[time-nuts] Sayrosa 607B Frequency Synthesizer
This unit is a part of the UK's Diplomatic Wireless Service's Piccolo HF RTTY network. I have acquired one of these am trying to get it working. It accepts a 10MHz (or 1 or 5) reference the output can be set to any frequency between 3MHz 29,999,900Hz, in 100Hz steps. My unit is showing a Fault LED on the display, which I believe is inhibiting the output. I can see a varying frequency at the o/p socket, but only a few mV, not the 1v into 50R as is normal. I suspect that the fault indication is because there's nothing plugged into either the Keying Frequency Control Input nor the Carrier Frequency Control Input sockets. (There's also a V.F. Inputs Carrier Output (BCD) sockets.) Can anyone help with a manual or connection details for the 2 input sockets, please? Many thanks, Mike M0MLM ___ 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] pulse height
Unless your coax is unusually long it should only look like 50 ohms on the leading and trailing edges of the pulse. A rough guide is 1nS per foot. So 10 ft of coax will look like 50 ohms for 10 nS. Of course the velocity factor of the coax will lengthen that time by roughly 50% for most coax you will find around the shop. You might want to set up a triggered 555 (556) or some such fed into some high speed CMOS (LVC or AHC etc) to see if it is your set up or the eqpt. For starters just the 555 will give you an indication. Start with 10 or 20uS pulses at around 100 Hz and slow the rep rate down. Dumb question: are you using a 10X probe? Have you accounted for that? Simon = Date: Sat, 24 Nov 2012 16:52:50 -0800 (PST) From: Mark Spencer mspencer12...@yahoo.ca To: time-nuts@febo.com Subject: Re: [time-nuts] Question re 1pps output on the Z3805A Message-ID: 1353804770.27074.yahoomailclas...@web121001.mail.ne1.yahoo.com Content-Type: text/plain; charset=us-ascii Thanks all for the responses. I am routing the signal via 50 ohm coax to the 1Meg ohm input of a 100 Mhz analog scope using dc coupling. After some fiddling with the trigger settings I am able to observe a brief pulse every second that appears to be .15 volts above ground. I'm not inclined to believe that the signal is actually .15 volts though. I did try terminating the scope end of the coax with a 50 ohm load and the signal as displayed on the scope didn't change. I recall making similar measurements in the past and seeing more reasonable results. I really don't want to blow the inputs on my 5370B's hence my caution here. I did try connecting the signal to one of my 5335B's and based on the trigger settings I was able to use to get that counter to trigger I'm inclined to believe it is 3.3 or 5 volt TTL level but I'm not 100 percent sure. I'll have to do some more experimenting with my analog with other 1pps signal sources to gain more confidence in my measurements and or ask Santa for a digital storage scope (: Regards Mark Spencer Engineering is the art of making what you want from what you can get at a profit. ___ 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] 5061A AC Power connector
What you have to file is the hard plastic connector block, not the shell of the connector. There are four (IIRC) possible 'rotations or positions' of the connector block/insert, labeled W, X, Y, and Z. I think the official part number for the 5061A connector is (IIRC) DMS3106A18-22SW, identifying the insert is rotated to the 'W' position. The insert has a 'ridge' of about 1/8 inch width with slots about 1/16th wide that allow the insert to fit in the shell only certain positions. However, only the 'default' position (one that doesn't work for the 5061A) has the entire 'slot' open. There is about a 1/16th wide by about 1/32 inch deep by about 1/16 inch long section that needs to be filed out to allow the insert to drop in in proper angle to accommodate the 5061A. There is a snap ring that has to be removed in order to remove the insert and has to be replaced in order to secure it in place once filing is completed. The Cannon brochure that Pete gave a link to explains it nicely, just not the need to do some filing. I suspect the need to file is unique to the DDK parts. However, for the savings, I can certainly do some filing. Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Peter Bell Sent: Saturday, November 24, 2012 10:07 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] 5061A AC Power connector If you are going to be filing them, then you should wear a face mask - the base plating on those things (even now) is normally Cadmium. What you actually want is a MS3106A18-22SW, but it looks like that vendor only supplies connectors with the default polarization. On Sun, Nov 25, 2012 at 10:48 AM, J. L. Trantham jlt...@att.net wrote: Forgot to mention, when you get the DMS3106A18-22S, you'll have to unscrew the back, remove the connector insert, file out a small 'key' in the material, and rotate the insert to achieve the desired alignment to mate with the connector on the 5061A or the 5065A. The alignment is the same on both but the wiring might be different. Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of J. L. Trantham Sent: Saturday, November 24, 2012 8:36 PM To: 'Discussion of precise time and frequency measurement' Subject: Re: [time-nuts] 5061A AC Power connector Pete, In the US, Galco sells a DDK product that works well. The connector and shell are a DMS3106A18-22S. http://www.galco.com/buy/DDK/DMS3106A18-22S You will also need a clamp and strain relief. I use a DMS3057-10A. http://www.galco.com/buy/DDK/DMS3057-10A It is the same connector as a 5065A though you have to be careful about the wiring. Some of the 5065A's are the same as the 5061A and others are different. Hope this helps. Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Pete Lancashire Sent: Saturday, November 24, 2012 6:51 PM To: Discussion of precise time and frequency measurement Subject: [time-nuts] 5061A AC Power connector What is the MS type for the power plug for a 5061A ? I could not find it in the PDF I have. -pete ___ 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] 5061A AC Power connector
Ah, OK - the last time I had to do any connector abuse like that the keying was a little different - there was a tab on the insert and a single keyway cut into the shell - if you wanted to change the polarization, you had to file another keyway in the shell and rotate the insert. It sounds like the connectors you are talking about make it quite a bit easier (and far less toxic). It also sounds like it might actually be an approved procedure - which it certainly wasn't with the connectors I was using :) Regards, Pete On Sun, Nov 25, 2012 at 7:54 PM, J. L. Trantham jlt...@att.net wrote: What you have to file is the hard plastic connector block, not the shell of the connector. There are four (IIRC) possible 'rotations or positions' of the connector block/insert, labeled W, X, Y, and Z. I think the official part number for the 5061A connector is (IIRC) DMS3106A18-22SW, identifying the insert is rotated to the 'W' position. The insert has a 'ridge' of about 1/8 inch width with slots about 1/16th wide that allow the insert to fit in the shell only certain positions. However, only the 'default' position (one that doesn't work for the 5061A) has the entire 'slot' open. There is about a 1/16th wide by about 1/32 inch deep by about 1/16 inch long section that needs to be filed out to allow the insert to drop in in proper angle to accommodate the 5061A. There is a snap ring that has to be removed in order to remove the insert and has to be replaced in order to secure it in place once filing is completed. The Cannon brochure that Pete gave a link to explains it nicely, just not the need to do some filing. I suspect the need to file is unique to the DDK parts. However, for the savings, I can certainly do some filing. Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Peter Bell Sent: Saturday, November 24, 2012 10:07 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] 5061A AC Power connector If you are going to be filing them, then you should wear a face mask - the base plating on those things (even now) is normally Cadmium. What you actually want is a MS3106A18-22SW, but it looks like that vendor only supplies connectors with the default polarization. On Sun, Nov 25, 2012 at 10:48 AM, J. L. Trantham jlt...@att.net wrote: Forgot to mention, when you get the DMS3106A18-22S, you'll have to unscrew the back, remove the connector insert, file out a small 'key' in the material, and rotate the insert to achieve the desired alignment to mate with the connector on the 5061A or the 5065A. The alignment is the same on both but the wiring might be different. Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of J. L. Trantham Sent: Saturday, November 24, 2012 8:36 PM To: 'Discussion of precise time and frequency measurement' Subject: Re: [time-nuts] 5061A AC Power connector Pete, In the US, Galco sells a DDK product that works well. The connector and shell are a DMS3106A18-22S. http://www.galco.com/buy/DDK/DMS3106A18-22S You will also need a clamp and strain relief. I use a DMS3057-10A. http://www.galco.com/buy/DDK/DMS3057-10A It is the same connector as a 5065A though you have to be careful about the wiring. Some of the 5065A's are the same as the 5061A and others are different. Hope this helps. Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Pete Lancashire Sent: Saturday, November 24, 2012 6:51 PM To: Discussion of precise time and frequency measurement Subject: [time-nuts] 5061A AC Power connector What is the MS type for the power plug for a 5061A ? I could not find it in the PDF I have. -pete ___ 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] Sayrosa 607B Frequency Synthesizer
Hi Mike I haven't seen too many of these in the wild so can I assume this was the unit recently sold on Ebay? If so you got an excellent drive unit at a very good price, even if it isn't working at the moment:-) FCO standard equipment with these was the HCD-1519 1MHz frequency reference and whilst they are specified to run from 1, 5, or 10MHz I've not run them from anything else so not sure offhand whether these frequencies are automatically accepted, which I suspect they were, or whether internal selection is required but I should be able to check on that. As you suggest, the output is inhibited whilst the fault indicator is illuminated. Is there a number showing on the display to go with your Fault indication, and are any other of the indicators illuminated? It's possible a link may be required on one of the rear connectors to enable stand alone operation but again I can't remember offhand so will check and come back to you on that too, but there shouldn't be any significant wiring needed. Like much equipment from that era though these units suffered the dreaded tantalum capacitor disease and it's quite possible that one or more modules may be afflicted. First thing to check is the power supply. There are 5 separate supply rails with two each of plus and minus 12 Volts and one of plus 5 Volts, each using an appropriate 78xx or 79xx regulator. If any are at zero this obviously indicates a possible failure but also perhaps a shorted supply line so this needs to be checked. Whatever the results here you though you should still check each of the internal modules. Where the supply rails attach to the circuit boards in the modules the first component in most, if not all cases, is a small series inductor which is followed by a 10uF tantalum capacitor to ground. If this or another capacitor has failed short circuit, which is the common failure mode, it could either be pulling the rail down or it's possible that the inductor will have burnt out which will restore the external supply but leaving part at least of the module non functional. If this does turn out to be the case and proper replacements aren't to hand a short term fix, although not recommended in the longer term, is to use standard electrolytics for the caps and wire links to replace the inductors. Good luck:-) Regards Nigel GM8PZR In a message dated 25/11/2012 09:39:11 GMT Standard Time, mike.millen...@gmail.com writes: This unit is a part of the UK's Diplomatic Wireless Service's Piccolo HF RTTY network. I have acquired one of these am trying to get it working. It accepts a 10MHz (or 1 or 5) reference the output can be set to any frequency between 3MHz 29,999,900Hz, in 100Hz steps. My unit is showing a Fault LED on the display, which I believe is inhibiting the output. I can see a varying frequency at the o/p socket, but only a few mV, not the 1v into 50R as is normal. I suspect that the fault indication is because there's nothing plugged into either the Keying Frequency Control Input nor the Carrier Frequency Control Input sockets. (There's also a V.F. Inputs Carrier Output (BCD) sockets.) Can anyone help with a manual or connection details for the 2 input sockets, please? Many thanks, Mike M0MLM ___ 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] Efratom MFS system
At a recent hamfest, I picked up an interesting looking Efratom Made in Germany MFS modular frequency standard system. It's basically a GPS disciplined FRK Rubidium with XO fail-over and a whole bunch of RF and PPS outputs, in a *very* heavy box. I've had a chance to play with it a bit and take some measurements, and was able to find some (but not a lot) of documentation on the web. I've put it all at http://www.febo.com/pages/efratom_mfs/index.html for your viewing pleasure. One thing I'd like to learn more about is how the MDC fail-over controller works, and also how to adjust the MXO backup crystal oscillator -- the Adjust XTAL indicator on mine is on the edge of being lit, but I haven't been able to find any way to trim the OCXO. The GPSDRb is working just fine, though. John ___ 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] 5061A AC Power connector
I stand corrected. My 5089 definitely uses the same connector as the 5061A. However, my 5085 uses a smaller connector, a DMS3106A10SL-3S. http://www.galco.com/buy/DDK/DMS3106A10SL-3S It uses a smaller clamp and strain relief, a DMS3057-4A, though I had to remove the strain relief due to the size of the cable I used to connect to 120 VAC. http://www.galco.com/buy/DDK/DMS3057-4A Sorry for the misleading info, but, perhaps, there are two different connectors for the 5085, depending on age/serial number of the equipment. Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of J. L. Trantham Sent: Saturday, November 24, 2012 9:36 PM To: 'Discussion of precise time and frequency measurement' Subject: Re: [time-nuts] 5061A AC Power connector Paul, According to the 5089 manual, the power connector is the same. Both the 5085 and 5089 call for the same HP part number for the AC power cord. Therefore, I suspect they are the same. I have a 5085 hooked up and I can make sure tomorrow if you need it. Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of paul swed Sent: Saturday, November 24, 2012 9:06 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] 5061A AC Power connector I hoped it helped also. I know it did for me. Will order 2 sets so I can finally have real connectors on the 5061 and 5065. I wonder if its the same for the standby power supply may need to order 3. Regards Paul WB8TSL On Sat, Nov 24, 2012 at 9:35 PM, J. L. Trantham jlt...@att.net wrote: Pete, In the US, Galco sells a DDK product that works well. The connector and shell are a DMS3106A18-22S. http://www.galco.com/buy/DDK/DMS3106A18-22S You will also need a clamp and strain relief. I use a DMS3057-10A. http://www.galco.com/buy/DDK/DMS3057-10A It is the same connector as a 5065A though you have to be careful about the wiring. Some of the 5065A's are the same as the 5061A and others are different. Hope this helps. Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Pete Lancashire Sent: Saturday, November 24, 2012 6:51 PM To: Discussion of precise time and frequency measurement Subject: [time-nuts] 5061A AC Power connector What is the MS type for the power plug for a 5061A ? I could not find it in the PDF I have. -pete ___ 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] Question re 1pps output on the Z3805A
Something else occurred to me after I posted. A 0.15 volt glitch could come from capacitive coupling if there was an open in the PPS output of if it was an adjacent pin. On Sat, 24 Nov 2012 16:52:50 -0800 (PST), Mark Spencer mspencer12...@yahoo.ca wrote: Thanks all for the responses. I am routing the signal via 50 ohm coax to the 1Meg ohm input of a 100 Mhz analog scope using dc coupling. After some fiddling with the trigger settings I am able to observe a brief pulse every second that appears to be .15 volts above ground. I'm not inclined to believe that the signal is actually .15 volts though. I did try terminating the scope end of the coax with a 50 ohm load and the signal as displayed on the scope didn't change. I recall making similar measurements in the past and seeing more reasonable results. I really don't want to blow the inputs on my 5370B's hence my caution here. I did try connecting the signal to one of my 5335B's and based on the trigger settings I was able to use to get that counter to trigger I'm inclined to believe it is 3.3 or 5 volt TTL level but I'm not 100 percent sure. I'll have to do some more experimenting with my analog with other 1pps signal sources to gain more confidence in my measurements and or ask Santa for a digital storage scope (: Regards Mark Spencer ___ 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 antenna in attic?
I'm beginning to set up in my new house and planning where all my various antennas are going to go. Being a wood frame building, I was wondering if it was sufficient to simply mount my Thunderbolt GPS antenna high in the attic. It would be convenient as there is already a high quality CATV line running from there to my lab area that I'm not going to use and the Thunderbolt antenna system is 75 ohms. Will I have much attenuation going through an asphalt shingle roof? What if it is wet? Or has some snow on it? Another advantage for me would be I could mount that antenna on the opposite end of the house from where I will have VHF and UHF transmitter antennas. 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] Efratom MFS system
Did you see that Symmetricom has the MFTS (Modular Frequency Timing System) which is described as the replacement for the MFS. The manual includes a warning not to interchange the modules between the two systems. There may be some value in reviewing the MFTS manual to see if there's anything applicable to the MFS. Ed On 11/25/2012 10:15 AM, John Ackermann N8UR wrote: At a recent hamfest, I picked up an interesting looking Efratom Made in Germany MFS modular frequency standard system. It's basically a GPS disciplined FRK Rubidium with XO fail-over and a whole bunch of RF and PPS outputs, in a *very* heavy box. I've had a chance to play with it a bit and take some measurements, and was able to find some (but not a lot) of documentation on the web. I've put it all at http://www.febo.com/pages/efratom_mfs/index.html for your viewing pleasure. One thing I'd like to learn more about is how the MDC fail-over controller works, and also how to adjust the MXO backup crystal oscillator -- the Adjust XTAL indicator on mine is on the edge of being lit, but I haven't been able to find any way to trim the OCXO. The GPSDRb is working just fine, though. John ___ 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 antenna in attic?
I do not know about the Thunderbolt in particular but some GPS receivers are more sensitive than others and will work acceptably like you describe. My house has similar construction and all of my GPS receivers except maybe for my GPS18-5Hz hockey puck will operate in the attic under the asphalt shingle roof. My better ones will operate with the one ceiling in the way as well. On Sun, 25 Nov 2012 11:50:31 -0500, Peter Gottlieb n...@verizon.net wrote: I'm beginning to set up in my new house and planning where all my various antennas are going to go. Being a wood frame building, I was wondering if it was sufficient to simply mount my Thunderbolt GPS antenna high in the attic. It would be convenient as there is already a high quality CATV line running from there to my lab area that I'm not going to use and the Thunderbolt antenna system is 75 ohms. Will I have much attenuation going through an asphalt shingle roof? What if it is wet? Or has some snow on it? Another advantage for me would be I could mount that antenna on the opposite end of the house from where I will have VHF and UHF transmitter antennas. 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] GPS antenna in attic?
Generally, it should work most of the time, which is probably good enough to discipline your local standard. Obviously, you want it above any foil backed insulation. Generally, near the ridge would be good, as ridges don't get that much snow cover. I've had a handhelg Garmin lock up OK in a lab on the top floor of a house, just below a similar attic. Generally, it probably won't be as good as outside on a pole, but it should work well enough. YMMV, -John = I'm beginning to set up in my new house and planning where all my various antennas are going to go. Being a wood frame building, I was wondering if it was sufficient to simply mount my Thunderbolt GPS antenna high in the attic. It would be convenient as there is already a high quality CATV line running from there to my lab area that I'm not going to use and the Thunderbolt antenna system is 75 ohms. Will I have much attenuation going through an asphalt shingle roof? What if it is wet? Or has some snow on it? Another advantage for me would be I could mount that antenna on the opposite end of the house from where I will have VHF and UHF transmitter antennas. 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. ___ 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] FE-5680A no 10MHz RF output?
Message: 3 Date: Sat, 24 Nov 2012 11:10:02 -0600 From: Ed Palmer ed_pal...@sasktel.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] FE-5680A no 10MHz RF output? Message-ID: 50b0ff6a.7030...@sasktel.net Content-Type: text/plain; charset=windows-1252; format=flowed I have a similar unit that I picked up a few years ago. It only has a 1 PPS output. That's the way it was designed. There are so many different versions of this stupid model that it's impossible to be sure what you're buying until you get it on your bench. If yours is like mine, the DDS is putting out 2^23 Hz (~8.39 MHz) which then goes through a fixed divider to 1 Hz. You can access the 8 MHz signal via a tiny socket on the DDS board. There is info online on how to modify the unit to bring that signal out to a connector and program it for other frequencies. If you change the frequency, the 1 PPS also changes frequency. Ed Ugh... Hopefully he'll let me return it. This is the first time I've bought an $80 item from China and I've been burned :( JP -- *Integrity is a binary state - either you have it or you don’t.* - John Doerr ___ 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] 12.8 MHz OCXO
Dave, Thanks for the link. That looks useful. Joe Gray W5JG On Sat, Nov 24, 2012 at 4:39 PM, Dave G4FRE g4...@g4fre.com wrote: I had a similar requirement a couple of years back. I ended up using a $10 VCXO, and a $20 Jupiter GPS. The circuit used was the one on page 12 of http://g4jnt.com/DDSVHFBeaconDriver.pdf by G4JNT. It just scraped in under $50 Dave Ww2r Message: 4 Date: Sat, 24 Nov 2012 09:01:25 -0700 From: Joseph Gray jg...@zianet.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] 12.8 MHz OCXO Message-ID: CAF7oPz2tiZTtqnmrp+xarCTowiJ==yqcgwk1_ebnozfdvna...@mail.gmail.com Content-Type: text/plain; charset=ISO-8859-1 Mike, Surprisingly, it isn' as uncommon as I first thought. The problem seems to be the cost, however. If I can't find something within my budget, I'll have to improvise. Joe Gray W5JG On Sat, Nov 24, 2012 at 1:53 AM, mike cook mc235...@gmail.com wrote: Le 24 nov. 2012 ? 09:26, Joseph Gray a ?crit : Can anyone recommend an inexpensive 12.8 MHz OCXO that outputs a sine wave? I've looked online, but the only ones I find costs hundreds of dollars. Anything 0.25 ppm or better is fine. A Vcc of 5-13.8 VDC preferred. An uncommon OCXO freq. If it is for hobby use, I would suggest using a more common quality reference and locking a cheap 12.8 vcxo / vctcxo to it with a pll. Joe Gray W5JG ___ 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] pulse height
Mark, Simon, First, I can check the 1PPS on my Z3805A with a small white LED. The pulse time is long enough to see in dark light conditions, and it verifies that the output voltage is 2V, and the driver can supply some mA of current. Primitive but works really well. Don't use a resistor on the LED. Second, the travel time through an open ended coax is back and forth, so 2x the time of your calculation. During that time the coax will look like 50 ohms, afterwards just like a cap. So 10 feet of coax would give you more like 30ns or more load time. This assumes the edge is much faster than the tpd, say it has a 2ns rise time. Bye, Said Sent from my iPad On Nov 25, 2012, at 2:03 AM, M. Simon msimon6...@yahoo.com wrote: Unless your coax is unusually long it should only look like 50 ohms on the leading and trailing edges of the pulse. A rough guide is 1nS per foot. So 10 ft of coax will look like 50 ohms for 10 nS. Of course the velocity factor of the coax will lengthen that time by roughly 50% for most coax you will find around the shop. You might want to set up a triggered 555 (556) or some such fed into some high speed CMOS (LVC or AHC etc) to see if it is your set up or the eqpt. For starters just the 555 will give you an indication. Start with 10 or 20uS pulses at around 100 Hz and slow the rep rate down. Dumb question: are you using a 10X probe? Have you accounted for that? Simon = Date: Sat, 24 Nov 2012 16:52:50 -0800 (PST) From: Mark Spencer mspencer12...@yahoo.ca To: time-nuts@febo.com Subject: Re: [time-nuts] Question re 1pps output on the Z3805A Message-ID: 1353804770.27074.yahoomailclas...@web121001.mail.ne1.yahoo.com Content-Type: text/plain; charset=us-ascii Thanks all for the responses. I am routing the signal via 50 ohm coax to the 1Meg ohm input of a 100 Mhz analog scope using dc coupling. After some fiddling with the trigger settings I am able to observe a brief pulse every second that appears to be .15 volts above ground. I'm not inclined to believe that the signal is actually .15 volts though. I did try terminating the scope end of the coax with a 50 ohm load and the signal as displayed on the scope didn't change. I recall making similar measurements in the past and seeing more reasonable results. I really don't want to blow the inputs on my 5370B's hence my caution here. I did try connecting the signal to one of my 5335B's and based on the trigger settings I was able to use to get that counter to trigger I'm inclined to believe it is 3.3 or 5 volt TTL level but I'm not 100 percent sure. I'll have to do some more experimenting with my analog with other 1pps signal sources to gain more confidence in my measurements and or ask Santa for a digital storage scope (: Regards Mark Spencer Engineering is the art of making what you want from what you can get at a profit. ___ 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] 5061A AC Power connector
Thanks will do some checking and order the right connectors Paul. On Sun, Nov 25, 2012 at 11:40 AM, J. L. Trantham jlt...@att.net wrote: I stand corrected. My 5089 definitely uses the same connector as the 5061A. However, my 5085 uses a smaller connector, a DMS3106A10SL-3S. http://www.galco.com/buy/DDK/DMS3106A10SL-3S It uses a smaller clamp and strain relief, a DMS3057-4A, though I had to remove the strain relief due to the size of the cable I used to connect to 120 VAC. http://www.galco.com/buy/DDK/DMS3057-4A Sorry for the misleading info, but, perhaps, there are two different connectors for the 5085, depending on age/serial number of the equipment. Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of J. L. Trantham Sent: Saturday, November 24, 2012 9:36 PM To: 'Discussion of precise time and frequency measurement' Subject: Re: [time-nuts] 5061A AC Power connector Paul, According to the 5089 manual, the power connector is the same. Both the 5085 and 5089 call for the same HP part number for the AC power cord. Therefore, I suspect they are the same. I have a 5085 hooked up and I can make sure tomorrow if you need it. Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of paul swed Sent: Saturday, November 24, 2012 9:06 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] 5061A AC Power connector I hoped it helped also. I know it did for me. Will order 2 sets so I can finally have real connectors on the 5061 and 5065. I wonder if its the same for the standby power supply may need to order 3. Regards Paul WB8TSL On Sat, Nov 24, 2012 at 9:35 PM, J. L. Trantham jlt...@att.net wrote: Pete, In the US, Galco sells a DDK product that works well. The connector and shell are a DMS3106A18-22S. http://www.galco.com/buy/DDK/DMS3106A18-22S You will also need a clamp and strain relief. I use a DMS3057-10A. http://www.galco.com/buy/DDK/DMS3057-10A It is the same connector as a 5065A though you have to be careful about the wiring. Some of the 5065A's are the same as the 5061A and others are different. Hope this helps. Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Pete Lancashire Sent: Saturday, November 24, 2012 6:51 PM To: Discussion of precise time and frequency measurement Subject: [time-nuts] 5061A AC Power connector What is the MS type for the power plug for a 5061A ? I could not find it in the PDF I have. -pete ___ 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. ___ 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] FE-5680A no 10MHz RF output?
Am 25.11.2012 18:29, schrieb James Peroulas: Message: 3 Date: Sat, 24 Nov 2012 11:10:02 -0600 From: Ed Palmered_pal...@sasktel.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] FE-5680A no 10MHz RF output? Message-ID:50b0ff6a.7030...@sasktel.net Content-Type: text/plain; charset=windows-1252; format=flowed I have a similar unit that I picked up a few years ago. It only has a 1 PPS output. That's the way it was designed. There are so many different versions of this stupid model that it's impossible to be sure what you're buying until you get it on your bench. If yours is like mine, the DDS is putting out 2^23 Hz (~8.39 MHz) which then goes through a fixed divider to 1 Hz. You can access the 8 MHz signal via a tiny socket on the DDS board. There is info online on how to modify the unit to bring that signal out to a connector and program it for other frequencies. If you change the frequency, the 1 PPS also changes frequency. Ed Ugh... Hopefully he'll let me return it. This is the first time I've bought an $80 item from China and I've been burned :( JP If this is so, it has to be a very unfortunate mischance. I've been trading with China numerous times, there was nothing to fault on. Cheers Volker ___ 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] Sayrosa 607B Frequency Synthesizer
gandal...@aol.com wrote: I haven't seen too many of these in the wild so can I assume this was the unit recently sold on Ebay? It was indeed. If so you got an excellent drive unit at a very good price, even if it isn't working at the moment:-) That's just what I thought. It's beautifully made... probably cost the taxpayer a fortune in its day. :) FCO standard equipment with these was the HCD-1519 1MHz frequency reference and whilst they are specified to run from 1, 5, or 10MHz I've tried it with both 1MHz 10MHz it locked up straight away with both. Is there a number showing on the display to go with your Fault indication, and are any other of the indicators illuminated? Sorry... I should have mentioned that in my first post... it's showing Fault 4. It's possible a link may be required on one of the rear connectors to enable stand alone operation but again I can't remember offhand so will check and come back to you on that too, but there shouldn't be any significant wiring needed. That's what I'm hoping. Like much equipment from that era though these units suffered the dreaded tantalum capacitor disease and it's quite possible that one or more modules may be afflicted. I brought it up gently on a variac, monitoring the rails as I went. They were all good until I reached 240v, then one of the +12v rails went to 0v. I traced it to a s/c tantalum in one of the modules. :-) All OK now. I'll be extremely pleased if you're able to shed any light on Fault 4, Nigel, or what jumpers/connnections I might need to make. If you have any printed data I'd be happy to pay all your costs for a copy. Regards, Mike M0MLM In a message dated 25/11/2012 09:39:11 GMT Standard Time, mike.millen...@gmail.com writes: This unit is a part of the UK's Diplomatic Wireless Service's Piccolo HF RTTY network. I have acquired one of these am trying to get it working. It accepts a 10MHz (or 1 or 5) reference the output can be set to any frequency between 3MHz 29,999,900Hz, in 100Hz steps. My unit is showing a Fault LED on the display, which I believe is inhibiting the output. I can see a varying frequency at the o/p socket, but only a few mV, not the 1v into 50R as is normal. I suspect that the fault indication is because there's nothing plugged into either the Keying Frequency Control Input nor the Carrier Frequency Control Input sockets. (There's also a V.F. Inputs Carrier Output (BCD) sockets.) Can anyone help with a manual or connection details for the 2 input sockets, please? ___ 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 antenna in attic?
n...@verizon.net said: I'm beginning to set up in my new house and planning where all my various antennas are going to go. Being a wood frame building, I was wondering if it was sufficient to simply mount my Thunderbolt GPS antenna high in the attic. It would be convenient as there is already a high quality CATV line running from there to my lab area that I'm not going to use and the Thunderbolt antenna system is 75 ohms. Will I have much attenuation going through an asphalt shingle roof? What if it is wet? Or has some snow on it? Another advantage for me would be I could mount that antenna on the opposite end of the house from where I will have VHF and UHF transmitter antennas. Try it. That's the only way to find out how well it works for you. Do you have software to monitor holdover? My TBolt antenna is inside, one ceiling under a similar roof. It switches into holdover several times a day. I think it happens more often when the roof is wet but I don't have numbers to back that up. No snow here so I can't comment on that. Part of my problems may be reflections (multi-path) from nearby buildings. -- 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] GPS antenna in attic?
My main GPS receiver used to see four to six satellites at a time when I used an antenna near a window in my workshop in a singe story house. I moved the antenna up into the attic near the peak, added 25 feet of TV cable, did not add any amplification, and now my system acquires and tracks eight to twelve satellites at a time. I did not want to move the antenna outside in order to reduce the chance of roof leaks and to avoid having to provide lightning strike protection. We do not get much, if any snow, and I have not noticed any problems with rain. John WA4WDL -- From: Peter Gottlieb n...@verizon.net Sent: Sunday, November 25, 2012 11:50 AM To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: [time-nuts] GPS antenna in attic? I'm beginning to set up in my new house and planning where all my various antennas are going to go. Being a wood frame building, I was wondering if it was sufficient to simply mount my Thunderbolt GPS antenna high in the attic. It would be convenient as there is already a high quality CATV line running from there to my lab area that I'm not going to use and the Thunderbolt antenna system is 75 ohms. Will I have much attenuation going through an asphalt shingle roof? What if it is wet? Or has some snow on it? Another advantage for me would be I could mount that antenna on the opposite end of the house from where I will have VHF and UHF transmitter antennas. 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. ___ 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] Efratom MFS system
Thanks, Ed. I wasn't aware of the MFTS. I'll look up those docs. John Ed Palmer said the following on 11/25/2012 12:12 PM: Did you see that Symmetricom has the MFTS (Modular Frequency Timing System) which is described as the replacement for the MFS. The manual includes a warning not to interchange the modules between the two systems. There may be some value in reviewing the MFTS manual to see if there's anything applicable to the MFS. Ed On 11/25/2012 10:15 AM, John Ackermann N8UR wrote: At a recent hamfest, I picked up an interesting looking Efratom Made in Germany MFS modular frequency standard system. It's basically a GPS disciplined FRK Rubidium with XO fail-over and a whole bunch of RF and PPS outputs, in a *very* heavy box. I've had a chance to play with it a bit and take some measurements, and was able to find some (but not a lot) of documentation on the web. I've put it all at http://www.febo.com/pages/efratom_mfs/index.html for your viewing pleasure. One thing I'd like to learn more about is how the MDC fail-over controller works, and also how to adjust the MXO backup crystal oscillator -- the Adjust XTAL indicator on mine is on the edge of being lit, but I haven't been able to find any way to trim the OCXO. The GPSDRb is working just fine, though. John ___ 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] pulse height
Depends on which end of the cable you are looking at. At the source end it is 2X the cable length. At the sink end only 1 cable length. One to two uS should be more than enough time for all the reflections to die out from cable losses alone. So even in a badly mismatched situation you should see the source voltage at the sink with lab conditions and an open circuit at the sink. Assuming a 10 to 20uS pulse. Thought experiment: Launch a one ns rising edge down your 10 ns long cable. When that pulse encounters a discontinuity (open) it will rise to about 2X the launch voltage - assuming a launch from a 50 ohm source with a 50 ohm cable - that is it rises to the source voltage. When the reflected pulse gets back to the source the source will then also be at the source voltage (which is to say the source resistance disappears). If the source is unmatched the reflections can go on for a while. Modern ICs (LVC say) are designed with about a 25 to 50 ohm output impedance to absorb line reflections. The older stuff (TTL and especially F) were low impedance devices so you needed a terminator in the line to kill reflections. About 33 ohms at the source seemed to work well. You wanted the smallest resistor possible (to minimize losses) while wanting something as close to 50 to 100 ohms as possible to absorb reflections. I had the very good fortune to work with all this back in '67 at Raytheon Computer when we were characterizing TTL for wire wrap. We used a Tek dual channel sampling scope capable of measuring time to better than .1 nS. The rule generally was that the wire should be shorter than the rise time for unterminated lines. i.e. about a foot long for 1nS rise times. = Message: 8 Date: Sun, 25 Nov 2012 10:03:46 -0800 From: Said Jackson saidj...@aol.com To: M. Simon msimon6...@yahoo.com, Discussion of precise time and frequency measurement time-nuts@febo.com Cc: time-nuts@febo.com time-nuts@febo.com Subject: Re: [time-nuts] pulse height Message-ID: 67f262eb-8e0b-4ac1-8bc6-56d696664...@aol.com Content-Type: text/plain; charset=us-ascii Mark, Simon, First, I can check the 1PPS on my Z3805A with a small white LED. The pulse time is long enough to see in dark light conditions, and it verifies that the output voltage is 2V, and the driver can supply some mA of current. Primitive but works really well. Don't use a resistor on the LED. Second, the travel time through an open ended coax is back and forth, so 2x the time of your calculation. During that time the coax will look like 50 ohms, afterwards just like a cap. So 10 feet of coax would give you more like 30ns or more load time. This assumes the edge is much faster than the tpd, say it has a 2ns rise time. Bye, Said Sent from my iPad On Nov 25, 2012, at 2:03 AM, M. Simon msimon6...@yahoo.com wrote: Unless your coax is unusually long it should only look like 50 ohms on the leading and trailing edges of the pulse. A rough guide is 1nS per foot. So 10 ft of coax will look like 50 ohms for 10 nS. Of course the velocity factor of the coax will lengthen that time by roughly 50% for most coax you will find around the shop. You might want to set up a triggered 555 (556) or some such fed into some high speed CMOS (LVC or AHC etc) to see if it is your set up or the eqpt. For starters just the 555 will give you an indication. Start with 10 or 20uS pulses at around 100 Hz and slow the rep rate down. Dumb question: are you using a 10X probe? Have you accounted for that? Simon = Date: Sat, 24 Nov 2012 16:52:50 -0800 (PST) From: Mark Spencer mspencer12...@yahoo.ca To: time-nuts@febo.com Subject: Re: [time-nuts] Question re 1pps output on the Z3805A Message-ID: 1353804770.27074.yahoomailclas...@web121001.mail.ne1.yahoo.com Content-Type: text/plain; charset=us-ascii Thanks all for the responses. I am routing the signal via 50 ohm coax to the 1Meg ohm input of a 100 Mhz analog scope using dc coupling. After some fiddling with the trigger settings I am able to observe a brief pulse every second that appears to be .15 volts above ground. I'm not inclined to believe that the signal is actually .15 volts though. I did try terminating the scope end of the coax with a 50 ohm load and the signal as displayed on the scope didn't change. I recall making similar measurements in the past and seeing more reasonable results. I really don't want to blow the inputs on my 5370B's hence my caution here. I did try connecting the signal to one of my 5335B's and based on the trigger settings I was able to use to get that counter to trigger I'm inclined to believe it is 3.3 or 5 volt TTL level but I'm not 100 percent sure. I'll have to do some more experimenting with my analog with other 1pps signal sources to gain more confidence in my measurements and or ask Santa for a digital storage scope (: Regards Mark Spencer Engineering is
Re: [time-nuts] pulse height (M. Simon)
Thanks all for the additional comments and suggestions, re the 1pps output voltage on my Z3805's. I did confirm that my measurement technique gives reasonable answers with other 1 pps signals. I also was able to observe an LED dimly flashing when connected to the 1pps output of one of my Z3805's. I believe something is wrong with my measurement technique vis a vis the signal from my Z3805's. I'm about to head out on the road for several weeks but will dig into this some more during the Holidays. (Hopefuly the ADEV of the units will continue to improve after another several weeks of operation.) The joys of knowingly buying used gear from China with no data sheets or manuals, still the price and the performance makes it worth the hassle for me (: Best regards Mark Spencer ___ 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] FE-5680A no 10MHz RF output?
Look on Didier's site or TvB's and you should find the hack that turns the 5680A into a variable output frequency device; there's a DDS with an rs232 interface. All is not lost? Don L Volker Esper Am 25.11.2012 18:29, schrieb James Peroulas: Message: 3 Date: Sat, 24 Nov 2012 11:10:02 -0600 From: Ed Palmered_pal...@sasktel.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] FE-5680A no 10MHz RF output? Message-ID:50b0ff6a.7030...@sasktel.net Content-Type: text/plain; charset=windows-1252; format=flowed I have a similar unit that I picked up a few years ago. It only has a 1 PPS output. That's the way it was designed. There are so many different versions of this stupid model that it's impossible to be sure what you're buying until you get it on your bench. If yours is like mine, the DDS is putting out 2^23 Hz (~8.39 MHz) which then goes through a fixed divider to 1 Hz. You can access the 8 MHz signal via a tiny socket on the DDS board. There is info online on how to modify the unit to bring that signal out to a connector and program it for other frequencies. If you change the frequency, the 1 PPS also changes frequency. Ed Ugh... Hopefully he'll let me return it. This is the first time I've bought an $80 item from China and I've been burned :( JP If this is so, it has to be a very unfortunate mischance. I've been trading with China numerous times, there was nothing to fault on. Cheers Volker ___ 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. -- Neither the voice of authority nor the weight of reason and argument are as significant as experiment, for thence comes quiet to the mind. De Erroribus Medicorum, R. Bacon, 13th century. If you don't know what it is, don't poke it. Ghost in the Shell Dr. Don Latham AJ7LL Six Mile Systems LLP 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 www.lightningforensics.com www.sixmilesystems.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] DDS - higher frequecies
Suppose I have an A/D running at 1 MHz. The standard simple minded approach is that it will work for any input signal with a bandwidth up to 1/2 MHz. We usually think of that in the baseband, but it also works for, say 1.25 to 1.5 MHz. The input signal gets aliased down into the baseband. (and if you are unlucky, which is easy, some of the aliasing reflects back and overlaps so you can't tell X-y from X+y) There is similar math for D/A, the reverse direction. I think this applies for a DDS making higher frequencies than simple arithmetic would allow it to generate. Does anybody have a good web page for how that works? My simple expectations are that it would have to generate lots of harmonics and then go through a filter to get rid of all the wrong stuff. I'm missing the step where all the harmonics come from. Are they just really tiny and I have to do a lot of good filtering and amplification? Do I need something other than a traditional DDS for this sort of stuff? -- 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] Efratom MFS system
HI Going from memory (never a good idea…): 1) There is a manual adjust on the MXO to line the EFC up so it's in range to lock. 2) The holdover / lock module is pretty simple, just a PLL running into a DAC. Holdover = freeze the DAC. 3) They aren't the most reliable thing Efratom ever made…. Bob On Nov 25, 2012, at 11:15 AM, John Ackermann N8UR j...@febo.com wrote: At a recent hamfest, I picked up an interesting looking Efratom Made in Germany MFS modular frequency standard system. It's basically a GPS disciplined FRK Rubidium with XO fail-over and a whole bunch of RF and PPS outputs, in a *very* heavy box. I've had a chance to play with it a bit and take some measurements, and was able to find some (but not a lot) of documentation on the web. I've put it all at http://www.febo.com/pages/efratom_mfs/index.html for your viewing pleasure. One thing I'd like to learn more about is how the MDC fail-over controller works, and also how to adjust the MXO backup crystal oscillator -- the Adjust XTAL indicator on mine is on the edge of being lit, but I haven't been able to find any way to trim the OCXO. The GPSDRb is working just fine, though. John ___ 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] DDS - higher frequecies
Hi The output spectrum is modified by the usual sin(x)/x based on the actual speed of the DAC. It's like any digital signal, the rise time of the edge and the spectrum are related to each other. Depending on exactly what sort of DAC architecture you have it may work ok, or it may not. If some bits propagate faster than others … not so good. Bob On Nov 25, 2012, at 7:30 PM, Hal Murray hmur...@megapathdsl.net wrote: Suppose I have an A/D running at 1 MHz. The standard simple minded approach is that it will work for any input signal with a bandwidth up to 1/2 MHz. We usually think of that in the baseband, but it also works for, say 1.25 to 1.5 MHz. The input signal gets aliased down into the baseband. (and if you are unlucky, which is easy, some of the aliasing reflects back and overlaps so you can't tell X-y from X+y) There is similar math for D/A, the reverse direction. I think this applies for a DDS making higher frequencies than simple arithmetic would allow it to generate. Does anybody have a good web page for how that works? My simple expectations are that it would have to generate lots of harmonics and then go through a filter to get rid of all the wrong stuff. I'm missing the step where all the harmonics come from. Are they just really tiny and I have to do a lot of good filtering and amplification? Do I need something other than a traditional DDS for this sort of stuff? -- 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.
Re: [time-nuts] DDS - higher frequecies
On 11/25/12 4:30 PM, Hal Murray wrote: Suppose I have an A/D running at 1 MHz. The standard simple minded approach is that it will work for any input signal with a bandwidth up to 1/2 MHz. We usually think of that in the baseband, but it also works for, say 1.25 to 1.5 MHz. The input signal gets aliased down into the baseband. (and if you are unlucky, which is easy, some of the aliasing reflects back and overlaps so you can't tell X-y from X+y) There is similar math for D/A, the reverse direction. I think this applies for a DDS making higher frequencies than simple arithmetic would allow it to generate. Yes.. you generate all the aliases.. Fx, Fs-Fx, Fs+Fx, 2Fs-Fx, 2Fs+Fx, etc. Does anybody have a good web page for how that works? My simple expectations are that it would have to generate lots of harmonics and then go through a filter to get rid of all the wrong stuff. I'm missing the step where all the harmonics come from. Not exactly harmonics, but aliases. What you are doing is convolving the sampling function (a series of ideal impulses, either in frequency or time domain) with the other signal. It's basically the opposite of an undersampling IF ANd, because the typical output has a sample/hold, it's not a series of impulses, but a staircase, so the frequency domain has a sin x/x shape to it. Are they just really tiny and I have to do a lot of good filtering and amplification? Yes.. And all the usual things about timing jitter aggravating the higher order outputs more than the first order, etc. Do I need something other than a traditional DDS for this sort of stuff? ___ 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] DDS - higher frequecies
On 11/26/2012 01:30 AM, Hal Murray wrote: Suppose I have an A/D running at 1 MHz. The standard simple minded approach is that it will work for any input signal with a bandwidth up to 1/2 MHz. We usually think of that in the baseband, but it also works for, say 1.25 to 1.5 MHz. The input signal gets aliased down into the baseband. (and if you are unlucky, which is easy, some of the aliasing reflects back and overlaps so you can't tell X-y from X+y) There is similar math for D/A, the reverse direction. I think this applies for a DDS making higher frequencies than simple arithmetic would allow it to generate. Does anybody have a good web page for how that works? My simple expectations are that it would have to generate lots of harmonics and then go through a filter to get rid of all the wrong stuff. I'm missing the step where all the harmonics come from. Are they just really tiny and I have to do a lot of good filtering and amplification? Do I need something other than a traditional DDS for this sort of stuff? I think you would enjoy digging up the Analog Devices DDS material, which goes into this and many other things. http://www.analog.com/static/imported-files/tutorials/450968421DDS_Tutorial_rev12-2-99.pdf See section 10. 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] DDS - higher frequecies
Hal, Check out the Analog Devices website. Good info on DDS Dacs there. You want to stay a bit away from the 1/2fs Nyquist limit in your DA. The reason is the image coming down from your 1MHz clock. If you output say 0.45MHz, you have an image at 0.55 MHz already (1MHz - 0.45MHz) so your filter has to be extremely steep to make that work and remove the spur at 0.55 MHz.. Check out the Mini Circuits LFCN low pass filters, they work at higher frequencies, and are very steep.. Your filter quality is going to determine how close you can get to Nyquist. Bye Said Sent From iPhone On Nov 25, 2012, at 16:30, Hal Murray hmur...@megapathdsl.net wrote: Suppose I have an A/D running at 1 MHz. The standard simple minded approach is that it will work for any input signal with a bandwidth up to 1/2 MHz. We usually think of that in the baseband, but it also works for, say 1.25 to 1.5 MHz. The input signal gets aliased down into the baseband. (and if you are unlucky, which is easy, some of the aliasing reflects back and overlaps so you can't tell X-y from X+y) There is similar math for D/A, the reverse direction. I think this applies for a DDS making higher frequencies than simple arithmetic would allow it to generate. Does anybody have a good web page for how that works? My simple expectations are that it would have to generate lots of harmonics and then go through a filter to get rid of all the wrong stuff. I'm missing the step where all the harmonics come from. Are they just really tiny and I have to do a lot of good filtering and amplification? Do I need something other than a traditional DDS for this sort of stuff? -- 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.
Re: [time-nuts] DDS - higher frequecies
On 11/25/12 5:19 PM, Said Jackson wrote: Hal, Check out the Analog Devices website. Good info on DDS Dacs there. You want to stay a bit away from the 1/2fs Nyquist limit in your DA. The reason is the image coming down from your 1MHz clock. If you output say 0.45MHz, you have an image at 0.55 MHz already (1MHz - 0.45MHz) so your filter has to be extremely steep to make that work and remove the spur at 0.55 MHz.. Check out the Mini Circuits LFCN low pass filters, they work at higher frequencies, and are very steep.. Your filter quality is going to determine how close you can get to Nyquist. There's also a variety of intermod type products that show up, particularly when you talk about spurs from phase truncation and the like. So you get not only the phase truncation spurs, but also all the aliases of those spurs. There's a fair amount of literature around about this, especially from about 10-20 years ago, when 1GHz ADCs and the logic to drive them weren't easy to come by. People wanted to generate signals in the hundreds of MHz range, but with logic and DACs that were slower. There's a reason that people do dithering in these sorts of applications: it degrades the peak performance, but at least it keeps you from having a big spur in the wrong place. There's a nice PhD dissertation out there (which name escapes me right now) that has a whole matlab code to simulate/analyze it. ___ 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 antenna in attic?
On Sun, Nov 25, 2012 at 8:50 AM, Peter Gottlieb n...@verizon.net wrote: I'm beginning to set up in my new house and planning where all my various antennas are going to go. Being a wood frame building, I was wondering if it was sufficient to simply mount my Thunderbolt GPS antenna high in the attic. It will work but it will be far from optimal. All you need to do is get a big drill bit and drill through the roof and put up an iron galvanized pipe. Put a pipe flange on the end and bolt the GPS antenna to that. You will need some metal flashing and roofing tar and then you will have a first class setup. You run the coax down the pipe. The timing antennas are pointed on top so snow falls off 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] GPS antenna in attic?
There are ways to do it w/o drilling holes. Most all houses have vent stacks for the plumbing, typically 3 or 4 inch cast iron or thick plastic. You can clamp a couple of feet of pipe onto one of those and run the wire to under an eve or through a gable end, adding a drip loop of course. But, if it were my house and I just wanted to discipline my local standard, I'd try the attic first. Among other things, you can get to the antenna w/o climbing on the roof! New England is not sunny CA. -John On Sun, Nov 25, 2012 at 8:50 AM, Peter Gottlieb n...@verizon.net wrote: I'm beginning to set up in my new house and planning where all my various antennas are going to go. Being a wood frame building, I was wondering if it was sufficient to simply mount my Thunderbolt GPS antenna high in the attic. It will work but it will be far from optimal. All you need to do is get a big drill bit and drill through the roof and put up an iron galvanized pipe. Put a pipe flange on the end and bolt the GPS antenna to that. You will need some metal flashing and roofing tar and then you will have a first class setup. You run the coax down the pipe. The timing antennas are pointed on top so snow falls off 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 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 antenna in attic?
Another possible option is running the cable through the same hole in the roof as the vent pipe. Frequently (for bath exhaust vents and such) there is a ~4-8 tin or aluminum shroud hat around the vent pipe, and in many cases, a gap between the pipe and roofing material (the shroud opening having a mesh to keep out critters). I used the gap to run my old Z3801A cable out before I had my roof replaced. I never replaced it because I upgraded to better cable, and it was too rigid for the old path (it had to bend enough to create a drip loop to keep the water out). I never did get around to rerouting the cable, so it's at ceiling level in the office. The performance is a little worse than I used to get but not bad enough to be a problem. In my case, the vent and main stack are about 2' apart, so mounting the antenna pipe (plastic) to the main stack worked nicely. -Dave - Original Message - From: J. Forster j...@quikus.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Sunday, November 25, 2012 7:15:05 PM Subject: Re: [time-nuts] GPS antenna in attic? There are ways to do it w/o drilling holes. Most all houses have vent stacks for the plumbing, typically 3 or 4 inch cast iron or thick plastic. You can clamp a couple of feet of pipe onto one of those and run the wire to under an eve or through a gable end, adding a drip loop of course. But, if it were my house and I just wanted to discipline my local standard, I'd try the attic first. Among other things, you can get to the antenna w/o climbing on the roof! New England is not sunny CA. -John On Sun, Nov 25, 2012 at 8:50 AM, Peter Gottlieb n...@verizon.net wrote: I'm beginning to set up in my new house and planning where all my various antennas are going to go. Being a wood frame building, I was wondering if it was sufficient to simply mount my Thunderbolt GPS antenna high in the attic. It will work but it will be far from optimal. All you need to do is get a big drill bit and drill through the roof and put up an iron galvanized pipe. Put a pipe flange on the end and bolt the GPS antenna to that. You will need some metal flashing and roofing tar and then you will have a first class setup. You run the coax down the pipe. The timing antennas are pointed on top so snow falls off 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 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.
