Re: [time-nuts] antennas was Re: Common-View GPS Network
If I read the paper correctly you can skip the choke ring if you mount the antenna on top of a 2 meter or longer mast. Iron pipe comes on 10 foot lengths. The choke ring is for portable survey antenna that can't be placed on tall rooftop masts. I think a 2 meter pole on a roof pretty much meets their criteria of multi path difference being over 10 meters. I can see now why surveyers need the choke ring type antenna, because they can not choose the location. They need to place it where they need to measure. But timing is different, we can choose the best location which would be two meters above the tallest object in the area. The cake pan certainly would work. This is not super critical. They are only blocking low elevation signals. and it would give you more option for the location On Wed, Apr 17, 2013 at 8:14 PM, Jim Lux jim...@earthlink.net wrote: Javad has a bunch of choke ring theory.. http://www.javad.com/jns/**index.html?/jns/technology/** Single-Depth%20Low-Multipath%**20Choke%20Ring.htmlhttp://www.javad.com/jns/index.html?/jns/technology/Single-Depth%20Low-Multipath%20Choke%20Ring.html http://www.javad.com/jns/**index.html?/jns/technology/** Choke%20Ring%20Theory.htmlhttp://www.javad.com/jns/index.html?/jns/technology/Choke%20Ring%20Theory.html Their conclusion is you want the depth of the ring to be slightly more than 1/4 lambda. lambda/4 for L1 is 1.87 so a 2 cake pan is just about the right size. -- Chris Albertson Redondo Beach, California ___ 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] Remote GPS Oscillator Steering
Hi Everyone, Recently, I have acquired a HP Frequency Counter and Signal Genny, and have set up a small lab in the house. This is great, but I'd like to hook it into my 3816A, which is 70 ft away in an outhouse, along with all my radio gear, to at least compare it to the 10811 in the Frequency Counter. I'd rather not drill a hole and run a cable (There are other issues with that as well as the hole, the outhouse is the other side of the garden path from the lab!) I do have fibre to the house for N/W connectivity, and (unshielded) CAT6 from the patch panel to the lab. Two problems here. One the patch panel is the other side of the house from the lab (so running a dedicated piece of coax is out without taking up the floors..), and Two, 10MHz over unshielded CAT6 is not good practice, to say the least, and simply not going to happen. So I started looking at other possibilities. It seems a lot of GPSDOs steer the Oscillator by using the PPS. Is that right ? 1 Hz over UTP is a bit more reasonable than 10 MHz, but I did not find many 10MHz oscillators with a PPS input. I thought of using a Z3801 instead of the Z3816, but patching out from the EFC SBM connector, then (optionally) converting that to fibre, sending it up the garden to the house, converting back to copper, then the CAT 6 to the Lab where a second Z3801 would sit I would rather fibre between the house and outhouse for EMC and grounding reasons. My hope is that thee 10MHz Osc would then be steered from the remote Z3801, although the lab Z3801 itself would complain bitterly about no lock no doubt. Does anyone have any comments on this madhat scheme ? Or have other suggestions of how I might go about getting that 10MHz signal converted to fibre, and back again to send into the lab equipment ? What are other people's experience with similar issues ? What do the big boys like NIST and NPL do to manage this ? I know they transfer time over large distances, and I know NPL transfer frequency as well to certain customers, so I guess other similar institutions do as well [Note, for me, plug and play is better. Soldering irons do not like me, and I wouldn't trust myself with one anywhere near anything like a precision instrument :), although putting pre-built modules in a metal box I'm okay with, but plug-and play preferred.] (Googling for fibre converters or similar these days brings up such a noise floor of Ethernet, Any suggestions on the best terms or part numbers to use to find raw (assembled) fibre transmitter / receiver modules that might be suitable would be gratefully received) Best Regards Iain ___ 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] LTC6957 Low Phase Noise Buffer/Driver
On Wed, 17 Apr 2013 17:40:29 +0200, Volker Esper ail...@t-online.de wrote: Am 17.04.2013 15:23, schrieb David: ... I have been looking into low jitter triggers for sampling systems recently and will probably end up using a discrete differential amplifier driving ECL logic. Why discrete? It is easier to tailor the response to handle poorly defined input signals. If anybody has suggestions, I am all ears. ___ 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] Remote GPS Oscillator Steering
I think that the best move is to get a second GPSDO for the lab. On Thu, Apr 18, 2013 at 10:35 AM, Iain Young i...@g7iii.net wrote: Hi Everyone, Recently, I have acquired a HP Frequency Counter and Signal Genny, and have set up a small lab in the house. This is great, but I'd like to hook it into my 3816A, which is 70 ft away in an outhouse, along with all my radio gear, to at least compare it to the 10811 in the Frequency Counter. I'd rather not drill a hole and run a cable (There are other issues with that as well as the hole, the outhouse is the other side of the garden path from the lab!) I do have fibre to the house for N/W connectivity, and (unshielded) CAT6 from the patch panel to the lab. Two problems here. One the patch panel is the other side of the house from the lab (so running a dedicated piece of coax is out without taking up the floors..), and Two, 10MHz over unshielded CAT6 is not good practice, to say the least, and simply not going to happen. So I started looking at other possibilities. It seems a lot of GPSDOs steer the Oscillator by using the PPS. Is that right ? 1 Hz over UTP is a bit more reasonable than 10 MHz, but I did not find many 10MHz oscillators with a PPS input. I thought of using a Z3801 instead of the Z3816, but patching out from the EFC SBM connector, then (optionally) converting that to fibre, sending it up the garden to the house, converting back to copper, then the CAT 6 to the Lab where a second Z3801 would sit I would rather fibre between the house and outhouse for EMC and grounding reasons. My hope is that thee 10MHz Osc would then be steered from the remote Z3801, although the lab Z3801 itself would complain bitterly about no lock no doubt. Does anyone have any comments on this madhat scheme ? Or have other suggestions of how I might go about getting that 10MHz signal converted to fibre, and back again to send into the lab equipment ? What are other people's experience with similar issues ? What do the big boys like NIST and NPL do to manage this ? I know they transfer time over large distances, and I know NPL transfer frequency as well to certain customers, so I guess other similar institutions do as well [Note, for me, plug and play is better. Soldering irons do not like me, and I wouldn't trust myself with one anywhere near anything like a precision instrument :), although putting pre-built modules in a metal box I'm okay with, but plug-and play preferred.] (Googling for fibre converters or similar these days brings up such a noise floor of Ethernet, Any suggestions on the best terms or part numbers to use to find raw (assembled) fibre transmitter / receiver modules that might be suitable would be gratefully received) Best Regards Iain __**_ 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] Remote GPS Oscillator Steering
I'd rather not drill a hole and run a cable You can feed the cable through a window or door and across the grass long enough to make an occasional measurement to tell you how accurate and stable the local oscillator is. 10MHz over unshielded CAT6 is not good practice, to say the least, and simply not going to happen. What do you mean by not good practice? Gigabit Ethernet works over CAT5. I think it's 125 megabaud, 5 level, 2 bits per baud. Whatever, it's way over 10 MHz. Here are some scope pictures of a PPS signal from a TBolt over 100 ft of Cat5e and Cat6. http://www.megapathdsl.net/~hmurray/time-nuts/coax/TP-20ns.png http://www.megapathdsl.net/~hmurray/time-nuts/coax/TP-100ns.png http://www.megapathdsl.net/~hmurray/time-nuts/coax/TP-1us.png That was clipleaded together on the bench. (I did adjust things until the termination was clean and kept the clipleads short.) I would rather fibre between the house and outhouse for EMC and grounding reasons. My hope is that thee 10MHz Osc would then be steered from the remote Z3801, although the lab Z3801 itself would complain bitterly about no lock no doubt. I can't figure out what you are trying to do. The lab Z3801 isn't setup to be steered by an external PPS or 10 MHz signal. Does anyone have any comments on this madhat scheme ? Or have other suggestions of how I might go about getting that 10MHz signal converted to fibre, and back again to send into the lab equipment ? I think you want to send 10 MHz from your outhouse to your house/lab. You may need a distribution amplifier if you want to send it to more than one device. Fiber transmitters and receivers are reasonably common. You can get modules targeted at Ethernet with both transmit and receive in the same package. There is a blizzard of variations depending on distance and bit rate and type of fiber. The trick is that the receiver includes AGC so you get logic level signals out. You can get separate transmit and receive modules. I haven't looked at that area for 15 years. Back then LEDs over multimode fibers at 155 megabits for a km was one sweet spot. For longer or faster, you needed single mode and lasers which were a lot more expensive. 10 MHz will be easy. Depending on your existing fiber connectors and/or the parts you find, it may be cheaper to get official Ethernet parts and throw away the other half rather than get adapter cables to match cheaper separate parts. -- These are my opinions. I hate spam. ___ 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] Remote GPS Oscillator Steering
On 18/04/13 11:50, Hal Murray wrote: 10MHz over unshielded CAT6 is not good practice, to say the least, and simply not going to happen. What do you mean by not good practice? Gigabit Ethernet works over CAT5. I think it's 125 megabaud, 5 level, 2 bits per baud. Whatever, it's way over 10 MHz. Oh I know it can handle it, I was trying to avoid a nice 10MHz signal on an unshielded conductor smack on the Amateur Radio 30m band :) It's more RF here than Time/Frequency, and if I can avoid clashes, so much the better... (I detest these ethernet over powerlines things, and it seemed hypercritical to complain about them, then smack a nice signal right on our 30m band. Maybe I worry too much about such things) [SNIP] I would rather fibre between the house and outhouse for EMC and grounding reasons. My hope is that thee 10MHz Osc would then be steered from the remote Z3801, although the lab Z3801 itself would complain bitterly about no lock no doubt. I can't figure out what you are trying to do. The lab Z3801 isn't setup to be steered by an external PPS or 10 MHz signal. Does anyone have any comments on this madhat scheme ? Or have other suggestions of how I might go about getting that 10MHz signal converted to fibre, and back again to send into the lab equipment ? I think you want to send 10 MHz from your outhouse to your house/lab. You may need a distribution amplifier if you want to send it to more than one device. Indeed, Sorry I wasn't clear, I guess I was trying to avoid sending the actual 10 MHz signal over that unshielded copper conductor, so was thinking about sending the data needed to steer the Oscillator instead With it ending up as a -5V to +5V signal to the 10811 in the end, The idea of sending the EFC came from reading http://www.realhamradio.com/joe-geller.htm and noting said EFC was available on a SMB connector. Fiber transmitters and receivers are reasonably common. You can get modules targeted at Ethernet with both transmit and receive in the same package. There is a blizzard of variations depending on distance and bit rate and type of fiber. The trick is that the receiver includes AGC so you get logic level signals out. Noted, thanks, I'll keep hunting :) All the Best Iain ___ 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] Remote GPS Oscillator Steering
Hi By the time you drop to 1 pps, transport the 1 pps, and lock a 10 MHz back up to it, you have done a lot of stuff. The work and the cost of the bits and pieces will add up. If the 10811 is the ultimate source, it's not going to be at GPSDO performance levels. A hundred dollar or so GPSDO would probably be less hassle and not much more cost. That said, yes you can feed signals over the twisted pair. If the only real need is to *check* the 10811, any frequency the counter will count is fine. PPS works as well as anything. I'd pick something I could transformer couple. Bob On Apr 18, 2013, at 4:35 AM, Iain Young i...@g7iii.net wrote: Hi Everyone, Recently, I have acquired a HP Frequency Counter and Signal Genny, and have set up a small lab in the house. This is great, but I'd like to hook it into my 3816A, which is 70 ft away in an outhouse, along with all my radio gear, to at least compare it to the 10811 in the Frequency Counter. I'd rather not drill a hole and run a cable (There are other issues with that as well as the hole, the outhouse is the other side of the garden path from the lab!) I do have fibre to the house for N/W connectivity, and (unshielded) CAT6 from the patch panel to the lab. Two problems here. One the patch panel is the other side of the house from the lab (so running a dedicated piece of coax is out without taking up the floors..), and Two, 10MHz over unshielded CAT6 is not good practice, to say the least, and simply not going to happen. So I started looking at other possibilities. It seems a lot of GPSDOs steer the Oscillator by using the PPS. Is that right ? 1 Hz over UTP is a bit more reasonable than 10 MHz, but I did not find many 10MHz oscillators with a PPS input. I thought of using a Z3801 instead of the Z3816, but patching out from the EFC SBM connector, then (optionally) converting that to fibre, sending it up the garden to the house, converting back to copper, then the CAT 6 to the Lab where a second Z3801 would sit I would rather fibre between the house and outhouse for EMC and grounding reasons. My hope is that thee 10MHz Osc would then be steered from the remote Z3801, although the lab Z3801 itself would complain bitterly about no lock no doubt. Does anyone have any comments on this madhat scheme ? Or have other suggestions of how I might go about getting that 10MHz signal converted to fibre, and back again to send into the lab equipment ? What are other people's experience with similar issues ? What do the big boys like NIST and NPL do to manage this ? I know they transfer time over large distances, and I know NPL transfer frequency as well to certain customers, so I guess other similar institutions do as well [Note, for me, plug and play is better. Soldering irons do not like me, and I wouldn't trust myself with one anywhere near anything like a precision instrument :), although putting pre-built modules in a metal box I'm okay with, but plug-and play preferred.] (Googling for fibre converters or similar these days brings up such a noise floor of Ethernet, Any suggestions on the best terms or part numbers to use to find raw (assembled) fibre transmitter / receiver modules that might be suitable would be gratefully received) Best Regards Iain ___ 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] Remote GPS Oscillator Steering
10 MHz over unshielded twisted pair works very well. That's what Ethernet 10BaseT is after all. Either scrounge some pulse com transformers out of ancient Ethernet cards or use a pair of 'video baluns' which are sold into the closed circuit television industry for transporting video over cat5 cable. Dale NV8U Sent from my iPhone On Apr 18, 2013, at 4:35, Iain Young i...@g7iii.net wrote: Hi Everyone, Recently, I have acquired a HP Frequency Counter and Signal Genny, and have set up a small lab in the house. This is great, but I'd like to hook it into my 3816A, which is 70 ft away in an outhouse, along with all my radio gear, to at least compare it to the 10811 in the Frequency Counter. I'd rather not drill a hole and run a cable (There are other issues with that as well as the hole, the outhouse is the other side of the garden path from the lab!) I do have fibre to the house for N/W connectivity, and (unshielded) CAT6 from the patch panel to the lab. Two problems here. One the patch panel is the other side of the house from the lab (so running a dedicated piece of coax is out without taking up the floors..), and Two, 10MHz over unshielded CAT6 is not good practice, to say the least, and simply not going to happen. So I started looking at other possibilities. It seems a lot of GPSDOs steer the Oscillator by using the PPS. Is that right ? 1 Hz over UTP is a bit more reasonable than 10 MHz, but I did not find many 10MHz oscillators with a PPS input. I thought of using a Z3801 instead of the Z3816, but patching out from the EFC SBM connector, then (optionally) converting that to fibre, sending it up the garden to the house, converting back to copper, then the CAT 6 to the Lab where a second Z3801 would sit I would rather fibre between the house and outhouse for EMC and grounding reasons. My hope is that thee 10MHz Osc would then be steered from the remote Z3801, although the lab Z3801 itself would complain bitterly about no lock no doubt. Does anyone have any comments on this madhat scheme ? Or have other suggestions of how I might go about getting that 10MHz signal converted to fibre, and back again to send into the lab equipment ? What are other people's experience with similar issues ? What do the big boys like NIST and NPL do to manage this ? I know they transfer time over large distances, and I know NPL transfer frequency as well to certain customers, so I guess other similar institutions do as well [Note, for me, plug and play is better. Soldering irons do not like me, and I wouldn't trust myself with one anywhere near anything like a precision instrument :), although putting pre-built modules in a metal box I'm okay with, but plug-and play preferred.] (Googling for fibre converters or similar these days brings up such a noise floor of Ethernet, Any suggestions on the best terms or part numbers to use to find raw (assembled) fibre transmitter / receiver modules that might be suitable would be gratefully received) Best Regards Iain ___ 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] OT: Far-out space navigation from sideways satnav signals
An interesting novel use of GPS stray signals ESA’s retired GIOVE-A navigation mission has become the first civilian satellite to perform GPS position fixes from high orbit. Its results demonstrate that current satnav signals could guide missions much further away in space, up to geostationary orbit or even as far as the Moon. See: http://www.esa.int/Our_Activities/Space_Engineering/Far-out_space_navigation_from_sideways_satnav_signals Cheers, David -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ 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] antennas was Re: Common-View GPS Network
On 4/18/13 12:01 AM, Chris Albertson wrote: If I read the paper correctly you can skip the choke ring if you mount the antenna on top of a 2 meter or longer mast. Iron pipe comes on 10 foot lengths. The choke ring is for portable survey antenna that can't be placed on tall rooftop masts. I think a 2 meter pole on a roof pretty much meets their criteria of multi path difference being over 10 meters. yes.. multipath that is more than a chip away is generally filtered out by the PN tracking loop, so all you really worry about is multipath signals within a chip. For C/A code at 1 Mchip/sec, the chips are 300 meters long. If you're doing P/Y code, it's a tenth of that. In reality, if the multipath signal is lower, and it's far away (a good fraction of a chip) it doesn't contribute much to the output of the correlator. So their 10 meter thing is probably a good number for a typical receiver they make. ___ 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] OT: Far-out space navigation from sideways satnav signals
On 4/18/13 4:01 AM, David J Taylor wrote: An interesting novel use of GPS stray signals ESA’s retired GIOVE-A navigation mission has become the first civilian satellite to perform GPS position fixes from high orbit. Its results demonstrate that current satnav signals could guide missions much further away in space, up to geostationary orbit or even as far as the Moon. See: http://www.esa.int/Our_Activities/Space_Engineering/Far-out_space_navigation_from_sideways_satnav_signals Interesting.. I know there's a bunch of analysis about how to use GPS at the moon. you need to look at the GPS satellites on the far side of the earth, grazing the limb. ___ 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] Remote GPS Oscillator Steering
Re the use of Baluns to send 10 Mhz signals over twisted pair cable, I currently do this at home and it works well. I also have no issues engaging in occasional HF amateur radio activity (including using the 10 Mhz band) at home. I also have routed the signal and power leads for the time nuts and radio equipment thru ferrite cores, use double shielded cables almost exclusively for the time nuts gear, all un used outputs are properly terminated etc. I have no issue listening to wwv on 5 and 10 Mhz despite the dozen or so pieces of equipment I have that generate 5 and 10 MHz signals. Best regards Mark Spencer Sent from my iPad ___ 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] Remote GPS Oscillator Steering
i...@g7iii.net said: Oh I know it can handle it, I was trying to avoid a nice 10MHz signal on an unshielded conductor smack on the Amateur Radio 30m band :) It's more RF here than Time/Frequency, and if I can avoid clashes, so much the better... Has anybody measured the radiation from various types of coax and/or twisted pairs? It would be interesting to see how they compare and/or how they compare to things like unterminated unused outputs or emissions from gear with the lid off and things like that. -- These are my opinions. I hate spam. ___ 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] Remote GPS Oscillator Steering
On 04/18/2013 09:23 AM, Hal Murray wrote: i...@g7iii.net said: Oh I know it can handle it, I was trying to avoid a nice 10MHz signal on an unshielded conductor smack on the Amateur Radio 30m band :) It's more RF here than Time/Frequency, and if I can avoid clashes, so much the better... Has anybody measured the radiation from various types of coax and/or twisted pairs? It would be interesting to see how they compare and/or how they compare to things like unterminated unused outputs or emissions from gear with the lid off and things like that. In my experience, unshielded twisted pair ethernet cables are quite noisy. The inexpensive coax used for ethernet leaks enough that the 10 MHz from my Thunderbolt wiped out WWV on 10 MHz. I replaced the cheap coax with instrumentation grade cables and WWV reception is much better. I replaced all the ethernet cables with shielded cables and the RFI and EMC problems pretty much disappeared. -- Chuck Forsberg WA7KGX 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.
[time-nuts] 10 MHz clock distribution for the lab
At what point does one require a distribution amp? My TBolt currently provides a reference clock for 2 instruments, and I know of no issues. Since the unit came with the 1:2 Mini-Circuits splitter, I expected this to be the case. If I switched to a ZFSC-4-1http://www.minicircuits.com/pdfs/ZFSC-4-1+.pdf1:4 splitter say, to add a reference to a 3rd instrument, at what point does this become an issue if the insertion loss is only -6dB on any port? HP provides both the input impedance and the capacitive load for a 5334 counter, which is nice, but this does not seem to be a standard or norm per se in the TM industry. OTOH, I don't want to over think this though :-) Russ ___ 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] Remote GPS Oscillator Steering
On Thu, Apr 18, 2013 at 4:23 AM, Iain Young i...@g7iii.net wrote: Oh I know it can handle it, I was trying to avoid a nice 10MHz signal on an unshielded conductor smack on the Amateur Radio 30m band :) It's more RF here than Time/Frequency, and if I can avoid clashes, so much the better... A transformer coupled signal is going to be well balanced and not radiate. You don't need more than a few millivolts If you are worried about a 10Mhz sine wave, then you need to be very much more worried about what Ethernet does. Those sharp edged pulses have harmonics all other the RF spectrum. But no problem because they are transformer couple and the wire is very tightly twisted.Why not try an experiment? Place an RF transformer in a diecast box and make and a 50 ohm load in a second box. Connect the boxes with 100 feet of cable. Put 1 mW of 10MHz into the transformer and then measure leakage from the mid span of the cable. Turn up the power until either you can detect some or the transformer fails. The trick is to use good quality transformers on each end so the signal really is well balanced. I salvage the transformers for old Ethernet cards. -- Chris Albertson Redondo Beach, California ___ 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] 10 MHz clock distribution for the lab
On 04/18/2013 09:55 AM, Russ Ramirez wrote: At what point does one require a distribution amp? My TBolt currently provides a reference clock for 2 instruments, and I know of no issues. Since the unit came with the 1:2 Mini-Circuits splitter, I expected this to be the case. If I switched to a ZFSC-4-1http://www.minicircuits.com/pdfs/ZFSC-4-1+.pdf1:4 splitter say, to add a reference to a 3rd instrument, at what point does this become an issue if the insertion loss is only -6dB on any port? HP provides both the input impedance and the capacitive load for a 5334 counter, which is nice, but this does not seem to be a standard or norm per se in the TM industry. OTOH, I don't want to over think this though :-) Russ ___ 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 FlexRadio 1500, Racal 1992 counter, HP 3586, Advantest U3641, and Gigatronics 6061A daisy-chained off my Thunderbolt. Don't throw out those BNC T connectors. The Gigatronics terminates the 10 MHz so a splitter or something may be required if I add another instrument that terminated the 10 MHz input. You need to use lab grade cables if you don't wish to interfere with WWV on 10 MHz., -- Chuck Forsberg WA7KGX 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] antennas was Re: Common-View GPS Network
On 04/18/2013 04:00 PM, Jim Lux wrote: On 4/18/13 12:01 AM, Chris Albertson wrote: If I read the paper correctly you can skip the choke ring if you mount the antenna on top of a 2 meter or longer mast. Iron pipe comes on 10 foot lengths. The choke ring is for portable survey antenna that can't be placed on tall rooftop masts. I think a 2 meter pole on a roof pretty much meets their criteria of multi path difference being over 10 meters. yes.. multipath that is more than a chip away is generally filtered out by the PN tracking loop, so all you really worry about is multipath signals within a chip. For C/A code at 1 Mchip/sec, the chips are 300 meters long. If you're doing P/Y code, it's a tenth of that. In reality, if the multipath signal is lower, and it's far away (a good fraction of a chip) it doesn't contribute much to the output of the correlator. So their 10 meter thing is probably a good number for a typical receiver they make. It's an interesting mix of sample-rate/bandwidth, code you track and distance between early-late detectors (normal distance is one chip) comes in when analyzing and combat the multi-path. I recall there is some subtle points with some of the C/A codes. 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] OT: Far-out space navigation from sideways satnav signals
On 04/18/2013 04:01 PM, Jim Lux wrote: On 4/18/13 4:01 AM, David J Taylor wrote: An interesting novel use of GPS stray signals ESA’s retired GIOVE-A navigation mission has become the first civilian satellite to perform GPS position fixes from high orbit. Its results demonstrate that current satnav signals could guide missions much further away in space, up to geostationary orbit or even as far as the Moon. See: http://www.esa.int/Our_Activities/Space_Engineering/Far-out_space_navigation_from_sideways_satnav_signals Interesting.. I know there's a bunch of analysis about how to use GPS at the moon. you need to look at the GPS satellites on the far side of the earth, grazing the limb. Would not an antenna with a deep zero focus on the earth center help to reduce earth-noise (ground temperature noise as well as man-made noise)? 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] antennas was Re: Common-View GPS Network
I hope I am not steering the thread to much, I have an Allen Osborne TurboRogue SMR12 RM L1 L2 GPS rec that came from JPL that appears specifically designed for Common View use. Does anyone know the history of these ,I can find almost nothing. Email me directly if you have info, or I can start a new thread. Tom Knox act...@hotmail.com Date: Thu, 18 Apr 2013 19:58:22 +0200 From: mag...@rubidium.dyndns.org To: time-nuts@febo.com Subject: Re: [time-nuts] antennas was Re: Common-View GPS Network On 04/18/2013 04:00 PM, Jim Lux wrote: On 4/18/13 12:01 AM, Chris Albertson wrote: If I read the paper correctly you can skip the choke ring if you mount the antenna on top of a 2 meter or longer mast. Iron pipe comes on 10 foot lengths. The choke ring is for portable survey antenna that can't be placed on tall rooftop masts. I think a 2 meter pole on a roof pretty much meets their criteria of multi path difference being over 10 meters. yes.. multipath that is more than a chip away is generally filtered out by the PN tracking loop, so all you really worry about is multipath signals within a chip. For C/A code at 1 Mchip/sec, the chips are 300 meters long. If you're doing P/Y code, it's a tenth of that. In reality, if the multipath signal is lower, and it's far away (a good fraction of a chip) it doesn't contribute much to the output of the correlator. So their 10 meter thing is probably a good number for a typical receiver they make. It's an interesting mix of sample-rate/bandwidth, code you track and distance between early-late detectors (normal distance is one chip) comes in when analyzing and combat the multi-path. I recall there is some subtle points with some of the C/A codes. 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. ___ 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] Remote GPS Oscillator Steering
On Thu, Apr 18, 2013 at 1:35 AM, Iain Young i...@g7iii.net wrote: ... Two problems here. One the patch panel is the other side of the house from the lab (so running a dedicated piece of coax is out without taking up the floors..), and Two, 10MHz over unshielded CAT6 is not good practice, to say the least, and simply not going to happen. Why is that. Cat6 cable s designef for much more bandwidth than that. The People use it mostly for Ethernet but it is designed to send video signals and other high bandwidth RF signals. You can in fast send pulse per second but you need to design and build differential drivers/receivers. Don't try to send an unbalanced signal. If the goal is to get a 10MHz freq. standard to the lab, I'd send the 10MHz over the wire. But transformer couple it so it is galvanically isolated. Don't connect the ground references Fiber would be nice. they make some very easy to use connectors and look like logic level ICs on each end. Send a 10MHz square wave in one and you get the same thing out the other end. A more creative idea is a laser. But if you already have cat6 cable you have what you need. -- Chris Albertson Redondo Beach, California ___ 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] OT: Far-out space navigation from sideways satnav signals
Hi Magnus, Would not an antenna with a deep zero focus on the earth center help to reduce earth-noise (ground temperature noise as well as man-made noise)? It might, although you'd need a large antenna to generate the angular resolution needed to reject Earth noise while listening to a GPS bird near the Earth's limb. If you make the tradeoff of using GPS satellites further from the limb (say at their max separation of ~5 degrees looking from lunar distance), hoping for less Earth noise, then you're working with a fainter sidelobe. I'm sure the proper tradeoff is known. The whole problem sounds much easier if you're merely at GEO. I wonder if there's any advantage in combining far-away GPS with X-ray pulsar navigation (XNAV), which is said to be good to a few kilometers, though long integration times are needed. For example, the rough system time from XNAV could enable very long (arbitrarily long?) coherent integration for very faint GPS signals obtained with a gain antenna pointed at the Earth. Cheers, Peter ___ 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] 10 MHz clock distribution for the lab
I'm on the road right now and don't have access to any data to support or expand upon this statement but I've found that a passive splitter out performs both of my hp 5087 distribution amps as long as you can live with the signal loss. In turn I recall that using the distribution amps worked better for me for than daisy chaining connections via t connectors. I doubt the differences would be meaningful in most real world applications. It seems reasonable to me that a passive splitter would out perform an active device of unknown heritage (both my distribution amps came from the usual auction site.) Your results may vary (: ___ 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] antennas was Re: Common-View GPS Network
Tom, Let's do a separate thread on that one. Cheers, Magnus On 04/18/2013 08:07 PM, Tom Knox wrote: I hope I am not steering the thread to much, I have an Allen Osborne TurboRogue SMR12 RM L1 L2 GPS rec that came from JPL that appears specifically designed for Common View use. Does anyone know the history of these ,I can find almost nothing. Email me directly if you have info, or I can start a new thread. Tom Knox act...@hotmail.com Date: Thu, 18 Apr 2013 19:58:22 +0200 From: mag...@rubidium.dyndns.org To: time-nuts@febo.com Subject: Re: [time-nuts] antennas was Re: Common-View GPS Network On 04/18/2013 04:00 PM, Jim Lux wrote: On 4/18/13 12:01 AM, Chris Albertson wrote: If I read the paper correctly you can skip the choke ring if you mount the antenna on top of a 2 meter or longer mast. Iron pipe comes on 10 foot lengths. The choke ring is for portable survey antenna that can't be placed on tall rooftop masts. I think a 2 meter pole on a roof pretty much meets their criteria of multi path difference being over 10 meters. yes.. multipath that is more than a chip away is generally filtered out by the PN tracking loop, so all you really worry about is multipath signals within a chip. For C/A code at 1 Mchip/sec, the chips are 300 meters long. If you're doing P/Y code, it's a tenth of that. In reality, if the multipath signal is lower, and it's far away (a good fraction of a chip) it doesn't contribute much to the output of the correlator. So their 10 meter thing is probably a good number for a typical receiver they make. It's an interesting mix of sample-rate/bandwidth, code you track and distance between early-late detectors (normal distance is one chip) comes in when analyzing and combat the multi-path. I recall there is some subtle points with some of the C/A codes. 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. ___ 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] OT: Far-out space navigation from sideways satnav signals
Peter, On 04/18/2013 09:15 PM, Peter Monta wrote: Hi Magnus, Would not an antenna with a deep zero focus on the earth center help to reduce earth-noise (ground temperature noise as well as man-made noise)? It might, although you'd need a large antenna to generate the angular resolution needed to reject Earth noise while listening to a GPS bird near the Earth's limb. If you make the tradeoff of using GPS satellites further from the limb (say at their max separation of ~5 degrees looking from lunar distance), hoping for less Earth noise, then you're working with a fainter sidelobe. I'm sure the proper tradeoff is known. The whole problem sounds much easier if you're merely at GEO. GEOs have it simpler. Recall that the side-lobe near the earth is actually quite strong, since the GPS birds antenna makes a first degree compensation of distance-difference path-loss compensation, so it has stronger output to the sides than straight down. So, if you look at signals near the earth, you can see quite good signal. As for GPS antenna with null, you can mount antennas on a linear boom and then sum them together with suitable delay, optimize for around 1,4 GHz as it is in the middle between L1 and L2. I wonder if there's any advantage in combining far-away GPS with X-ray pulsar navigation (XNAV), which is said to be good to a few kilometers, though long integration times are needed. For example, the rough system time from XNAV could enable very long (arbitrarily long?) coherent integration for very faint GPS signals obtained with a gain antenna pointed at the Earth. Multiple sources if feasable to include all the detectors. 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] 10 MHz clock distribution for the lab
c...@omen.com said: I have a FlexRadio 1500, Racal 1992 counter, HP 3586, Advantest U3641, and Gigatronics 6061A daisy-chained off my Thunderbolt. Don't throw out those BNC T connectors. I thought most boxes would have an internal 50 ohm terminator so at first, I'm a bit surprised that it works. If cables are short (which is not hard at 10 MHz), it would just be a resistive divider. If the source impedance is low, it's just more work for the driver. If the source includes 50 ohms, that's a 5:1 (1/6) divider so it probably works if the receivers are reasonably sensitive. -- These are my opinions. I hate spam. ___ 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] OT: Far-out space navigation from sideways satnav signals
pmo...@gmail.com said: I wonder if there's any advantage in combining far-away GPS with X-ray pulsar navigation (XNAV), which is said to be good to a few kilometers, though long integration times are needed. For example, the rough system time from XNAV could enable very long (arbitrarily long?) coherent integration for very faint GPS signals obtained with a gain antenna pointed at the Earth. Why are X-Ray pulsars better than radio pulsars for navigation? What's the adev of pulsars at long times? How long is long? Where is the knee of the curve? How good a clock could you build with a pulsar-DO? (Assume you have a good crystal but no atomic clocks.) Would you have to watch multiple pulsars at the same time? (Multiple antennas.) -- These are my opinions. I hate spam. ___ 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] OT: Far-out space navigation from sideways satnav signals
On 4/18/13 11:02 AM, Magnus Danielson wrote: On 04/18/2013 04:01 PM, Jim Lux wrote: On 4/18/13 4:01 AM, David J Taylor wrote: An interesting novel use of GPS stray signals ESA’s retired GIOVE-A navigation mission has become the first civilian satellite to perform GPS position fixes from high orbit. Its results demonstrate that current satnav signals could guide missions much further away in space, up to geostationary orbit or even as far as the Moon. See: http://www.esa.int/Our_Activities/Space_Engineering/Far-out_space_navigation_from_sideways_satnav_signals Interesting.. I know there's a bunch of analysis about how to use GPS at the moon. you need to look at the GPS satellites on the far side of the earth, grazing the limb. Would not an antenna with a deep zero focus on the earth center help to reduce earth-noise (ground temperature noise as well as man-made noise)? But then you'd need to point it. A bigger issue might be the sun. Either way, the question is whether it makes much difference. The typical GPS receiver has a hemisphere field of view (granted, mostly at 3K) and the satellite is at 20-40,000 km. At the moon, your antenna would have a 4-5 degree field of view (if pointed at the earth), so 30dB more gain, but looking at a 300K load, as well. At 300,000 km, that's about 10 times the distance, or 40 dB less signal.. So a net of -10dB.. Typical GPS receiver Tsys is 100K or something (in space). So, 3 times the noise. Maybe you need more gain (earth is 2 degrees wide viewed from the sun, so you could go to a 3 degree beamwidth.. that's like 36 dB gain ___ 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] antennas was Re: Common-View GPS Network
Magnus, Jim, On 04/18/2013 04:00 PM, Jim Lux wrote: On 4/18/13 12:01 AM, Chris Albertson wrote: If I read the paper correctly you can skip the choke ring if you mount the antenna on top of a 2 meter or longer mast. Iron pipe comes on 10 foot lengths. The choke ring is for portable survey antenna that can't be placed on tall rooftop masts. I think a 2 meter pole on a roof pretty much meets their criteria of multi path difference being over 10 meters. yes.. multipath that is more than a chip away is generally filtered out by the PN tracking loop, so all you really worry about is multipath signals within a chip. For C/A code at 1 Mchip/sec, the chips are 300 meters long. If you're doing P/Y code, it's a tenth of that. In reality, if the multipath signal is lower, and it's far away (a good fraction of a chip) it doesn't contribute much to the output of the correlator. So their 10 meter thing is probably a good number for a typical receiver they make. It's an interesting mix of sample-rate/bandwidth, code you track and distance between early-late detectors (normal distance is one chip) comes in when analyzing and combat the multi-path. I recall there is some subtle points with some of the C/A codes. All of the high quality GNSS receiver manufacturers have their own version of correlator that try to mitigate multipath. See for example this Ashtech-document (for a ca 10 year old L1 only receiver (DG14/16)). ftp://ftp.ashtech.com/OEM,%20Sensor%20%20ADU/DG16%20%20DG14/Reference%20Material/Correlator.doc /Björn ___ 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] OT: Far-out space navigation from sideways satnav signals
On 4/18/13 12:15 PM, Peter Monta wrote: I wonder if there's any advantage in combining far-away GPS with X-ray pulsar navigation (XNAV), which is said to be good to a few kilometers, though long integration times are needed. For example, the rough system time from XNAV could enable very long (arbitrarily long?) coherent integration for very faint GPS signals obtained with a gain antenna pointed at the Earth. Of course, building an X-ray detector for XNAV is an unsolved problem, at least for spacecraft practical systems. ___ 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] antennas was Re: Common-View GPS Network
On 4/18/13 1:40 PM, b...@lysator.liu.se wrote: All of the high quality GNSS receiver manufacturers have their own version of correlator that try to mitigate multipath. See for example this Ashtech-document (for a ca 10 year old L1 only receiver (DG14/16)). ftp://ftp.ashtech.com/OEM,%20Sensor%20%20ADU/DG16%20%20DG14/Reference%20Material/Correlator.doc I'm sure.. I wonder, though, if you have a GPS receiver for which you do not know how it works internally, can one come up with a guideline for how much multipath suppression you want. At some level, all those fancy algorithms are trying to build an adaptive equalizer and/or filter for the multipath, helped by the knowledge that the true path is the shortest one. In theory, one should be able to deconvolve arbitrary multipath (if you collect all signals from all directions of the sky, etc.), but I think the idea of the chokering (and other clever antenna designs) is to reduce the work for the back end processing. ___ 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] Z3805A OCXO p/n 3505A09422?
Hi: I'm trying to learn more about the HP Z3805A GPSDO. http://www.prc68.com/I/Z3805A.html It has an OCXO that I haven't seen before with a paper sticker with it's p/n: 3505A09422 The A normally means made in America. Does anyone know more about it? http://www.prc68.com/I/Z3805A.html#OCXO Also is the DB-25 pin out known? http://www.prc68.com/I/Z3805A.html#DB-25 -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html ___ 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] Z3805A OCXO p/n 3505A09422?
On 4/18/2013 5:41 PM, Brooke Clarke wrote: It has an OCXO that I haven't seen before with a paper sticker with it's p/n: 3505A09422 The A normally means made in America. It's a double oven HP 10811A, you're looking at the serial number sticker. ___ 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] Z3805A OCXO p/n 3505A09422?
Hi Brooke, On 04/18/2013 11:41 PM, Brooke Clarke wrote: Hi: I'm trying to learn more about the HP Z3805A GPSDO. http://www.prc68.com/I/Z3805A.html It has an OCXO that I haven't seen before with a paper sticker with it's p/n: 3505A09422 The A normally means made in America. Does anyone know more about it? http://www.prc68.com/I/Z3805A.html#OCXO Looks like the same as in Z3801A, that is a 10811 with additional oven wrapped around it and put in a case. Lots of details on it if you look at Z3801A sources of material. Also is the DB-25 pin out known? http://www.prc68.com/I/Z3805A.html#DB-25 Check the Z3801A manual. 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] Z3805A OCXO p/n 3505A09422?
It looks more like a HP serial number. Tom - Original Message - From: Brooke Clarke bro...@pacific.net To: time-nuts@febo.com Sent: Thursday, April 18, 2013 5:41 PM Subject: [time-nuts] Z3805A OCXO p/n 3505A09422? Hi: I'm trying to learn more about the HP Z3805A GPSDO. http://www.prc68.com/I/Z3805A.html It has an OCXO that I haven't seen before with a paper sticker with it's p/n: 3505A09422 The A normally means made in America. Does anyone know more about it? http://www.prc68.com/I/Z3805A.html#OCXO Also is the DB-25 pin out known? http://www.prc68.com/I/Z3805A.html#DB-25 -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html ___ 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] Z3805A OCXO p/n 3505A09422?
The OCXO is a 'double oven' 10811 and that is the serial number. I have a 'spare' and can probably find more information in my 'files' if needed. Good luck. Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Brooke Clarke Sent: Thursday, April 18, 2013 4:41 PM To: time-nuts@febo.com Subject: [time-nuts] Z3805A OCXO p/n 3505A09422? Hi: I'm trying to learn more about the HP Z3805A GPSDO. http://www.prc68.com/I/Z3805A.html It has an OCXO that I haven't seen before with a paper sticker with it's p/n: 3505A09422 The A normally means made in America. Does anyone know more about it? http://www.prc68.com/I/Z3805A.html#OCXO Also is the DB-25 pin out known? http://www.prc68.com/I/Z3805A.html#DB-25 -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html ___ 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] Z3805A OCXO p/n 3505A09422?
On 18/04/13 22:41, Brooke Clarke wrote: Hi: I'm trying to learn more about the HP Z3805A GPSDO. http://www.prc68.com/I/Z3805A.html It has an OCXO that I haven't seen before with a paper sticker with it's p/n: 3505A09422 The A normally means made in America. Does anyone know more about it? As others have said, it's a 18011, and you are looking at the serial number. IIRC, It was made in late 1995 (1960+35). The 05 is the 5th week of HP's Fiscal year that begins Nov 1 (still today), which I think puts the date of manufacture between Nov 29th and Dec 6th 1995. It's also a darned fine bit of kit :) (Sorry, I know I'm sad and bad, I just couldn't resist :)] Iain (who can probably still remember what he was doing that Nov 1 at HP!) ___ 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] Z3805A OCXO p/n 3505A09422?
Brooke wrote: I'm trying to learn more about the HP Z3805A GPSDO. http://www.prc68.com/I/Z3805A.html It has an OCXO that I haven't seen before with a paper sticker with it's p/n: 3505A09422 The A normally means made in America. Check the output on a spectrum analyzer for 5 MHz content. I've seen several internet-sourced Z3805As that were explicitly claimed to have HP 10811-60165 oscillators, but actually contained unlabeled oscillators that look like this one and appear to be 5 MHz oscillators with doublers (the output contains 5 MHz at ~ -50 dBc). I have heard that Symmetricom may have made oscillators fitting this description, but have no further knowledge. 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] 10 MHz clock distribution for the lab
I am using, with no problems a used modular video amp I purchased on ebay (Claimed power supply problem but actually worked fine). As is common with video, the inputs are loop through, each module has 8 outputs, with as many looped and terminated as necessary. Certainly not up to Boulder standards for noise and isolation but works fine, for me, driving counters and signal generators. BTW, two different GPSDOs, one driving a 18 GHz locked signal generator, the other driving the microwave counter at 1 Hz resolution; Counters reads bang on most of the time, occasional short walks up or down 2 Hz. Not having precise TI and Allan variance analysis, it shows me, quick and dirty, it is as good as I need. Lester B Veenstra MØYCM K1YCM W8YCM les...@veenstras.com US Postal Address: 5 Shrine Club Drive HC84 Box 89C Keyser WV 26726 GPS: 39.33675 N 78.9823527 W (Google) GPS: 39.33682 N 78.9023741 W (GPSDO) Telephones: Home: +1-304-289-6057 US cell +1-304-790-9192 UK cell +44-(0)7849-248-749 Guam Cell: +1-671-929-8141 Jamaica: +1-876-456-8898 This e-mail and any documents attached hereto contain confidential or privileged information. The information is intended to be for use only by the individual or entity to whom they are addressed. If you are not the intended recipient or the person responsible for delivering the e-mail to the intended recipient, be aware that any disclosure, copying, distribution or use of the contents of this e-mail or any documents attached hereto is prohibited. ___ 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] Z3805A OCXO p/n 3505A09422?
I have two of these units and am quite pleased with them. Other than an app note indicating that they are leap second compliant I've never seen any documentation re the Z3805. Sent from my iPad ___ 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] Z3805A OCXO p/n 3505A09422?
Yes, indeed, I've got one with a 10811 and one with a symmetricom 5 MHz oscillator with doubler. Volker Am 19.04.2013 01:15, schrieb Charles P. Steinmetz: Check the output on a spectrum analyzer for 5 MHz content. I've seen several internet-sourced Z3805As that were explicitly claimed to have HP 10811-60165 oscillators, but actually contained unlabeled oscillators that look like this one and appear to be 5 MHz oscillators with doublers (the output contains 5 MHz at ~ -50 dBc). I have heard that Symmetricom may have made oscillators fitting this description, but have no further knowledge. ... ___ 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] 10 MHz clock distribution for the lab
External reference inputs are definitely not all '50-ohms.' 'Learned the hard way. You need to read the specs on each piece of equipment. Input impedances will vary all over the map, even within the HP line. -Don Hal Murray hmur...@megapathdsl.net wrote: c...@omen.com said: I have a FlexRadio 1500, Racal 1992 counter, HP 3586, Advantest U3641, and Gigatronics 6061A daisy-chained off my Thunderbolt. Don't throw out those BNC T connectors. I thought most boxes would have an internal 50 ohm terminator so at first, I'm a bit surprised that it works. If cables are short (which is not hard at 10 MHz), it would just be a resistive divider. If the source impedance is low, it's just more work for the driver. If the source includes 50 ohms, that's a 5:1 (1/6) divider so it probably works if the receivers are reasonably sensitive. -- These are my opinions. I hate spam. ___ 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.
