[time-nuts] Double oven ocxo's was Tbolt reception problems

Warren, Perhaps I am being too hard on the Tbolt. If I never had a Z3801, I am sure I would like the Tbolt a lot more. The Z3801 seems to just sit there and work without having to assure either its voltage or temperature or anything else for that matter. I do believe the things I am seeing are comi

Re: [time-nuts] Thunderbolt reception problems

Warren, Thanks for the Tbolt tips. The power supply was a good linear supply so I doubt that was causing what I see. The room temp was cycling a degree, maybe two, I did sometime see some quick shifts that were not coincident with temperature but they were all less than 10 nS. The largest swings al

Re: [time-nuts] Thunderbolt reception problems

I have been following the discussion regarding Tbolt performance closely. I have 2 of them and have not seen performance even close to what others report. I don't seem to have sensitivity related issues that others have reported. I am feeding Tbolt and Z3801 from a common antenna through a purpose

[time-nuts] MTBF/MTTF etc.

The discussion on the merits of failure rate calculations is fascinating. I was asked by one of our customers to provide MTBF for our products. After some research, I told them I couldn't provide that data and didn't think it would be of much use if I did. I asked if MTTF wouldn't be a better figur

[time-nuts] 80 MHz Crystal

Do you need 80 MHz exactly? I have a number of tcxos around that frequency but I doubt any that are exactly 80 MHz. By the way, $12 for a good crystal doesn't sound all that high. Seems the last ones I bought from ICM for channel elements which aren't all that precise, were close to $20. __

[time-nuts] Jamming GPS

All the discussion regarding jamming GPS has been very interesting. Because it is spread spectrum, I always assumed it would be difficult to jam GPS. The Monterey Bay incident indicates that it is extremely easy to jam GPS. So, as soon as another project is out of the way, I intend to do some exper

[time-nuts] Speaking of 10544As

I have one that I bought at least 25 years ago. Never been turned on. I believe it was brand new. It had the HP spec sheet with it. I keep saying I am going to power it up and see what it does. Now that I have some equipment that can actually do that, I'll give it a try. Maybe sooner than another 2

Re: [time-nuts] Trimble Z3801 look alike

I did find this: http://www.realhamradio.com/GPS_Trimble_Receiver.htm Looks kind of like a Tbolt in a fancy case. Article says it doesn't work with Satstat. I'll bet it does work with Tboltmon. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscri

[time-nuts] Trimble copy of Z3801

There is what appears to be a Trimble copy of a Z3801 on eBay. number 370234484785. I can't seem to find any info. Is this really a Z3801 copy or just a Tbolt in a fancy case? ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://

Re: [time-nuts] Conical inductors

Just so you know, Colicraft makes them too. http://www.coilcraft.com/bcl-s.cfm#table Probably quite a bit cheaper than Piconics and they are available either with flying leads or surface mount. I don't believe they use any core material but the specifications look like they would be suitable for a

Re: [time-nuts] Tbolt instability

Mark Sims wrote: A lot depends upon the temperature sensor in the Tbolt. ? ?Dallas Semi changed the guts of the sensor ship in such a way that the Tbolt can only get 1 degree resolution out of it. ? Later production Tbolts all have that sensor. ?Does your Tbolt show a mostly flat line temp curve wi

Re: [time-nuts] Tbolt instability

I think I might have found at least part of the answer. Extreme sensitivity to ambient temperature. I held a heat gun a couple of feet away and in under a minute, it went nuts. I don't think I was heating the OCXO that much. I believe it was the internal temperature sensor. I didn't get it that hot

[time-nuts] Tbolt instability

Tbolts seem to have a very good reputation for accuracy and stability. Most comments I have seen compare them favorably to the HP/Symmetricom Z3801. Mine may be OK in the very long term but doesn't look too good in the short term. Let me explain. First, I'll describe my set up. I have a Z3801 which

[time-nuts] Morion MV89 Temperature

My MV89 runs 56 C on the outside of its case in a room with a 27 C ambient. I can touch it but can't leave my fingers there long. I realize that OCXOs are supposed to be warm but this is way hotter than anything else I have. The current draw seems OK, less than 300 mA after warm up. Is this normal?

Re: [time-nuts] LT1763

Poul Henning wrote: You should pick your poison carefully here: Low noise regulators are usually not very stable, typically they are quite sensitive to temperature. Precision regulators are stable, but tend to be noisy. If your OCXO is voltage sensitive, make sure to connect the sense resistor t

Re: [time-nuts] LT1763

Thanks Poul,I had not considered that one probably because of the package. It does look like a contender. I am considering the LT3080 because of the tight regulation and it is available in not one, but 2 power packages. The tab is tied to the output though. The max current is around 300 mA cold an

[time-nuts] Has anyone designed with a LT3080?

I have a project where I need to supply a nice, steady 12 volts to an OCXO. >From the spec sheet, the LT3080 looks much better than the venerable 7812. However, when I started to look at the application data closely, my enthusiasm waned a bit. It seems the voltage set pin is so sensitive to outside

[time-nuts] RoHS Solder

Interesting comments regarding. lead free solder. I was not aware of the tin whisker problem. We went lead free here at work several years ago. I really don't like the lead free solder we have to use on several accounts. As mentioned, you don't get nice shiny joints. They look pretty much like cold

Re: [time-nuts] MV89 Problem

Murray wrote:I have an MV89, and it draws about 320mA steady state. No cycling of the current at all once warmed up. The surface temperature is warm, but you can leave your hand on it. Performance wise, the MV89 is very good. The ageing is particularly low - after only a week from power-up it's ru

Re: [time-nuts] Morion MV89

I looked up the specifications to be sure, they state a steady state current of less than 350 mA after warm up. Also, after about 10 minutes, it is too hot to touch. Definitely bad. I am going to contact the seller.Thanks ___ time-nuts mailing list -- tim

[time-nuts] Morion MV89 Problem

I got one of them from one of those Chinese eBay sources. Hooked it up, let it warm up,it does get rather warm to the touch. Problem is that I can't get it on 10 MHz. Even if I connect the control voltage input directly to the reference voltage out, it is still low by about 4 Hz. Another thing, the

Re: [time-nuts] Alcohol and acetone storage

You see, We had a quart can of Alcohol and a quart can of Acetone from Home Depot. In retrospect I should have called in "60 Minutes" to show them up for the fools they were. FWIW, -John We routinely keep 50 gallon drums of both and have never had a minutes trouble from anyone. __

[time-nuts] Please disregard what I said

The more I kept looking at the data I was getting with regard to comparing the Z3801 to the Tbolt, the less sense it made. Finally, I concluded that I made some kind of fundamental error either in how I was measuring or there was a problem with what I was measuring with. The only thing I am sure of

[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

Re: [time-nuts] Crystal aging

I realize that making measurements over a day or two says very little about long term aging. Most of my crystal oscillator experience has been with TCXOs in the communications industry. We are talking about orders of magnitude difference with regard to just about everything. In my experience, a goo

[time-nuts] OCXO aging behavior

I had always thought that crystals changed frequency consistently in one direction as they age. That is until recently. I was trying to get the reference in my 1992 as close as possible to my Z3801 and noticed that as I adjusted the fine pot, there didn't seem to be a place where the frequency stay

[time-nuts] 1992 Jumper location

Harry Hindriks wrote: You can switch the mode to standard language instead of MATE/CIIL by changing a jumper inside the counter. There is an option jumper on the GPIB board labeled "SK4". I moved the suitcase jumper from the lower position to the upper. Here's hoping that is the correct one. It wa

[time-nuts] 1992 power up message

Antonio wrote:At power on, I read 1992 first, then 8572 0404 Mine does the same. I will have to try that jumper. GPIB is bad enough. I have no interest in learning some obscure military format. My manual has info on the MATE format. I believe the online version has all the GPIB commands. I hope to

Re: [time-nuts] Racal 1992 drift after standby

Ed,Mine comes out of standby pretty much where it is going to be. I see from information posted that I seem to have option 4E. Mine doesn't look quite that good compared to GPS. I believe mine is an 02M model though there is nothing on the unit to say so. The manual says the GPIB should be a 401820

Re: [time-nuts] Racal 1992

Ed Palmer wrote:Which timebase does yours have? I've got option 4E (similar to 4B). Although the timebase appears to be stable, I've noticed that the counter drifts about 5e-9 during warmup, even when the oscillator has been on standby for many days. It takes a couple of hours to settle down. Do

[time-nuts] Couple of questions for Racal 1992 owners

Just acquired a used 1992 off eBay. Excellent, almost like new with manual and even spare fuses. I noticed that the internal reference's waveform is more like a nasty sawtooth than a nice sine wave. Is that normal? Also, when I hook my GPSDO through a two way splitter and two different length cable

[time-nuts] USB to GPIB converter

I had been eyeing the Softmark unit. Thanks for the heads up. I think I'll go with the prologix though it will have to wait. It is a little outside of the budget at the moment. We have a piece of Agilent test equipment that can act as a bus controller. I might dig out the book and play with that so

[time-nuts] How do you communicate with your Racal Dana 1992?

I can't afford LabView, so what are my options? Is there a preferable USB to GPIB converter? I am looking for a way to take readings and put them into a file for further processing. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to ht

[time-nuts] Taking apart timing GPS antenna

Hal Murray wrote: How did you get it apart? The Motorola/Andrew antenna that I have has screws. Best I remember, I just removed them and yanked the top off. I do believe there was a seal that had to be overcome. ___ time-nuts mailing list -- time-nuts@feb

[time-nuts] How to tell a "survey grade" antenna

Thanks guys. I bookmarked that site. I don't know that I'll be able to find one but at least I know what to look for now. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and fo

[time-nuts] Difference in GPS antennas

Mark Sims wrote:The quality of the results match the quality of the antenna. A geodetic/survey grade antenna gives results to within a few inches. A conical timing antenna within 8 inches. A cheap patch antenna around a foot. I took one of those conical timing antennas apart only to find that it

Re: [time-nuts] OCXO sensitive to gravitational effects

Interesting. It makes sense that it is the holder and not the crystal itself that is sensitive. I only implied that the oscillator as a whole displayed this sensitivity. While I didn't try to actually measure the change, I would estimate it at almost 1e-8. I will try to use a strong magnet nearby t

[time-nuts] OCXO sensitive to gravity

A while back there was some discussion about crystal oscillator's changing frequency due to the effects of gravity. Since I got my Z3801 up and running full time, I have been trying to characterize some OCXOs I had picked off eBay but had no specifications for. I was trying to fine tune one to the

Re: [time-nuts] Allan deviation plots etc

Ulrich Bangert wrote: my point has not been to judge who has to be interested in what. My point has only been to use the right terms for it. Let me give an example: John uses the term > ...but I am more concerned with ... and stability over time Well, stability over time is what exacly is display

Re: [time-nuts] Method for comparing oscillators

Part of using this method is that, at some point, the DUT must be set to the same frequency as the reference. (As close as I can get it anyway.) So, accuracy and stability are addressed separately. For TCXOs, set to frequency and watch the drift over time. I have an environmental chamber so I can d

Re: [time-nuts] Method for comparing oscillators

I have studied the dual mixer approach and the consensus is that it is the most accurate method. However, it seems pretty difficult to obtain that accuracy. I do have some DBMs with IF response down to DC. I don't have a 10811 but do have a pretty good oscillator to use for the offset. The problem

[time-nuts] Methods for comparing oscillators

I've been hanging around and reading long enough to understand that when measuring the differences between oscillators the preferred methods are the HP 5370A Time difference counter or the dual mixer method. I want to evaluate some ocxo's and Rb sources against either a Tbolt or Z3801 and I don't h

Re: [time-nuts] An easy to generate 5, 1 MHz from 10 MHz

A cheap and easy way is to use a 74HC14, 74HC390. Capacitively couple the 10 MHz into one of the 6 inputs of the HC14 to square it up, out of that into one of the divide by 2 inputs of the HC390, that goes to another input of the HC14 to act as a buffer which provides the 5 MHz output. Next, into t

[time-nuts] Is this normal for a Z3801?

I got the mute Tbolt talking so I let it sit to do it's self survey. Due to a not so great view of the sky here at work, it took a couple of hours to complete. Afterwards,everything seemed OK. (I am not at all familiar with the Tbolt.) Next, I hooked up my Z3801 to the same antenna and it keeps giv

[time-nuts] Mute Tbolt solved

I happened to notice that the 5 volt supply was set at around 4.9 volts, not usually a problem. I upped it to 5.1 and started getting receive data packets. As usual, an operator headspace problem. Thanks for all the help. ___ time-nuts mailing list -- tim

[time-nuts] A couple of Tbolt questions

I opened the mute Tbolt up to check the solder connections on the DB9 and I see it has version 2.2 firmware. How big a deal is it that it doesn't have 3.0? Also, it has the Trimble 37265 OCXO. I understand that there were good and not so good OCXOs used in these. Is this one of the good ones? _

[time-nuts] Tbolt not talking

I got one of the Chinese Tbolts off eBay and when I powered it up and ran Tboltmon, I got nothing. I checked the com port and it is correct. I am using a USB to serial converter but I don't believe that is what the problem is since I have used it to program some Motorola radios that have a reputati

[time-nuts] Spec. Sheet for Ovenaire OSC 49-4-1

Anyone have any info on this oscillator? Google turned up nothing. Thanks. ___ 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] Low cost multifrequency reference

This really more about frequency than time but I thought it might be of interest. The Agilent 8920 series of instruments have an A15 module, the reference, which takes an external 10 MHz input and locks an internal TCXO to it then producing 1 GHz, 500 MHz, 20 MHz, 10 MHz, 1 MHz or 200 KHz outputs.

[time-nuts] Datum LPRO units on eBay

I bought, but haven't received yet, one of the Datum LPRO units from eBay. In trying to find information, I was able to locate some info on the LPRO-101. However, looking at the picture on eBay, The model looks like LPRO-FLX. Is this the same as the dash 101? Also, are these units nearing the end

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