[time-nuts] VNG in a Box

2013-09-24 Thread Murray Greenman
questions about the project, just send me an email. By the way, if you're looking for a good homebrew GPS Reference (VNG in a Box is a lot more than that), try my Simple GPSDO: http://www.qsl.net/zl1bpu/MICRO/SIMPLE/SimpleGPS.htm 73, Murray Greenman ZL1BPU

[time-nuts] Z38XX PFORTH interpreter question

2013-06-17 Thread Murray Greenman
Hi, Has anyone made further progress in understanding the PFORTH commands? I find with my Z3815A (with an E1938A hockey puck oscillator installed) that the command 'puck' returns: a= -6.305066e-13 b= 0.00e00 a/d = 1.60e+01 puck communication is alive puck warm= 1 puck EFC ADC err= 0

[time-nuts] Changing FE-56XX frequency

2013-04-08 Thread Murray Greenman
As Bill suggests, the best way to achieve any-frequency performance with the newer FE-56xx devices is to pull out the Rb reference frequency and run an external DDS off it. I found that the Rb loop frequency in the one I played with was exactly 60MHz, rather than the 50.255MHz of the older

[time-nuts] Open source GPSDO

2012-12-06 Thread Murray Greenman
Keenan, You can see my GPSDO source code for a mere $50. It comes with manual and executables. The executables alone are $20. See http://www.qsl.net/zl1bpu/MICRO/SIMPLE/SimpleGPS.htm While this design does not use a Kalmann filter, it has pretty good holdover, and you can see how the phase

[time-nuts] Open source

2012-12-06 Thread Murray Greenman
My mistake was inferring that my GPSDO software was open source. It's absolutely not. It is proprietary to me and written in AVR assembler. There is no reference anywhere in it to any libraries from any other source. So don't get too excited. You can still see what's inside it for $50, but

[time-nuts] FE-5680A firmware dump

2012-11-08 Thread Murray Greenman
Disassemblers are hardly rocket science. They are only a parser with a pile of memory to remember labels. Why not write your own? I've written them in the past (a long way in the past, and I've written cross-assemblers too), so I don't see anything difficult about writing one for the 8051.

[time-nuts] Z3805 etc

2012-10-15 Thread Murray Greenman
Ulrich is right about the use of MTI 260 use in GPSDOs. I have a Korean-made Z3815A clone (it's labelled Agilent) which has a little daughter board with a 5MHz MTI 260 DOCXO in place of the original E1938A used in these models. I understand that there were production and reliability issues with

[time-nuts] 57600 baud rate with Basic etc

2012-10-10 Thread Murray Greenman
Corby, Power Basic certainly does the job. However, there's a fairly big learning curve. I use Just Basic, which is a FREE cut-down version of Liberty Basic. While there are a few limitations, and some things you need to do aren't entirely intuitive, it works very well and the serial comms

[time-nuts] Best GPSDO

2012-09-28 Thread Murray Greenman
Ulrich, I think this is a bit like discussing one's favourite wine or favourite stereo! Especially since many of the participants here will not have the capability to compare GPSDO performance reliably. I have a few GPSDOs, and it's my impression that of them all the Agilent Z3815A with

[time-nuts] NTGS50AA RS422

2012-05-20 Thread Murray Greenman
Bjorn, I don't know of an RS422 connection at the back of the NTGS50AA. There is a 'CMOS' level serial output (essentailly a monitor point) on the top pin, 7th row along from the end the power is applied. There are also 10MHz PECL outputs at the other end of the connector. I use either

[time-nuts] NTGS50AA RS422

2012-05-20 Thread Murray Greenman
Bjorn, Sorry, I have no further info re the RS422. Perhaps you could try tracing it from the processor or at least the 422 interface chip, if you can find it. Nobody so far has come up with a definitove pinout for the rear connector. About the only thing GPS Monitor does that's different is

[time-nuts] NTGS50AA undoc 8F-AE data

2012-05-08 Thread Murray Greenman
it running on an old P1 Tosh laptop. 73, Murray Greenman ZL1BPU ___ 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] NTGS50AA, better than Thunderbolt

2012-05-03 Thread Murray Greenman
Mark, I agree with you. I've been using an NTGS50AA here for some time, and it is an excellent unit with none of the thermal problems of the Tbolt. Easily as good as the old Z3801A, and much lower power consumption. I use the NTGS50AA with the Thunderbolt software in TSIP mode, although not

Re: [time-nuts] time-nuts Digest, Vol 94, Issue 21

2012-05-03 Thread Murray Greenman
John, Good stuff. Excellent news. You will be very impressed with the performance of the NTGS50AA. If you have any questions, or need real Trimble software to test it with, let me know. I did some spying on the comms using the Trimble software, but it was very difficult. TSIP is not a

[time-nuts] NTGS50AA 1pps

2012-05-03 Thread Murray Greenman
Kevin, No, I've not found a 1PPS output. Not that I've looked, and I don't have the official pinouts for the big connector on the back. It would be easy enough to synthesize one, for example using a divider on one of the other products, resetting it if necessary with the 1PPS2 (2 sec) pulse.

[time-nuts] HBG clocks

2012-01-01 Thread Murray Greenman
Marco, I have had an HBG-controlled clock for some years. Not that it ever received HBG at this range! The clock is an 'Irox HB13P' projection clock, and has the logo 'Official Swiss Time' on the front, which you can clearly see at http://www.irox.com/Web/en/Products/Archive/HB13P.htm. The

[time-nuts] Simple GPSDO

2011-12-30 Thread Murray Greenman
Two thoughts re Simple GPSDOs: 1. For a conventional 1pps approach, see 'A Simple GPS Disciplined Reference http://www.qsl.net/zl1bpu/MICRO/SIMPLE/SimpleGPS.htm, by yours truly. It uses a high performance 10MHz OCXO and gently disciplines it. Despite not having a Kalmann filter, the holdover

[time-nuts] 63.8976 OCXO is useful

2011-12-14 Thread Murray Greenman
Hi, I can think of at least one excellent use for the unwanted 63.8976MHz OCXO that comes free with some of the recently offered FE-5680A units. It would make a great reference for a DDS synthesizer, such as an AD9852/AD9854. These chips have a 4x reference multiplier capability, and thus would

[time-nuts] FE-5680A results

2011-11-29 Thread Murray Greenman
Bert, There's a very nice way to separate diurnal thermal sensitivity from long term ageing. It applies equally well to Rb sources as to OCXOs, which is where I've used it. What you do is set up to make frequency observations against a more stable reference (of course in this case a GPSDO or

[time-nuts] Ways to use unclean RF from FE-56xx

2011-11-15 Thread Murray Greenman
As noted by others, the internal Rb locked signals of some FEI units are not especially nice sine waves. One way to profitably use them is to operate an external DDS generator. The phase noise of the source will afffect the result, but not the harmonics. I have an FE-5680B which has an

[time-nuts] AD9832 in FE-5680A

2011-11-12 Thread Murray Greenman
Bert, Your comment about the AD9832 being a 25MHz part made me think, and I too wonder how it might all work. The data sheet calls it a 25MHz part, and I agree with you that it might be expected that some extra division occurred between the ~60MHz Rb loop and the synthesizer MCLK. That's not

[time-nuts] FE-5680A power

2011-11-10 Thread Murray Greenman
It's my experience (and I have two FE-5680A and an FE-5680B, plus a couple of FE-5650As) that you don't need a +5V supply with the FE-5680x devices, just a +15V supply. Now of course the model number has little to do with what we find inside - there seem to be many variants - so I recommend

[time-nuts] Better option than oil

2011-09-20 Thread Murray Greenman
Folk looking for alternatives to dunking things in oil might consider trying a variant of the following technique which I have used with success: The thermal stability of TCXOs and XOs can be improved considerably for experimental purposes by slowing down the thermal time constant between the

[time-nuts] OCXO settling

2011-09-14 Thread Murray Greenman
There are of course many levels of performance in OCXOs, but in general the ageing slows down with time, and veteran OCXOs can be very good. I recently tested the OCXO in an old HP5245L counter (circa 1970), last calibrated in 1985, and it was still within 100ppb of 10MHz after 24 hours warmup!

[time-nuts] OCXO burn-in

2011-09-14 Thread Murray Greenman
Paul, Whenever you make changes to the physical setup you will cause mechanical disturbance to the OCXO which it is likely to take some time to recover from. A couple of days continuous operating should suffice. Add to that an hour for every day it's been switched off. Even tipping the unit

[time-nuts] Insulating OCXOs

2011-09-14 Thread Murray Greenman
Bob, Many OCXOs, and definitely the CMAC (now RAKON) STP2145A, use ambient compensation technology. It is not possible to place the heater, the crystal and the temperature sensor in exactly the same place, and consequently there will be a thermal profile within the OCXO which depends on the

[time-nuts] Plessey PR152

2011-08-16 Thread Murray Greenman
My thanks to those who suggested I join the vintage radio forum www.vintage-radio.net. I have joined, and it certainly looks like a very helpful group. 73, Murray ZL1BPU ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to

[time-nuts] OT - Plessey PR152

2011-08-14 Thread Murray Greenman
dial. Ideally I'd like a schematic or manual so I can fix the receiver, but I'd be grateful for any crumbs, such as suggestions about who might know more about the receiver. I can send photos if anyone is interested. Contact me direct if you are. Regards, Murray Greenman ZL1BPU

[time-nuts] Oscillator Buddy

2011-08-11 Thread Murray Greenman
reference in the OCXO, resulting in very good thermal performance. The design is described in some detail at http://www.qsl.net/zl1bpu/MICRO/SIMPLE/SimpleGPS.htm. Regards, Murray Greenman ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go

[time-nuts] FTS 1050A

2011-08-09 Thread Murray Greenman
are very good - any frequency I want with microHz resolution. Regards, Murray Greenman ___ 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] Broadband synthesizer (WB6BNQ)

2011-07-13 Thread Murray Greenman
Bill, One method I've found convenient is to use a DDS Development kit such as the AD9852 one and drive that from a Rubidium or GPSDO source. I have a 60MHz FEI-5680B driving mine and easily get 0 - 200MHz out. No, it won't give all the range you want, but there are few alternatives that will,

[time-nuts] Lady Heather

2011-06-13 Thread Murray Greenman
We had the REAL Lady Heather on TV last night here in New Zealand! It was the CSI episode about cats. Any tenuous connection with Time-Nuts, perhaps? Murray ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to

[time-nuts] Synchronous LF Reception

2011-05-31 Thread Murray Greenman
Hi, There was a discussion a week or so back about SoftPAL and techniques for LF reception which would allow us to study the phase and signal strength of VLF and LF transmissions. Effects to be studied include detection of solar events and prediction of earthquakes. At the time I forgot to

[time-nuts] Softpal VLF software

2011-05-19 Thread Murray Greenman
indeed do as he claims, and we have had some useful discussions. Like you guys, I'd love to try it out! I'm trying to negotiate a shared development for use with a conventional Windows platform. Kit is interested in doing this, but don't hold your breath! Regards, Murray Greenman ZL1BPU

[time-nuts] HP 8508A Vector Voltmeter

2011-05-18 Thread Murray Greenman
Hi, I found an old HP 8508A in the store room at work, and it looks like a useful candidate for Time Nuts activities. It seems to work OK, and while it has GPIB, I don't at present have GPIB on my computer, but I can connect up a chart recorder. Has anybody any comments about using this

[time-nuts] FE-5680A pinout

2011-04-20 Thread Murray Greenman
The confusion is understandable. There are so many different variants of the FE-5680A, and they are not easy to identify. Some of the information you see out there is from folk who measure the voltage on the pins with a meter, not understanding what they are looking at. When I've investigated

[time-nuts] Choice of Rb vendor

2011-04-20 Thread Murray Greenman
Joe, If all you need is a fixed 10MHz source, you might be better getting an Efratom LPRO-101, which are available from the same sources. The LPRO-101 doesn't need a heatsink, and does not have the confusing array of different versions and options that the FEI units suffer from. As for suppliers,

[time-nuts] FEI FE-5650A and FE-5680A caution

2011-04-07 Thread Murray Greenman
Jerry has described the situation fairly well. You take pot luck, and the Chinese supplier does not know which are which. Out of four units I have, two are remote controllable, one is fixed at (reasonably close to) 10MHz, while the fourth had no output at all. I've since discovered that this last

[time-nuts] Oncore battery backup

2011-04-06 Thread Murray Greenman
Why not just put a bigger battery in your UPS? I have a couple of old ones, and they run just fine with an old car battery, and thus give me many hours of backup for my Trimble/Nortel GPSDO. Just be careful though - in some UPS units the battery is live to the mains! The APC ones seem to be OK.

[time-nuts] Portable standard - Rb query

2011-04-06 Thread Murray Greenman
Joe, I have several of the FEI units. You pay more for these, because (assuming you get the right one) they have a DDS synthesizer included, which (with suitable modification) allows them to operate from about 1kHz to 15MHz in 10mHz steps. Some models require +15V and +5V, others just +15V. My

[time-nuts] JJY40

2011-03-28 Thread Murray Greenman
I've also observed that JJY40 is now off the air. It has been excellent reception down here in New Zealand for many years, generally better than the JJY signal on 60kHz, where of course it competes with other signals. JJY40 was typically strong enough to hear by ear during the day as well as at

[time-nuts] FE5860A CONNECTIONS

2011-03-14 Thread Murray Greenman
Dan, Yes, you are right. There are so many variants of the FE-56xx devices that I'm sure even FEI don't have a clue which is which! The FE-5680 family are invariably single supply, although the connectors vary. Pull the lid off and with an Ohm-meter trace the input to the regulators back to the

[time-nuts] STP2145A

2011-03-08 Thread Murray Greenman
Robert, I've attached the data sheet for the STP2145A. The device is 12V operated, and has an internal 8V reference which you can use to supply the EFC circuit. Have a look at http://www.qsl.net/zl1bpu/MICRO/SIMPLE/SimpleGPS.htm, where I describe a simple home-brew GPS Disciplined Reference based

[time-nuts] Pulling oscillators

2011-03-06 Thread Murray Greenman
Don, You haven't explained how much you want to pull the oscillator, but assuming it's less than 1ppm, what you suggest is quite viable. Replace one of the caps in the Pierce oscillator PI network (preferably the output one) with an NPO one of slightly smaller value and add across it a

[time-nuts] NMEA time off

2011-03-03 Thread Murray Greenman
Many older GPS units sending NMEA at 4800 baud will in effect indicate one second slow, either all the time or some of the time, if there are too many GPS sentences turned on. There's too much data in the queue. Either drop the number of sentences enabled, or increase the baud rate, or both.

[time-nuts] Earthquake meets time ball

2011-02-23 Thread Murray Greenman
Hi, You may recall we discussed here some time back about how time was disseminated in days gone past, and mentioned Time Balls at various locations from Greenwich onward. I'd forgotten that there was (and still is) one at Lyttleton, NZ, right at the epicentre of the big earthquake. This

[time-nuts] Freq cal to 1ppm without GPSDO

2011-02-16 Thread Murray Greenman
John, I've had quite a bit of experience doing what you want to do, and have tried several methods. TV used to be a good way, but now that everything's gone digital that method is out. Despite advice to the contrary, comparing with WWV or similar on HF is NOT reliable to 1ppm. This is because

[time-nuts] FE-5680A

2011-02-06 Thread Murray Greenman
Bud, I have a couple of these units going nicely, but I agree with Bob, you are best to sort the pinouts for yourself since they vary. Take the lid off (it's fairly simple, screws on the base, on the side and by the connector) and identify the 5V regulator input, then use an Ohmmeter to find

[time-nuts] SECAM vs NTSC

2011-01-18 Thread Murray Greenman
Rick, Maybe the French had a point... we all know NTSC stands for 'Never Twice Same Colour'! Regards, Murray Greenman ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts

[time-nuts] UBLOX 1pps vs Z3801A

2010-12-21 Thread Murray Greenman
John, The Z3801A 1pps is based on the mean UTC/GPS time, but regenerated from the local (very stable) 10MHz reference, so has little jitter. The UBLOX GPS module 1pps output is more or less instantaneous, so has jitter resulting from each individual position solution. If you provide it with a

[time-nuts] Plastic covered OCXOs

2010-11-25 Thread Murray Greenman
I could tell you but... There's a lot of interesting IP in these little guys! Regards, Murray Greenman RAKON ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow

[time-nuts] Setting clocks 100 years ago

2010-11-04 Thread Murray Greenman
Navigators used chronometers to determine their longitude. If they were stopped in one place long enough, they could work out longitude by a complicated process of star and lunar observations; however, when they left an established port, they usually took with them a time standard based on local

[time-nuts] Distribution Amp suggestions

2010-10-25 Thread Murray Greenman
distribution. Since we need to purchase several of these, can anyone suggest a unit with similar performance and quality that would be lower cost than the Symmetricom 4036B? Regards, Murray Greenman RAKON Ltd ___ time-nuts mailing list -- time-nuts@febo.com

[time-nuts] Drake DSR-2 Rx

2010-09-19 Thread Murray Greenman
Nigel, Thanks very much! I'm not able to download it from here at work (the IT Police policies block so much the internet isn't fun any more!), but will as soon as I'm home. I have the receiver going quite well, and it certainly looks impressive with its Nixie display. It's no great performer by

[time-nuts] Drake DSR-2 Receiver manual

2010-09-16 Thread Murray Greenman
I know this is a bit off-topic, but I wonder if any of you guys have available the manual for the old (1970s) Drake DSR-2 receiver? I've you are able to send me a PDF copy, I'd be most grateful. 73, Murray ZL1BPU ___ time-nuts mailing list --

[time-nuts] Homebrew WWVB simulator

2010-09-14 Thread Murray Greenman
I designed and built a similar thing a while back, which emulated the full VNG time code (which could be decoded by 'Radio Clock' and other clock software). My unit was GPS locked, using two microcontrollers, but it wouldn't need to be that complex for setting clocks/watches. It generated all the

Re: [time-nuts] Basic question regarding comparing two frequencies

2010-07-26 Thread Murray Greenman
You guys are trying to crack a nut with a sledgehammer! For a start, as Didier says, you can't possibly read the frequency of a sky-wave signal to 0.01Hz in any short time frame since the Doppler on the signal can be as much as 1ppm (i.e. 10Hz at 10MHz). You can only infer it closer than that by

[time-nuts] Rapid startup GPSDO

2010-07-14 Thread Murray Greenman
Jim, Would an inexpensive Rubidium unit do what you want? I know it won't be closer than a few ppb, but in my experience (LPR101, FE-5650A, FE-5680A) they are stable inside about four minutes. The big advantage is they don't need GPS at all. Regards, Murray ZL1BPU Message: 1 Date: Wed, 14 Jul

[time-nuts] Yet another GPSDO - locking to 10MHz

2010-06-27 Thread Murray Greenman
I can't share the code (belongs to my employer), the idea is simple enough and I could share the schematic. Eight of these units have been built. I used the excellent Rakon STP2402E OCXO. Regards, Murray Greenman ZL1BPU ___ time-nuts mailing list

[time-nuts] Z3815A

2010-06-10 Thread Murray Greenman
different but externally identical. Software includes a monitor program with multiple windows and a rather cool retro and very realistic Nixie Clock. Regards, Murray Greenman -- Message: 4 Date: Thu, 10 Jun 2010 09:41:00 +0200 From: Magnus Danielson mag

[time-nuts] Most accurate small crystal

2010-05-27 Thread Murray Greenman
the 2nd order model. Regards, Murray Greenman -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of time-nuts-requ...@febo.com Sent: Thursday, 27 May 2010 5:31 p.m. To: time-nuts@febo.com Subject: time-nuts Digest, Vol 70, Issue 75 Send time

[time-nuts] FE-5680 commands

2010-03-25 Thread Murray Greenman
of the currently known commands, a collection of modification information, and also a PC program to download, which controls the FE-5650A and FE-5680A in an easy to use manner, where you dial in the frequency in Hz. These are great little units! Regards, Murray Greenman ZL1BPU

[time-nuts] DIY frequency counter help (Gerard PG5G)

2010-02-28 Thread Murray Greenman
Gerard, By now you've no doubt had more offers to assist than you need, and in particular from far more local enthusiasts than me. However, if I can help answer any particular points, I would be pleased to do so. My reason for suggesting this is that I have available a Pendulum CNT-90 counter,

[time-nuts] Rock, gas, and air

2010-02-28 Thread Murray Greenman
Probably hot air... Murray -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of time-nuts-requ...@febo.com Sent: Monday, 1 March 2010 2:56 p.m. To: time-nuts@febo.com Subject: time-nuts Digest, Vol 68, Issue 3 Send time-nuts mailing list

[time-nuts] Double vs single oven TBOLT

2010-02-23 Thread Murray Greenman
Warren, I take the point that you are testing the SAME oscillator as a means of adding some consistency to the test. However, leaving aside this consistency and issues relating to the disciplining device (your TBOLT), I suggest your test of double vs single oven OCXO may be unfair to the single

[time-nuts] 1pps to 10kHz

2010-02-21 Thread Murray Greenman
. Regards, Murray Greenman ___ 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] 64MHz derived from 10MHz

2010-02-09 Thread Murray Greenman
Now I realize I'm known as an injection locking fan, but here's my 2 cents worth: Divide 10MHz by 5 to 2MHz using a Johnson ring counter (74HC4017). Use that to injection lock a 64MHz XO. A low noise solution and no PLLs required. I'd not be surprised if you could injection lock directly with

[time-nuts] Low noise PLL for transceiver locking

2010-02-02 Thread Murray Greenman
Frank, My suggestion would be to try injection locking, rather than a PLL. No change is made to the 22MHz and 42MHz oscillators, except to find a way to inject enough reference power to force them to lock to it. Injection locking works well with modest harmonic relationships, and gives good noise

[time-nuts] FW: Injection locking

2010-02-02 Thread Murray Greenman
-Original Message- From: Murray Greenman Sent: Wednesday, 3 February 2010 9:00 a.m. To: 'time-nuts@febo.com' Subject: Injection locking Frank, Bruce's collection would be a good place to start. Thanks Bruce. Most of the examples relate to microwave applications, where often

[time-nuts] Injection Locking

2010-02-02 Thread Murray Greenman
Frank, As Bruce suggests, you can in theory lock any rational number ratio, including 11/5 and 21/5. However, the locking gain drops off as the ratio becomes more extreme, and thus the lock range and potential stability are degraded. Yes, you could certainly use a regenerative divider to

[time-nuts] Z3815A

2010-01-18 Thread Murray Greenman
Steve, There are at least 20 Z3815A units in ZL Amateur hands that I know of, and many more in VK. They were 'rescued' by a friend in VK, and have been distributed with firmware and manual that we've worked out for them. As far as I can make out, they were not used in cellular systems here.

[time-nuts] Z3815A vs Z3816A

2010-01-17 Thread Murray Greenman
Alberto, The Z3815A is certainly less common - except down here in VK/ZL. I have one, and can try to answer your questions. The oscillator used in the Z3815A is generally the HP E1938A, although mine is a more recent Symmetricom version with a Milliren 260 OCXO adaptation. Power supply is 20 -

[time-nuts] Z3805A vs Z3815A

2010-01-17 Thread Murray Greenman
Steve, No, I've not seen a Z3805A at all. Not that I know all there is to know about the Z3815A either. 73, Murray ZL1BPU ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts

[time-nuts] EROS Oscillators

2009-11-23 Thread Murray Greenman
EROS is an abbreviation used by the Electronic Research Company. They used to be in Overland Park, KS, USA. They made OCXOs for government and space applications. I have some of their 5MHz devices which were widely used in Transit (pre-GPS) satellite navigation receivers. These OCXOs were fixed

[time-nuts] FE-5680 frequency change

2009-11-02 Thread Murray Greenman
dedicated unit for 2.048MHz. Bob Mokia (NHBBob on Ebay) has the 1pps versions for sale, and these are easily converted to remote frequency programming, as described in the links above. Regards, Murray Greenman ___ time-nuts mailing list -- time-nuts

[time-nuts] Down under Time Nuts

2009-10-07 Thread Murray Greenman
Ray, There are several of us down here on the list. I can think of several in AU and at least three or four in NZ. If they don't identify themselves to you, let me know. We also know the whereabouts of some nice gear. Regards, Murray Greenman ZL1BPU www.qsl.net/zl1bpu

[time-nuts] Time running backwards down under

2009-10-07 Thread Murray Greenman
Think about it... no it doesn't. Just takes a while to get used to the sun being on the wrong side and the moon being upside down (think about that one!). And yes, the water goes down the plug hole the other way, and hurricanes rotate the other way. However, here in New Zealand we are currently

[time-nuts] Morion MV89

2009-10-07 Thread Murray Greenman
John, Yes, the temperature and current are completely normal. I have my MV89 running on the bench here, and it's drawing 300mA and too hot to hold. Don't think about lagging it to keep it warm, or adding cooling, as you'll mess up the internal thermal profile, and then the calibration and

[time-nuts] Newbie question - what use is a Ruby?

2009-10-05 Thread Murray Greenman
, Murray Greenman ___ 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] Calibration of Rb

2009-10-05 Thread Murray Greenman
Someone asked what the Time-Nuts way of calibrating a Rb source would be. I'm no expert, but here's my 2c worth: I don't like making adjustments, as they can lead to lowered reliability, lowered understanding of the processes of ageing, and are also more work. As someone else pointed out,

[time-nuts] Lifetime of Rb references

2009-10-05 Thread Murray Greenman
I've not found this to be a problem. I simply turn mine on 5 minutes before I need it. If it was necessary to run it for weeks, I'd find a way to use an OCXO or GPSDO instead. It's a bit different with the old-style Rb References such as the HP 5065A, which take longer to get going. Mine has

[time-nuts] Morion MV89

2009-09-23 Thread Murray Greenman
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 running at

[time-nuts] High accuracy? GPS position

2009-09-09 Thread Murray Greenman
Mark, How do you KNOW your position to such accuracy? Is it in fact possible to survey your position to that accuracy by any independent means? If, for example, you use official survey marks to determine your position by direct measurement, are the survey marks really that accurate? Murray

[time-nuts] Gravity and OCXOs

2009-08-13 Thread Murray Greenman
Rick is right. The effect you see when turning your GPSDO upside down will be predominantly the direct gravitational effect on the OCXO crystal and its mountings. You see this with any OCXO, and the good ones will have a '2G turnover' or other G rating quoted. For example, the well known HP

[time-nuts] Generating 66.666...MHz from 10MHz

2009-06-28 Thread Murray Greenman
Here's an idea which actually works (I tried it). Rather than lock at 10MHz, you lock directly to 1pps. You can lock an XO to 1/3 Hz steps by locking to 1pps and ignoring two out of three results from the TIC. I did it at 7.333MHz, using an AT90S2313 micro, and you could just as easily do it at

[time-nuts] Long Wave Receiver ideas

2009-06-25 Thread Murray Greenman
phase and power plots which are achieved by maths from the I and Q followed by 'leaky integrators'. That bit was my contribution. The whole idea originated with Peter G3PLX, the source of many good ideas. Give it a try - it's quite a tricky bit of software to drive. Regards, Murray Greenman ZL1BPU

[time-nuts] Long wave receiver ideas

2009-06-24 Thread Murray Greenman
at a range of 8000km, and for my own 80uW EIRP transmission on 181kHz to be detected 500km away. See http://www.qsl.net/zl1bpu/ZL2AFP/CLICK/click.htm for more information and Clicklock software by Con Wassilief ZL2AFP. 73, Murray Greenman ZL1BPU ___ time

[time-nuts] Lady Heather question

2009-06-18 Thread Murray Greenman
John/Mark, I don't own a Thunderbolt, but I do have a very nice Trimble NTGS50AA GPSDO which works very well, and it also operates very nicely with TBOLTMON, in both TSIP and SCPI modes. However, I've just fired up Lady Heather V2.0 for the first time, and although the program starts, nothing

[time-nuts] FE-5680A heat sink

2009-06-09 Thread Murray Greenman
I think we've all learned from this. Good info about the Efratom unit, and sounds as though we should aim for around 38C with the FEI units as well. The FE-5680 looks to be easier to deal with than the FE-5650, so I'll look into that first. Murray ZL1BPU

[time-nuts] FE-5680A thermal management

2009-06-08 Thread Murray Greenman
Leigh, I agree with Chuck. I have both an FE-5650A and an FE-5680A. With the former I was concerned about the heat, and so ran it only for short periods, until I understood what was going on. I had the impression from the data sheet that there were different heatsink options for different

[time-nuts] Msg to N.Z. time nuts re time pips

2009-05-18 Thread Murray Greenman
Geoff, I'm not in a position to check at present, but have also noticed discrepancies in the time pips in the past. I'd not use a GPS receiver for this, as they can easily indicate a second or so out. I use a GPS Disciplined Receiver (HP Z3801A or Trimble NTGS50AA) for the job. I suggest you talk

[time-nuts] Wrong date on Samsung GCRU-D

2009-03-01 Thread Murray Greenman
My Samsung GPSDO is a very good and fairly new unit, but I've just spotted that the date it is reporting is incorrect! It should be 1 March, but it is reporting 29 Feb, and there isn't one this year. The GPS module I'm also running at present (u-BLOX Antaris) does report the date correctly. 73,

[time-nuts] Indoor GPS for GPSDO

2009-02-17 Thread Murray Greenman
You might as well forget using an indoor antenna for GPSDO use. For best performance, you need an antenna which sees the top of the sky (say down to 30° elevation) really clearly, and ideally you want an antenna designed for timing applications, which favours high angle satellites. This is

[time-nuts] Roof-mount GPS antenna

2009-02-17 Thread Murray Greenman
Down here in NZ, a common form of TV antenna mount is the 'hockey stick', which is a J-shaped pole with a plate for barge-board or gable mount (on a vertical surface) and a vertical pipe about 1m long and 20mm diameter. A typical pipe-mount GPS antenna is easy to mount on this, either directly

[time-nuts] Coddling your TBOLT

2008-11-19 Thread Murray Greenman
Personally, I'd just leave the TBOLT to get on with the job. It's probably a good idea to exclude draughts, but adding further insulation will probably not help matters and may hinder them. I'm thinking specifically of what happens to the ambient compensation of OCXOs when the insulation thermal

[time-nuts] Tek 602

2008-11-06 Thread Murray Greenman
Magnus, I can't help you with the manual, but I agree, it will be useful for TF applications. I have a newer model X-Y display (the one with storage, forget the model) which I intend to use for TF. By the way, for anyone who is wondering, a conventional TV Vectorscope works great as a phase

[time-nuts] STLN4096A / HP Z3817

2008-10-29 Thread Murray Greenman
Skip, How about sending me some photos of the unit? I know the Z3815A and E1938A well, and if it's the same in different packaging, I'll be able to tell. 73, Murray ZL1BPU ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to

Re: [time-nuts] time-nuts Digest, Vol 51, Issue 8

2008-10-05 Thread Murray Greenman
Steve, The suggestion of using the mains frequency as a reference is not practical. There will be no certainty, even after counting for a week that the mains frequency will give you a reliable reference. You said it yourself - the instantaneous frequency of the mains is not always spot on. The

[time-nuts] Mains and TV 50Hz

2008-10-05 Thread Murray Greenman
Hal and others, I am sure that if one could accumulate mains cycles long enough, a reasonable level of accuracy could be obtained, but you need to ask yourself (1) to what standard is this 'reference' traceable, and (2) what happens if there is a power failure? On this latter point, let's say

[time-nuts] Which GPS receiver?

2008-09-10 Thread Murray Greenman
Ulrich, Living where you do, I'd suggest checking out the U-BLOX range of modules. The model you need is the LEA-5T. The LEA-5 family is state-of-the-art, and I believe uses an ATMEL DSP software baseband engine (with reportedly one million correlators!) I have two of their modules (LEA-5H and

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