[time-nuts] Re: Best frequency to start for GHz synth ?
An interferogram showing the nodes etc. of such a resonating quartz crystal ring was posted by me in either February or March 2020. Bruce > On 01 April 2021 at 15:16 Bob kb8tq wrote: > > > Hi > > Some of the early 100 KHz resonators were ring shaped. The British really > pioneered > this side of things ( while the US was still doing bars …) back in the > 1930’s. AFIK the > mode is not a whispering gallery. > > Given the low frequency of a 100 KHz resonator, a “not space limited” design > might get > to some pretty insane Q values. Meter level dimensions probably would be > involved. > Good luck sourcing the raw quartz :) :) :) ( …. and yes, that’s only the > first of a long list > of issues ….). > > Bob > > > On Mar 31, 2021, at 3:23 PM, Poul-Henning Kamp wrote: > > > >> If you were going insane on a fountain, you likely would go with one of > >> the > >> sapphire whispering gallery devices as the start of your chain. A good one > >> will blow a quartz crystal based part away …. > > > > That reminds me: > > > > I think the first quartz-crystal at Bell Labs was ring-shaped, do you know > > if that used a whispering gallery vibration mode ? > > > > > > -- > > Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 > > p...@freebsd.org | TCP/IP since RFC 956 > > FreeBSD committer | BSD since 4.3-tahoe > > Never attribute to malice what can adequately be explained by incompetence. > ___ > 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 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 ?
Louis Essen was THE man - hence to the Essen Ring quartz oscillator which was a development from Dye's original work on that particular quartz configuration. The British PO used a bank of Essen Ring references as their standard immediately prior to- and I think during most of- WW2. Not sure re oscillation mode but IIRC the rings had to be suspended from several silk threads. DaveB, NZ -Original Message- From: Bob kb8tq [mailto:kb...@n1k.org] Sent: Thursday, April 01, 2021 15:16 To: Poul-Henning Kamp Cc: Discussion of precise time and frequency measurement Subject: [time-nuts] Re: Best frequency to start for GHz synth ? Hi Some of the early 100 KHz resonators were ring shaped. The British really pioneered this side of things ( while the US was still doing bars …) back in the 1930’s. AFIK the mode is not a whispering gallery. Given the low frequency of a 100 KHz resonator, a “not space limited” design might get to some pretty insane Q values. Meter level dimensions probably would be involved. Good luck sourcing the raw quartz :) :) :) ( …. and yes, that’s only the first of a long list of issues ….). Bob > On Mar 31, 2021, at 3:23 PM, Poul-Henning Kamp wrote: > >> If you were going insane on a fountain, you likely would go with one >> of the sapphire whispering gallery devices as the start of your >> chain. A good one will blow a quartz crystal based part away …. > > That reminds me: > > I think the first quartz-crystal at Bell Labs was ring-shaped, do you know if > that used a whispering gallery vibration mode ? > > > -- > Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 > p...@freebsd.org | TCP/IP since RFC 956 > FreeBSD committer | BSD since 4.3-tahoe > Never attribute to malice what can adequately be explained by incompetence. ___ 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 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 ?
Hi Some of the early 100 KHz resonators were ring shaped. The British really pioneered this side of things ( while the US was still doing bars …) back in the 1930’s. AFIK the mode is not a whispering gallery. Given the low frequency of a 100 KHz resonator, a “not space limited” design might get to some pretty insane Q values. Meter level dimensions probably would be involved. Good luck sourcing the raw quartz :) :) :) ( …. and yes, that’s only the first of a long list of issues ….). Bob > On Mar 31, 2021, at 3:23 PM, Poul-Henning Kamp wrote: > >> If you were going insane on a fountain, you likely would go with one of the >> sapphire whispering gallery devices as the start of your chain. A good one >> will blow a quartz crystal based part away …. > > That reminds me: > > I think the first quartz-crystal at Bell Labs was ring-shaped, do you know if > that used a whispering gallery vibration mode ? > > > -- > Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 > p...@freebsd.org | TCP/IP since RFC 956 > FreeBSD committer | BSD since 4.3-tahoe > Never attribute to malice what can adequately be explained by incompetence. ___ 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]
I have not yet heard what GB wants to do, but if it's long range work (return time of 10's of sec or longer), the problems related to T/R switching, Tn degradation of the receiver, etc, get a lot more tractable than one might suppose. At Arecibo, the S-band radar was intended solely for long range work. A big part ot T/R switching was to use separate (optimized) feeds for transmitting and receiving, and swap feeds during turnaround. The receive feed was covered by a carefully- fitted sliding cover during transmit times, which provided excellent isolation. There was a microswitch to sense cover position and which would block transmission if it was not satisfied. Feed horn turnaround time was about 7 seconds as I recall. The transmitter was basically operated CW, and the "imaging" technique was "range- Doppler". So, the transmitter was run for slightly under the round-trip travel time, then feed turnaround was initiated, timed to finish shortly before the leading edge of the return was expected. The receiver would do its thing for the duration of the return. Note that it was also necessary to completely shut down the beam current of the transmit Klystrons during receive so that shot noise on the beam did not spoil the receiver's noise temperature. After the receive interval was finished, the feeds were again swapped and a new cycle was started. During each transmit period the crew of scientists would have time for a preliminary look at the just-recorded data to see if anything was going wrong. OTOH, Arecibo's 430 MHz ISR for ionospheric studies clearly had to have almost instantaneous turnaround time, and arrangements were rather more complicated (more so than I can take time to describe at the moment). But they worked well, and loss in the receive state of some big PIN switches in the path was tolerably low. The first 35-40 dB of TX-RX isolation came from use of a "turnstile junction", with the remainder coming from the PIN switches. For both radars, the non-participating receivers would also be covered, but with a simpler flap arrangement, some powered by small DC motors and some by small pneumatic cylinders. Dana (retired from Arecibo Dec 2016) On Wed, Mar 31, 2021 at 2:30 PM ew via time-nuts wrote: > During my days at UTC I was among other things responsible for our > Industrial Laser Group. We sold some 50 KW CW CO2 lasers! We had the only > aero dynamic window that allowed a vacuum on one side. When not in use you > put a pencil through it. Patented. > Bert Kehren In a message dated 3/31/2021 3:17:21 PM > Eastern Standard Time, rich...@karlquist.com writes: > > > On 3/31/2021 11:57 AM, Lux, Jim wrote: > > > > > In some ways it's like high power laser labs. It's not the direct beam > > you worry about - nobody is going to put their hand in the beam path. > > It's the stray reflection when something gets bumped and falls across > > the optical bench and reflects a stray beam at 0.01% power into your > eyes. > > I did consulting at Coherent Laser Group working on CO2 lasers. > In that lab, actually, many people had the misfortune of accidentally > putting their hand or arm in the invisible beam. You could see the > scars on their arms. There were also accidents where the laser > burned the ceiling, etc. Very scary place to work; fortunately, > I never got injured. They made lasers up to 1kW optical power out. > > 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 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 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]
During my days at UTC I was among other things responsible for our Industrial Laser Group. We sold some 50 KW CW CO2 lasers! We had the only aero dynamic window that allowed a vacuum on one side. When not in use you put a pencil through it. Patented. Bert Kehren In a message dated 3/31/2021 3:17:21 PM Eastern Standard Time, rich...@karlquist.com writes: On 3/31/2021 11:57 AM, Lux, Jim wrote: > > In some ways it's like high power laser labs. It's not the direct beam > you worry about - nobody is going to put their hand in the beam path. > It's the stray reflection when something gets bumped and falls across > the optical bench and reflects a stray beam at 0.01% power into your eyes. I did consulting at Coherent Laser Group working on CO2 lasers. In that lab, actually, many people had the misfortune of accidentally putting their hand or arm in the invisible beam. You could see the scars on their arms. There were also accidents where the laser burned the ceiling, etc. Very scary place to work; fortunately, I never got injured. They made lasers up to 1kW optical power out. 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 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 ?
On 3/31/2021 11:02 AM, Bob kb8tq wrote: Hi If you were going insane on a fountain, you likely would go with one of the sapphire whispering gallery devices as the start of your chain. A good one will blow a quartz crystal based part away …. Bob When I left Keysight in 2014, they were still trying to solve the microphonic problem in their sapphire resonator oscillator. Also, it is still necessary to lock the oscillator to a 5 or 10 MHz OCXO. The oscillator is tuned by varying its oven temperature set ppoint. 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: Best frequency to start for GHz synth ?
>If you were going insane on a fountain, you likely would go with one of the >sapphire whispering gallery devices as the start of your chain. A good one >will blow a quartz crystal based part away …. That reminds me: I think the first quartz-crystal at Bell Labs was ring-shaped, do you know if that used a whispering gallery vibration mode ? -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ 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 3/31/2021 11:57 AM, Lux, Jim wrote: In some ways it's like high power laser labs. It's not the direct beam you worry about - nobody is going to put their hand in the beam path. It's the stray reflection when something gets bumped and falls across the optical bench and reflects a stray beam at 0.01% power into your eyes. I did consulting at Coherent Laser Group working on CO2 lasers. In that lab, actually, many people had the misfortune of accidentally putting their hand or arm in the invisible beam. You could see the scars on their arms. There were also accidents where the laser burned the ceiling, etc. Very scary place to work; fortunately, I never got injured. They made lasers up to 1kW optical power out. 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 3/31/21 11:33 AM, Wes wrote: 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. In the airborne radar environment, typically the other receivers already are designed to take a fairly high signal without damage (after all, you get painted by someone else's radar). They may have a limiter on the input (there are low capacitance back to back schottky diodes for this), and you accept the loss in signal or raised noise floor from the protection circuit But for radio astronomy, they don't want to give up anything - these receivers have noise temperatures in single digit K and they are optimized for "small signal" performance. All those wideband cryogenic receivers for other frequencies are what people would be nervous about. There are other receivers at GB, not on the 100m GBT, too. You'd worry about a stray reflection from some structural member shooting a few hundred watts toward your sensitive radiometer which burns out at femtowatts or something like that. The feed would be designed with some illumination taper, so there's still going to be spillover and scattering. If the taper is -17dB, the power density at the *edge* of the aperture is down 17 dB from the center. 100m is about 7800 square meters, so the average power density with a 500 kW transmitter is about 63 W/square meter. That's a pretty big power density. http://www.naic.edu/~astro/sdss5/talks/ReceiverSystem.pdf In some ways it's like high power laser labs. It's not the direct beam you worry about - nobody is going to put their hand in the beam path. It's the stray reflection when something gets bumped and falls across the optical bench and reflects a stray beam at 0.01% power into your eyes. ___ 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]
RX up here at Green Bank Lester B Veenstra K1YCM MØYCM W8YCM 6Y6Y les...@veenstras.com 452 Stable Ln (HC84 RFD USPS Mail) Keyser WV 26726 -Original Message- From: Wes [mailto:w...@triconet.org] Sent: Wednesday, March 31, 2021 2:34 PM To: time-nuts@lists.febo.com Subject: [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 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: Best frequency to start for GHz synth ?
Hi If you were going insane on a fountain, you likely would go with one of the sapphire whispering gallery devices as the start of your chain. A good one will blow a quartz crystal based part away …. Past that, lower is better for crystals and “Time Nut” parameters. Q will be higher at lower frequencies. Physics is the source of that, so no change in process will “help” you. Package size limits just how low you can go with a low-loss design. If at some future date a bigger package got tooled up ( think government funding ….) those limits might change. In this case “tooled up” involves tooling a lot more than just the can and base ….. So, yes, you still are “stuck” with 5 MHz ( or something close to that) for really good ADEV and close in phase noise. The other thing that might happen some day is the same sort of money being spent to get another piezo material up and running. There are some that might give you higher Q. So far all the attempts I’ve heard of have hit walls in various areas. Best guess is that it goes back to learning how to “grow” high stability bars for some of these odd materials….. Unless something really strange happens, the odds of somebody putting big money into any of this is in the “very remote” category. The people who are crazy needy already have the sapphire stuff. Bob > On Mar 31, 2021, at 12:44 PM, Poul-Henning Kamp wrote: > > Somewhat related to the discussion about GPSDO's I have a basic question: > > It used to be that 5MHz was the "hot spot" for crystals on the parameters we > care about as time-nuts. > > Have advances in X-tal science changed that ? > > To make it a concrete question: > > If tasked with designing a Cs/Rb beam/fountain/whatever today, would one > still start the synthesizer-chain at 5 MHz or would a higher frequency give > better results ? > > -- > Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 > p...@freebsd.org | TCP/IP since RFC 956 > FreeBSD committer | BSD since 4.3-tahoe > Never attribute to malice what can adequately be explained by incompetence. > ___ > 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 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] Best frequency to start for GHz synth ?
Somewhat related to the discussion about GPSDO's I have a basic question: It used to be that 5MHz was the "hot spot" for crystals on the parameters we care about as time-nuts. Have advances in X-tal science changed that ? To make it a concrete question: If tasked with designing a Cs/Rb beam/fountain/whatever today, would one still start the synthesizer-chain at 5 MHz or would a higher frequency give better results ? -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ 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: time-nuts Digest, Vol 200, Issue 46
Hi Chris. Presuming you're interested in receiving QO100 with a LNB that doesn't drift like crazy (in our terms at least.) There are numerous pages on the intenet, that show how to modify some of the common LNB's to take an external LO reference. There are also some pre-modified on sale too (at a price.) As to the Leo Bodnar device (I don't have one of them.) That needs to be configured to provide the 25, 27MHz (or whatever) reference frequency that the LNB needs. Depending on the LNB (number of and type of IF ports) you may need a bias 'T' to combine the power for the LNB, and the reference signal. I guess one coax can work, but then you also need a duplexer too, to separate the IF from the LNB, while also passing the Reference signal and DC power out towards the LNB. I know it can all be done, in any of several different ways. The easiest way is to buy a pre-modified LNB and any needed bias 'T'. For example... https://remoteqth.com/lnb_gps.php (No affiliation, just one of several hits to a simple Google query.) https://wiki.batc.org.uk/Es'hail-2_LNBs_and_Antennaes More generic info, again no affiliation. The lowest cost (perhaps?) Involves doing all that yourself. Skill's tools and eyesight(!) permitting. (The insides of those LNB's are full of tiny SMD stuff. *Very* tiny! 73. Dave G8KBV. On 31/03/2021 14:04, time-nuts-requ...@lists.febo.com wrote: From: Chris Wilson Subject: [time-nuts] Re: Ublox NEO-M8T-0-10as a LO question To: Discussion of precise time and frequency measurement Message-ID:<1274452908.20210331130...@chriswilson.tv> Content-Type: text/plain; charset=utf-8 Hello everyone Monday, March 29, 2021 Thanks for the replies, some went a little over my head, which is not hard:) I am wondering how people successfully use a Leo Bodnar programmable GPS source to provide an external LO for an LNB as opposed to its internal xtal. What is different, in simple terms please, between my Ublox output and the Leo Bodnar one? Best regards, Chrismailto:ch...@chriswilson.tv -- Created on and sent from a Unix like PC running and using free and open source software: ___ 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: Ublox NEO-M8T-0-10as a LO question
Hi Chris -- The difference is that the ublox module is outputting a signal that's being generated without much concern for its phase noise. The digital process used creates a lot of jitter in the edges of the output waveform. It simply wasn't intended for the TIMEPULSE output to be used in RF (analog) circuits. The Bodnar GPSDO follows the GPS output with a synthesizer chip that also functions as a "jitter attenuator" which in addition to allowing a wide range of frequency outputs also cleans up the input signal. The synth chip output has much lower phase noise than the GPS by itself. But the synth output is still noisier than a simple crystal oscillator and might not be sufficiently good to be multiplied up to the 10 GHz range. That's why others have suggested starting the LO chain with a higher frequency XO that is locked (in a narrow loop bandwidth) to the GPS signal. That will result in significantly lower phase noise when multiplied up to 10 GHz. 73, John On 3/31/21 8:09 AM, Chris Wilson wrote: Hello everyone Monday, March 29, 2021 Thanks for the replies, some went a little over my head, which is not hard :) I am wondering how people successfully use a Leo Bodnar programmable GPS source to provide an external LO for an LNB as opposed to its internal xtal. What is different, in simple terms please, between my Ublox output and the Leo Bodnar one? Best regards, Chrismailto:ch...@chriswilson.tv LJ> On 3/29/21 10:14 AM, John Ackermann N8UR wrote: That's probably a really bad idea. The phase noise from the TIMEPULSE output is pretty bad compared to a "real" RF source, and by the time it's multiplied up to 10 GHz you'll have more noise than signal. Attached are some phase noise plots and a couple of spectrum analyzer captures to give you some idea what to expect. BTW, even the Bodnar unit may not look too good at 10 GHz -- remember that you increase phase noise by 20 dB for 10 times multiplication. John LJ> What's the signal bandwidth from Es'Hail? LJ> The optimum strategy is a *very quiet* crystal oscillator that you LJ> discipline with the 1pps, and choose that oscillator so its frequency is LJ> what you need. LJ> What we've done in the past is use the reference to clock a NCO in FPGA, LJ> and use one of the well known spur reduction techniques that pushes the LJ> spurs away from the center before running it to the DAC. This degrades LJ> the performance at, say, 100kHz away, but improves the performance LJ> within 1 kHz. This relies on knowing what the loop bandwidth is in your LJ> 10GHz LO PLL, since inside that bandwidth it's the reference, but LJ> outside it's the DRO or GaAs oscillator. LJ> There might be some DDS chips that implement this kind of thing - the LJ> latest chips from ADI are pretty sophisticated. On 3/29/21 12:25 PM, Chris Wilson wrote: 29/03/2021 17:20 Can I use my Ublox NEO-M8T-0-10 as a LO for a modified satellite LNB on 10 GHz? It needs 25 MHz and the Ublox is my only GPS locked source for such a frequency. I want to receive the Es Hail downlink with excellent stability. I can lock the receiver to 10 MHz which is available from my Trimble Thunderbolt. If the Ublox would do I would not have to buy something like the Leo Bodnar GPS. Thanks. ___ 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. LJ> ___ LJ> time-nuts mailing list -- time-nuts@lists.febo.com -- To LJ> unsubscribe send an email to time-nuts-le...@lists.febo.com LJ> To unsubscribe, go to and follow the instructions there. ___ 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 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: Ublox NEO-M8T-0-10as a LO question
Hi When you add noise to the local oscillator that down converts the signal, that noise shows up on the output of the LNB. Depending on what you are doing, this or that kind of noise can be a major or a not so major issue. Indeed the uBlox output is more noisy than the Leo Bodnar device …. Bob > On Mar 31, 2021, at 8:09 AM, Chris Wilson wrote: > > Hello everyone > > Monday, March 29, 2021 > > Thanks for the replies, some went a little over my head, which is not hard :) > I am wondering how people successfully use a Leo Bodnar programmable GPS > source to provide an external LO for an LNB as opposed to its internal xtal. > What is different, in simple terms please, between my Ublox output and the > Leo Bodnar one? > > > Best regards, > Chrismailto:ch...@chriswilson.tv > > > LJ> On 3/29/21 10:14 AM, John Ackermann N8UR wrote: >>> That's probably a really bad idea. The phase noise from the TIMEPULSE >>> output is pretty bad compared to a "real" RF source, and by the time >>> it's multiplied up to 10 GHz you'll have more noise than signal. >>> Attached are some phase noise plots and a couple of spectrum analyzer >>> captures to give you some idea what to expect. > >>> BTW, even the Bodnar unit may not look too good at 10 GHz -- remember >>> that you increase phase noise by 20 dB for 10 times multiplication. > >>> John > > LJ> What's the signal bandwidth from Es'Hail? > > LJ> The optimum strategy is a *very quiet* crystal oscillator that you > LJ> discipline with the 1pps, and choose that oscillator so its frequency is > LJ> what you need. > > LJ> What we've done in the past is use the reference to clock a NCO in FPGA, > LJ> and use one of the well known spur reduction techniques that pushes the > LJ> spurs away from the center before running it to the DAC. This degrades > LJ> the performance at, say, 100kHz away, but improves the performance > LJ> within 1 kHz. This relies on knowing what the loop bandwidth is in your > LJ> 10GHz LO PLL, since inside that bandwidth it's the reference, but > LJ> outside it's the DRO or GaAs oscillator. > > > LJ> There might be some DDS chips that implement this kind of thing - the > LJ> latest chips from ADI are pretty sophisticated. > > > > > >>> On 3/29/21 12:25 PM, Chris Wilson wrote: > > 29/03/2021 17:20 > Can I use my Ublox NEO-M8T-0-10 as a LO for a modified satellite LNB on 10 GHz? It needs 25 MHz and the Ublox is my only GPS locked source for such a frequency. I want to receive the Es Hail downlink with excellent stability. I can lock the receiver to 10 MHz which is available from my Trimble Thunderbolt. If the Ublox would do I would not have to buy something like the Leo Bodnar GPS. Thanks. > > >>> ___ >>> 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. > > LJ> ___ > LJ> time-nuts mailing list -- time-nuts@lists.febo.com -- To > LJ> unsubscribe send an email to time-nuts-le...@lists.febo.com > LJ> To unsubscribe, go to and follow the instructions there. > ___ > 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 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: Ublox NEO-M8T-0-10as a LO question
Andy, I agree with you if that's the intended use. But unless I've missed something, the original inquirer has yet to state what he is trying to do, so the sky's the limit. Dana On Wed, Mar 31, 2021 at 7:40 AM Andy Talbot wrote: > More to do with amateurs using narrow band modulations, and the LB GPSDO > being moderately good close in. Phase noise out beyond a few kHz goes > more or less unnoticed on SSB > > Andy > www.g4jnt.com > > > > On Wed, 31 Mar 2021 at 13:35, Dana Whitlow wrote: > > > Chris, > > > > It may be that the modulation and subsequent demodulation scheme used for > > satellite TV and the > > like is rather more robust than many people give it credit for. > > > > Dana > > > > > > On Wed, Mar 31, 2021 at 7:09 AM Chris Wilson > wrote: > > > > > Hello everyone > > > > > > Monday, March 29, 2021 > > > > > > Thanks for the replies, some went a little over my head, which is not > > > hard :) I am wondering how people successfully use a Leo Bodnar > > > programmable GPS source to provide an external LO for an LNB as opposed > > to > > > its internal xtal. What is different, in simple terms please, between > my > > > Ublox output and the Leo Bodnar one? > > > > > > > > > Best regards, > > > Chrismailto:ch...@chriswilson.tv > > > > > > > > > LJ> On 3/29/21 10:14 AM, John Ackermann N8UR wrote: > > > >> That's probably a really bad idea. The phase noise from the > TIMEPULSE > > > >> output is pretty bad compared to a "real" RF source, and by the time > > > >> it's multiplied up to 10 GHz you'll have more noise than signal. > > > >> Attached are some phase noise plots and a couple of spectrum > analyzer > > > >> captures to give you some idea what to expect. > > > > > > >> BTW, even the Bodnar unit may not look too good at 10 GHz -- > remember > > > >> that you increase phase noise by 20 dB for 10 times multiplication. > > > > > > >> John > > > > > > LJ> What's the signal bandwidth from Es'Hail? > > > > > > LJ> The optimum strategy is a *very quiet* crystal oscillator that you > > > LJ> discipline with the 1pps, and choose that oscillator so its > frequency > > > is > > > LJ> what you need. > > > > > > LJ> What we've done in the past is use the reference to clock a NCO in > > > FPGA, > > > LJ> and use one of the well known spur reduction techniques that pushes > > the > > > LJ> spurs away from the center before running it to the DAC. This > > degrades > > > LJ> the performance at, say, 100kHz away, but improves the performance > > > LJ> within 1 kHz. This relies on knowing what the loop bandwidth is in > > your > > > LJ> 10GHz LO PLL, since inside that bandwidth it's the reference, but > > > LJ> outside it's the DRO or GaAs oscillator. > > > > > > > > > LJ> There might be some DDS chips that implement this kind of thing - > the > > > LJ> latest chips from ADI are pretty sophisticated. > > > > > > > > > > > > > > > > > > >> On 3/29/21 12:25 PM, Chris Wilson wrote: > > > > > > > > > >>>29/03/2021 17:20 > > > > > > >>> Can I use my Ublox NEO-M8T-0-10 as a LO for a modified > satellite > > > >>> LNB on 10 GHz? It needs 25 MHz and the Ublox is my only GPS locked > > > >>> source for such a frequency. I want to receive the Es Hail downlink > > > >>> with excellent stability. I can lock the receiver to 10 MHz which > is > > > >>> available from my Trimble Thunderbolt. If the Ublox would do I > would > > > >>> not have to buy something like the Leo Bodnar GPS. Thanks. > > > > > > > > > >> ___ > > > >> 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. > > > > > > LJ> ___ > > > LJ> time-nuts mailing list -- time-nuts@lists.febo.com -- To > > > LJ> unsubscribe send an email to time-nuts-le...@lists.febo.com > > > LJ> To unsubscribe, go to and follow the instructions there. > > > ___ > > > 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 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 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 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: Ublox NEO-M8T-0-10as a LO question
More to do with amateurs using narrow band modulations, and the LB GPSDO being moderately good close in. Phase noise out beyond a few kHz goes more or less unnoticed on SSB Andy www.g4jnt.com On Wed, 31 Mar 2021 at 13:35, Dana Whitlow wrote: > Chris, > > It may be that the modulation and subsequent demodulation scheme used for > satellite TV and the > like is rather more robust than many people give it credit for. > > Dana > > > On Wed, Mar 31, 2021 at 7:09 AM Chris Wilson wrote: > > > Hello everyone > > > > Monday, March 29, 2021 > > > > Thanks for the replies, some went a little over my head, which is not > > hard :) I am wondering how people successfully use a Leo Bodnar > > programmable GPS source to provide an external LO for an LNB as opposed > to > > its internal xtal. What is different, in simple terms please, between my > > Ublox output and the Leo Bodnar one? > > > > > > Best regards, > > Chrismailto:ch...@chriswilson.tv > > > > > > LJ> On 3/29/21 10:14 AM, John Ackermann N8UR wrote: > > >> That's probably a really bad idea. The phase noise from the TIMEPULSE > > >> output is pretty bad compared to a "real" RF source, and by the time > > >> it's multiplied up to 10 GHz you'll have more noise than signal. > > >> Attached are some phase noise plots and a couple of spectrum analyzer > > >> captures to give you some idea what to expect. > > > > >> BTW, even the Bodnar unit may not look too good at 10 GHz -- remember > > >> that you increase phase noise by 20 dB for 10 times multiplication. > > > > >> John > > > > LJ> What's the signal bandwidth from Es'Hail? > > > > LJ> The optimum strategy is a *very quiet* crystal oscillator that you > > LJ> discipline with the 1pps, and choose that oscillator so its frequency > > is > > LJ> what you need. > > > > LJ> What we've done in the past is use the reference to clock a NCO in > > FPGA, > > LJ> and use one of the well known spur reduction techniques that pushes > the > > LJ> spurs away from the center before running it to the DAC. This > degrades > > LJ> the performance at, say, 100kHz away, but improves the performance > > LJ> within 1 kHz. This relies on knowing what the loop bandwidth is in > your > > LJ> 10GHz LO PLL, since inside that bandwidth it's the reference, but > > LJ> outside it's the DRO or GaAs oscillator. > > > > > > LJ> There might be some DDS chips that implement this kind of thing - the > > LJ> latest chips from ADI are pretty sophisticated. > > > > > > > > > > > > >> On 3/29/21 12:25 PM, Chris Wilson wrote: > > > > > > >>>29/03/2021 17:20 > > > > >>> Can I use my Ublox NEO-M8T-0-10 as a LO for a modified satellite > > >>> LNB on 10 GHz? It needs 25 MHz and the Ublox is my only GPS locked > > >>> source for such a frequency. I want to receive the Es Hail downlink > > >>> with excellent stability. I can lock the receiver to 10 MHz which is > > >>> available from my Trimble Thunderbolt. If the Ublox would do I would > > >>> not have to buy something like the Leo Bodnar GPS. Thanks. > > > > > > >> ___ > > >> 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. > > > > LJ> ___ > > LJ> time-nuts mailing list -- time-nuts@lists.febo.com -- To > > LJ> unsubscribe send an email to time-nuts-le...@lists.febo.com > > LJ> To unsubscribe, go to and follow the instructions there. > > ___ > > 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 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 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: Ublox NEO-M8T-0-10as a LO question
Chris, It may be that the modulation and subsequent demodulation scheme used for satellite TV and the like is rather more robust than many people give it credit for. Dana On Wed, Mar 31, 2021 at 7:09 AM Chris Wilson wrote: > Hello everyone > > Monday, March 29, 2021 > > Thanks for the replies, some went a little over my head, which is not > hard :) I am wondering how people successfully use a Leo Bodnar > programmable GPS source to provide an external LO for an LNB as opposed to > its internal xtal. What is different, in simple terms please, between my > Ublox output and the Leo Bodnar one? > > > Best regards, > Chrismailto:ch...@chriswilson.tv > > > LJ> On 3/29/21 10:14 AM, John Ackermann N8UR wrote: > >> That's probably a really bad idea. The phase noise from the TIMEPULSE > >> output is pretty bad compared to a "real" RF source, and by the time > >> it's multiplied up to 10 GHz you'll have more noise than signal. > >> Attached are some phase noise plots and a couple of spectrum analyzer > >> captures to give you some idea what to expect. > > >> BTW, even the Bodnar unit may not look too good at 10 GHz -- remember > >> that you increase phase noise by 20 dB for 10 times multiplication. > > >> John > > LJ> What's the signal bandwidth from Es'Hail? > > LJ> The optimum strategy is a *very quiet* crystal oscillator that you > LJ> discipline with the 1pps, and choose that oscillator so its frequency > is > LJ> what you need. > > LJ> What we've done in the past is use the reference to clock a NCO in > FPGA, > LJ> and use one of the well known spur reduction techniques that pushes the > LJ> spurs away from the center before running it to the DAC. This degrades > LJ> the performance at, say, 100kHz away, but improves the performance > LJ> within 1 kHz. This relies on knowing what the loop bandwidth is in your > LJ> 10GHz LO PLL, since inside that bandwidth it's the reference, but > LJ> outside it's the DRO or GaAs oscillator. > > > LJ> There might be some DDS chips that implement this kind of thing - the > LJ> latest chips from ADI are pretty sophisticated. > > > > > > >> On 3/29/21 12:25 PM, Chris Wilson wrote: > > > >>>29/03/2021 17:20 > > >>> Can I use my Ublox NEO-M8T-0-10 as a LO for a modified satellite > >>> LNB on 10 GHz? It needs 25 MHz and the Ublox is my only GPS locked > >>> source for such a frequency. I want to receive the Es Hail downlink > >>> with excellent stability. I can lock the receiver to 10 MHz which is > >>> available from my Trimble Thunderbolt. If the Ublox would do I would > >>> not have to buy something like the Leo Bodnar GPS. Thanks. > > > >> ___ > >> 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. > > LJ> ___ > LJ> time-nuts mailing list -- time-nuts@lists.febo.com -- To > LJ> unsubscribe send an email to time-nuts-le...@lists.febo.com > LJ> To unsubscribe, go to and follow the instructions there. > ___ > 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 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: Ublox NEO-M8T-0-10as a LO question
Hello everyone Monday, March 29, 2021 Thanks for the replies, some went a little over my head, which is not hard :) I am wondering how people successfully use a Leo Bodnar programmable GPS source to provide an external LO for an LNB as opposed to its internal xtal. What is different, in simple terms please, between my Ublox output and the Leo Bodnar one? Best regards, Chrismailto:ch...@chriswilson.tv LJ> On 3/29/21 10:14 AM, John Ackermann N8UR wrote: >> That's probably a really bad idea. The phase noise from the TIMEPULSE >> output is pretty bad compared to a "real" RF source, and by the time >> it's multiplied up to 10 GHz you'll have more noise than signal. >> Attached are some phase noise plots and a couple of spectrum analyzer >> captures to give you some idea what to expect. >> BTW, even the Bodnar unit may not look too good at 10 GHz -- remember >> that you increase phase noise by 20 dB for 10 times multiplication. >> John LJ> What's the signal bandwidth from Es'Hail? LJ> The optimum strategy is a *very quiet* crystal oscillator that you LJ> discipline with the 1pps, and choose that oscillator so its frequency is LJ> what you need. LJ> What we've done in the past is use the reference to clock a NCO in FPGA, LJ> and use one of the well known spur reduction techniques that pushes the LJ> spurs away from the center before running it to the DAC. This degrades LJ> the performance at, say, 100kHz away, but improves the performance LJ> within 1 kHz. This relies on knowing what the loop bandwidth is in your LJ> 10GHz LO PLL, since inside that bandwidth it's the reference, but LJ> outside it's the DRO or GaAs oscillator. LJ> There might be some DDS chips that implement this kind of thing - the LJ> latest chips from ADI are pretty sophisticated. >> On 3/29/21 12:25 PM, Chris Wilson wrote: >>>29/03/2021 17:20 >>> Can I use my Ublox NEO-M8T-0-10 as a LO for a modified satellite >>> LNB on 10 GHz? It needs 25 MHz and the Ublox is my only GPS locked >>> source for such a frequency. I want to receive the Es Hail downlink >>> with excellent stability. I can lock the receiver to 10 MHz which is >>> available from my Trimble Thunderbolt. If the Ublox would do I would >>> not have to buy something like the Leo Bodnar GPS. Thanks. >> ___ >> 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. LJ> ___ LJ> time-nuts mailing list -- time-nuts@lists.febo.com -- To LJ> unsubscribe send an email to time-nuts-le...@lists.febo.com LJ> To unsubscribe, go to and follow the instructions there. ___ 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.
