[time-nuts] Re: GPSDO - GPS1300-10-1000 by RFX Ltd. UK
I just acquired my second Bodnar GPSDO, a single frequency model. I have the two frequency model already. They don't do 1pps. They are sold in the US by Airspy but I have had better luck buying from SDR-Kits in the UK. Not much difference in price, they are friendlier and the delivery is just as fast. Wes N7WS. On 3/1/2022 4:11 PM, Tom Holmes wrote: John... If you haven't already, look into the Leo Bodnar GPSDO. It is a couple hundred bucks US, and the people I know who have them are pretty happy with them. Not sure off the top of my head if they make a PPS, however. And, he is in the UK. Tom Holmes, N8ZM ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: Where do people get the time?
On 1/2/2022 1:17 PM, Lux, Jim wrote: I watched a Titan IV launch from about 10km away. You saw the ignition, a 5-10 seconds later you felt the ground shaking, and the rocket was maybe 300-400 meters up and hitting the scattered clouds before the sound got to you 30 seconds later, and then you have the weird phenomenon of the rocket getting smaller and farther away, while the sound gets louder. ___ I did some work for the Standard Missile program when I was still at Hughes. As a perk I was invited to a test firing at White Sands, Because of a foul up, my security clearance wasn't received so instead of being in the indoor VIP viewing area I was relegated to some outdoor bleachers in the hinderlands where the countdown was from some distant speakers. By the time I heard it, the missile was long gone. Wes ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: Thunderbolts
https://v3.airspy.us/product/lb-gpsdo-mini/ I've been considering ordering a Bodnar just for frequency agility, but have been holding off out of concern for the complications of dealing with a foreign supplier. Dana ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: Thunderbolts ...
I guess I was thinking about being a man with three watches. I have a Leo Bodnar (dual frequency model) and a BG7TBL GPSDO, 2019 model, already. Leo makes (or made) two models, neither to my knowledge have ovenized oscillators. The programming software is not friendly on my model. The Chinese unit has an OCXO. I had it apart once and noted what parts were used, but I've misplaced those notes. I have no good method(s), equipment wise, to compare these. Wes N7WS On 7/20/2021 10:42 AM, John Ackermann wrote: The Bodnar GPSDO is great for what it is, and has the great advantages of small size, low power consumption, low cost, and frequency agility. But it doesn't have an OCXO so its short term and holdover performance isn't in the same league as the T'bolt or Z38whatever boxes. John ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: Thunderbolts ...
I wrote Tom, at the address he gave, on Saturday with a query. So far, no reply. Wes N7WS On 7/19/2021 4:59 PM, John Miles wrote: If you're looking for a low cost surplus GPSDO, the ones Tom mentioned in his post on Saturday are the ones you want. Not a Thunderbolt-E, and not something from the China surplus/e-waste market. -- john, KE5FX ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Test
No messages in weeks. ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: Best frequency to start for GHz synth ?
A bit more contemporaneous... it's too long a story to relate here, but I discovered that the internal speaker, as well as my voice, tapping on the case, etc would FM the VCO in the synthesizer in my Elecraft K3 transceiver. This was a birth defect that affected every one of them. They used my radio (never figured out why they didn't use one of their own) to come up with a fix that entailed bonding a 1/8" thick aluminum stiffener to the circuit card. This found it's way into production and a retrofit kit was offered for others. Wes N7WS On 4/1/2021 11:16 AM, Richard (Rick) Karlquist wrote: On 4/1/2021 10:32 AM, Lux, Jim wrote: And for what it's worth DROs have their microphonic problems too. We had a breadboard deep space transponder and you could demodulate your voice (poorly) using the spectrum analyzer's FM demod feature. Very cool. Unimpressive to the folks who wanted to push the technology. We were Back around 1970, as LM radio switched from AM to FM, the HP 608 signal generator was losing market share because it couldn't do FM. Believe it or not, there was actually an Ap Note describing how to obtain FM by bolting a 4" loud speaker to the 608 cabinet and driving it with an audio signal generator. Those were the days ... Rick N6RK ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: The Collapse of Puerto Rico’s Iconic Telescope [April 5th, 2021 New Yorker]
On 3/30/2021 4:33 PM, Lux, Jim wrote: On 3/30/21 2:56 PM, Wes wrote: You would know better than I, but I was thinking of physical size; 100m v. 70m. Obviously a BIG difference in TX power. Wes It's all about EIRP, baby. I know they're talking about half a megawatt for GB, but I don't see it happening. They've spent so much time making it "radio quiet", putting a big honkin transmitter there seems odd. Just think, a return loss from the feed of -30dB (which is pretty good) is good fraction of a kilowatt. But AFAIK the system is bistatic (pseudo-monostatic) so there's no local receiver to be subjected to transmitter leakage. We worried about leakage in the pulse doppler radars I'm familiar with; AMRAAM and Phoenix missiles, but even they were bistatic for most of their flights, tracking off the aircraft fire control radar which had significantly higher ERP. Only when close to the targets did they go active. Wes ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: The Collapse of Puerto Rico’s Iconic Telescope [April 5th, 2021 New Yorker]
You would know better than I, but I was thinking of physical size; 100m v. 70m. Obviously a BIG difference in TX power. Wes On 3/30/2021 2:00 PM, Lux, Jim wrote: On 3/30/21 6:40 AM, Wes wrote: Was a pity. China's FAST is receive only. I believe that leaves Green Bank as the biggest transmitting telescope. More likely the Goldstone Solar System Radar function of DSN on the 70m (DSS-14) - 500kW in X band at 8560 MHz There *is* a new transmitter for GB - but it's a demo - 700 W and temporarily installed up at the feed for a test. I don't know what frequency. People are pitching a 500kW system, but we shall see. ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: The Collapse of Puerto Rico’s Iconic Telescope [April 5th, 2021 New Yorker]
Was a pity. China's FAST is receive only. I believe that leaves Green Bank as the biggest transmitting telescope. I remember 417s. I had them in a copy of a design by W2AZL. I also had a two-meter preamp I designed using 416Bs. Of course uW cooled preamps are not unusual now, but back then a blower on a receive amplifier was unusual :-) Wes Stewart N7WS On 3/30/2021 4:06 AM, ew via time-nuts wrote: GOOD Morning Tom Thank you for the super information Read it over and over. To me no joy, sadness for Astronomy, Science, Puerto Rico and the US. China is now the leader with a 500 meter unit! Did follow it since the seventies because of the low noise receivers. Remember the 417 Triodes? I had some for Ham use. Any body knows what happened to its Maser? Bert Kehren ___ ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
Re: [time-nuts] Used Hydrogen Maser
Although Mr. Wineland's IQ must be at least 50 points higher than mine, we do have something in common. I too owned a '36 Ford in my youth, about the same time as he did, although mine was a Cabriolet not a coupe, and I fitted it with an OHV Studebaker V8, a smaller displacement clone of a Cadillac V8. Wes N7WS On 2/6/2021 1:23 PM, Tom Van Baak wrote: > ptti/1981papers/Vol%2013_30.pdf Note the dialog on the last page. Dave Wineland went on to win the 2012 Nobel prize in Physics: ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] 20th year of time nuts mailing list
Congratulations Tom! Happy, prosperous and healthy New Year to you and all of the other nuts. Wes Stewart, N7WS On 12/31/2020 10:02 PM, Tom Van Baak wrote: Hello time nuts, Ah, it is 2021-01-01 (JD 2459215.5, MJD 59215) which is nice because that means it's not 2020 anymore. One reason I've been looking forward to 2021 is that it's now officially the 20th year of the time nuts mailing list. So this is a note to say *thank you* to everyone for making it so amazing over the years. I get comments all the time about this mailing list; its depth, its high SNR, its focus, its vast archive of quality postings, and especially, the community that evolved around the list. On the web the phrase "time nut" is now a proper noun, sometimes an adjective, or occasionally a diagnosis or disease. Never in my wildest dreams did I think any of this would happen. I thought my early interest in nixie tubes, clocks, electronics, and precise timing might be a passing phase, and that the frequency of eBay purchases would fade. But no. This turns out to be an incredibly wide, deep, interesting, and rewarding hobby. The mailing list started with 6 people (half of whom are still active) and we now have 1850 members. [1] Speaking of history, and also to put time-nuts into perspective, I'd like to mention that leapsecond.com (tvb) and febo.com (jra) predate Y2K (2000), wikipedia (2001), facebook (2004), youtube (2005), twitter (2006), reddit (2006), iPhone (2007), duckduckgo (2008), gmail (2004, 2009), eevblog (2009), instagram (2010), snapchat (2011), outlook (2012), and literally millions of other web sites and mailing lists. When this all started for us it was WWV on short-wave, ACTS by phone, Loran-C, GOES, WWVB, GPS, Win98, dial-up, and my search engine was altavista.dec.com. It's scary to think how much has changed in 20 years. Fun fact: I started leapsecond.com so I could post the results of a Y2K Colorado visit to NIST. If the world was going to crash I was going to be at ground zero, with a camera. [2] Anyway, stay safe, stay healthy, stay timely. Here's to a new decade and a happy new year to all of us. /tvb [1] http://leapsecond.com/time-nuts.htm#history [2] http://leapsecond.com/y2k/ ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Examples of traditional phase noise analyzers
The paper "Choosing a Phase Noise Measurement Technique", available on John Miles' site might be of interest. BTW, I worked with one of the authors, Terry Decker, for some years at Hughes. Sharp lady. Wes On 12/17/2020 4:02 AM, Attila Kinali wrote: Good afternoon, In the process of writing my thesis I stumbled over the problem that the definition of what phase noise is in IEEE 1139 is a bit confusing, to put it mildly. After a short discussion with Magnus, it seems clear to me that I need to have a better understanding of how phase noise measurement was done in the past to properly understand what the standard means to say. I think, I have a decent grasp on how modern phase noise analyzer work, safe for a few details here and there, where they seem to try to mimic what the old analog analyzers did. Before I go on a wild goose chace, I thought I ask here for advice: Could you point me at as detailed as possible descriptions on how phase noise analyzers used to work in the purely analog times? Preferably also as many different approaches as possible. And, if you are aware of anything that I should have a look at that might not be obvious to a youngster like me, I would very much appreciate if you would let me know. Thanks in advance Attila Kinali ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Looking for "The Theory and Design of Quartz Crystal Units" by V.Bottom
Attila, Amazon says (Out of print): * Publisher : McMurray Press; 1st Edition (January 1, 1968) * Language: : English * ASIN : B0007H97C8 Not exactly the same book but the same author: "Introduction to quartz crystal unit design" There seems to be a copy in the UK https://www.abebooks.com/servlet/BookDetailsPL?bi=30743123492_ven=sws_cat=sws_pla=sws_ite=30743123492=Qzn1vAxnixyLUx7wUx0Mo3bxUkExvSymuVekS80_mmc=aff-_-ir-_-353196-_-77798=imprad353196_sr=impact Also for what it's worth: https://archive.org/details/introductiontoqubott/page/n9/mode/2up?q=introduction+to+quartz+crystal+unit+design Wes N7WS On 10/23/2020 2:11 PM, Attila Kinali wrote: Moin, I'm again hunting for some old stuff. Quite a few older papers, books and technotes (including an article by Bernd Neubig from 1978) reference V.Bottom's "The Theory and Design of Quartz Crystal Units" from 1974 Unfortunately, the internet does not seem to have that, neither could I find it in any library I have access to. Does someone know where that was published, or who might have a copy of it? Attila Kinali ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Oscilloquartz BVA has been sold. Thank you all who expressed an interest.
When I was still RVing and wanted an electrically quiet charger I built my own "smart charger: using the guts of an Astron 35A linear power supply with an added uc3906 based controller. I later replaced it with a higher efficiency Iota 30A supply with an IQ4 charge controller. It doesn't hurt that they are based here in Tucson :-) Wes N7WS On 9/25/2020 11:25 AM, John Ackermann N8UR wrote: I've had good luck with Iota brand chargers for 12 and 24 volt... I think they are "DCL" series or something similar. They are available in various amperage and include a smart-charger circuit. I know Amazon sells several models and the prices are in the $100-200 range. One of their selling points is that they are electrically quiet, though I haven't done any real tests, and are designed to work as a regular power supply (ie, they don't flake out if there's no battery load attached. John ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] HP 5316B External Reference
Thanks again for your insight Rick. I'll be passing on acquiring one of these. Wes N7WS On 7/13/2020 9:02 AM, Richard (Rick) Karlquist wrote: On 7/13/2020 6:26 AM, Wes wrote: Hi Magnus, I did have the manual when I posed the original question but I had not delved into the cal procedure until you mentioned it. It seems to be a bit complicated for what it does. I wonder how stable this is and how often might it need to be repeated. Why they didn't use the external reference more directly is a puzzle. I appreciate your time in looking into this. Regards, Wes I don't know the specific engineer who designed this injection locking scheme, but IMHO it's a "too clever by half" sort of thing (and that's being charitable). Unfortunately, I encountered many examples of that in the 5334A, and other counters. I took out around a dozen of these "clever" circuits in the process of replacing the 5334A with the 5334B. The engineers involved were outside their lane as the saying goes; I actually talked to them about why they designed the circuit in that way. Didn't have a valid reason IMHO. Just having been in that environment, I would be distrustful of the 5316 design for anything important application like time nuts work. Actually, I would be distrustful of any injection locking multiplier no matter who designed it. Unfortunately, you can't conclude that a design is good simply because it came out of HP. In some ways, it was disillusioning to go to work for HP and see what is really going on. Rick N6RK ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] HP 5316B External Reference
Thank you Paul. On 7/11/2020 6:59 PM, paul swed wrote: Wes many of the HP sig gens and counters use that method I might guess starting in the 70s. They all lock very well to the external reference and are as good as the external reference is. One gotcha. It seems some people pull the oscillators to sell on auction sites. So if its missing thats a bit of a mess to deal with. Regards Paul ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] HP 5316B External Reference
Thanks for your insights Rick. The manual specifically states: "The HP 5316B does not actually use the external input signal for a time base but locks-on to the signal with an injection-lock-multiplier. The external signal must be 1,5, or 10 MHz" My only experience with injection locking was with the Phoenix Missile IMPATT diode "amplifier" which was actually three circulator-coupled oscillator stages using one, three and sixteen diodes respectively. I don't currently own one of these counters, I'm just investigating the idea of using one for off-the-air frequency measurements where the unknown is mixed down to audio. Wes N7WS On 7/11/2020 6:46 PM, Richard (Rick) Karlquist wrote: On 7/11/2020 3:51 PM, Wes wrote: As I understand it this counter has an external reference input that isn't used directly as the time base but injection locks the internal time base. Does anyone here know how well this works. Is using a GPSDO as a reference a worthwhile accuracy improvement? Wes Stewart N7WS I worked in Frequency Counter R at the HP Santa Clara division around the time the 5316B introduced, but didn't know about this detail. AFAIK, most counters we made did NOT work this way. Whatever external reference you fed in (warts and all) was used to clock the counter. OTOH, most RF instruments (other than counters) used a PLL (not injection locking) to lock the internal oscillator to the external reference. IMHO, this architecture only made sense on sig gens and spec ans, not on counters. I will point out that the 5316B was a cost reduced version of the 5316A. I was the project manager for the 5334B, which was a cost reduced version of the 5334A. I believe there was a third model where the B version was cost reduced from the A version, but I don't remember which one. As a group, these were called the "killer B's" because they would supposedly kill off Racal Dana sales or some silly marketing nonsense to that effect. It's possible that for some obscure reason, a scheme was employed to save money that superficially resembled injection locking. I'm guessing a multifunction chip was used that had a built in oscillator with an external crystal, but no access to the connection from the oscillator output (on the chip) to the downstream circuit. Are you sure that the 5316B actually uses injection locking, rather than having the external reference simply drive the crystal pins on the IC? This would be easy to verify by feeding in an external reference that was say 100 ppm off frequency and seeing if the counter still worked OK. No injection locking scheme AFAIK would ever pull that far. If it actually is true injection locking, the problem is that whether it worked would depend on the relationship between the free running frequency and the external reference frequency, of course. IOW, it might work in some cases and not in others. Rick N6RK ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] HP 5316B External Reference
As I understand it this counter has an external reference input that isn't used directly as the time base but injection locks the internal time base. Does anyone here know how well this works. Is using a GPSDO as a reference a worthwhile accuracy improvement? Wes Stewart N7WS ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Vibration isolation of quartz oscillators
In my youth I worked for a time in my dad's automotive machine shop. We did a lot of work on medium-sized industrial engines, Cummins V-12s, GMC V16-71s, International TD-24s, etc. To handle these we bought a Van Norman crankshaft grinder, a sizable machine, which I operated. The shop was in downtown Tucson, right across the street from the (then) Southern Pacific Railroad tracks. The grinder was originally installed right on the 6" thick concrete slab floor. It wasn't long before I noticed that if I was grinding a journal when a trail rumbled by I got runout and had to pause grinding until the train passed We wound up moving the machine and digging a hole about 2-3 meters deep and about 2 by 3 meters "square", lining it with fiberboard and filling it up with concrete and reinstalling the machine on top. About two years ago that building was demolished as part of a "modernization" of downtown (it's still a vacant lot) and I wondered how surprised they were when they went to remove the slab. Wes N7WS On 6/28/2020 8:05 AM, Dr. David Kirkby wrote: Dr David Kirkby Ph.D C.Eng MIET Email: drkir...@kirkbymicrowave.co.uk Web: https://www.kirkbymicrowave.co.uk/ Kirkby Microwave Ltd (Tel 01621-680100 / +44 1621-680100) Stokes Hall Lodge, Burnham Rd, Chelmsford, Essex, CM3 6DT. On Sun, 28 Jun 2020 at 12:44, Tom Van Baak wrote: About slabs and stability... Around the world there must be a hundred precision time labs, including official NMI (National Metrology Institute) labs that contribute to the calculation of UTC itself. You run into photos of these labs and their T gear on the web all the time when you search for time nutty stuff. Those of us with home labs -- even if just a few vintage frequency standards -- can relate. Anyone, one of my favorite lab photos is from VSL, the Dutch Metrology Institute. Photo attached. [1] Spend time time pan/zooming around the gear in the photo. The usual suspects: hp 105 quartz; TimeTech (I think); lots of SDI (Spectradynamics); also Truetime or Symmetricom stuff; maybe that's an old Tracor/Fluke VLF receiver on the far right (?); and of course lots of Stanford Research SR620 counters, the TIC still used by almost every time lab. But what really caught my eye was not just the four hp 5071A in the foreground but *how they are mounted* -- on top of massive granite blocks! There's a picture of a granite block here, at a former place I used to work as a student - EQD Aquila, the MODs calibration labs. https://www.derelictplaces.co.uk/main/military-sites/14101-aquila-mod-testing-facility-bromley-march-2004-a.html#.XvirQuco9PY about 60% of the way down the page. (Some of the pictures are quite amusing, as well as some of scientific interest). There's a couple of guys at my radio club used to work somewhere where a milling machine was turning high precision device. I just phoned one to ask what they used for anti-vibration, as I knew they took some precautions. He said they had dug a hole about 2 m into the ground, above that was 600 mm of "rubber", then 1.4 m of reinforced concrete. That used to stop lorries messing up the work. That's a different sort of application. I assume the OPs objects are quite large - not wrist watches. Otherwise, I was wondering if an active damping system might be practical. They certainly exist for laser tables https://www.newport.com/n/active-vibration-damping but I would imagine that for heavy 19" rack equipment, there would need to be quite a bit of power consumed in such a system. I've never done any calculations - just intuitively, I can't imagine that one could achieve anything useful without some pretty big power amplifiers. When I worked at UCL we had a laser table. Our department was near a main road. The laser table had gas-filled "dampers", but apparently these made the vibration problems worse rather than better, so the gas was removed. We never had any active system. Dave ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] ThunderBolt question
Dana, I have about 45 feet of RG6 into a two-way splitter, currently feeding two receivers, a BG7TBL GPSDO (U-blox) and a TAPR/Synergy GPS Timing Kit (M12+). So each device has about 7 dB loss in front of it. As a crude test if I add a stepped attenuator in the line to the TAPR receiver and look at the dBc report in LH, a 10 dB step is hardly noticed, but a 20 dB step makes a noticeable change. I still see tracking at 30 dB but at 40, gone. So there is a lot of margin but I don't see any issues and the plan is to go to a four-way split and add a couple of devices. I'm in a rural area outside of Tucson so hopefully Ligado won't be an issue. We'll have to see if their technical expertise is as good as the PR and lobby lawyers are. Wes On 6/6/2020 8:49 AM, Dana Whitlow wrote: Wes, it sounds like you're in pretty good shape with one thing that concerns me. Unless your transmission line is long enough to have substantial loss, that 40 dB gain figure seems awfully high and you may find yourself overloading the front end of your receiver. Most modern receivers are sensitive enough to do just fine with no antenna LNA at all, in the absence of line loss. I remember reading a note from Garmin on this topic years ago when they were recommending no more than about 15 dB net gain between the antenna and the receiver. With your receiver and 40 dB antenna, even if it seems to work well now, beware of Ligado! If/when they go on the air near you, you may find yourself needing an attenuator. Dana ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] ThunderBolt question
Conventional wisdom says yes to this. I'm not so sure, if the cable is well-made, but some of the stuff is really garbage. I'm using RG-6 cable purchased at DX Engineering, mainly because I had a gift certificate for my last order. It's quality stuff, but if you're going to use F connectors be sure they will work with quad-shielded. I bought some (blue) that were claimed to work and there was no way in hell that I could get them on. I had to buy another batch (purple) that do work. Regarding mismatches; my recently installed antenna is a PCTEL GPSL1-TMG-SPI-40NCB. This is advertised as a "timing" antenna, so I assume they're worried about timing. The data sheet says the "nominal impedance" is 50 ohm. Butthe VSWR spec is <2.0:1. Of course this antenna has an internal amplifier (40 dB), whose match to the helix antenna is unknown but I'm guessing it's for NF optimization. So is the spec the nominal output Z (s21) of the internal amplifier or is it the load the amplifier needs to be presented with to deliver advertised gain? Who knows? Either way, my 75 ohm coax is within limits. Wes N7WS On 6/5/2020 4:56 PM, DON MURRAY via time-nuts wrote: Robert... Try to find QUAD SHIELD RG-6. 73 Don W4WJ ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] ThunderBolt question
A 1.5:1 SWR = ~14 dB return loss. On 6/5/2020 6:42 PM, Tom Holmes wrote: Dana... I think that you are neglecting two important mitigating factors. 1. the cable loss at 1575MHz, even for a 25' run of RG-6, reduces those reflections quite a lot from one end to the other. It amounts to 2 - 3 dB in 25', depending on cable quality. 2. a 1.5:1 SWR is not a very big reflection to begin with, on the order of 20% of the incident power, about 7 dB. I am rounding a lot here just to keep the math easy...for me. By the time a reflection has made the round trip from the receiver back to the antenna and them back to the receiver, which is how the delay would have to manifest itself, it will be down at least 15 dB from its original self, and probably more. Given the coding of GPS signals which allows several satellites to share a common frequency band, that is not going to be much of a problem. And if only one end of the path actually is 75 ohms, then there won't be a delayed signal. Tom Holmes, N8ZM ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] time sync by moonbounce
You talked me in to it. Wes N7WS On 5/23/2020 8:19 AM, Jeremy Nichols wrote: Sufficiently interesting that I bought a paper copy through Abebooks. Looks like a somewhat later version, author given as Douglas Mudgway, title “ Uplink-Downlink: A History of the Deep Space Network 1957-1997.” “Oversized,” 674 pages. Abebooks lists a couple dozen copies in both hardback and paperback at prices from reasonable to ridiculous, as is usual for bookstores. Jeremy On Sat, May 23, 2020 at 3:47 AM ew via time-nuts wrote: This is a must read. Could not put it down, JPL, NASA, Eisenhowe,r did learn a lot at the same time fascinating Bert Kehren In a message dated 5/22/2020 10:36:53 PM Eastern Standard Time, jim...@earthlink.net writes: Apparently, they used moonbounce between DSN stations to synchronize to 5 microseconds in 1968. It was easier and cheaper than flying cesium clocks around. (And the Rb standards weren't good enough). https://ntrs.nasa.gov/search.jsp?R=19770007245 History of DSN - mostly about politics, history, transmitters and receivers, but a whole section on timekeeping, phase measurements, etc. starting around page 133 (The DSN Inherent accuracy project), and the discovery during Mariner that UTC and UTI were different enough to cause nav errors. ___time-nuts mailing list -- time-n...@lists.febo.comTo unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.comand follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] OCXO Support Board
I can remember "wiring" up some X-band test equipment with WR90 waveguide, flanges and a brazing torch. We "miniaturized" the missile hardware by using 1/4 height W/G. Circa 1966. Wes On 5/13/2020 9:12 AM, ew via time-nuts wrote: You give away your age, was there did a lot of it and off to the repro shop and than the board manufacturer. All local in Houston. Bert Kehren ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] OCXO Support Board
AC0XU (Jim) I responded to your email address and it bounced. I would be happy to get a board from you. Let me know how to proceed. Thanks, Wes ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] OCXO Support Board
Thank you to all who have written, on and off list, with offers of boards and advice on how to make my own. Much appreciated. I think I'm on to one that meets my fairly simple needs and uses through-hole components. I have done SMT construction in the past but things have shrunk in size by an order of magnitude since then it seems. (I can remember laying out boards by hand, taping up the artwork 4:1, reducing it photographically, exposing and etching boards. So today's technology is magical.) Many of you are doing some awesome work. Well done. Wes N7WS ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] OCXO Support Board
Does anyone know of a ready made board that will allow me to mount and at the least, minimally support the operation of an MV89A oscillator. I have one which I've powered up deadbug style and would like to clean up the mess a little. Thanks Wes N7WS ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] GPSDO advice on BG7TBL DO
Bill, Yes, thank you, I am subscribed to this. In a response to a pre-purchase question about the innards the seller responded: "3627-CTS OCXO,ublox-u8 module we offer two years warranty,so feel free to contact us if you get any problem." I finally got LH to listen to it last night. The receiver is amazing. I'm receiving 10 birds with the puck antenna inside. The Motorola Oncore sees 5 or 6 as does a Garmin GPSMAP60. Wes On 5/3/2020 6:56 AM, Bill Notfaded wrote: Wes- A great resource for info is the BG7TBL master thread at eevblog. We track everything we know about these units to compare them: https://www.eevblog.com/forum/testgear/bg7tbl-gpsdo-master-reference/ Bill ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] GPSDO advice
The seller and the PO did a yeoman job and the device arrived at 1 PM this afternoon. It turns out to be a date code 2019-08-03 instead of the pictured 2018 unit. A pleasant surprise, but not the latest which is (I think) 2019-10-20. This one still says, "GPS Disciplined Oscillator", the newer one says, "GNSS Disciplined Oscillator." The OCXO is a CTS, labeled "970-2178-46". The receiver is unlabeled. I powered it up and it indicated lock in about 10 minutes using the supplied puck antenna on the workbench inside the house (concrete exterior walls.) For comparison, the TAPR Kit M12+ Oncore receiver located a couple feet away with a similar antenna situation shows lock on only three satellites using LH) That said, the only way I have to evaluate it is with the BG7TBL FA-2 counter with a Bodnar reference that has been running for weeks. It's continued to drift for over two hours and now has approached 10 MHz but is still wandering around 4-5 mHz with respect to the Bodnar. Which is correct is anyone's guess. I guess the next project should be to get the external antenna mounted and splitter installed so everything is using the same source. Wes ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] GPSDO advice
Good question and the answer is, I don't know. The photo shows June 2018, but who know whether that's representative. Being antsy, I opted to buy from a seller in the US with quick shipping, rather than waiting six weeks for one from Asia. On 5/1/2020 8:37 PM, Bill Notfaded wrote: Did you get a newer one with late 2019 at least on the front BG7TBL panel? The one I got doesn't have the frequency offset bug and works really well. It locks on multiple birds really quickly. For the money it's hard to beat. I've been comparing it to my Thunderbolt E. It obviously doesn't provide the extra info you get with Trimble protocol (so no ocxo info in Lady Heather) but I'd say it locks onto a lot more and faster than my Trimble does even if I put it on GPS only constellation for fair playing field. I hate to say it but I'm not sure my Thunderbolt is really much better. You won't be sorry if it's a later BG7TBL GNSS model. I've been running mine on GPS and Galileo lately. Bill ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] GPSDO advice
Hi Bob, According to the USPS tracking number I'll have a BG7TBL GPSDO on Monday :-) I really wanted to "Buy American" but a 10 dB price difference is worth taking the risk. Wes On 5/1/2020 7:29 PM, Bob kb8tq wrote: Hi I would guess that the vast majority of folks on the list and an even larger percentage doing the FMT are buying their GPSDO’s on eBay. Which ones they buy and how well the work is very much a “that depends sort of thing”. The crop of devices at low(er) prices changes every 3 to 5 years. Whatever is being torn apart right now will be contributing the low cost stuff. If you bought 5 years ago your choices were very different. Go back 5 or 10 years past that and the devices change again and then again. There’s no reason to believe that “things were better in the old days”. Mostly just different. The issues have been worked out on stuff that hit eBay 20 years ago. That’s just the way it works. How well they have been worked out …. that depends on the device and how picky you are. This does not simply apply to GPSDO’s. A while back eBay was awash in telecom Rb’s. Some bought so many they can’t keep track of all of them. Today a $35 listing for an Rb is pretty unusual. That’s just supply and demand. Wait another 5 or 10 years and we probably will be awash in cheap ones again. Right now “entry level” GPSDO’s are still below $100 delivered. That’s not all that crazy compared to a lot of gear in a typical shack or on a typical bench. Bob On May 1, 2020, at 9:25 PM, Wes wrote: An update on this: I emailed both Jackson and Brandywine for prices on both the Desktop Fury, in Jackson's case, and the board versions from each of them. The good news is that they both were responsive. The bad news is they are both out of my price range. Jackson by about 3 dB. Brandywine clearly didn't want to sell me anything, as exemplified by a fee of $47 to use a credit card. As much as I would like to be more nutty, I can't justify spending this kind of money just to participate in ARRL FMTs where the only direction I have to go is down. Wes N7WS On 4/24/2020 11:56 AM, Wes wrote: Taking some of the advice offered, I've emailed them for P I'll let you know if I hear back. Wes On 4/24/2020 10:45 AM, Kevin Rowett wrote: On Apr 24, 2020, at 10:32 AM, Mark Spencer wrote: Speaking both as an amateur radio operator and some one who modestly pursues precision time and frequency as a hobby, I am extremely happy with my Jackson Labs Fury GPSDO. Speaking of Jackson Labs, has anyone heard from them, since the lockdown commenced? KR ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] GPSDO advice
An update on this: I emailed both Jackson and Brandywine for prices on both the Desktop Fury, in Jackson's case, and the board versions from each of them. The good news is that they both were responsive. The bad news is they are both out of my price range. Jackson by about 3 dB. Brandywine clearly didn't want to sell me anything, as exemplified by a fee of $47 to use a credit card. As much as I would like to be more nutty, I can't justify spending this kind of money just to participate in ARRL FMTs where the only direction I have to go is down. Wes N7WS On 4/24/2020 11:56 AM, Wes wrote: Taking some of the advice offered, I've emailed them for P I'll let you know if I hear back. Wes On 4/24/2020 10:45 AM, Kevin Rowett wrote: On Apr 24, 2020, at 10:32 AM, Mark Spencer wrote: Speaking both as an amateur radio operator and some one who modestly pursues precision time and frequency as a hobby, I am extremely happy with my Jackson Labs Fury GPSDO. Speaking of Jackson Labs, has anyone heard from them, since the lockdown commenced? KR ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] GPSDO advice
Hi Bob, Honestly, I don't have any particular holdover requirements in mind, just that it has some :-) This is just one of those nutty things. You must understand. Wes N7WS On 4/24/2020 10:14 AM, Bob kb8tq wrote: Hi On Apr 24, 2020, at 12:56 PM, Wes wrote: No, I'm not looking for advice on how to build one but what I might buy. My need is strictly hobbyist (ham radio). I currently have a Bodnar dual frequency unit, that gives me frequency and a TAPR, (Synergy Systems) that gives me 1 pps, but I would like something that gives me both, with better performance (holdover). ….. holdover? What are your holdover requirements and what drives them? That is likely to have a significant impact on “what makes sense”. Holdover on most GPSDO’s is driven by a network timing requirement ( X us over Y hours ….). Most basement lab needs are not driven in the same fashion. The Jackson Lab FireFly-IIA I’m sure a call to Jackson Labs will get you the current price on any of their products. Bob and the lookalike Symmetricom GPS-2500 both look interesting. But, price and availability are elusive. Any advice on these or alternatives will be appreciated. Wes N7WS ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] GPSDO advice
Taking some of the advice offered, I've emailed them for P I'll let you know if I hear back. Wes On 4/24/2020 10:45 AM, Kevin Rowett wrote: On Apr 24, 2020, at 10:32 AM, Mark Spencer wrote: Speaking both as an amateur radio operator and some one who modestly pursues precision time and frequency as a hobby, I am extremely happy with my Jackson Labs Fury GPSDO. Speaking of Jackson Labs, has anyone heard from them, since the lockdown commenced? KR ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] GPSDO advice
No, I'm not looking for advice on how to build one but what I might buy. My need is strictly hobbyist (ham radio). I currently have a Bodnar dual frequency unit, that gives me frequency and a TAPR, (Synergy Systems) that gives me 1 pps, but I would like something that gives me both, with better performance (holdover). The Jackson Lab FireFly-IIA and the lookalike Symmetricom GPS-2500 both look interesting. But, price and availability are elusive. Any advice on these or alternatives will be appreciated. Wes N7WS ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] 10811 performance
A long time ago when the Titan Missile sites that ringed Tucson were being shut
down, the Air Force approached Pima Community College with a request for a class
that would prepare some of the techs who were losing their jobs with training in
microwave theory and measurements. A coworker of mine at Hughes, who had been
tenured at the U of AZ, ("They can't fire you but they can make you want to
quit") agreed to take the job of teaching the theory part but didn't want to
teach lab work. He asked me to share the job.
I held the labs in their shop on the base. I was astounded when at the end of a
session they put all of the equipment in storage cabinets, wiped down the
workbenches and mopped the floors. The equipment included an HP5245L counter,
unplugged and tucked away for the night.
I decided my next session would include a discussion of time bases and why you
needed to keep them powered at all times. Afterwords, I was approached by a
woman Sgt. who told me that when she was sent out to a silo to make an
adjustment, that from the sound of it included an hour or so comparison to a
WWVB receiver, she instead just threw the '5245 in the truck and used it to
tweak whatever it was. I was forever grateful that we never fired any of these
in anger.
Wes N7WS
On 1/5/2020 7:50 PM, Bob kb8tq wrote:
Hi
Well, back in the 1970’s the orders went out for most government labs that they
*must*
power gear down at night. They had to re-wire so that the OCXO’s did not stay
powered
on …… Apparently somebody did the math and decided it did matter.
Bob
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Re: [time-nuts] FA2 Programming
Thank you, Mark. That worked beautifully. BTW, for my unit and taste, a value of 45 was the best compromise between contrast and viewing angle. The latter changes with contrast. Wes On 10/3/2019 3:54 PM, Mark Sims wrote: The command $Cxx* will set the contrast. xx can be 00 to 63. Ignore the measurement data that the FA2 sends continuously and just type over it (or disconnect the input signal). It should respond with something like CONTCOK if the command is accepted. Note that the value is stored in EEPROM and there is no way to read back the current setting. Note that the FA2 (rather weirdly) uses the '*' character as the end-of-line character when sending commands instead of the much more rational carriage return key... perhaps China has a shortage of keystrokes ;-) I am currently adding the various FA2 config commands to Lady Heather. --- I am able to connect using USB and tried Putty in serial mode. When I connect the port, the FA2 dutifully starts outputting the measured frequency but that's the extent of my control, or lack thereof. Has anyone more skilled than I done any programming? ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] DC distribution
On 10/4/2019 12:17 PM, MLewis wrote: With audio signals, a soldered crimp is one of the worst possible connections. Please explain. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] FA2 Programming
I finally got my FA2 yesterday. Seems to work fine, except for one thing (so far) the screen is blinding and viewable from only straight on. I'm afraid it won't last long in this state. According to the manual there is a programmable adjustment for contrast but my programing skills ended with writing instrument control software in HP Basic in the 1980s. I am able to connect using USB and tried Putty in serial mode. When I connect the port, the FA2 dutifully starts outputting the measured frequency but that's the extent of my control, or lack thereof. Has anyone more skilled than I done any programming? Wes N7WS ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] FA2 counter
An impedance sweep of the input might give a clue about the LPF. When I get mine I'll measure it. On 9/27/2019 11:43 AM, Mark Sims wrote: A list member did some experimenting with the unit and came up with this very useful information: "press and hold RST button, then MODE toggles LPF (low pass filter), GATE toggles input impedance" I wonder what the LPF cutoff freq is? I am currently doing a noise floor test (connect ref out to input) on my FA2. The initial (12 hour) results are REALLY good... ADEVs at long (1+) tau are in the high E-15 range. I'll post results after I get 24 hours of data. That annoying freq offset of the FA1 is gone. A 12 hour average of the FA2 freq readings is 10,000,000.000 001 Hz (FA2 clocked by a 5071A). ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] FA2 counter
Thanks for the input. I just ordered one. (My 78th birthday will be next month. I should be downsizing but here I am buying more stuff.) Wes N7WS On 9/26/2019 6:25 PM, Mark Sims wrote: Miy FA2 came in today. A very quick test shows that it works. It does not appear to have the -0.0002 Hz freq measurement bias that the FA1 has. The 0.1 second gate time mode is pretty useless... there appears to be a 300 msec dead time between measurements in 0.1 (and 10 sec) gate time modes so you only get a new reading every 400 msecs. 10 second gate time produces a reading every 10300 msecs. 1 sec gate time outputs readings every 1100 msecs (like the FA1). It auto-detects the presence of an external reference... no way to manually switch between internal and exterrnal references. I have not done any testing on the internal ref or the high freq channel. The screen shows a LPF setting and a 50 ohm setting... no idea if these are switchable there is no documentation. The screen shows the input signal level. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] FA-2 Precision Frequency Counter BG7TBL 20190622
I saw that too a few days ago and was intrigued. It sort of looks like an FA1 with some smarts and a display. I'm also interested in others' experience. Wes On 9/4/2019 9:53 AM, Perry Sandeen via time-nuts wrote: Yo Bubba Dudes!, While looking on ebay at the BG7TBL FA1 analyzer I looked on the bottom of the page where other items are advertised an saw ads for the FA-2 Precision Frequency counter which is sold by multiple vendors in the $115 range. As I have to down-size It appears to be just what I could use albeit it requires a wall-wart PS.:( It seems to have a very good price/performance ratio. Does anyone have one or experience with one and could share their experience? Regards, Perrier ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] FSA3011 Frequency Stability Analyzer, HP 8405A or TAPR TIC
I have an 8405, fortunately in excellent condition, along with the BNC adapters, the resistive splitter and the 50-ohm line samplers. The probe tips are very delicate and are probably unobtainium these days. The electronics in the probes can be repaired. I've been careful with mine and had no failures, but I did repair another one many years ago. (See: http://www.peakbagging.com/Electronic/HP8405A%20repair.pdf) One can digitize the analog outputs which I did for some test or another about 40 years ago. Wes N7WS On 7/30/2019 5:30 AM, Bob kb8tq wrote: Hi The 8405 is a fine device and with working probes can be very useful to have around. Without the probes .. not so much. Since they have been around since the 1960’s, the probes may have seen quite a bit of wear and tear. For comparing standards, an RPD-1 and a DVM will kind of / sort of do the same thing. A pair of RPD-1’s and a quadrature hybrid into a pair of DVM’s (or ADC’s) will very much do the same thing. Bob On Jul 30, 2019, at 2:04 AM, Perry Sandeen via time-nuts wrote: Yo Bubba Dudes!, I've been following the discussion of the FSA3011 with great interest. Now I'm not in the upper levels of TN esoteric knowledge or have a burning desire to ever get there. After seeing some small reference somewhere I looked at the HP 8405A on ebay and the price range seemed comparable to the FSA3011. Now the HP 8405 is a huge beast but i was thinking that it might be easier for me to use. I'm interested in just 5 and 10 MHz oscillator comparison. I know nothing about computer programs or writing any code. I also looked at the TAPR TIC. So my conclusion are: The FSA3011 may be technically the best BUT it seems to be having some teething problems and I don't really know about what programs it runs or needs. The HP 8405A is a big beast, but it maybe simpler for me to run and get the results I want which is stopping around 10 to ^12th. But I may have to watch it for a long time. The TAPR TIC is small (needed) cheaper (also a plus) and seems to run available software. but needs a dedicated laptop, which is not a real problem. I also have several extra HP 18011's available. Your opinions are gratefully solicited, Regards, Perrier Perrier If I can just download programs AFAIK I could use the TAPR TIC as I have a spare laptop that I could dedicate for its use. The two advantaages ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Garmin GPS12XL V3.51
Mine had the batteries out for about a year. Put some fresh ones in, turned it on and set it outside for several minutes. It located position and is showing today's date and time just fine. Software version on mine is 4.58. Wes It had to On 4/6/2019 12:10 AM, David J Taylor via time-nuts wrote: Just checked my wonderful Garmin GPS12XL tonight. before midnight UTC I checked navigation and UTC time and all was well. I did not bother to check date for some reason. Well now April 6 2019 at 03:39:19 UTC I see the time is 21 August 99 and no apparent way to change. The navigation and time seem correct. I heard there was a way to reset these to current date. Any thoughts? Can I still use this as a tool for gathering waypoints with precision? Joe Leikhim == Joe, My 12 XL runs 24x7 so I tried switching it off and on, and the date and time are still correct, but maybe that's stored data it's using? When it boots, it shows 4.60 (1966-2003) as the software, so perhaps you can update? Whether that fixes the issue I don't know Cheers, David ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] multimeter
I have a Fluke 87V that I bought from a fellow on one of these reflectors for about a third the price of new. It does more than I need. A lesser model would be fine for general purpose use. As we used to say in the lab at work, "If it works, it's a Fluke." Wes N7WS On 3/23/2019 5:05 AM, Jim Palfreyman wrote: Hi all, I think I'm in the market for a new digital multimeter. Could I have some recommendations? Jim ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] HP History with Dymec: "Becoming Hewlett Packard. Why Strategic Leadership Matters"
A little more topic drift, but on the subject of books about HP (forgive me if this one has already been mentioned) I have a copy of "Inventions of Opportunity: Matching Technology with Market Needs". This is mostly selections from HP Journal with an introduction by Bill Hewlett. It does have a couple of Timenuts stories: "The High-Speed Frequency Counter---A new Solution to an Old Problem", which describes the HP 524 from January 1951 and "A New Performance of the "Flying Clock" Experiment" from July 1964. Wes N7WS On 1/23/2019 6:41 PM, Rice, Hugh (IPH Writing Systems) wrote: Hello Time Nuts, Being a bit new to HP (only 35 years), I never head of Dymec before. A quick Google search yielded this link, which is an excerpt from the book "Becoming Hewlett Packard, Why Strategic Leadership Matters." You can read about 10 pages of the book from the preview, which talks about HPs creation of the Dymec corporation, which then became a division. Scroll back to page 102 for some context. https://books.google.com.sg/books?id=Zr1jDQAAQBAJ=PA104=PA104=dymec+company+history=bl=Q_66Bj1viA=ACfU3U2ITctr8yhZ_yXWCQ_v8qWClLXafw=en=X=2ahUKEwixtsCj-oTgAhXJh3AKHXd3DqMQ6AEwDHoECAUQAQ#v=onepage=dymec%20company%20history=false I plan to buy a copy of the book and read it on my trip to Hong Kong this weekend. If it is interesting, I'll write a quick review for you all. Tom V: Let us know if we are wandering too far off topic for time-nuts. Hugh Rice ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Modern signal generators
I am reminded of the time before retirement that I put together an RF lab at Hughes Missile Systems. All of the equipment was housed in a shielded room, since in addition to all of the garbage generated in our own factory we were located at Tucson International Airport with all of their comm and radar stuff operating. I specified the room to have 120 dB isolation from a few kHz to 10 GHz. It was modular panels 2 inches thick with galvanized steel shielding on both sides. The door was massive with a brass jam and a knife edge that was driven into double finger stock backed up by conductive foam. The vendor performed proof-of-performance by putting a spectrum analyzer fed with a standard gain X-band horn inside and a TWT amplifier on the outside also feeding a horn aimed at the one inside. The system was normalized with the door open and then tested with the door closed. It met the requirement, but with little margin. I was given instructions on how to maintain the room, with emphasis on cleaning the door edge and finger stock. To drive home the importance, the guy took a dollar bill out of his wallet and placed it across the finger stock channel and then closed the door. The isolation dropped over 20 dB. Wes N7WS On 12/12/2018 10:56 AM, jimlux wrote: At JPL we regularly do measurements of signals at <-150 dBm into sensitive deep space receivers, and we're obsessive about phase (since that's how we measure the distance to spacecraft to a gnat's eyelash). Historically, we found, for instance that most signal generators leak more through the chassis than come out the output jack at minimum level. We test the receivers in a screen room, with the generators outside, so you get about 100dB from the screen room to help. Waveguide helps too (WG below cutoff is a very effective filter) and it's not too tough to make waveguide joints that have better than 150dB isolation to the outside (lap them smooth, use pins, wrap in foil tape) Coax is always a challenge because the shields leak. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] OCXO Board
I'm not up to doing the whole project, but I would certain be interested in 2 or 3 boards for sure. Wes Stewart N7WS On 10/26/2018 5:51 AM, Bob Martin wrote: Bert, That looks like a useful board. Certainly some of the oscillators I'm giving away would fit nicely on it. Since it looks like a two layer board, a quick check at pcbway.com puts the cost at $.79 apiece at the 100 quantity exclusive of shipping. Best, Bob Martin On 10/26/2018 4:17 AM, ew via time-nuts wrote: There recently was a request for an OCXO board. I did a layout, see attached and had Corby do his usual QC test. If some one is interested to make boards and maybe sell to other time nuts please contact me off list and I will get you code and possible suppliers. Board does not have an amp but could be added, if so, please advise, what should be added. Regardless what the direct output will remain Bert Kehren ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Programmable clock for BFO use....noise
I'd look for the appropriate crystals. If it will help, I have a 250.00 kHz one you can have. Wes N7WS On 9/14/2018 9:14 AM, lstosk...@cox.net wrote: Off topic for this list, but you guys are experts in oscillator noise! Playing with some mechanical filters. Need USB and LSB crystals for the BFO. No one seems to make crystals anymore, especially in the 253 KHz range! Looking at the DigiKey Cardinal programmable oscillators. Cheap and available: CPPC1LZ A5B6 Anyone have an idea how noisy these would be after a division by 4 to get them in range? Thanks, N0UU ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] NIST
Before retiring I did some field work on the Tomahawk AGR (https://www.raytheon.com/capabilities/products/gps_anti-jam) Wes N7WS On 8/30/2018 4:05 PM, Gregory Maxwell wrote: However, the short wavelengths of GPS make beam forming a reasonable countermeasure against jamming. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Loss of NIST transmitters at Colorado and Hawaii
Comment in the link about visiting WWV reminds me of my experience. Many years ago my late wife and I were roving around Colorado and I telephoned WWV and asked if I could get a tour. I mentioned that I was a ham, an EE, blah blah. This had worked before at other installations (not NAA however) including the Apollo tracking station at Guaymas Mexico a day after a splashdown. The fellow I talked to was somewhat taken aback and said that they didn't give tours. I expressed some dismay and was about to hang up when he said, "Actually, we have some contractors doing some work here and the gate is unlocked. If you were to come in you could look at the antennas, but please stay in your car." So we did. Wes On 8/12/2018 4:05 PM, Bill Hawkins wrote: Group, This subject needs some additional detail. I found an article with comments at https://swling.com/blog/2018/08/nist-fy2019-budget-includes-request-to-shutdown-wwv-and-wwvh/ ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] NIST
Yep, just like "government shutdowns" where all non-essential people stay home. (I always wondered why, it they are non-essential they are on the payroll in the first place, but what do I know, I'm just a taxpayer.) But what gets shut down first are things like National Parks, which have immediate effect on lots of people. What are the effects on the budget of running WWV/WWVB? The electric bill I would guess. When John Q. Public's "atomic clock" stops working, they'll find a way to pay the bill. Wes On 8/12/2018 11:58 AM, djl wrote: Just a word: When budget cuts are announced, the agencies put the most valued "stuff" to be cut first, such as the Washington monument, etc. This is a recognized ploy. When the dust settles, all may be well. . . Don ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] OCXO Support board
In a moment of weakness and impulse, for no particular reason I bought a Morion MV80 on the auction site. Now I'd like to power it up and am looking for an easy way to do that. So, rather than reinventing the wheel, I'm looking for something similar to this: https://www.tindie.com/products/AnalysIR/10mhz-ocxo-frequency-standard-module-or-kit/?pt=ac_prod_search with a footprint that will accept the MV80. Does anyone know of such a source? Thanks, Wes ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
