Re: [time-nuts] HP 117/10509a
Don wrote: the fet breakdown voltage has of course got to be high enough. If the nuvistor is used as a common-cathode or common-grid amplifier, you can cascode the fet with a bipolar to extend its drain voltage range. You will need to come up with an appropriate bias source for the bipolar. Generally, you would want at least 10-15 volts across the FET channel. Choose an appropriate JFET (transconductance, drain current, and gate-drain voltage similar to the nuvistor at the nuvistor's operating point). You can add degeneration (source resistance) to lower the FET's transconductance if it is higher than the nuvistor's. Best regards, Charles ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP 117/10509a
Thanks Charles: I will consider your ideas as they seem to be excellent! I wonder if I could just make the whole unit run off of +24VDC or +12 VDC. I need to look at the schematics and see what would be the best way to proceed. I currently do not have an antenna for WWVB and need to get up and running before I do anything with it. If successful, would anyone want information on my conversion? I also have a fluke 207 that needs to be recapped. Thanks, Ron -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Charles P. Steinmetz Sent: Wednesday, July 04, 2012 11:10 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] HP 117/10509a Don wrote: the fet breakdown voltage has of course got to be high enough. If the nuvistor is used as a common-cathode or common-grid amplifier, you can cascode the fet with a bipolar to extend its drain voltage range. You will need to come up with an appropriate bias source for the bipolar. Generally, you would want at least 10-15 volts across the FET channel. Choose an appropriate JFET (transconductance, drain current, and gate-drain voltage similar to the nuvistor at the nuvistor's operating point). You can add degeneration (source resistance) to lower the FET's transconductance if it is higher than the nuvistor's. Best regards, Charles ___ 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.
Re: [time-nuts] timelab
Don, what do you mean by not getting them sequentially? The stop signal should determine the rate of the samples and if the stop signal is the test signal then any non-uniformity in time is due to that signal. Maybe a good idea to feed the stop trigger with the reference to assure the best time uniformity. Once the sample is ready then feeding it at the exact time when it is available or deferred should be irrelevant. A process is ergodic when more than one statistic give the same result but in this case I can't see how to check for ergodicity. One move maybe to apply the average to groups of samples and see if the average is the same for every group of samples. We already know that this may not happen and the Allan statistic was introduced exactly to account for that. On Thu, Jul 5, 2012 at 7:54 AM, John Miles jmi...@pop.net wrote: -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Ron Ward Sent: Wednesday, July 04, 2012 10:12 PM To: 'Discussion of precise time and frequency measurement' Subject: Re: [time-nuts] timelab Hi: I am also new and would like information about ADEV, MDEV, HDEV, TDEV, Phase and Frequency Difference. Thanks, Ron One place (of many) to start is a page of links I maintain at http://www.ke5fx.com/stability.htm . It's not very well organized, but it's worth looking over to see what catches your interest. NIST Technical Note 1337 is still the best way to start drinking from the fire hose, I think. -- john, KE5FX www.miles.io ___ 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.
Re: [time-nuts] HP 117/10509a
You get an idea of the required changes when you look at the 10509A antenna/preamplifier schematics in the 117A manual changes section. There are both versions, nuvistor and FET covered. It's perhaps not as trivial as one might wish. Adrian Ron Ward schrieb: Thanks Charles: I will consider your ideas as they seem to be excellent! I wonder if I could just make the whole unit run off of +24VDC or +12 VDC. I need to look at the schematics and see what would be the best way to proceed. I currently do not have an antenna for WWVB and need to get up and running before I do anything with it. If successful, would anyone want information on my conversion? I also have a fluke 207 that needs to be recapped. Thanks, Ron -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Charles P. Steinmetz Sent: Wednesday, July 04, 2012 11:10 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] HP 117/10509a Don wrote: the fet breakdown voltage has of course got to be high enough. If the nuvistor is used as a common-cathode or common-grid amplifier, you can cascode the fet with a bipolar to extend its drain voltage range. You will need to come up with an appropriate bias source for the bipolar. Generally, you would want at least 10-15 volts across the FET channel. Choose an appropriate JFET (transconductance, drain current, and gate-drain voltage similar to the nuvistor at the nuvistor's operating point). You can add degeneration (source resistance) to lower the FET's transconductance if it is higher than the nuvistor's. Best regards, Charles ___ 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. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP 117/10509a
Schematics for all versions of the 10509A antenna: http://www.leapsecond.com/museum/10509a/ /tvb (iPhone4) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] timelab
Hi Ron, On 07/05/2012 07:12 AM, Ron Ward wrote: Hi: I am also new and would like information about ADEV, MDEV, HDEV, TDEV, Phase and Frequency Difference. You can start of with the Allan Deviation article on Wikipedia. It has the focus on ADEV, from that the modified Allan Deviation is achieved by simply averaging the input. The Hadamard uses the third degree derivative of the phase data, when Allan only uses the second, and that helps overcome the linear drift sensitivity that Allan variance has, but providing essentially the same scale. The Hadamard is also available in the modified form to achieve the same distinction of frequency flicker and frequency white noise that MDEV does. TDEV is really a time stability measure rather than the frequency stability measure that the ADEV is, it is defined out of MDEV but in reality you can use ADEV measures for higher taus. NIST TN1337 is still highly recommended reading, but it is drinking from the hose. NIST SP 1065 is also recommended. If there is something on the Wikipedia article that can be improved, please let me know. Oh, welcome Ron! :) Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] timelab
On 07/05/2012 07:14 AM, Don Latham wrote: So if the 5370 determines the data rate, then in calculating adev or other such products, we're assuming the time differences are ergodic because we're not getting them sequentially, but rather selecting the delay intervals at long inetrvals between them? It's trying to determine the tau0. It's actually determining the T factor, the time between measurement results. The difference T-tau0 will be your deadtime and it will bias your measurements. This bias function was first shown by Dr. Allan in his Feb 1966 paper. Since we have modernized the analysis somewhat. Please see http://en.wikipedia.org/wiki/Allan_variance#Bias_functions and in particular the B2 bias function. There is two ways to approach it for propper values: 1) Set up the measurement for no (apparent) deadtime. I use a PPS (or other rate) trigger out of something like the TADD-2 either for start or for measurement arming. 2) Compensate for it using the bias function. If you ever skip over measurements, toss the measurement result or at least stop. The series ends when a skip occurs and a new series begins. You can combine the results, but it is tricky, error prone and you loose data on long taus which is what is hard to get much of anyway. Hence, just averaging the sample arrival time without critically analyze the pauses can lead you into incorrect values as things will be biased in all kinds of ways. Inferring the time-base on arrival time should be avoided whenever possible. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] timelab
On 07/05/2012 10:21 AM, Azelio Boriani wrote: Don, what do you mean by not getting them sequentially? The stop signal should determine the rate of the samples and if the stop signal is the test signal then any non-uniformity in time is due to that signal. Maybe a good idea to feed the stop trigger with the reference to assure the best time uniformity. Once the sample is ready then feeding it at the exact time when it is available or deferred should be irrelevant. A process is ergodic when more than one statistic give the same result but in this case I can't see how to check for ergodicity. One move maybe to apply the average to groups of samples and see if the average is the same for every group of samples. We already know that this may not happen and the Allan statistic was introduced exactly to account for that. It the time of the sample he means, and as a delay factor it should experience flicker and white phase noise in which case the assumption is fair. The trouble is if he doesn't have stable values and in particular if it skips over measure. I tried to sketch that in the previous post. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP 117/10509a
Some time ago I made a 60 kHz antenna by winding a zillion turns of wire on a ferrite loopstick tuned with a padder condenser. This connected to the gate of a 2n4416 or mpf102. This was quite selective and sensitive. On 07/05/2012 02:45 AM, Tom Van Baak (lab) wrote: Schematics for all versions of the 10509A antenna: http://www.leapsecond.com/museum/10509a/ /tvb (iPhone4) ___ 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. -- Chuck Forsberg WA7KGX N2469R c...@omen.com www.omen.com Developer of Industrial ZMODEM(Tm) for Embedded Applications Omen Technology Inc The High Reliability Software 10255 NW Old Cornelius Pass Portland OR 97231 503-614-0430 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] timelab
Well, so I have to have stable values... but if I'm measuring my clock I wouldn't expect stable values (of course at most, say, 1nS apart one to the other for every second). That is, assuming that my counter samples at the stop, have I to sample exactly at 1 second using the reference as the stop and the DUT as the start so that the uncertainty will affect the start instant that has no influence on the sampling interval? On Thu, Jul 5, 2012 at 12:44 PM, Magnus Danielson mag...@rubidium.dyndns.org wrote: On 07/05/2012 10:21 AM, Azelio Boriani wrote: Don, what do you mean by not getting them sequentially? The stop signal should determine the rate of the samples and if the stop signal is the test signal then any non-uniformity in time is due to that signal. Maybe a good idea to feed the stop trigger with the reference to assure the best time uniformity. Once the sample is ready then feeding it at the exact time when it is available or deferred should be irrelevant. A process is ergodic when more than one statistic give the same result but in this case I can't see how to check for ergodicity. One move maybe to apply the average to groups of samples and see if the average is the same for every group of samples. We already know that this may not happen and the Allan statistic was introduced exactly to account for that. It the time of the sample he means, and as a delay factor it should experience flicker and white phase noise in which case the assumption is fair. The trouble is if he doesn't have stable values and in particular if it skips over measure. I tried to sketch that in the previous post. Cheers, Magnus __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://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.
Re: [time-nuts] HP 117/10509a
Ron, I would certainly be interested in any conversion scheme that you come up with. I have 2 117's and hope to get them operational sooner rather than later. -:) Gordon WA4FJC Date: Thu, 5 Jul 2012 00:14:32 -0700 From: Ron Ward n6idl...@comcast.net To: 'Discussion of precise time and frequency measurement' time-nuts@febo.com Subject: Re: [time-nuts] HP 117/10509a Message-ID: A12C52D31F1E4BFB96841D691B4E86DE@RonPC Content-Type: text/plain; charset=us-ascii Thanks Charles: I will consider your ideas as they seem to be excellent! I wonder if I could just make the whole unit run off of +24VDC or +12 VDC. I need to look at the schematics and see what would be the best way to proceed. I currently do not have an antenna for WWVB and need to get up and running before I do anything with it. If successful, would anyone want information on my conversion? I also have a fluke 207 that needs to be recapped. Thanks, Ron ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP 117/10509a
You do know that neither a 117A or a 207 will work when WWVB changes to BPSK fairy soon? -John === Thanks Charles: I will consider your ideas as they seem to be excellent! I wonder if I could just make the whole unit run off of +24VDC or +12 VDC. I need to look at the schematics and see what would be the best way to proceed. I currently do not have an antenna for WWVB and need to get up and running before I do anything with it. If successful, would anyone want information on my conversion? I also have a fluke 207 that needs to be recapped. Thanks, Ron -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Charles P. Steinmetz Sent: Wednesday, July 04, 2012 11:10 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] HP 117/10509a Don wrote: the fet breakdown voltage has of course got to be high enough. If the nuvistor is used as a common-cathode or common-grid amplifier, you can cascode the fet with a bipolar to extend its drain voltage range. You will need to come up with an appropriate bias source for the bipolar. Generally, you would want at least 10-15 volts across the FET channel. Choose an appropriate JFET (transconductance, drain current, and gate-drain voltage similar to the nuvistor at the nuvistor's operating point). You can add degeneration (source resistance) to lower the FET's transconductance if it is higher than the nuvistor's. Best regards, Charles ___ 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. ___ 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] gps jamming in las vegas
___ 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] gps jamming in las vegas
I noticed the jamming begin at 0542 today 7-4-12. It's precisely at 5 minute intervals and lasting 75 seconds each time My loss of signal is 1 second after each 5 minute interval (using atomic PDT). Signal returns 75 seconds later at 17 seconds after the next minute. Date 7-5-12 los = loss of signalaos aqusition of signal all times pdt ** exact times of loss of signal losaos 0542 0547 0557 15 0602 54 -- 0603 23 0607 05 -- 0608 19 0612 05 -- 0613 18 0617 05 -- 0618 18 0622 01 -- 0623 17 ** 0627 02 -- 0628 18 0632 02 -- 0633 18 0637 02 -- 0638 17 0642 01 -- 0643 17 ** 0647 01 -- 0648 17 ** 0652 01 -- 0653 17 ** 0657 01 -- 0658 17 ** 0702 01 -- 0703 17 ** 0707 01 -- 0708 17 ** 0712 01 -- 0713 17 ** 0717 01 -- 0718 17 ** I'm using sirf III sirf demo all satelites signals drop from high 30's to the teens complete loss of signal.. My magellan explorist 500 however looses only half the satellites every 5 minutes in exact syncronization with total loss of satellites on holux sirf III receiver. Must be lightsquared wireless I've noticed wierd satellite reception on magellan explorist several months ago and wondered if it was lightsquared jamming... I'm sure of it now. exact same behavier from explorist today that I've seen it the past.. I havent monitored gps for months till today ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] gps jamming in las vegas
I didn't see a message there. The closest jamming I could find follows: ZLA LOS ANGELES (ARTCC)PALMDALE, CA. !GPS 07/006 (KZLA A1678/12) ZLA NAV GPS IS UNRELIABLE AND MAY BE UNAVAILABLE WITHIN A RADIUS OF 400 NM AND CENTERED AT 393316N/1174400W OR THE LOCATION ALSO KNOWN AS THE MINA /MVA/ VOR 013 RADIAL AT 61 NM AT FL400 AND ABOVE; DECREASING IN AREA WITH A DECREASE IN ALTITUDE TO A RADIUS OF 346 NM AT FL250; A RADIUS OF 268 NM AT 1FT MSL; A RADIUS OF 268 NM AT 4000FT AGL; AND A RADIUS OF 249 NM AT 50 FT AGL. 1500-2359 DLY WEF 1207051500-1207062359 -Original Message- From: tom jones epoch_t...@yahoo.com Sender: time-nuts-boun...@febo.com Date: Thu, 5 Jul 2012 07:11:03 To: time-nuts@febo.com Reply-To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: [time-nuts] gps jamming in las vegas ___ 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.
Re: [time-nuts] HP 117/10509a
Yes. I would definitely be interested in information on your conversion. Like you I would prefer attempting a successful conversion as I don't have the knowledge to develop one myself. Thanks, Merchison On 2012-07-05 3:14 AM, Ron Ward wrote: Thanks Charles: I will consider your ideas as they seem to be excellent! I wonder if I could just make the whole unit run off of +24VDC or +12 VDC. I need to look at the schematics and see what would be the best way to proceed. I currently do not have an antenna for WWVB and need to get up and running before I do anything with it. If successful, would anyone want information on my conversion? I also have a fluke 207 that needs to be recapped. Thanks, Ron ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP 117/10509a
NO! WOW! If this is true then you just saved me hours of work and lots of for something that would end up being useless. Will WWVB still be useable for frequency phase comparisons, perhaps by long integrating periods? I spent a lot of time and effort with LORAN and they just killed it. Technology just keeps costing me! Ron -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of J. Forster Sent: Thursday, July 05, 2012 6:31 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] HP 117/10509a You do know that neither a 117A or a 207 will work when WWVB changes to BPSK fairy soon? -John === Thanks Charles: I will consider your ideas as they seem to be excellent! I wonder if I could just make the whole unit run off of +24VDC or +12 VDC. I need to look at the schematics and see what would be the best way to proceed. I currently do not have an antenna for WWVB and need to get up and running before I do anything with it. If successful, would anyone want information on my conversion? I also have a fluke 207 that needs to be recapped. Thanks, Ron -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Charles P. Steinmetz Sent: Wednesday, July 04, 2012 11:10 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] HP 117/10509a Don wrote: the fet breakdown voltage has of course got to be high enough. If the nuvistor is used as a common-cathode or common-grid amplifier, you can cascode the fet with a bipolar to extend its drain voltage range. You will need to come up with an appropriate bias source for the bipolar. Generally, you would want at least 10-15 volts across the FET channel. Choose an appropriate JFET (transconductance, drain current, and gate-drain voltage similar to the nuvistor at the nuvistor's operating point). You can add degeneration (source resistance) to lower the FET's transconductance if it is higher than the nuvistor's. Best regards, Charles ___ 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. ___ 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.
Re: [time-nuts] HP 117/10509a
As John has mentioned all of the old receivers are dead! They will not lock to the new BPSK signal. Though John and I have been working to see what can be done I have to say to date lots of methods have been tried and none really all that successful. These methods include phase lock, squaring/doubling and dividing. The normal types of things used to de-bpsk a signal. Or as I call the system the d-psk-r. I can see how these methods in general work. But the noise hits on the east coast are pretty troubling in causing phase flips. Essentially you need a way to force the the system into one side of the phase always at 120 Khz. So here is the approach I would take. The RF stage you are speaking about has 3 nuvistors and those would easily be replaced by 2 op amps with about 10 db of gain to spare. Simply build 60 KC tuned tanks between stages and you would be in business. I have no idea but the existing L+Cs might be useful here. Then when done you would have a fantastic wwvb signal strength meter and thats all. Its funny on the nuvistors I thought they would be an issue also. But I have been getting them for 2-3 dollars each and they do not really die all that often. On 7/5/2012 8:42 AM, Gordon Batey wrote: Ron, I would certainly be interested in any conversion scheme that you come up with. I have 2 117's and hope to get them operational sooner rather than later. -:) Gordon WA4FJC Date: Thu, 5 Jul 2012 00:14:32 -0700 From: Ron Ward n6idl...@comcast.net To: 'Discussion of precise time and frequency measurement' time-nuts@febo.com Subject: Re: [time-nuts] HP 117/10509a Message-ID: A12C52D31F1E4BFB96841D691B4E86DE@RonPC Content-Type: text/plain; charset=us-ascii Thanks Charles: I will consider your ideas as they seem to be excellent! I wonder if I could just make the whole unit run off of +24VDC or +12 VDC. I need to look at the schematics and see what would be the best way to proceed. I currently do not have an antenna for WWVB and need to get up and running before I do anything with it. If successful, would anyone want information on my conversion? I also have a fluke 207 that needs to be recapped. Thanks, Ron ___ 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.
Re: [time-nuts] HP 117/10509a
Hi again: Well I guess I will just use the Fluke 207 and HP117 for local standard comparisons. Ron -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of J. Forster Sent: Thursday, July 05, 2012 6:31 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] HP 117/10509a You do know that neither a 117A or a 207 will work when WWVB changes to BPSK fairy soon? -John === Thanks Charles: I will consider your ideas as they seem to be excellent! I wonder if I could just make the whole unit run off of +24VDC or +12 VDC. I need to look at the schematics and see what would be the best way to proceed. I currently do not have an antenna for WWVB and need to get up and running before I do anything with it. If successful, would anyone want information on my conversion? I also have a fluke 207 that needs to be recapped. Thanks, Ron -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Charles P. Steinmetz Sent: Wednesday, July 04, 2012 11:10 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] HP 117/10509a Don wrote: the fet breakdown voltage has of course got to be high enough. If the nuvistor is used as a common-cathode or common-grid amplifier, you can cascode the fet with a bipolar to extend its drain voltage range. You will need to come up with an appropriate bias source for the bipolar. Generally, you would want at least 10-15 volts across the FET channel. Choose an appropriate JFET (transconductance, drain current, and gate-drain voltage similar to the nuvistor at the nuvistor's operating point). You can add degeneration (source resistance) to lower the FET's transconductance if it is higher than the nuvistor's. Best regards, Charles ___ 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. ___ 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.
Re: [time-nuts] HP 117/10509a
Yes they will still work well for that and the 207 does much better then the 117 by about 10 X Regards Paul On 7/5/2012 10:52 AM, Ron Ward wrote: Hi again: Well I guess I will just use the Fluke 207 and HP117 for local standard comparisons. Ron -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of J. Forster Sent: Thursday, July 05, 2012 6:31 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] HP 117/10509a You do know that neither a 117A or a 207 will work when WWVB changes to BPSK fairy soon? -John === Thanks Charles: I will consider your ideas as they seem to be excellent! I wonder if I could just make the whole unit run off of +24VDC or +12 VDC. I need to look at the schematics and see what would be the best way to proceed. I currently do not have an antenna for WWVB and need to get up and running before I do anything with it. If successful, would anyone want information on my conversion? I also have a fluke 207 that needs to be recapped. Thanks, Ron -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Charles P. Steinmetz Sent: Wednesday, July 04, 2012 11:10 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] HP 117/10509a Don wrote: the fet breakdown voltage has of course got to be high enough. If the nuvistor is used as a common-cathode or common-grid amplifier, you can cascode the fet with a bipolar to extend its drain voltage range. You will need to come up with an appropriate bias source for the bipolar. Generally, you would want at least 10-15 volts across the FET channel. Choose an appropriate JFET (transconductance, drain current, and gate-drain voltage similar to the nuvistor at the nuvistor's operating point). You can add degeneration (source resistance) to lower the FET's transconductance if it is higher than the nuvistor's. Best regards, Charles ___ 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. ___ 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. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP 117/10509a
Hi: What is the new bandwidth for BPSK WWVB going to be? Why are they going to BPSK, cheaper clocks? How am I going to compare GPS to something to see if GPS is accurate? What about 400.1 MHz GEOS? Thanks, Ron -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of paul Sent: Thursday, July 05, 2012 7:49 AM To: time-nuts@febo.com Subject: Re: [time-nuts] HP 117/10509a As John has mentioned all of the old receivers are dead! They will not lock to the new BPSK signal. Though John and I have been working to see what can be done I have to say to date lots of methods have been tried and none really all that successful. These methods include phase lock, squaring/doubling and dividing. The normal types of things used to de-bpsk a signal. Or as I call the system the d-psk-r. I can see how these methods in general work. But the noise hits on the east coast are pretty troubling in causing phase flips. Essentially you need a way to force the the system into one side of the phase always at 120 Khz. So here is the approach I would take. The RF stage you are speaking about has 3 nuvistors and those would easily be replaced by 2 op amps with about 10 db of gain to spare. Simply build 60 KC tuned tanks between stages and you would be in business. I have no idea but the existing L+Cs might be useful here. Then when done you would have a fantastic wwvb signal strength meter and thats all. Its funny on the nuvistors I thought they would be an issue also. But I have been getting them for 2-3 dollars each and they do not really die all that often. On 7/5/2012 8:42 AM, Gordon Batey wrote: Ron, I would certainly be interested in any conversion scheme that you come up with. I have 2 117's and hope to get them operational sooner rather than later. -:) Gordon WA4FJC Date: Thu, 5 Jul 2012 00:14:32 -0700 From: Ron Ward n6idl...@comcast.net To: 'Discussion of precise time and frequency measurement' time-nuts@febo.com Subject: Re: [time-nuts] HP 117/10509a Message-ID: A12C52D31F1E4BFB96841D691B4E86DE@RonPC Content-Type: text/plain; charset=us-ascii Thanks Charles: I will consider your ideas as they seem to be excellent! I wonder if I could just make the whole unit run off of +24VDC or +12 VDC. I need to look at the schematics and see what would be the best way to proceed. I currently do not have an antenna for WWVB and need to get up and running before I do anything with it. If successful, would anyone want information on my conversion? I also have a fluke 207 that needs to be recapped. Thanks, Ron ___ 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. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP 117/10509a
Not sure why the email did not send As John has mentioned all of the old receivers are dead! They will not lock to the new BPSK signal. Though John and I have been working to see what can be done I have to say to date lots of methods have been tried and none really all that successful. These methods include phase lock, squaring/doubling and dividing. The normal types of things used to de-bpsk a signal. Or as I call the system the d-psk-r. I can see how these methods in general work. But the noise hits on the east coast are pretty troubling in causing phase flips. Essentially you need a way to force the the system into one side of the phase always at 120 Khz. So here is the approach I would take. The RF stage you are speaking about has 3 nuvistors and those would easily be replaced by 2 op amps with about 10 db of gain to spare. Simply build 60 KC tuned tanks between stages and you would be in business. I have no idea but the existing L+Cs might be useful here. Then when done you would have a fantastic wwvb signal strength meter and thats all. Its funny on the nuvistors I thought they would be an issue also. But I have been getting them for 2-3 dollars each and they do not really die all that often. Regards Paul On 7/5/2012 10:58 AM, Ron Ward wrote: Hi: What is the new bandwidth for BPSK WWVB going to be? Why are they going to BPSK, cheaper clocks? How am I going to compare GPS to something to see if GPS is accurate? What about 400.1 MHz GEOS? Thanks, Ron -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of paul Sent: Thursday, July 05, 2012 7:49 AM To: time-nuts@febo.com Subject: Re: [time-nuts] HP 117/10509a As John has mentioned all of the old receivers are dead! They will not lock to the new BPSK signal. Though John and I have been working to see what can be done I have to say to date lots of methods have been tried and none really all that successful. These methods include phase lock, squaring/doubling and dividing. The normal types of things used to de-bpsk a signal. Or as I call the system the d-psk-r. I can see how these methods in general work. But the noise hits on the east coast are pretty troubling in causing phase flips. Essentially you need a way to force the the system into one side of the phase always at 120 Khz. So here is the approach I would take. The RF stage you are speaking about has 3 nuvistors and those would easily be replaced by 2 op amps with about 10 db of gain to spare. Simply build 60 KC tuned tanks between stages and you would be in business. I have no idea but the existing L+Cs might be useful here. Then when done you would have a fantastic wwvb signal strength meter and thats all. Its funny on the nuvistors I thought they would be an issue also. But I have been getting them for 2-3 dollars each and they do not really die all that often. On 7/5/2012 8:42 AM, Gordon Batey wrote: Ron, I would certainly be interested in any conversion scheme that you come up with. I have 2 117's and hope to get them operational sooner rather than later. -:) Gordon WA4FJC Date: Thu, 5 Jul 2012 00:14:32 -0700 From: Ron Ward n6idl...@comcast.net To: 'Discussion of precise time and frequency measurement' time-nuts@febo.com Subject: Re: [time-nuts] HP 117/10509a Message-ID: A12C52D31F1E4BFB96841D691B4E86DE@RonPC Content-Type: text/plain; charset=us-ascii Thanks Charles: I will consider your ideas as they seem to be excellent! I wonder if I could just make the whole unit run off of +24VDC or +12 VDC. I need to look at the schematics and see what would be the best way to proceed. I currently do not have an antenna for WWVB and need to get up and running before I do anything with it. If successful, would anyone want information on my conversion? I also have a fluke 207 that needs to be recapped. Thanks, Ron ___ 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. ___ 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.
[time-nuts] HP 117/10509a...
Many years ago I had one of these antennas that I used with a Gertsch RLF-1 WWVB receiver. When the Nuvistors became old and feeble I decided to change the 6CW4 Nuvistors to FETs. Being young and foolish and thinking this is basically audio, I went to Radio Shack and got some N-Channel FETs and stuffed the FET's leads into the appropriate Nuvistor socket pins: Gate to Grid, Source to Cathode, and Drain to Plate. As I recall, I had to add a wee bit of capacitance to make it tune back down to 60 KC - back then I didn't know from kHz. I made a voltage divider inside the antenna's junction box to get the higher voltage down to what the FETs wanted. It ran fine for the remaining 8 to10 years that I used the RLF-1's. I forget where the antenna went, but it may still be in use somewhere. At least I hope so. Burt, K6OQK From: Merchison Burke merchi...@yahoo.co.uk To: time-nuts@febo.com Subject: [time-nuts] HP 117/10509a Hello, Has anyone successfully replaces the Nuvistors in the 117 and the 10509a with FETs. I would like to replace them with inexpensive FETs instead of buying the expensive Nunistors. Thanks for all help, Merchison Burt I. Weiner Associates Broadcast Technical Services Glendale, California U.S.A. b...@att.net www.biwa.cc K6OQK ___ 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] gps jamming source found
It turns out my lacross projection, atomic, external temperature transmitter, clock is the source of the jamming.. Apparently its trying to communicate with its external temp sensor which has had a dead battery for months.. The projection clock is powered from ac mains and transmitts for long intervals looking for external temperature sensor... It transmitts around 433mhz Sorry for any previous post.Well be carfull of wireless weather, temperature equipment around gps ... I do hope government puts an end to lightsquared frequency allocations near gps frequencies ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] gps jamming source found
Quite interesting the indoor unit that transmits hunting for the outdoor sensor... usually the indoor unit receives only and the external sensor transmits only. Your words imply that the LaCrosse clock/sensor is a transceiver pair... On Thu, Jul 5, 2012 at 5:21 PM, tom jones epoch_t...@yahoo.com wrote: It turns out my lacross projection, atomic, external temperature transmitter, clock is the source of the jamming.. Apparently its trying to communicate with its external temp sensor which has had a dead battery for months.. The projection clock is powered from ac mains and transmitts for long intervals looking for external temperature sensor... It transmitts around 433mhz Sorry for any previous post.Well be carfull of wireless weather, temperature equipment around gps ... I do hope government puts an end to lightsquared frequency allocations near gps frequencies ___ 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.
Re: [time-nuts] HP 117/10509a
NO! WOW! If this is true then you just saved me hours of work and lots of for something that would end up being useless. It is true. It was discussed a few months ago. I have posted on the testing repeatedly. Will WWVB still be useable for frequency phase comparisons, perhaps by long integrating periods? No. The receivers must be modified or replaced. The mods are non-trivial in practice. I spent a lot of time and effort with LORAN and they just killed it. t least a year ago. -John = Technology just keeps costing me! Ron -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of J. Forster Sent: Thursday, July 05, 2012 6:31 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] HP 117/10509a You do know that neither a 117A or a 207 will work when WWVB changes to BPSK fairy soon? -John === Thanks Charles: I will consider your ideas as they seem to be excellent! I wonder if I could just make the whole unit run off of +24VDC or +12 VDC. I need to look at the schematics and see what would be the best way to proceed. I currently do not have an antenna for WWVB and need to get up and running before I do anything with it. If successful, would anyone want information on my conversion? I also have a fluke 207 that needs to be recapped. Thanks, Ron -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Charles P. Steinmetz Sent: Wednesday, July 04, 2012 11:10 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] HP 117/10509a Don wrote: the fet breakdown voltage has of course got to be high enough. If the nuvistor is used as a common-cathode or common-grid amplifier, you can cascode the fet with a bipolar to extend its drain voltage range. You will need to come up with an appropriate bias source for the bipolar. Generally, you would want at least 10-15 volts across the FET channel. Choose an appropriate JFET (transconductance, drain current, and gate-drain voltage similar to the nuvistor at the nuvistor's operating point). You can add degeneration (source resistance) to lower the FET's transconductance if it is higher than the nuvistor's. Best regards, Charles ___ 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. ___ 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.
Re: [time-nuts] gps jamming source found
Thanks for posting this and I'm glad you solved your problem. It's nice to see actual examples of this type of interference. --- On Thu, 7/5/12, tom jones epoch_t...@yahoo.com wrote: From: tom jones epoch_t...@yahoo.com Subject: [time-nuts] gps jamming source found To: time-nuts@febo.com Received: Thursday, July 5, 2012, 11:21 AM It turns out my lacross projection, atomic, external temperature transmitter, clock is the source of the jamming.. Apparently its trying to communicate with its external temp sensor which has had a dead battery for months.. The projection clock is powered from ac mains and transmitts for long intervals looking for external temperature sensor... It transmitts around 433mhz Sorry for any previous post.Well be carfull of wireless weather, temperature equipment around gps ... I do hope government puts an end to lightsquared frequency allocations near gps frequencies ___ 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.
Re: [time-nuts] HP 117/10509a...
I thought about doing that but I did not want to spend a lot of time experimenting fruitlessly. Thanks for the encouragement. Merchison On 2012-07-05 11:19 AM, Burt I. Weiner wrote: Many years ago I had one of these antennas that I used with a Gertsch RLF-1 WWVB receiver. When the Nuvistors became old and feeble I decided to change the 6CW4 Nuvistors to FETs. Being young and foolish and thinking this is basically audio, I went to Radio Shack and got some N-Channel FETs and stuffed the FET's leads into the appropriate Nuvistor socket pins: Gate to Grid, Source to Cathode, and Drain to Plate. As I recall, I had to add a wee bit of capacitance to make it tune back down to 60 KC - back then I didn't know from kHz. I made a voltage divider inside the antenna's junction box to get the higher voltage down to what the FETs wanted. It ran fine for the remaining 8 to10 years that I used the RLF-1's. I forget where the antenna went, but it may still be in use somewhere. At least I hope so. Burt, K6OQK From: Merchison Burke merchi...@yahoo.co.uk To: time-nuts@febo.com Subject: [time-nuts] HP 117/10509a Hello, Has anyone successfully replaces the Nuvistors in the 117 and the 10509a with FETs. I would like to replace them with inexpensive FETs instead of buying the expensive Nunistors. Thanks for all help, Merchison Burt I. Weiner Associates Broadcast Technical Services Glendale, California U.S.A. b...@att.net www.biwa.cc K6OQK ___ 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. - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.1913 / Virus Database: 2437/5112 - Release Date: 07/05/12 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP 117/10509a
On 7/4/2012 11:09 PM, Charles P. Steinmetz wrote: Don wrote: the fet breakdown voltage has of course got to be high enough. If the nuvistor is used as a common-cathode or common-grid amplifier, you can cascode the fet with a bipolar to extend its drain voltage range. You will need to come up with an appropriate bias source for the bipolar. Generally, you would want at least 10-15 volts across the FET channel. Choose an appropriate JFET (transconductance, drain current, and gate-drain voltage similar to the nuvistor at the nuvistor's operating point). You can add degeneration (source resistance) to lower the FET's transconductance if it is higher than the nuvistor's. Best regards, Charles ___ 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. I have a PDF document that covers this for Fetrons. This is from Teledyne. It shows some of the more common tube replacements with the circuit and actual device number. Let me know if you would like a copy and I will sent it to you. Or, maybe a better option would be to upload it to something like Didiers site. . . Randy ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP 117/10509a...
Dear Group, This thread just saved me from a prospective purchase of an HP 117. Now the big question. Which instruments in general will be affected by the BPSK transition? I have been reading about Kinemetrics 60DC WWVB receiver and clock. It appeals to me if I find one. Will other WWVB instruments not designed specifically for phase comparisons be affected for the WWVB signal modulation changes? Which kind of instruments and interactions with WWVB should I avoid? Thank you. Your comments are surely welcome. Regards, Edgardo Molina Dirección IPTEL www.iptel.net.mx T : 55 55 55202444 M : 04455 20501854 Piensa en Bits SA de CV Información anexa: CONFIDENCIALIDAD DE INFORMACION Este mensaje tiene carácter confidencial. Si usted no es el destinarario de este mensaje, le suplicamos se lo notifique al remitente mediante un correo electrónico y que borre el presente mensaje y sus anexos de su computadora sin retener una copia de los mismos. Queda estrictamente prohibido copiar este mensaje o hacer usode el para cualquier propósito o divulgar su en forma parcial o total su contenido. Gracias. NON-DISCLOSURE OF INFORMATION This email is strictly confidential and may also be privileged. If you are not the intended recipient please immediately advise the sender by replying to this e-mail and then deleting the message and its attachments from your computer without keeping a copy. It is strictly forbidden to copy it or use it for any purpose or disclose its contents to any third party. Thank you. On Jul 5, 2012, at 11:32 AM, Merchison Burke wrote: I thought about doing that but I did not want to spend a lot of time experimenting fruitlessly. Thanks for the encouragement. Merchison On 2012-07-05 11:19 AM, Burt I. Weiner wrote: Many years ago I had one of these antennas that I used with a Gertsch RLF-1 WWVB receiver. When the Nuvistors became old and feeble I decided to change the 6CW4 Nuvistors to FETs. Being young and foolish and thinking this is basically audio, I went to Radio Shack and got some N-Channel FETs and stuffed the FET's leads into the appropriate Nuvistor socket pins: Gate to Grid, Source to Cathode, and Drain to Plate. As I recall, I had to add a wee bit of capacitance to make it tune back down to 60 KC - back then I didn't know from kHz. I made a voltage divider inside the antenna's junction box to get the higher voltage down to what the FETs wanted. It ran fine for the remaining 8 to10 years that I used the RLF-1's. I forget where the antenna went, but it may still be in use somewhere. At least I hope so. Burt, K6OQK From: Merchison Burke merchi...@yahoo.co.uk To: time-nuts@febo.com Subject: [time-nuts] HP 117/10509a Hello, Has anyone successfully replaces the Nuvistors in the 117 and the 10509a with FETs. I would like to replace them with inexpensive FETs instead of buying the expensive Nunistors. Thanks for all help, Merchison Burt I. Weiner Associates Broadcast Technical Services Glendale, California U.S.A. b...@att.net www.biwa.cc K6OQK ___ 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. - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.1913 / Virus Database: 2437/5112 - Release Date: 07/05/12 ___ 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.
Re: [time-nuts] HP 117/10509a...
The only ones that will work are very recent designs. The HP 117 and Fluke 207 will not work. Many Spectracoms will not work. A few will. See their web site The Stanford 620 will not, I believe. Some models may. I posted a partial list some time ago. Apparently, NIST is working on a receiver and possibly a retrofit. When it will be available and how much it will cost is TBD. I suspect the 'retrofit' will be the receiver with a 60 kHz output added, nothing more, but don't know. Seems to me, we are down to one egg in one basket. :(( -John Dear Group, This thread just saved me from a prospective purchase of an HP 117. Now the big question. Which instruments in general will be affected by the BPSK transition? I have been reading about Kinemetrics 60DC WWVB receiver and clock. It appeals to me if I find one. Will other WWVB instruments not designed specifically for phase comparisons be affected for the WWVB signal modulation changes? Which kind of instruments and interactions with WWVB should I avoid? Thank you. Your comments are surely welcome. Regards, Edgardo Molina Dirección IPTEL www.iptel.net.mx T : 55 55 55202444 M : 04455 20501854 Piensa en Bits SA de CV Información anexa: CONFIDENCIALIDAD DE INFORMACION Este mensaje tiene carácter confidencial. Si usted no es el destinarario de este mensaje, le suplicamos se lo notifique al remitente mediante un correo electrónico y que borre el presente mensaje y sus anexos de su computadora sin retener una copia de los mismos. Queda estrictamente prohibido copiar este mensaje o hacer usode el para cualquier propósito o divulgar su en forma parcial o total su contenido. Gracias. NON-DISCLOSURE OF INFORMATION This email is strictly confidential and may also be privileged. If you are not the intended recipient please immediately advise the sender by replying to this e-mail and then deleting the message and its attachments from your computer without keeping a copy. It is strictly forbidden to copy it or use it for any purpose or disclose its contents to any third party. Thank you. On Jul 5, 2012, at 11:32 AM, Merchison Burke wrote: I thought about doing that but I did not want to spend a lot of time experimenting fruitlessly. Thanks for the encouragement. Merchison On 2012-07-05 11:19 AM, Burt I. Weiner wrote: Many years ago I had one of these antennas that I used with a Gertsch RLF-1 WWVB receiver. When the Nuvistors became old and feeble I decided to change the 6CW4 Nuvistors to FETs. Being young and foolish and thinking this is basically audio, I went to Radio Shack and got some N-Channel FETs and stuffed the FET's leads into the appropriate Nuvistor socket pins: Gate to Grid, Source to Cathode, and Drain to Plate. As I recall, I had to add a wee bit of capacitance to make it tune back down to 60 KC - back then I didn't know from kHz. I made a voltage divider inside the antenna's junction box to get the higher voltage down to what the FETs wanted. It ran fine for the remaining 8 to10 years that I used the RLF-1's. I forget where the antenna went, but it may still be in use somewhere. At least I hope so. Burt, K6OQK From: Merchison Burke merchi...@yahoo.co.uk To: time-nuts@febo.com Subject: [time-nuts] HP 117/10509a Hello, Has anyone successfully replaces the Nuvistors in the 117 and the 10509a with FETs. I would like to replace them with inexpensive FETs instead of buying the expensive Nunistors. Thanks for all help, Merchison Burt I. Weiner Associates Broadcast Technical Services Glendale, California U.S.A. b...@att.net www.biwa.cc K6OQK ___ 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. - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.1913 / Virus Database: 2437/5112 - Release Date: 07/05/12 ___ 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. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP 117/10509a...
Hi Simple answer - they are still playing around with the signal format. It is totally unclear what the final format will really look like. Until they make up their minds there is only one safe bet - the clock on grandma's wall will still handle the wwvb format they use. Anything more complex than that is very much in the who knows category. Bob On Jul 5, 2012, at 1:07 PM, Edgardo Molina wrote: Dear Group, This thread just saved me from a prospective purchase of an HP 117. Now the big question. Which instruments in general will be affected by the BPSK transition? I have been reading about Kinemetrics 60DC WWVB receiver and clock. It appeals to me if I find one. Will other WWVB instruments not designed specifically for phase comparisons be affected for the WWVB signal modulation changes? Which kind of instruments and interactions with WWVB should I avoid? Thank you. Your comments are surely welcome. Regards, Edgardo Molina Dirección IPTEL www.iptel.net.mx T : 55 55 55202444 M : 04455 20501854 Piensa en Bits SA de CV Información anexa: CONFIDENCIALIDAD DE INFORMACION Este mensaje tiene carácter confidencial. Si usted no es el destinarario de este mensaje, le suplicamos se lo notifique al remitente mediante un correo electrónico y que borre el presente mensaje y sus anexos de su computadora sin retener una copia de los mismos. Queda estrictamente prohibido copiar este mensaje o hacer usode el para cualquier propósito o divulgar su en forma parcial o total su contenido. Gracias. NON-DISCLOSURE OF INFORMATION This email is strictly confidential and may also be privileged. If you are not the intended recipient please immediately advise the sender by replying to this e-mail and then deleting the message and its attachments from your computer without keeping a copy. It is strictly forbidden to copy it or use it for any purpose or disclose its contents to any third party. Thank you. On Jul 5, 2012, at 11:32 AM, Merchison Burke wrote: I thought about doing that but I did not want to spend a lot of time experimenting fruitlessly. Thanks for the encouragement. Merchison On 2012-07-05 11:19 AM, Burt I. Weiner wrote: Many years ago I had one of these antennas that I used with a Gertsch RLF-1 WWVB receiver. When the Nuvistors became old and feeble I decided to change the 6CW4 Nuvistors to FETs. Being young and foolish and thinking this is basically audio, I went to Radio Shack and got some N-Channel FETs and stuffed the FET's leads into the appropriate Nuvistor socket pins: Gate to Grid, Source to Cathode, and Drain to Plate. As I recall, I had to add a wee bit of capacitance to make it tune back down to 60 KC - back then I didn't know from kHz. I made a voltage divider inside the antenna's junction box to get the higher voltage down to what the FETs wanted. It ran fine for the remaining 8 to10 years that I used the RLF-1's. I forget where the antenna went, but it may still be in use somewhere. At least I hope so. Burt, K6OQK From: Merchison Burke merchi...@yahoo.co.uk To: time-nuts@febo.com Subject: [time-nuts] HP 117/10509a Hello, Has anyone successfully replaces the Nuvistors in the 117 and the 10509a with FETs. I would like to replace them with inexpensive FETs instead of buying the expensive Nunistors. Thanks for all help, Merchison Burt I. Weiner Associates Broadcast Technical Services Glendale, California U.S.A. b...@att.net www.biwa.cc K6OQK ___ 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. - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.1913 / Virus Database: 2437/5112 - Release Date: 07/05/12 ___ 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. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] gps jamming source found
The wireless data links in those R/C sensor type things don't operate near GPS carriers, but their harmonics can land there. The transmitted power allowed should be too small to interfere with anyone's receiver farther away - yours is probably pretty close. I believe that the remote senders do not wait for any polling signals - if so, they would have to be receiving on a regular basis, taking precious battery life. It makes more sense for them to just burst transmit at regular intervals, while the line-powered (or bigger-battery-powered) base station is always listening, or listens at various intervals to see if any remotes are calling. That's why it takes a while to get the initial temperature data when the system starts up. The base station receivers used for simple, cheap VHF data are typically super-regenerative type for high sensitivity, so when they're fired up it may appear that they're transmitting, but actually are only receiving, with lots of crap kicking out of the super-regen circuit. A common carrier used for VHF remotes is around 315 MHz - the fifth harmonic of that one is especially bad, landing almost right on top of GPS. When you add in the loose frequency stability and modulation, and the regen signals, the transmitters and receivers can cause quite a spectral mess. Ed ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP 117/10509a...
Hi: This is so frustrating! Who makes cheap clocks? CHINA. Who uses phase comparison? DOD, American Colleges and Universities, Laboratories, Astronomers, American Private Industry, Time Nuts, ETC. What is our government doing? They appear to be the best friend Chinese manufacturers ever had! Ron -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of J. Forster Sent: Thursday, July 05, 2012 10:29 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] HP 117/10509a... The only ones that will work are very recent designs. The HP 117 and Fluke 207 will not work. Many Spectracoms will not work. A few will. See their web site The Stanford 620 will not, I believe. Some models may. I posted a partial list some time ago. Apparently, NIST is working on a receiver and possibly a retrofit. When it will be available and how much it will cost is TBD. I suspect the 'retrofit' will be the receiver with a 60 kHz output added, nothing more, but don't know. Seems to me, we are down to one egg in one basket. :(( -John Dear Group, This thread just saved me from a prospective purchase of an HP 117. Now the big question. Which instruments in general will be affected by the BPSK transition? I have been reading about Kinemetrics 60DC WWVB receiver and clock. It appeals to me if I find one. Will other WWVB instruments not designed specifically for phase comparisons be affected for the WWVB signal modulation changes? Which kind of instruments and interactions with WWVB should I avoid? Thank you. Your comments are surely welcome. Regards, Edgardo Molina Dirección IPTEL www.iptel.net.mx T : 55 55 55202444 M : 04455 20501854 Piensa en Bits SA de CV Información anexa: CONFIDENCIALIDAD DE INFORMACION Este mensaje tiene carácter confidencial. Si usted no es el destinarario de este mensaje, le suplicamos se lo notifique al remitente mediante un correo electrónico y que borre el presente mensaje y sus anexos de su computadora sin retener una copia de los mismos. Queda estrictamente prohibido copiar este mensaje o hacer usode el para cualquier propósito o divulgar su en forma parcial o total su contenido. Gracias. NON-DISCLOSURE OF INFORMATION This email is strictly confidential and may also be privileged. If you are not the intended recipient please immediately advise the sender by replying to this e-mail and then deleting the message and its attachments from your computer without keeping a copy. It is strictly forbidden to copy it or use it for any purpose or disclose its contents to any third party. Thank you. On Jul 5, 2012, at 11:32 AM, Merchison Burke wrote: I thought about doing that but I did not want to spend a lot of time experimenting fruitlessly. Thanks for the encouragement. Merchison On 2012-07-05 11:19 AM, Burt I. Weiner wrote: Many years ago I had one of these antennas that I used with a Gertsch RLF-1 WWVB receiver. When the Nuvistors became old and feeble I decided to change the 6CW4 Nuvistors to FETs. Being young and foolish and thinking this is basically audio, I went to Radio Shack and got some N-Channel FETs and stuffed the FET's leads into the appropriate Nuvistor socket pins: Gate to Grid, Source to Cathode, and Drain to Plate. As I recall, I had to add a wee bit of capacitance to make it tune back down to 60 KC - back then I didn't know from kHz. I made a voltage divider inside the antenna's junction box to get the higher voltage down to what the FETs wanted. It ran fine for the remaining 8 to10 years that I used the RLF-1's. I forget where the antenna went, but it may still be in use somewhere. At least I hope so. Burt, K6OQK From: Merchison Burke merchi...@yahoo.co.uk To: time-nuts@febo.com Subject: [time-nuts] HP 117/10509a Hello, Has anyone successfully replaces the Nuvistors in the 117 and the 10509a with FETs. I would like to replace them with inexpensive FETs instead of buying the expensive Nunistors. Thanks for all help, Merchison Burt I. Weiner Associates Broadcast Technical Services Glendale, California U.S.A. b...@att.net www.biwa.cc K6OQK ___ 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. - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.1913 / Virus Database: 2437/5112 - Release Date: 07/05/12 ___ 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
Re: [time-nuts] HP 117/10509a...
Hi: This is so frustrating! Agreed. Who makes cheap clocks? CHINA. Who uses phase comparison? DOD, American Colleges and Universities, Laboratories, Astronomers, American Private Industry, Time Nuts, ETC. Not really. They have all drunk the GPS Kool-Aid. To allow a second source for a standard of time interval, carries the implication that GPS is not invulnerable. If that's true, people may wonder what else needs a backup, like navigation? Electric grid synchronization? Phones? What is our government doing? One man, one vote, (one time?). There are a lot more cheap Chinese 'Atomic' clocks sold every day than timing receivers sold in a year. Numbers count. They appear to be the best friend Chinese manufacturers ever had! Certainly true, in The Donald's view. The US government plays checkers, the Chinese and Japanese play Chess... to steal an analogy. US companies, driven by Wall Street quarter-over-quarter greed, think about the next quarter; Asian companies think about the next few decades. The switch to HDTV was supposed to be a giant stimulus for the US electronics industry, hence a US 'standard'. How did that work out? What fraction of HDTVs are US made? YMMV, -John == Ron -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of J. Forster Sent: Thursday, July 05, 2012 10:29 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] HP 117/10509a... The only ones that will work are very recent designs. The HP 117 and Fluke 207 will not work. Many Spectracoms will not work. A few will. See their web site The Stanford 620 will not, I believe. Some models may. I posted a partial list some time ago. Apparently, NIST is working on a receiver and possibly a retrofit. When it will be available and how much it will cost is TBD. I suspect the 'retrofit' will be the receiver with a 60 kHz output added, nothing more, but don't know. Seems to me, we are down to one egg in one basket. :(( -John Dear Group, This thread just saved me from a prospective purchase of an HP 117. Now the big question. Which instruments in general will be affected by the BPSK transition? I have been reading about Kinemetrics 60DC WWVB receiver and clock. It appeals to me if I find one. Will other WWVB instruments not designed specifically for phase comparisons be affected for the WWVB signal modulation changes? Which kind of instruments and interactions with WWVB should I avoid? Thank you. Your comments are surely welcome. Regards, Edgardo Molina Dirección IPTEL www.iptel.net.mx ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP 117/10509a...
Hi The real question is weather the BPSK will help us get significantly better accuracy out of WWVB or not. If it does, time marches on. If not - total waste of effort. DSP based low frequency receivers are pretty easy to make. You still will need those antennas and preamps to make them work though. If I can get Loran-C type accuracy out of WWVB with the new modulation, I'll certainly build or buy a receiver. Bob On Jul 5, 2012, at 5:43 PM, J. Forster wrote: Hi: This is so frustrating! Agreed. Who makes cheap clocks? CHINA. Who uses phase comparison? DOD, American Colleges and Universities, Laboratories, Astronomers, American Private Industry, Time Nuts, ETC. Not really. They have all drunk the GPS Kool-Aid. To allow a second source for a standard of time interval, carries the implication that GPS is not invulnerable. If that's true, people may wonder what else needs a backup, like navigation? Electric grid synchronization? Phones? What is our government doing? One man, one vote, (one time?). There are a lot more cheap Chinese 'Atomic' clocks sold every day than timing receivers sold in a year. Numbers count. They appear to be the best friend Chinese manufacturers ever had! Certainly true, in The Donald's view. The US government plays checkers, the Chinese and Japanese play Chess... to steal an analogy. US companies, driven by Wall Street quarter-over-quarter greed, think about the next quarter; Asian companies think about the next few decades. The switch to HDTV was supposed to be a giant stimulus for the US electronics industry, hence a US 'standard'. How did that work out? What fraction of HDTVs are US made? YMMV, -John == Ron -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of J. Forster Sent: Thursday, July 05, 2012 10:29 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] HP 117/10509a... The only ones that will work are very recent designs. The HP 117 and Fluke 207 will not work. Many Spectracoms will not work. A few will. See their web site The Stanford 620 will not, I believe. Some models may. I posted a partial list some time ago. Apparently, NIST is working on a receiver and possibly a retrofit. When it will be available and how much it will cost is TBD. I suspect the 'retrofit' will be the receiver with a 60 kHz output added, nothing more, but don't know. Seems to me, we are down to one egg in one basket. :(( -John Dear Group, This thread just saved me from a prospective purchase of an HP 117. Now the big question. Which instruments in general will be affected by the BPSK transition? I have been reading about Kinemetrics 60DC WWVB receiver and clock. It appeals to me if I find one. Will other WWVB instruments not designed specifically for phase comparisons be affected for the WWVB signal modulation changes? Which kind of instruments and interactions with WWVB should I avoid? Thank you. Your comments are surely welcome. Regards, Edgardo Molina Dirección IPTEL www.iptel.net.mx ___ 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.
Re: [time-nuts] HP 117/10509a...
From what I've read, the mods are to improve the Time of Day, not the Time Interval accuracy. In my location (MA) WWVB was never as good as LORAN-C because of propagation issues. -John === Hi The real question is weather the BPSK will help us get significantly better accuracy out of WWVB or not. If it does, time marches on. If not - total waste of effort. DSP based low frequency receivers are pretty easy to make. You still will need those antennas and preamps to make them work though. If I can get Loran-C type accuracy out of WWVB with the new modulation, I'll certainly build or buy a receiver. Bob ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP 117/10509a...
Hi Propagation isn't going to change with modulation format, so that part will still be with us. I'm wondering if some fancy processing on the new code might have some advantages. It's not worth digging into until they have a final format though. Bob On Jul 5, 2012, at 6:19 PM, J. Forster wrote: From what I've read, the mods are to improve the Time of Day, not the Time Interval accuracy. In my location (MA) WWVB was never as good as LORAN-C because of propagation issues. -John === Hi The real question is weather the BPSK will help us get significantly better accuracy out of WWVB or not. If it does, time marches on. If not - total waste of effort. DSP based low frequency receivers are pretty easy to make. You still will need those antennas and preamps to make them work though. If I can get Loran-C type accuracy out of WWVB with the new modulation, I'll certainly build or buy a receiver. Bob ___ 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.
Re: [time-nuts] HP 117/10509a
On 7/5/2012 9:49 AM, Randy D. Hunt wrote: On 7/4/2012 11:09 PM, Charles P. Steinmetz wrote: Don wrote: the fet breakdown voltage has of course got to be high enough. If the nuvistor is used as a common-cathode or common-grid amplifier, you can cascode the fet with a bipolar to extend its drain voltage range. You will need to come up with an appropriate bias source for the bipolar. Generally, you would want at least 10-15 volts across the FET channel. Choose an appropriate JFET (transconductance, drain current, and gate-drain voltage similar to the nuvistor at the nuvistor's operating point). You can add degeneration (source resistance) to lower the FET's transconductance if it is higher than the nuvistor's. Best regards, Charles ___ 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. I have a PDF document that covers this for Fetrons. This is from Teledyne. It shows some of the more common tube replacements with the circuit and actual device number. Let me know if you would like a copy and I will sent it to you. Or, maybe a better option would be to upload it to something like Didiers site. . . Randy ___ 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 do upload it. I have some Fetrons and want to know what they replace. And in my other life, I ordered some custom Fetrons to replace some WE tubes that was used in WE K carrier. If you don't upload it, send a copy. Bill K7NOM ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP 117/10509a
Hi: Yes, please make a .PDF File available! Thanks, Ron -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of bill Sent: Thursday, July 05, 2012 3:57 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] HP 117/10509a On 7/5/2012 9:49 AM, Randy D. Hunt wrote: On 7/4/2012 11:09 PM, Charles P. Steinmetz wrote: Don wrote: the fet breakdown voltage has of course got to be high enough. If the nuvistor is used as a common-cathode or common-grid amplifier, you can cascode the fet with a bipolar to extend its drain voltage range. You will need to come up with an appropriate bias source for the bipolar. Generally, you would want at least 10-15 volts across the FET channel. Choose an appropriate JFET (transconductance, drain current, and gate-drain voltage similar to the nuvistor at the nuvistor's operating point). You can add degeneration (source resistance) to lower the FET's transconductance if it is higher than the nuvistor's. Best regards, Charles ___ 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. I have a PDF document that covers this for Fetrons. This is from Teledyne. It shows some of the more common tube replacements with the circuit and actual device number. Let me know if you would like a copy and I will sent it to you. Or, maybe a better option would be to upload it to something like Didiers site. . . Randy ___ 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 do upload it. I have some Fetrons and want to know what they replace. And in my other life, I ordered some custom Fetrons to replace some WE tubes that was used in WE K carrier. If you don't upload it, send a copy. Bill K7NOM ___ 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.
Re: [time-nuts] HP 117/10509a...
If propagation goes south, you loose track of the carrier phase, the basis of the system. If your local standard is stable and close to right, that's not a big deal. If not, you can easily go down the garden path. -John === Hi Propagation isn't going to change with modulation format, so that part will still be with us. I'm wondering if some fancy processing on the new code might have some advantages. It's not worth digging into until they have a final format though. Bob On Jul 5, 2012, at 6:19 PM, J. Forster wrote: From what I've read, the mods are to improve the Time of Day, not the Time Interval accuracy. In my location (MA) WWVB was never as good as LORAN-C because of propagation issues. -John === Hi The real question is weather the BPSK will help us get significantly better accuracy out of WWVB or not. If it does, time marches on. If not - total waste of effort. DSP based low frequency receivers are pretty easy to make. You still will need those antennas and preamps to make them work though. If I can get Loran-C type accuracy out of WWVB with the new modulation, I'll certainly build or buy a receiver. Bob ___ 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. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] gps jamming source found
A badly tuned/designed super-regenerative receiver can put out a lot of garbage. For commercial products, the receiver needs FCC approval to ensure this doesn't happen. Mike On 7/5/2012 4:03 PM, ed breya wrote: The wireless data links in those R/C sensor type things don't operate near GPS carriers, but their harmonics can land there. The transmitted power allowed should be too small to interfere with anyone's receiver farther away - yours is probably pretty close. I believe that the remote senders do not wait for any polling signals - if so, they would have to be receiving on a regular basis, taking precious battery life. It makes more sense for them to just burst transmit at regular intervals, while the line-powered (or bigger-battery-powered) base station is always listening, or listens at various intervals to see if any remotes are calling. That's why it takes a while to get the initial temperature data when the system starts up. The base station receivers used for simple, cheap VHF data are typically super-regenerative type for high sensitivity, so when they're fired up it may appear that they're transmitting, but actually are only receiving, with lots of crap kicking out of the super-regen circuit. A common carrier used for VHF remotes is around 315 MHz - the fifth harmonic of that one is especially bad, landing almost right on top of GPS. When you add in the loose frequency stability and modulation, and the regen signals, the transmitters and receivers can cause quite a spectral mess. Ed ___ 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.
Re: [time-nuts] HP 117/10509a...
WWVB is weak in the Oregon Rain Forest. Oregon Scientific weather station consoles rarely get a good signal at my place. Ditto for a Radio Shack alarm clock. I did get workable reception back in the 70s using a PLL circuit from a book. That was before CFLs and switching power supplies. Loran-C signals were strong enough to overload some active antennas. -- Chuck Forsberg WA7KGX N2469R c...@omen.com www.omen.com Developer of Industrial ZMODEM(Tm) for Embedded Applications Omen Technology Inc The High Reliability Software 10255 NW Old Cornelius Pass Portland OR 97231 503-614-0430 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP 117/10509a...
Hi And possibly if the bpsk does something useful, you can identify a carrier phase slip and correct for it…. Bob On Jul 5, 2012, at 7:19 PM, J. Forster wrote: If propagation goes south, you loose track of the carrier phase, the basis of the system. If your local standard is stable and close to right, that's not a big deal. If not, you can easily go down the garden path. -John === Hi Propagation isn't going to change with modulation format, so that part will still be with us. I'm wondering if some fancy processing on the new code might have some advantages. It's not worth digging into until they have a final format though. Bob On Jul 5, 2012, at 6:19 PM, J. Forster wrote: From what I've read, the mods are to improve the Time of Day, not the Time Interval accuracy. In my location (MA) WWVB was never as good as LORAN-C because of propagation issues. -John === Hi The real question is weather the BPSK will help us get significantly better accuracy out of WWVB or not. If it does, time marches on. If not - total waste of effort. DSP based low frequency receivers are pretty easy to make. You still will need those antennas and preamps to make them work though. If I can get Loran-C type accuracy out of WWVB with the new modulation, I'll certainly build or buy a receiver. Bob ___ 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. ___ 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.
Re: [time-nuts] HP 117/10509a
On 7/5/2012 3:57 PM, bill wrote: On 7/5/2012 9:49 AM, Randy D. Hunt wrote: On 7/4/2012 11:09 PM, Charles P. Steinmetz wrote: Don wrote: the fet breakdown voltage has of course got to be high enough. If the nuvistor is used as a common-cathode or common-grid amplifier, you can cascode the fet with a bipolar to extend its drain voltage range. You will need to come up with an appropriate bias source for the bipolar. Generally, you would want at least 10-15 volts across the FET channel. Choose an appropriate JFET (transconductance, drain current, and gate-drain voltage similar to the nuvistor at the nuvistor's operating point). You can add degeneration (source resistance) to lower the FET's transconductance if it is higher than the nuvistor's. Best regards, Charles ___ 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. I have a PDF document that covers this for Fetrons. This is from Teledyne. It shows some of the more common tube replacements with the circuit and actual device number. Let me know if you would like a copy and I will sent it to you. Or, maybe a better option would be to upload it to something like Didiers site. . . Randy ___ 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 do upload it. I have some Fetrons and want to know what they replace. And in my other life, I ordered some custom Fetrons to replace some WE tubes that was used in WE K carrier. If you don't upload it, send a copy. Bill K7NOM ___ 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. I uploaded the PDF to Didiers' site. Hope this helps some of you out there. . . Randy, KI6WAS ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] gps jamming source found
I believe all electronics needs FCC approval for emissions. [Not my job, but I know engineers that complain about compliance testing.] 433MHz is a freeband (ISM). Still, you are supposed to be clean. On 7/5/2012 4:41 PM, Michael Blazer wrote: A badly tuned/designed super-regenerative receiver can put out a lot of garbage. For commercial products, the receiver needs FCC approval to ensure this doesn't happen. Mike ___ 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] gps jamming source found
I bought some low power 315 Mhz, 2400 bps transmitter and receiver modules to use as a GPS data link. It turns out that the transmitter module can jam gps within a half mile radius. Later, the maker of the modules disavowed all knowledge of their existence ___ 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] Tracor 599J Mods?
Does anyone know if there are any mods for these receivers for when WWVB changes their modulation format? Is the WWVB change a done deal? It makes no sense to me to change this format as most people that carry a cell phone don't need a watch (nor wear one) anymore, much less a WWVB enabled watch. Sam W3OHM ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP 117/10509a...
On Thu, Jul 05, 2012 at 04:19:25PM -0700, J. Forster wrote: If propagation goes south, you loose track of the carrier phase, the basis of the system. If your local standard is stable and close to right, that's not a big deal. If not, you can easily go down the garden path. If I read this correctly, you mean you have a 180 degree ambiguity due to the BPSK - obviously losing track of the carrier phase in general with a significantly wrong local standard loses... I have not devoted enough time to this to be absolutely sure but it sure sounds like from what I read that if you know the accurate time to one second it should be possible to unambiguously predict the carrier phase sequences simply because you know the message format exactly, AND you know the exact time of day message that is being transmitted or most of it. There are of course two forms of encoding in PSK modulations - absolute, and differential (or transition) ... naively to me it would seem that if absolute encoding is used for this and you know most of the bits of the message most of the time you could predict which phase will be used a lot of the time, and also know when you don't know (message bits you might be uncertain about)... Differential encoding has the down side for this that UNLESS you know all previous message bits accurately starting from some phase reference datum you cannot predict what phase is in use at a particular moment. Absolute encoding (eg 0 phase for a 0, 180 for a one) doesn't have that liability and if the time of day message is aligned to, well, the time of day if you know that with reasonable accuracy (and you do since you are being sent it in the first place) you should be able to predict a very large percentage of phases used accurately. Again, deferring to those who have done the experiments (which I have clearly not), it would seem that the ability to predict the phase most of the time would allow creation of a reliable local 60 KHz reference which could be used to disambiguate those bits you don't know apriori My naive scheme would be to drive a balanced modulator on the output of the 60 KHz loop antenna with either two or maybe three values (1 and -1 or 1, 0 and -1) using some cheapie micro (Arduino, PIC etc) with a software PLL to keep the bit timing in sync with the signal. For bits that one could not predict, one could either output 0 to the balanced modulator for the entire bit interval which would produce a drop in the 60 KHz carrier, or do a fast timed fraction of a bit look at the output of a synchronous detector and choose the most likely value for the bit and use that, maybe after a brief 0 no carrier interval to avoid a detectable phase glitch. Of course the other approach is to start with the assumption you have a pretty good stable source of clock or you would not be doing this to begin with, and simply A/D the 60 KHz with the stable clock (say at 10 MHz), delay it by storing samples in RAM for one bit time of the low speed code and use that entire interval to decide which phase you were seeing and suitably adjust the output phase accordingly when you spit out the samples delayed by one bit time. This later approach would certainly be doable with modern processors mostly in software, certainly so if you could live with say 1-2 MHz sampling of the 60 KHz or so... and quite possibly also pretty nicely with a modest FPGA complete with the sample storage in the chip. Both approaches would be helped a lot if the architecture of the system allows prediction of absolute phase (eg not differential encoding of unpredictable messages)... and AFAIK that is not yet set in stone and could be changed to allow this. The intent of both of these schemes would be to ultimately output a De-psk'd signal that older equipment could process using its antique analog circuitry without serious issues. Thus the output would be an attempt at a phase stable corrected version of the original signal... Certainly using a lab reference stable 10 MHz derived 960 Khz or whatever sampling clock to delay the signal one time code bit time should not produce significant 60 KHz phase wanderings at all... -- Dave Emery N1PRE/AE, d...@dieconsulting.com DIE Consulting, Weston, Mass 02493 An empty zombie mind with a forlorn barely readable weatherbeaten 'For Rent' sign still vainly flapping outside on the weed encrusted pole - in celebration of what could have been, but wasn't and is not to be now either. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP 117/10509a...
Glad to know that it is not finalised as yet. When I read about this wrinkle, I was about to put my units up for sale. Merchison On 2012-07-05 1:54 PM, Bob Camp wrote: Hi Simple answer - they are still playing around with the signal format. It is totally unclear what the final format will really look like. Until they make up their minds there is only one safe bet - the clock on grandma's wall will still handle the wwvb format they use. Anything more complex than that is very much in the who knows category. Bob ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] gps jamming source found
On 7/5/12 6:33 PM, gary wrote: I believe all electronics needs FCC approval for emissions. [Not my job, but I know engineers that complain about compliance testing.] 433MHz is a freeband (ISM). Still, you are supposed to be clean. 433 is NOT an ISM band in the US (or in region 2, for that matter), but it is in Region 1 (EU), so there's lots of parts available. It is also not an Part 15 band (distinguish from Part 18 ISM)... 27 MHz, 49 MHz, 900 MHz, 2.45 GHz, those are ISM and Part 15 bands... On 7/5/2012 4:41 PM, Michael Blazer wrote: A badly tuned/designed super-regenerative receiver can put out a lot of garbage. For commercial products, the receiver needs FCC approval to ensure this doesn't happen. Mike ___ 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.
Re: [time-nuts] Tracor 599J Mods?
Paul Swed and I have been working on this for a few months, mostly using a standard method of extracting the carrier from a BPSK signal by analog squaring it to make 120 kHz, then dividing that by two. The problem is, with the poor signal on the east coast, the divider, whether a flip-flop or a Miller Divider, occasionally slips a half cycle, causing the receiver's loop to do precisely the wrong thing. Best, -John == Does anyone know if there are any mods for these receivers for when WWVB changes their modulation format? Is the WWVB change a done deal? It makes no sense to me to change this format as most people that carry a cell phone don't need a watch (nor wear one) anymore, much less a WWVB enabled watch. Sam W3OHM ___ 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.
Re: [time-nuts] HP 117/10509a...
On Thu, Jul 05, 2012 at 04:19:25PM -0700, J. Forster wrote: If propagation goes south, you loose track of the carrier phase, the basis of the system. If your local standard is stable and close to right, that's not a big deal. If not, you can easily go down the garden path. If I read this correctly, you mean you have a 180 degree ambiguity due to the BPSK - obviously losing track of the carrier phase in general with a significantly wrong local standard loses... David, Most of what has been tried is an analog squareing, then a divide by two. No additional PLLs in the system, beyond what is already in the Rx. I have not devoted enough time to this to be absolutely sure but it sure sounds like from what I read that if you know the accurate time to one second it should be possible to unambiguously predict the carrier phase sequences simply because you know the message format exactly, AND you know the exact time of day message that is being transmitted or most of it. The BPSK rate is 1 bit per second, There are 120,000 half cycles in that time. Fades can last seconds, minutes, or hours. It comes down to how long does it take your local standard take to drift roughly 4 uS. At the moment we are not looking at the message at all. Certainly a correlating receiver that uses the message as well as the carrier could be built. But, IMO, that'd be a whole lot easier done from scratch with a micro. The object here is a small, fairly simple, retrofit for the existing receivers. The message format may not be fully defined as yet. The squareing approach is message independant. There are of course two forms of encoding in PSK modulations - absolute, and differential (or transition) ... naively to me it would seem that if absolute encoding is used for this and you know most of the bits of the message most of the time you could predict which phase will be used a lot of the time, and also know when you don't know (message bits you might be uncertain about)... If you used the signal to set your local clock, and knew the format, it should be easy to predict at least a good part, if not all, of the message. Differential encoding has the down side for this that UNLESS you know all previous message bits accurately starting from some phase reference datum you cannot predict what phase is in use at a particular moment. Absolute encoding (eg 0 phase for a 0, 180 for a one) doesn't have that liability and if the time of day message is aligned to, well, the time of day if you know that with reasonable accuracy (and you do since you are being sent it in the first place) you should be able to predict a very large percentage of phases used accurately. Again, deferring to those who have done the experiments (which I have clearly not), it would seem that the ability to predict the phase most of the time would allow creation of a reliable local 60 KHz reference which could be used to disambiguate those bits you don't know apriori My naive scheme would be to drive a balanced modulator on the output of the 60 KHz loop antenna with either two or maybe three values (1 and -1 or 1, 0 and -1) using some cheapie micro (Arduino, PIC etc) with a software PLL to keep the bit timing in sync with the signal. This is what Equatorial did, in TTL, 30+ years ago. For bits that one could not predict, one could either output 0 to the balanced modulator for the entire bit interval which would produce a drop in the 60 KHz carrier, or do a fast timed fraction of a bit look at the output of a synchronous detector and choose the most likely value for the bit and use that, maybe after a brief 0 no carrier interval to avoid a detectable phase glitch. Of course the other approach is to start with the assumption you have a pretty good stable source of clock or you would not be doing this to begin with, and simply A/D the 60 KHz with the stable clock (say at 10 MHz), delay it by storing samples in RAM for one bit time of the low speed code and use that entire interval to decide which phase you were seeing and suitably adjust the output phase accordingly when you spit out the samples delayed by one bit time. This later approach would certainly be doable with modern processors mostly in software, certainly so if you could live with say 1-2 MHz sampling of the 60 KHz or so... and quite possibly also pretty nicely with a modest FPGA complete with the sample storage in the chip. Both approaches would be helped a lot if the architecture of the system allows prediction of absolute phase (eg not differential encoding of unpredictable messages)... and AFAIK that is not yet set in stone and could be changed to allow this. The intent of both of these schemes would be to ultimately output a De-psk'd signal that older equipment could process using its antique analog circuitry without serious issues. Thus the output would be an
Re: [time-nuts] HP 117/10509a...
On Thu, Jul 05, 2012 at 11:13:32PM -0400, Merchison Burke wrote: Glad to know that it is not finalised as yet. When I read about this wrinkle, I was about to put my units up for sale. Put them up for sale. If you can find a buyer. I asked Mr. Lowe this week and was told there'd be no residual carrier or workaround for existing phase locking receivers, even time of day receivers. Debating what to do with mine, really, keep them as nice pieces of hardware (albeit in my own personal museum) -- they can go next to the LORAN and GOES receivers. The pile is getting pretty big these days. Anyone have an OMEGA receiver they want to part with? Sorry, but if you want something besides GPS, you're on your own. The US government has made its priorities clear -- if it's not GPS, it's an 'obsolete waste.' Somehow, we lose out vs 12 million WWVB clocks, despite the fact that not 3 years ago they were willing to obsolete all those clocks with an added 40 or 75 kHz station. At least, as long as 'stimulus' funds were being waved around. Along the lines of developing a receiver: Since they haven't settled on the format, there's no additional documentation available [that was the second part of my question..] I'm torn on the subject anyway...part of me wants the challenge, and part of me thinks that if the format can be changed without a public comment period or a phase out timeframe, that it may not be worth the risk of developing one. As it stands I guess I'm back to WWV/WWVH as a backup. But I can have all the self setting wall-clocks I want -- provided I don't mind flipping them between PST and MST, since few allow you to disable DST. :) --msa ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP 117/10509a...
No residual carrier is required. -John On Thu, Jul 05, 2012 at 11:13:32PM -0400, Merchison Burke wrote: Glad to know that it is not finalised as yet. When I read about this wrinkle, I was about to put my units up for sale. Put them up for sale. If you can find a buyer. I asked Mr. Lowe this week and was told there'd be no residual carrier or workaround for existing phase locking receivers, even time of day receivers. Debating what to do with mine, really, keep them as nice pieces of hardware (albeit in my own personal museum) -- they can go next to the LORAN and GOES receivers. The pile is getting pretty big these days. Anyone have an OMEGA receiver they want to part with? Sorry, but if you want something besides GPS, you're on your own. The US government has made its priorities clear -- if it's not GPS, it's an 'obsolete waste.' Somehow, we lose out vs 12 million WWVB clocks, despite the fact that not 3 years ago they were willing to obsolete all those clocks with an added 40 or 75 kHz station. At least, as long as 'stimulus' funds were being waved around. Along the lines of developing a receiver: Since they haven't settled on the format, there's no additional documentation available [that was the second part of my question..] I'm torn on the subject anyway...part of me wants the challenge, and part of me thinks that if the format can be changed without a public comment period or a phase out timeframe, that it may not be worth the risk of developing one. As it stands I guess I'm back to WWV/WWVH as a backup. But I can have all the self setting wall-clocks I want -- provided I don't mind flipping them between PST and MST, since few allow you to disable DST. :) --msa ___ 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.
Re: [time-nuts] gps jamming source found
Hi Ed, It's not just just cheap and nasy regens that cause this problem. Some aircraft navigation and communication receivers where found to have enough local oscillator harmonic leakage at 1575 MHz through the antenna port to jam GPS then tuned to specific frequences. The cure was a tuned stub filter on the Nav or Comm. see http://www.aircraftspruce.com/catalog/avpages/tednotch.php for an example. Robert G8RPI. From: ed breya e...@telight.com To: time-nuts@febo.com Sent: Thursday, 5 July 2012, 22:03 Subject: Re: [time-nuts] gps jamming source found The wireless data links in those R/C sensor type things don't operate near GPS carriers, but their harmonics can land there. The transmitted power allowed should be too small to interfere with anyone's receiver farther away - yours is probably pretty close. I believe that the remote senders do not wait for any polling signals - if so, they would have to be receiving on a regular basis, taking precious battery life. It makes more sense for them to just burst transmit at regular intervals, while the line-powered (or bigger-battery-powered) base station is always listening, or listens at various intervals to see if any remotes are calling. That's why it takes a while to get the initial temperature data when the system starts up. The base station receivers used for simple, cheap VHF data are typically super-regenerative type for high sensitivity, so when they're fired up it may appear that they're transmitting, but actually are only receiving, with lots of crap kicking out of the super-regen circuit. A common carrier used for VHF remotes is around 315 MHz - the fifth harmonic of that one is especially bad, landing almost right on top of GPS. When you add in the loose frequency stability and modulation, and the regen signals, the transmitters and receivers can cause quite a spectral mess. Ed ___ 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.
