has no practical use whatsoever, other than to demonstrate that the counter is functional, but I suspect most, if not all, list members will generally be operating counters with external references anyway Whilst I wouldn't even consider swapping my 53132A for a 199x I must be a glutton for punishment as I've just bought another 1991 after also selling my previous one some time ago. Aside from the reported key pad problems, which haven't affected me so far, and the lesser resolution, it's a good solid workhorse and, something not to be sneezed at, this one in very good condition cost me at least 80% less than I'd expect to pay for a similar condition 53132A:-) Earlier 19xx counters also strike me as being underrated these days. Although it's lacking in resolution for most of my current needs I've still got a 1905 I bought new in the late 70s/early 80s and that has served me very well as a general purpose counter. I'd suggest that too as an excellent workhorse and more than adequate for such things as transmitter or receiver adjustment etc and, at the give-away prices the 1904 and 1905 often seem to fetch on Ebay, they can be quite a bargain. regards Nigel GM8PZR ___ 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] More Z3801/Tbolt comparisons
Yes, the sidereal day is definitely the proper interval to survey for. The technique that I am using analyzes the data over minute, hour, and 24 hour intervals. The Tbolt outputs data at one second intervals. There is not a good way to evenly divide those 236 seconds over those intervals, so I stick with the 24 hour day. The difference is not noticeable. If we are being this careful, I wonder if you should use a SIDEREAL day of averaging - 236 seconds short of a solar day ? _ Hotmail® is up to 70% faster. Now good news travels really fast. http://windowslive.com/online/hotmail?ocid=PID23391::T:WLMTAGL:ON:WL:en-US:WM_HYGN_faster:082009 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS Antenna Voltage-Dropping
Darren, this is a very nice find. I made an offer for two and got them for several dollars less, each, then their asking price. At that time I believe they had in excess of 250 available. Had K7MLR At 06:49 PM 9/3/2009, you wrote: Hi, the model of bias tee referenced below works well, with very low insertion loss, down towards 1GHz, despite the manufacturer's specifications: http://www.ohiomicrowave.com/things/hwe32biasteetranscept1000204C.pdf Item #270287524274 on a well known Internet auction site, lists the "Buy-It-Now" price as $19.95 for brand new units. If you are worried about return loss, I can provide plots for GPS frequencies. Performance really falls off below 500MHz, where the insertion losses approach 50dB! For the money, the build quality is superb. HTH Darren A fine is a tax for doing wrong. A tax is a fine for doing well. Peter Cooper, of Fermi Lab, says, "Every experimentalist knows that the apparatus, or at least your understanding of it, is always at fault until demonstrated otherwise." He also says, "Nature is really unmoved by what I, or anyone else, believes." ___ 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] HP 5372a error 160
Francesco, I saw in the troubleshooting section that a weak internal battery could be the cause. HA!!! Just found the procedure in the manual!! Looks deceptively easy. Thanks, Norm n3ykf Francesco Ledda wrote: You need to replace the internal battery (3.6) and calibrate the inputs; the procedure is simple. -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on Behalf Of Norman J McSweyn Sent: Friday, September 04, 2009 8:16 AM To: Discussion of precise time and frequency measurement Subject: [time-nuts] HP 5372a error 160 Hi all!! Bid on and got an HP 5372a. Supposed to be tested, working. Powers up to error 160 out of sensitivity calibration. Did download the svc man from Agilent. Spent a few minutes looking through the manual. Not sure what to make of it. It's not obvious whether a complete cal needs to be done. Questions, comments cheerfully received. Will be on a boat trip for our holiday (US) from 10z Saturday until Tuesday 10z or so. Thanks, Norm n3ykf ___ 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] OCXO sensitive to gravitational effects
More realistically, it's not that hard to simulate 2 G 9.8 = V^2/r or (2*pi)^2*r*rotation rate^2. Say you have an r of one meter (should fit conveniently in your garage)... 10/12 /1 = rotation rate^2... About 1 rev/second -> 60 rpm. 12 m/s tangential velocity. That would actually get you sqrt(5) = 2.23 G For comparison, airplane props have a tangential speed at the tip close to mach 1.. 300m/s, are about 1 meter radius, and turn at 2400 RPM. It's doing zero G that is a challenge.. A big drop tower works. On 9/3/09 10:30 PM, "Peter Putnam" wrote: You have all been a bit stingy with your gravitational inputs on the hp 18011 oscillator... one G this way... two Gs the other way... Here you can see the result of some serious Gs, all applied at the same time... e*.* auction item:160360186935 Add only $56.55 to your bid to ship the carcass. ___ 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] HP 5372a error 160
You need to replace the internal battery (3.6) and calibrate the inputs; the procedure is simple. -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on Behalf Of Norman J McSweyn Sent: Friday, September 04, 2009 8:16 AM To: Discussion of precise time and frequency measurement Subject: [time-nuts] HP 5372a error 160 Hi all!! Bid on and got an HP 5372a. Supposed to be tested, working. Powers up to error 160 out of sensitivity calibration. Did download the svc man from Agilent. Spent a few minutes looking through the manual. Not sure what to make of it. It's not obvious whether a complete cal needs to be done. Questions, comments cheerfully received. Will be on a boat trip for our holiday (US) from 10z Saturday until Tuesday 10z or so. Thanks, Norm n3ykf ___ 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] HP 5372a error 160
Hi all!! Bid on and got an HP 5372a. Supposed to be tested, working. Powers up to error 160 out of sensitivity calibration. Did download the svc man from Agilent. Spent a few minutes looking through the manual. Not sure what to make of it. It's not obvious whether a complete cal needs to be done. Questions, comments cheerfully received. Will be on a boat trip for our holiday (US) from 10z Saturday until Tuesday 10z or so. Thanks, Norm n3ykf ___ 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] More Z3801/Tbolt comparisons
Hi Mark, If we are being this careful, I wonder if you should use a SIDEREAL day of averaging - 236 seconds short of a solar day ? TTFN, Peter Vince (G8ZZR, London, England) On Thu Sep 3 19:40 , Mark Sims sent: >... > The next version of Lady Heather will have a very precise self-survey routine. > It takes data for 48 hours (which has 24 overlapping 24 hour intervals) and > statistically processes it to get a very precise location. Typically the > error > is around 1 foot lat/lon, 1 meter altitude (there he goes, mixing measurement > systems again). With good antennas in good locations it can get to under 4 > inches > of error. Poor antennas in bad locations might be 2 feet off. > ___ 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] OCXO sensitive to gravitational effects
Nah... That'll polish out OK!... Dave G0WBX. -- Message: 4 Date: Fri, 04 Sep 2009 02:13:27 -0600 From: Ed Palmer Subject: Re: [time-nuts] OCXO sensitive to gravitational effects To: Discussion of precise time and frequency measurement Message-ID: <4aa0cc27.8020...@sasktel.net> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Peter Putnam wrote: >You have all been a bit stingy with your gravitational inputs on the hp >18011 oscillator... one G this way... two Gs the other way... >Here you can see the result of some serious Gs, all applied at the same >time... >e*.* auction item:160360186935 >Add only $56.55 to your bid to ship the carcass. > Here's a matching generator to go with the counter. It might need a bit of a tuneup: 160349277602 "Some assembly required" :-) I wonder if they were both left in the van that was sent to the crusher. Ed ___ 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] More Z3801/Tbolt comparisons
In a message dated 04/09/2009 11:18:07 GMT Daylight Time, phill...@btinternet.com writes: Racal 19## Counters are something else - - I got rid of mine some years back, not only the ongoing problems with the key-pad, but I don't think they put much cost into the oven osc. Perhaps you should consider moving on to an HP or other quality counter, "you deserve it" -- Even the best counters can sometimes suffer from poor internal oscillators. The basic onboard oscillator in the HP53132A for example has no practical use whatsoever, other than to demonstrate that the counter is functional, but I suspect most, if not all, list members will generally be operating counters with external references anyway Whilst I wouldn't even consider swapping my 53132A for a 199x I must be a glutton for punishment as I've just bought another 1991 after also selling my previous one some time ago. Aside from the reported key pad problems, which haven't affected me so far, and the lesser resolution, it's a good solid workhorse and, something not to be sneezed at, this one in very good condition cost me at least 80% less than I'd expect to pay for a similar condition 53132A:-) Earlier 19xx counters also strike me as being underrated these days. Although it's lacking in resolution for most of my current needs I've still got a 1905 I bought new in the late 70s/early 80s and that has served me very well as a general purpose counter. I'd suggest that too as an excellent workhorse and more than adequate for such things as transmitter or receiver adjustment etc and, at the give-away prices the 1904 and 1905 often seem to fetch on Ebay, they can be quite a bargain. regards Nigel GM8PZR ___ 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] More Z3801/Tbolt comparisons
John Interesting stuff - - I'm not anti Racal, in fact I have a Racal T & F Mainframe, fed by a Trimble NTX, and the T&F Mainframe is very well made and performs in an excellent manner. But, - - - Racal 19## Counters are something else - - I got rid of mine some years back, not only the ongoing problems with the key-pad, but I don't think they put much cost into the oven osc. Perhaps you should consider moving on to an HP or other quality counter, "you deserve it" Roy - Original Message - From: "John Green" To: Sent: Thursday, September 03, 2009 8:05 PM Subject: [time-nuts] More Z3801/Tbolt comparisons Yesterday, I thought the Tbolt was wandering around too much. So, I did a factory reset and started a new 5K fix self survey. At about the same time, I started a new self survey on the Z3801 thinking that if they were both looking at the same satellites with the same antenna at the same time, they might be closer together. When I arrived back at work this morning, I looked at the final positions they had arrived at. The latitude difference was .17 deg. and Longitude was .26 deg. Great. This is probably within the margin of error of how they report. But, the altitude was 36.05 meters different. That, I can't explain. I have been looking at the time difference all morning and it seems to cycle +/- 6 ns every couple of minutes. It also seems to move maybe 30 nsec every hour or so.This also seems to be cyclic. I also see sudden jumps of around 4 to 5 nsec. I assume this is due to DAC voltage corrections. I thought some of this might be due to the Z3801 since I was using it as the reference to the 1992. I switched back to the internal reference and couldn't tell any difference. Could some of this still be the 1992? I noticed the Tbolt was set to not look at any satellites below 10 deg. I changed that to 0 deg. like the Z3801 and it didn't seem to make a difference. I am going to let a Rb start warming up and use it as a reference later to see if some of what I am seeing is the Z3801. Anyone have any ideas why the altitude is so much different? I am going to look at a topo map to see what it says. I might also change the disciplining constants of the Tbolt to see if it makes a difference. I can always do a factory reset later. None of this is meant to say that the Tbolt isn't as good as the Z3801. I just wanted to see what they looked like compared to each other. To folks used to seeing charts and exact numbers these casual observations may be a bit annoying. I haven't yet been able to use the GPIB facilities of my 1992. Hope to later. These are only meant to be casual observations. Though I trust what I see and read from my instruments, these aren't meant to be written in stone or quoted as specifications. Just some things to think about. ___ 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] OCXO sensitive to gravitational effects
Peter Putnam wrote: You have all been a bit stingy with your gravitational inputs on the hp 18011 oscillator... one G this way... two Gs the other way... Here you can see the result of some serious Gs, all applied at the same time... e*.* auction item:160360186935 Add only $56.55 to your bid to ship the carcass. Here's a matching generator to go with the counter. It might need a bit of a tuneup: 160349277602 "Some assembly required" :-) I wonder if they were both left in the van that was sent to the crusher. Ed ___ 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] Crystal aging
Rick, while the discussion was about the frequency control loops of GPSDOs and not the temperature control loops of their OCXOs your answer applies as well to what I have been asking. That was what I thought of when I talked about "3rd ore more order plls". Best regards Ulrich Bangert > -Ursprungliche Nachricht- > Von: time-nuts-boun...@febo.com > [mailto:time-nuts-boun...@febo.com] Im Auftrag von Richard > (Rick) Karlquist > Gesendet: Donnerstag, 3. September 2009 17:47 > An: Discussion of precise time and frequency measurement > Betreff: Re: [time-nuts] Crystal aging > > > > > Maybe! But for the sake of clarity: I have been asking how > > HP/Symmetricom manage to handle the regulation loop appearantly > > WITHOUT time constant adaption/switching and with a fixed time > > constant that seems to be much too high to start with for a > cold OCXO. > > > > Best regards > > Ulrich Bangert > > > > One answer might be the use of a second integrator. The > HP5061 used an analog second integrator, which was quite non > trivial to implement at the time. The 5071 also uses a > second integrator, which is of course digital. The oven > control loop of the E1938A uses first and second integrators > (PID + I^2) to get the best of both worlds. None of these use > switched time constants. > > 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.
