I ground one side of the tuning diode and use the 2 to 12 V as the external OCXO for my FRK's along with increasing the time constant. I have not verified it but I think removing the zener Voltage should also improve ADEV. Bert Kehren In a message dated 11/17/2014 8:46:34 P.M. Eastern Standard Time, kb8tq@n1k.org writes: Hi The 10811 is a leaded part pc board construction. If you don’t mind tearing it down to pieces, you can make the EFC do just about anything you wish. Bob > On Nov 17, 2014, at 8:32 PM, S. Jackson via time-nuts <time-nuts@febo.com> wrote: > > On the PSTI message fields question, I am checking into it, will get back > soon with an answer. > > On the 10811, that OCXO can typically be mechanically tuned to have a 1.5V > nominal EFC set voltage. The LTE-Lite can drive from 0V to 3.0V EFC, so > that should be more than required on a good (well aged and good thermal > stability) 10811. We have not tried driving a 10811 with it yet though, so can't > say for sure. One requirement is that the OCXO has a positive EFC slope. > > Bye, > Said > > > In a message dated 11/17/2014 16:28:51 Pacific Standard Time, > bill.riches@verizon.net writes: > > Said, > > Patiently waiting for my 10 mhz unit. What are your ideas on using it to > control a 10811 instead of the built in 10 mhz osc? Will there be enough > control voltage for the 10811? > > Regards, > > Bill Riches > Cape May, NJ > > -----Original Message----- > From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of S. Jackson > via time-nuts > Sent: Monday, November 17, 2014 6:40 PM > To: jim@jtmiller.com; time-nuts@febo.com > Subject: Re: [time-nuts] LTE Lite Came!! > > Hi Jim, > > thanks for your question. The reason we put that note in there is > two-fold: > > 1) On these 20MHz units the TCXO output in fact can drive 50 Ohms inputs as > we put a strong buffer on the board, but the synthesized RF output and the > 1PPS output cannot drive 50 Ohms. Those two are CMOS 1M Ohms input only. > > Using 50 Ohms impedance on the TCXO output will however heavily tax the > internal power supply and CMOS buffer, and create heating on the board > right next to the TCXO which will affect stability somewhat. So can it be > done? > Yes. Should it be done? That's up to the user to decide. > > 2) On the next batch of 10MHz DIP-14 TCXO units the external TCXO itself > drives the output directly without a buffer. That TCXO is not capable of > driving 50 Ohms inputs, only CMOS 1M Ohms inputs. So a buffer is required > on these 10MHz units if 50 Ohms test equipment is to be used. > > Hope that explains it, > bye, > Said > > > In a message dated 11/17/2014 15:27:21 Pacific Standard Time, > jim@jtmiller.com writes: > > > Hello Said > > > I got a nice surprise in my mail today: LTE-Lite! > > > There was a note with it that said (in effect) none of the outputs are > 50ohm capable. So it looks like I should build up a little board with the > divide by two and incorporate on that a 50ohm capable buffer for clock > transmission to the rest of my system? > > > BTW, you're welcome to answer via Timenuts as I'm sure others will have > the same question. > > > Thanks! > > > Jim AB3CV > > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > > --- > This email has been checked for viruses by Avast antivirus software. > http://www.avast.com > > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.

On 11/17/2014 5:54 PM, Bert Kehren via time-nuts wrote: > I ground one side of the tuning diode and use the 2 to 12 V as the external > OCXO for my FRK's along with increasing the time constant. I have not > verified it but I think removing the zener Voltage should also improve ADEV. > Bert Kehren > The choice for the Zener diode came from my old boss at HP, who was very knowledgeable about using discrete zener diodes as low noise references. According to him, this particular part number has very respectable noise. This is just something you have to know experientially, there is no theory of zener noise AFAIK. You might try measuring the noise of the 6.2V reference voltage directly at baseband, and then multiplying by the 1 Hz/volt sensitivity. Let us know your results. Rick Karlquist N6RK (Now retired from HP/Agilent/Keysight)

Hi Rick: When working on Tunnel Diode amplifiers we used (AFAICR) 5.1 V Zener diodes to stabilize the lower voltage that drive the diode. 5.1V was supposed to have excellent temperature characteristics in terms of repeatability (don't remember if low noise was part of the selection criteria). http://www.prc68.com/I/Aertech.shtml#TDA The boards with the terminals have the Zener and a custom compensation network using both Veco (spelling?) (-TC) and Balco (+TC) and fixed resistors so that the gain stays constant over mil temperature ranges. Mail_Attachment -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html http://www.prc68.com/I/DietNutrition.html Richard (Rick) Karlquist wrote: > > > On 11/17/2014 5:54 PM, Bert Kehren via time-nuts wrote: >> I ground one side of the tuning diode and use the 2 to 12 V as the external >> OCXO for my FRK's along with increasing the time constant. I have not >> verified it but I think removing the zener Voltage should also improve ADEV. >> Bert Kehren >> > > The choice for the Zener diode came from my old boss at HP, > who was very knowledgeable about using discrete zener diodes > as low noise references. According to him, this particular > part number has very respectable noise. This is just something > you have to know experientially, there is no theory of zener > noise AFAIK. You might try measuring the noise of the 6.2V > reference voltage directly at baseband, and then multiplying > by the 1 Hz/volt sensitivity. Let us know your results. > > Rick Karlquist N6RK > (Now retired from HP/Agilent/Keysight) > > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. >

Yes below about 4v is the only place where you get the real "Zener" effect, as you go above 5v it becomes Avalanche Breakdown. The trick is zener effect has a negative tempco and avalanche a positive one (I think....they are opposite senses anyway :-)) ) the result is a regulator diode ("zener"....so called) specced at around 5 to 5.5 volts has a near zero overall tempco. Alan G3NYK ----- Original Message ----- From: "Brooke Clarke" <brooke@pacific.net> To: "Discussion of precise time and frequency measurement" <time-nuts@febo.com> Sent: Tuesday, November 18, 2014 10:31 PM Subject: Re: [time-nuts] 10811 > Hi Rick: > > When working on Tunnel Diode amplifiers we used (AFAICR) 5.1 V Zener > diodes to stabilize the lower voltage that drive the diode. > 5.1V was supposed to have excellent temperature characteristics in terms > of repeatability (don't remember if low noise was part of the selection > criteria). > http://www.prc68.com/I/Aertech.shtml#TDA > The boards with the terminals have the Zener and a custom compensation > network using both Veco (spelling?) (-TC) and Balco (+TC) and fixed > resistors so that the gain stays constant over mil temperature ranges. > > Mail_Attachment -- > Have Fun, > > Brooke Clarke > http://www.PRC68.com > http://www.end2partygovernment.com/2012Issues.html > http://www.prc68.com/I/DietNutrition.html > Richard (Rick) Karlquist wrote: >> >> >> On 11/17/2014 5:54 PM, Bert Kehren via time-nuts wrote: >>> I ground one side of the tuning diode and use the 2 to 12 V as the >>> external >>> OCXO for my FRK's along with increasing the time constant. I have not >>> verified it but I think removing the zener Voltage should also improve >>> ADEV. >>> Bert Kehren >>> >> >> The choice for the Zener diode came from my old boss at HP, >> who was very knowledgeable about using discrete zener diodes >> as low noise references. According to him, this particular >> part number has very respectable noise. This is just something >> you have to know experientially, there is no theory of zener >> noise AFAIK. You might try measuring the noise of the 6.2V >> reference voltage directly at baseband, and then multiplying >> by the 1 Hz/volt sensitivity. Let us know your results. >> >> Rick Karlquist N6RK >> (Now retired from HP/Agilent/Keysight) >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there.

Yes, 5.1V Zeners (or something like that) have a "magic" zero tempco if you put a conventional diode in series with it. I used to know stuff like that during the Jurassic period. However, the diode in the 10811 is ovenized, so that is not so important. 6.2V was chosen to get +/- 5V tuning range, which was probably a spec inherited from the 10544. Everything was done for a reason relevant to HP, which may or may not be a reason relevant to you. The frequency of the 10811 is more sensitive to the temperature of the oscillator transistor (a selected 2N5179) than the diode. This inspired the E1938A. Rick On 11/18/2014 2:31 PM, Brooke Clarke wrote: > Hi Rick: > > When working on Tunnel Diode amplifiers we used (AFAICR) 5.1 V Zener > diodes to stabilize the lower voltage that drive the diode. > 5.1V was supposed to have excellent temperature characteristics in terms > of repeatability (don't remember if low noise was part of the selection > criteria). > http://www.prc68.com/I/Aertech.shtml#TDA > The boards with the terminals have the Zener and a custom compensation > network using both Veco (spelling?) (-TC) and Balco (+TC) and fixed > resistors so that the gain stays constant over mil temperature ranges. > > Mail_Attachment -- > Have Fun, > > Brooke Clarke > http://www.PRC68.com > http://www.end2partygovernment.com/2012Issues.html > http://www.prc68.com/I/DietNutrition.html > Richard (Rick) Karlquist wrote: >> >> >> On 11/17/2014 5:54 PM, Bert Kehren via time-nuts wrote: >>> I ground one side of the tuning diode and use the 2 to 12 V as the >>> external >>> OCXO for my FRK's along with increasing the time constant. I have not >>> verified it but I think removing the zener Voltage should also >>> improve ADEV. >>> Bert Kehren >>> >> >> The choice for the Zener diode came from my old boss at HP, >> who was very knowledgeable about using discrete zener diodes >> as low noise references. According to him, this particular >> part number has very respectable noise. This is just something >> you have to know experientially, there is no theory of zener >> noise AFAIK. You might try measuring the noise of the 6.2V >> reference voltage directly at baseband, and then multiplying >> by the 1 Hz/volt sensitivity. Let us know your results. >> >> Rick Karlquist N6RK >> (Now retired from HP/Agilent/Keysight) >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > >

Hi Most charts show the temperature coefficient going through zero around 5V and passing 2 mV/C in the vicinity of 6V. Bob > On Nov 18, 2014, at 12:10 PM, Richard (Rick) Karlquist <richard@karlquist.com> wrote: > > > > On 11/17/2014 5:54 PM, Bert Kehren via time-nuts wrote: >> I ground one side of the tuning diode and use the 2 to 12 V as the external >> OCXO for my FRK's along with increasing the time constant. I have not >> verified it but I think removing the zener Voltage should also improve ADEV. >> Bert Kehren >> > > The choice for the Zener diode came from my old boss at HP, > who was very knowledgeable about using discrete zener diodes > as low noise references. According to him, this particular > part number has very respectable noise. This is just something > you have to know experientially, there is no theory of zener > noise AFAIK. You might try measuring the noise of the 6.2V > reference voltage directly at baseband, and then multiplying > by the 1 Hz/volt sensitivity. Let us know your results. > > Rick Karlquist N6RK > (Now retired from HP/Agilent/Keysight) > > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there.