Re: [time-nuts] Zero dead time and average frequency estimation
Pete Rawson wrote: Gentlemen, You've hit a topic I've become more confused about after researching some of the original papers on this subject. Here are a few questions which I would like to become educated about. 1) Will the calculated results of ADEV, ODEV, MDEV TOTDEV suggest which result applies best to the data being analyzed? 2) What attributes of the data to be analyzed suggest which computation is most appropriate? 3) Will some computed results indicate that the analysis is NOT appropriate? (Are false results obvious?) There are two things to keep in mind, the bias and the error bars. Some of these estimators produces biased values as a result of the dominant noise source. You need to identify the dominant noise source (use the lag 1 autocorrelation noise identification, almost trivial to perform). Then with the dominant noise source identified the bias can be determined. Error bars will high-light in which area of the graph where a particular estimator has problems. Comparing the spread of the error-bars between various estimators allow for identifying which is best for the task. Look at TOTAL and Theo variants. Error bars is essentially a reformulation of the Equivalent Degrees of Freedom (EDF) and EDF change quite drastically with m. Comparison between different measurements can be done on EDF for m, and highest EDF wins. It's a measurement on how well the data in the sequence is used by the estimator. I'm sure there are more aspects worth learning than these, but they might serve to get a conversation underway. Any enlightenment would be greatly appreciated. This has been the point of the exercise... spreading the knowledge. I am digging too... but the little stuff I have picked up could probably be good knowledge to others, so I stirred the pot a little. 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] Strange event on my Z3805A
I've been a little lax in keeping my eye on the baby for over a day but was astonished to see the display on GPSCon just a few minutes ago. Things are usually very predictable with my EFC voltage showing a linear downward slope but I was surprised to see that the trace showed a very irregular upwards slope. Tracking back 36 hours I found a very strange event and have attached traces of the various stages of this. Trace 1 is 72 hour period. http://homepages.slingshot.co.nz/~sar10538/GPSCon_export_72h.png Trace 2 is the 36h before the event. ftp://homepages.slingshot.co.nz/GPSCon_export_previous_36h.png Trace 3 covers the event. ftp://homepages.slingshot.co.nz/GPSCon_export_event.png Trace 4 covers the period after the event. ftp://homepages.slingshot.co.nz/GPSCon_export_subsequent_32h.png It's not easy for me to accurately select start and stop parts of the graphs as my GPSCon window is quite small running under Wine in Linux. Steve -- Steve Rooke - ZL3TUV G8KVD A man with one clock knows what time it is; A man with two clocks is never quite sure. -- Steve Rooke - ZL3TUV G8KVD A man with one clock knows what time it is; A man with two clocks is never quite sure. ___ 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] Strange event on my Z3805A
Steve, I can only see the first screenshot, all the rest ask for a username and password. Best 73's Nic VK2KXN / VK5ZAT Trace 1 is 72 hour period. http://homepages.slingshot.co.nz/~sar10538/GPSCon_export_72h.png Trace 2 is the 36h before the event. ftp://homepages.slingshot.co.nz/GPSCon_export_previous_36h.png Trace 3 covers the event. ftp://homepages.slingshot.co.nz/GPSCon_export_event.png Trace 4 covers the period after the event. ftp://homepages.slingshot.co.nz/GPSCon_export_subsequent_32h.png It's not easy for me to accurately select start and stop parts of the graphs as my GPSCon window is quite small running under Wine in Linux. Steve -- Steve Rooke - ZL3TUV G8KVD A man with one clock knows what time it is; A man with two clocks is never quite sure. -- Steve Rooke - ZL3TUV G8KVD A man with one clock knows what time it is; A man with two clocks is never quite sure. ___ 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] Strange event on my Z3805A [REVISED to correct links]
Sorry, my bad, the links on traces 2-4 are incorrect. I've been a little lax in keeping my eye on the baby for over a day but was astonished to see the display on GPSCon just a few minutes ago. Things are usually very predictable with my EFC voltage showing a linear downward slope but I was surprised to see that the trace showed a very irregular upwards slope. Tracking back 36 hours I found a very strange event and have attached traces of the various stages of this. Trace 1 is 72 hour period. http://homepages.slingshot.co.nz/~sar10538/GPSCon_export_72h.png Trace 2 is the 36h before the event. http://homepages.slingshot.co.nz/~sar10538/GPSCon_export_previous_36h.png Trace 3 covers the event. http://homepages.slingshot.co.nz/~sar10538/GPSCon_export_event.png Trace 4 covers the period after the event. http://homepages.slingshot.co.nz/~sar10538/GPSCon_export_subsequent_32h.png It's not easy for me to accurately select start and stop parts of the graphs as my GPSCon window is quite small running under Wine in Linux. Steve -- Steve Rooke - ZL3TUV G8KVD A man with one clock knows what time it is; A man with two clocks is never quite sure. -- Steve Rooke - ZL3TUV G8KVD A man with one clock knows what time it is; A man with two clocks is never quite sure. -- Steve Rooke - ZL3TUV G8KVD A man with one clock knows what time it is; A man with two clocks is never quite sure. ___ 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] Strange event on my Z3805A [REVISED to correct links]
Seems that things have started to return to some normality but variations in the EFC are very high. The status line from the unit as reported shows everything is OK and it's tracking 7 sats. Trace of proceeding 60h from current time 1st Feb 10:30 UTC http://homepages.slingshot.co.nz/~sar10538/GPSCon_export_current_60h.png Steve -- Steve Rooke - ZL3TUV G8KVD A man with one clock knows what time it is; A man with two clocks is never quite sure. ___ 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] Zero dead time and average frequency estimation
Magnus Magnus Danielson wrote: Tom, Tom Van Baak wrote: Magnus, Correct, all the terms cancel between the end points. Note that this is exactly equivalent to the way a traditional gated frequency counter works -- you open the gate, wait some sample period (maybe 1, 10, or 100 seconds) and then close the gate. In this scenario it's clear that all the phase information during the interval is ignored; the only points that matter are the start and the stop. There is a technical merit to take samples in between even if they cancel... you avoid counter overflow, but you can do better, much better. Modern high-resolution frequency counters don't do this; and instead they use a form of continuous counting and take a massive number of short phase samples and create a more precise average frequency out of that. Yes, and the main point for creating this little thread is to make people aware that how you process your data do make a difference. It can make a huge difference in fact. The effective two-point frequency calculation only use two sample point to estimate the frequency and thus also use the systematic value and noise of one sample to cancel the noise of the first sample. For 1/f power noises this is an effect that can even becomes larger (for 1/f^3 noise) with time as it is non-convergent, so by looking at it briefly you don't realize it is a noisy number. There are some excellent papers on the subject; start with the one by Rubiola: http://www.femto-st.fr/~rubiola/pdf-articles/journal/2005rsi-hi-res-freq-counters.pdf There are additional papers (perhaps Bruce can locate them). In particular, there is one paper that corrects some mistakes of Rubiola, Australian if I remember correctly. Yes, the paper by Dawkins, McFerran and Luiten: http://ieeexplore.ieee.org/Xplore/login.jsp?url=http%3A%2F%2Fieeexplore.ieee.org%2Fiel5%2F4318993%2F4318994%2F04319178.pdf%3Farnumber%3D4319178authDecision=-203 http://ieeexplore.ieee.org/Xplore/login.jsp?url=http%3A%2F%2Fieeexplore.ieee.org%2Fiel5%2F4318993%2F4318994%2F04319178.pdf%3Farnumber%3D4319178authDecision=-203 Bruce ___ 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] help from Electronic Vibration Compensation
Hi Are you interested in simple tip over compensation or are you really after vibration compensation? If so, to how high a frequency? To what levels of vibration? On what sort of oscillator? A fairly simple 2G 3 axis accelerometer can compensate just about any oscillator for tip over. There are some fairly cheap digital ones out there from several semiconductor outfits. The question would be - how fast can I tip it? Some oscillators respond to temperature effects of a tip as well as gravity. That's going to slow things down a *lot*. The simple approach wold be to pick another oscillator, that may not be an option in your case. Lots of options / questions / routes to run down. Lots of answers that all start out with that depends Pretty much the best case hardware for vibration: 1) Military ruggedized OCXO designed specifically for good G sensitivity 2) Accelerometer with a G level adequate to read out your G level with good signal to noise 3) Accelerometer and DSP adequate to handle the upper frequency you want to compensate 4) Good equipment to measure phase noise under vibration Even with all that stuff, you need to ask, how far down do you want to compensate, and at what frequency? Bob On Feb 1, 2010, at 2:55 AM, weijiaz...@sina.com wrote: Now I am interested in low-g oscillators. http://www.freqelec.com/oscillators/g-comp_qz_brfg_04-07.pdf Which accelerometer is selected in the low-g oscillator? How to hack my normal oscillator to low-g one ? Anynbsp;othernbsp;suggestion? wei ___ 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] More IKEA hardware...
http://wiki.eth-0.nl/index.php/LackRack (Please try to avoid a long wandering thread on this one...) -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Info Needed on MOT KX1516AA VC-TCXO
Hi, I have some Motorola K1516AA, 10MHz, VC-TXCO devices (date-coded 1988) but with only a basic pin-out diagram to their name and am wondering if anyone knows a little more about them. Specifically I'm concerned with the apparent high output-Z which means that a sniff of 'C' or a tad of loading drags down the output to a fraction of the off-load value. Unless they were made for a very specific purpose, this characteristic would seem to me as pointless. Also, by measurement and experimentation, I'm fairly sure that they don't use an open collector or emitter follower output port. They may work as a current source but I haven't gone that route as yet. TIA - Joe G3LLV ___ 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] More IKEA hardware...
While we are briefly back on the subject of IKEA, I recall someone commenting that IKEA does not do web sales. According to the catalog my better half received a couple of weeks ago, in the States it is www.ikea-usa.com for web sales. But I admit I haven't tried it out, yet. Regards, Tom Holmes, N8ZM Tipp City, OH EM79xx -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Poul-Henning Kamp Sent: Monday, February 01, 2010 7:17 AM To: Discussion of precise time and frequency measurement Subject: [time-nuts] More IKEA hardware... http://wiki.eth-0.nl/index.php/LackRack (Please try to avoid a long wandering thread on this one...) -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list -- time-nuts@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] More IKEA hardware...
Hi They are available for order on the internet in the USA. I just ordered a couple for putting the Symmetricom boxes into. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Tom Holmes, N8ZM Sent: Monday, February 01, 2010 10:57 AM To: 'Discussion of precise time and frequency measurement' Subject: Re: [time-nuts] More IKEA hardware... While we are briefly back on the subject of IKEA, I recall someone commenting that IKEA does not do web sales. According to the catalog my better half received a couple of weeks ago, in the States it is www.ikea-usa.com for web sales. But I admit I haven't tried it out, yet. Regards, Tom Holmes, N8ZM Tipp City, OH EM79xx -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Poul-Henning Kamp Sent: Monday, February 01, 2010 7:17 AM To: Discussion of precise time and frequency measurement Subject: [time-nuts] More IKEA hardware... http://wiki.eth-0.nl/index.php/LackRack (Please try to avoid a long wandering thread on this one...) -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list -- time-nuts@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] Info Needed on MOT KX1516AA VC-TCXO
Hi From what little I can find, the oscillator is specified as a sine wave output into a 1K ohm resistive load. The supply voltage shows up as 8 volts and as 9.6 volts. I have seen other oscillators specified as high as 10K ohm resistive load, so 1K isn't as crazy as it might first sound. Back 30 years ago (Motorola was a while back) the intention was that the oscillator would be run into a tuned tank. They all went into radios, and things like radio spurs from oscillator harmonics were a concern. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Joe McElvenney Sent: Monday, February 01, 2010 9:09 AM To: Time Nuts Digest Subject: [time-nuts] Info Needed on MOT KX1516AA VC-TCXO Hi, I have some Motorola K1516AA, 10MHz, VC-TXCO devices (date-coded 1988) but with only a basic pin-out diagram to their name and am wondering if anyone knows a little more about them. Specifically I'm concerned with the apparent high output-Z which means that a sniff of 'C' or a tad of loading drags down the output to a fraction of the off-load value. Unless they were made for a very specific purpose, this characteristic would seem to me as pointless. Also, by measurement and experimentation, I'm fairly sure that they don't use an open collector or emitter follower output port. They may work as a current source but I haven't gone that route as yet. TIA - Joe G3LLV ___ 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] Zero dead time and average frequency estimation
Magnus, I see there are other versions of the Rubiola paper: http://www.femto-st.fr/~rubiola/pdf-articles/archives/2004-arxiv-0411227v2-counters.pdf http://www.femto-st.fr/~rubiola/pdf-articles/journal/2005rsi-hi-res-freq-counters.pdf http://www.femto-st.fr/~rubiola/pdf-articles/conference/2005-ifcs-counters.pdf And here is a slide presentation: http://www.femto-st.fr/~rubiola/pdf-slides/2008T-femto-counters.pdf Actually, all of Enrico's papers are a good read: http://www.femto-st.fr/~rubiola/indexx-publications.html http://www.femto-st.fr/~rubiola/indexx-oscillator-noise.html http://www.femto-st.fr/~rubiola/ There's also a bunch of phase noise papers that would be of interest to those of you working on Dual Mixer Time Difference (DMTD) implementations. In particular, there is one paper that corrects some mistakes of Rubiola, Australian if I remember correctly. Yes, the paper by Dawkins, McFerran and Luiten: http://ieeexplore.ieee.org/Xplore/login.jsp?url=http... Bruce, thanks for that link. Time to renew my IEEE subscription... /tvb ___ 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] Zero dead time and average frequency estimation
I was digging through the rubiola site. Some good stuff On Mon, Feb 1, 2010 at 1:29 PM, Tom Van Baak t...@leapsecond.com wrote: Magnus, I see there are other versions of the Rubiola paper: http://www.femto-st.fr/~rubiola/pdf-articles/archives/2004-arxiv-0411227v2-counters.pdf http://www.femto-st.fr/~rubiola/pdf-articles/journal/2005rsi-hi-res-freq-counters.pdf http://www.femto-st.fr/~rubiola/pdf-articles/conference/2005-ifcs-counters.pdf And here is a slide presentation: http://www.femto-st.fr/~rubiola/pdf-slides/2008T-femto-counters.pdf Actually, all of Enrico's papers are a good read: http://www.femto-st.fr/~rubiola/indexx-publications.html http://www.femto-st.fr/~rubiola/indexx-oscillator-noise.html http://www.femto-st.fr/~rubiola/ There's also a bunch of phase noise papers that would be of interest to those of you working on Dual Mixer Time Difference (DMTD) implementations. In particular, there is one paper that corrects some mistakes of Rubiola, Australian if I remember correctly. Yes, the paper by Dawkins, McFerran and Luiten: http://ieeexplore.ieee.org/Xplore/login.jsp?url=http... Bruce, thanks for that link. Time to renew my IEEE subscription... /tvb ___ 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] The WWVB Atomic Clock Kit #7
I noted this while looking for a DDS VFO, and thought it interesting and affordable if you are interested in a 60khz WWVB receiver kit for $30 plus postage. As a standard disclaimer, I have no affiliation with the gents producing the kit. The URL is: http://www.qsl.net/k5bcq/Kits/Kits.html And verbage from the site is as follows: This not your father's WWVB clock. Many CW output features and even Westminster chimes have been added. In fact we have 22 selectable parameters for those who like pushing buttons. Since it is very difficult to maintain a 60Khz RF link to WWVB during the day the Atomic Clock indicates when it was last synced to WWVB. This will allow you to experiment with various VLF antennas to see which is best. Antenna orientation is also important and you can experiment there. I've been using some larger ferrite rods (off eBay) with great success. Also tried some Litz wire antennas. Great fun. The best way to describe all of it's features is to walk through the setup process. Power: The Atomic Clock draws 0.22 mA running current, and 1.08 mA beeping current. To reduce power consumption the microcontroller hunts for the correct WWVB signal during the first 10 minutes of every hour. Two AA batteries should last a long time. Construction: A diagram is located on the schematic page. Components on the back are shown in mirror image. Mount a 2pin header on the CMMR-6P-60 for antenna attachment and experimentation. Remember this is “H” field, locate the ferrite rod away from metal and at right angles to Ft Collins CO, WWVB for best reception….mostly in the late evening and very early morning hours. Use: Step forward through the Modes by pushing the Mode button. Backup by holding in the Mode button until you hear the first half second tick. You can repeat this. If you hold the Mode button in for two half second ticks you go back to the “clock”. All data is immediately stored in flash memory at the time you change it. Clean display (no prefix) means you are “set” to WWVB, otherwise U,S,E,L is displayed for Unsynced (no sync detected), Second sync detected (it requires two good sync pulses before updating the time data with WWVB), Error (noise), or Loss of any signal. The microcontroller wll attempt to detect WWVB and sync up during the first 10 minutes of the hour (drawing ~1mA) it will then revert to 0.22mA for the remaining 50 minutes whether synced or not to conserve the battery. You can use #22 (below) to determine antenna effectiveness. Modes/Parameters: Initial default is Clock shown as “HH – MM – SS” with; Offset = -6, Interval = 1min, Beeper On, Call On, Tick On, and Westminster On Offset ….GMT offset selectable from -12 to 12 Beeper On/Off ….One mode provides all sound On/Off for quiet running (wife's request) Beeper Tone …. Frequency selectable from 294 Hz to 2093 Hz Beeper Speed …. Morse WPM selectable from 3 WPM to 40 WPM Beeper Interval …..Selectable output interval of #14 and/or #15 from 1 to 60 minutes. Test mode output including everything for “0” interval Call 1 …. Callsign entry (saved) by number A-Z = 1 - 26, 1234567890 = 27-36 Call 2 ….same as #6 Call 3 ….same as #6 Call 4 ….same as #6 Call 5 ….same as #6 Call 6 ….same as #6 Call 7 ….same as #6 Call 8 ….same as #6 Call On/Off ….Send Morse Code call sign de Callsign Callsign up to 8 characters for output to Beeper, LED, and Key output for rig Time On/Off …. Send Morse Code Time to Beeper, LED, and Key output for rig Westminster On/Off …. Westminster Chimes on Quarter Hour with Hour(s) “Gong” on the Hour Tick On/Off ….One second tick RS232 9600/4800 Baud ….9600 or 4800 Baud selectable for $GPZDA time data RS-232 output Display 12Hr/24Hr …. 12Hr or 24Hr mode shown on the LCD Set Hour …. Manual setting of Hours and Minutes if necessary Set Minute …. Manual setting of Hours and Minutes if necessary Tells you when the last successful setting to WWVB occurred, format: YYMMDDHHMMSS The price for the WWVB Atomic Clock Kit #7 (without the CMMR-6P-60) is $20 plus $2 postage in the USA and $5 postage for DX. The CMMR-6P-60 is available for $10 with no additional postage if ordered with the kit. We did that since several local people already have this WWVB receiver and the other worldwide time standards require different receivers and microcode (which is TBD). ___ 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] More IKEA hardware...
Hi Tom: You can NOT order lamps in the U.S on line. Have Fun, Brooke Clarke http://www.PRC68.com Tom Holmes, N8ZM wrote: While we are briefly back on the subject of IKEA, I recall someone commenting that IKEA does not do web sales. According to the catalog my better half received a couple of weeks ago, in the States it is www.ikea-usa.com for web sales. But I admit I haven't tried it out, yet. Regards, Tom Holmes, N8ZM Tipp City, OH EM79xx -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Poul-Henning Kamp Sent: Monday, February 01, 2010 7:17 AM To: Discussion of precise time and frequency measurement Subject: [time-nuts] More IKEA hardware... http://wiki.eth-0.nl/index.php/LackRack (Please try to avoid a long wandering thread on this one...) ___ 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] Standard Resistor oil
Hi Chris: Maybe used to be PCB's (yuck) You can use mineral oil, available at your friendly drugstore. Make sure everything is covered, leave a little for thermal expansion, don't need too much airspace. Use 'em on a paper towel, and if they are over full, they'll leak out the pinhole that lurks somewhere :-) on first use... Don Chris Erickson I bought some old Leeds Northrup standard resistors on ebay and and seller dumped the oil out before sending them. Does anyone know what the correct kind of oil to put back in these? How full should they be? ___ 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. -- 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.
Re: [time-nuts] Standard Resistor oil
What I have seen in the old text books is that these resistors all sit in a tub with oil around them. The oil is at some higher temperature. I have a few of these resistors and no oil in them nor will I be putting oil in them. They seem to work to the limits of resolution of my test gear. 5.5 digit HP meters. Gud enough as they say. I do keep them on absorbent paper because they do leak a bit even after 10 years. On Mon, Feb 1, 2010 at 4:27 PM, Don Latham d...@montana.com wrote: Hi Chris: Maybe used to be PCB's (yuck) You can use mineral oil, available at your friendly drugstore. Make sure everything is covered, leave a little for thermal expansion, don't need too much airspace. Use 'em on a paper towel, and if they are over full, they'll leak out the pinhole that lurks somewhere :-) on first use... Don Chris Erickson I bought some old Leeds Northrup standard resistors on ebay and and seller dumped the oil out before sending them. Does anyone know what the correct kind of oil to put back in these? How full should they be? ___ 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. -- 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 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] Test Equipment
Hi I do believe the last (or maybe next to last) of the Amtronix E8285A's is now on it's way to a basement in Pennsylvania. If anybody else here is looking for one, I'd sure call Rick pretty quick. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of John Ackermann N8UR Sent: Thursday, January 21, 2010 4:14 PM To: john.fo...@gmail.com; Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Test Equipment If RF measurement is your bag, and you're able to spend a couple of $K (actually, $2K if what I've seen recently holds), consider a communications service monitor like the HP 8920A/8920B/8921/8924/8935/E8285 (all pretty much the same thing). You get an RF generator, RF power meter, RX frequency meter and modulation analyzer, audio generator, audio analyzer, digital o'scope, and in most units a spectrum analyzer (many have a tracking generator, too) in one box. And I've probably forgotten a few things. If you get one with spec analyzer and tracking generator, there's software that lets you do swept insertion/return loss and cable fault finding. None of its capabilities are as good as those of a dedicated box performing a single function, but they're good enough for the vast majority of uses. An 8920 was the first significant piece of test gear I bought, and if I ever have to sell out, it'll be the last one to go. The prices came down a lot when Lucent surplused hundreds (thousands?) of them from their portable and cell phone production lines. I saw an 8935 with spec an, fully functional (as far as I could tell) for about $1500 this summer. A guy who sells and services a lot of these boxes is Rick at http://www.amtronix.com -- that web site will give you lots of info about the various versions and options. (I just noticed he has some Agilent 8285As as a hobbyist special with spec an and tracking generator for $650. That looks like a deal.) John john.fo...@gmail.com said the following on 01/21/2010 03:43 PM: Just that John, I'm looking to setup a general purpose lab. I'd lean towards RF type stuff since I'm a HAM. Sent via BlackBerry by ATT -Original Message- From: J. Forster j...@quik.com Date: Thu, 21 Jan 2010 12:22:11 To: did...@cox.net; Discussion of precise time and frequency measurementtime-nuts@febo.com Subject: Re: [time-nuts] Test Equipment I made the mistake of setting up a purpose-built lab once, and soon discovered to do most things, you really need at least a basic general purpose lab. The only exception is, I suppose, if you are going to repair a specific instrument and do nothing else. Also, as others have pointed out, you really need to define what are your area(s) of interest. Specialized gear gets $$$ pretty quickly. -John John, That sounds like asking what is the best vehicle for you to buy. If you do not know what you want to do with it, I am not sure we can help you all that much. However, if you have a specific objective, I am sure you will get a lot of valuable information here. You have a (good) analog scope, you may want a power supply or two, a soldering iron and maybe a desoldering station if you do surface mount. You also want a good hand-held multimeter. Some sort of signal or function generator may be useful too. These vary widely depending on frequency range and features. There is no good single answer to any of these questions without knowing more about what you do with it. Many of us on this list have more than one of pretty much everything (I am guilty of that too) to reflect the fact that no single instrument is universal, with possibly one exception: my favorite hand held DMM is a Fluke 8060A, but I am sure some people will have another favorite :) Don't start spending what little money you have until you know what you need. If you just need to spend money, may I interest you in a wonderful business opportunity in Nigeria? Didier KO4BB Sent from my BlackBerry Wireless thingy while I do other things... -Original Message- From: John Foege john.fo...@gmail.com Date: Thu, 21 Jan 2010 13:35:22 To: Discussion of precise time and frequency measurementtime-nuts@febo.com Subject: [time-nuts] Test Equipment I realize that this e-mail is somewhat off topic, however, I also believe that I will get some of the best answers from the members of this list: I have recently started to build an electronics lab, and am currently trying to acquire test and general equipment for my little basement workshop of horrors. So far, being on a limited budget, I have acquired a Tek 2465A in good working order, a Fluke 1953A counter, and my little gem (ok not quite so little) HP5345A with the 4-ghz freq converter plugin w/ opt 11 12. I'd just like to ask everyone what they would be, if they were in my shoes, attempting to acquire.
Re: [time-nuts] Strange event on my Z3805A [REVISED to correct links]
I've seen similar results when the receiver switches satellites. Multipath?? On Mon, 1 Feb 2010 23:43:01 +1300, Steve Rooke sar10...@gmail.com wrote: Seems that things have started to return to some normality but variations in the EFC are very high. The status line from the unit as reported shows everything is OK and it's tracking 7 sats. Trace of proceeding 60h from current time 1st Feb 10:30 UTC http://homepages.slingshot.co.nz/~sar10538/GPSCon_export_current_60h.png Steve -- kc0ukk at msosborn dot 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.
Re: [time-nuts] Test Equipment
Just bought one last week. As advertised, came with a cal and checkout sheet. BTW, cost another $150 to have manuals printed out. But, I'm old fashioned and have a hard time using manuals onscreen... I also got the feeling (phone order) that I can call Amtronix and at least reach a Real Person who will talk to me. I think the E8285A will replace at least three present instruments with better, once I master Instrument Basic :-). Does anyone know which low-cost PCMCIA memory card will work? They're on Epay for as little as $10 Don Bob Camp Hi I do believe the last (or maybe next to last) of the Amtronix E8285A's is now on it's way to a basement in Pennsylvania. If anybody else here is looking for one, I'd sure call Rick pretty quick. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of John Ackermann N8UR Sent: Thursday, January 21, 2010 4:14 PM To: john.fo...@gmail.com; Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Test Equipment If RF measurement is your bag, and you're able to spend a couple of $K (actually, $2K if what I've seen recently holds), consider a communications service monitor like the HP 8920A/8920B/8921/8924/8935/E8285 (all pretty much the same thing). You get an RF generator, RF power meter, RX frequency meter and modulation analyzer, audio generator, audio analyzer, digital o'scope, and in most units a spectrum analyzer (many have a tracking generator, too) in one box. And I've probably forgotten a few things. If you get one with spec analyzer and tracking generator, there's software that lets you do swept insertion/return loss and cable fault finding. None of its capabilities are as good as those of a dedicated box performing a single function, but they're good enough for the vast majority of uses. An 8920 was the first significant piece of test gear I bought, and if I ever have to sell out, it'll be the last one to go. The prices came down a lot when Lucent surplused hundreds (thousands?) of them from their portable and cell phone production lines. I saw an 8935 with spec an, fully functional (as far as I could tell) for about $1500 this summer. A guy who sells and services a lot of these boxes is Rick at http://www.amtronix.com -- that web site will give you lots of info about the various versions and options. (I just noticed he has some Agilent 8285As as a hobbyist special with spec an and tracking generator for $650. That looks like a deal.) John john.fo...@gmail.com said the following on 01/21/2010 03:43 PM: Just that John, I'm looking to setup a general purpose lab. I'd lean towards RF type stuff since I'm a HAM. Sent via BlackBerry by ATT -Original Message- From: J. Forster j...@quik.com Date: Thu, 21 Jan 2010 12:22:11 To: did...@cox.net; Discussion of precise time and frequency measurementtime-nuts@febo.com Subject: Re: [time-nuts] Test Equipment I made the mistake of setting up a purpose-built lab once, and soon discovered to do most things, you really need at least a basic general purpose lab. The only exception is, I suppose, if you are going to repair a specific instrument and do nothing else. Also, as others have pointed out, you really need to define what are your area(s) of interest. Specialized gear gets $$$ pretty quickly. -John John, That sounds like asking what is the best vehicle for you to buy. If you do not know what you want to do with it, I am not sure we can help you all that much. However, if you have a specific objective, I am sure you will get a lot of valuable information here. You have a (good) analog scope, you may want a power supply or two, a soldering iron and maybe a desoldering station if you do surface mount. You also want a good hand-held multimeter. Some sort of signal or function generator may be useful too. These vary widely depending on frequency range and features. There is no good single answer to any of these questions without knowing more about what you do with it. Many of us on this list have more than one of pretty much everything (I am guilty of that too) to reflect the fact that no single instrument is universal, with possibly one exception: my favorite hand held DMM is a Fluke 8060A, but I am sure some people will have another favorite :) Don't start spending what little money you have until you know what you need. If you just need to spend money, may I interest you in a wonderful business opportunity in Nigeria? Didier KO4BB Sent from my BlackBerry Wireless thingy while I do other things... -Original Message- From: John Foege john.fo...@gmail.com Date: Thu, 21 Jan 2010 13:35:22 To: Discussion of precise time and frequency measurementtime-nuts@febo.com Subject: [time-nuts] Test Equipment I realize that this e-mail is somewhat off topic, however, I also believe
Re: [time-nuts] Test Equipment
sounds like you are off to a good start. the 5345A is a great counter other then size and the fan, check the Yahoo Tektronix group for changing all the nasty caps in the 2465, they have a habit of failing and destroying the circuit board. I believe someone even has the parts list of what to replace. As to a signal source the two biggies are noise and upper freq, for the SA if you want higher the 2-3 Ghz it is going to cost a lot, lot more. Mine is based on the HP 7/MMS and for now I'm happy with the 2.9 Ghz front end. .. join the Yahoo Tek and HP groups and have fun ! -pete On Thu, Jan 21, 2010 at 10:35 AM, John Foege john.fo...@gmail.com wrote: I realize that this e-mail is somewhat off topic, however, I also believe that I will get some of the best answers from the members of this list: I have recently started to build an electronics lab, and am currently trying to acquire test and general equipment for my little basement workshop of horrors. So far, being on a limited budget, I have acquired a Tek 2465A in good working order, a Fluke 1953A counter, and my little gem (ok not quite so little) HP5345A with the 4-ghz freq converter plugin w/ opt 11 12. I'd just like to ask everyone what they would be, if they were in my shoes, attempting to acquire. Unforunately, however, I am just out of engineering school and not working with much of a budget here. I'd kill to have all the fancy gear some of you nuts have. I'd really love a DSO instead of the Tek 2465A I have. I'd kill for a good spectrum analyzer or VNA etc. Any suggestions on what I should acquire and/or suggestions for economical equipment that I should make that is a must have? I am a good DIYer when it comes to building equipment, so often I attempt to build that which I cannot afford. I appreciate everyone's' opinions in advance. Thank you. Sincerely, John Foege KB1FSX starving-engineer! ___ 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] Test Equipment
Hi I *suspect* that any size that was common in 2003 will be ok. I have no basis for that claim. That likely will limit you to 2 gig and down. Each time I called Amtronix, Rick answered on the first ring. It's definitely someplace I would recommend dealing with. How's the display on your unit? That sees to be the weakness of a lot of test gear these days. Can't wait to measure -100 dbc/Hz phase noise with mine :) Bob On Feb 1, 2010, at 5:34 PM, Don Latham wrote: Just bought one last week. As advertised, came with a cal and checkout sheet. BTW, cost another $150 to have manuals printed out. But, I'm old fashioned and have a hard time using manuals onscreen... I also got the feeling (phone order) that I can call Amtronix and at least reach a Real Person who will talk to me. I think the E8285A will replace at least three present instruments with better, once I master Instrument Basic :-). Does anyone know which low-cost PCMCIA memory card will work? They're on Epay for as little as $10 Don Bob Camp Hi I do believe the last (or maybe next to last) of the Amtronix E8285A's is now on it's way to a basement in Pennsylvania. If anybody else here is looking for one, I'd sure call Rick pretty quick. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of John Ackermann N8UR Sent: Thursday, January 21, 2010 4:14 PM To: john.fo...@gmail.com; Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Test Equipment If RF measurement is your bag, and you're able to spend a couple of $K (actually, $2K if what I've seen recently holds), consider a communications service monitor like the HP 8920A/8920B/8921/8924/8935/E8285 (all pretty much the same thing). You get an RF generator, RF power meter, RX frequency meter and modulation analyzer, audio generator, audio analyzer, digital o'scope, and in most units a spectrum analyzer (many have a tracking generator, too) in one box. And I've probably forgotten a few things. If you get one with spec analyzer and tracking generator, there's software that lets you do swept insertion/return loss and cable fault finding. None of its capabilities are as good as those of a dedicated box performing a single function, but they're good enough for the vast majority of uses. An 8920 was the first significant piece of test gear I bought, and if I ever have to sell out, it'll be the last one to go. The prices came down a lot when Lucent surplused hundreds (thousands?) of them from their portable and cell phone production lines. I saw an 8935 with spec an, fully functional (as far as I could tell) for about $1500 this summer. A guy who sells and services a lot of these boxes is Rick at http://www.amtronix.com -- that web site will give you lots of info about the various versions and options. (I just noticed he has some Agilent 8285As as a hobbyist special with spec an and tracking generator for $650. That looks like a deal.) John john.fo...@gmail.com said the following on 01/21/2010 03:43 PM: Just that John, I'm looking to setup a general purpose lab. I'd lean towards RF type stuff since I'm a HAM. Sent via BlackBerry by ATT -Original Message- From: J. Forster j...@quik.com Date: Thu, 21 Jan 2010 12:22:11 To: did...@cox.net; Discussion of precise time and frequency measurementtime-nuts@febo.com Subject: Re: [time-nuts] Test Equipment I made the mistake of setting up a purpose-built lab once, and soon discovered to do most things, you really need at least a basic general purpose lab. The only exception is, I suppose, if you are going to repair a specific instrument and do nothing else. Also, as others have pointed out, you really need to define what are your area(s) of interest. Specialized gear gets $$$ pretty quickly. -John John, That sounds like asking what is the best vehicle for you to buy. If you do not know what you want to do with it, I am not sure we can help you all that much. However, if you have a specific objective, I am sure you will get a lot of valuable information here. You have a (good) analog scope, you may want a power supply or two, a soldering iron and maybe a desoldering station if you do surface mount. You also want a good hand-held multimeter. Some sort of signal or function generator may be useful too. These vary widely depending on frequency range and features. There is no good single answer to any of these questions without knowing more about what you do with it. Many of us on this list have more than one of pretty much everything (I am guilty of that too) to reflect the fact that no single instrument is universal, with possibly one exception: my favorite hand held DMM is a Fluke 8060A, but I am sure some people will have another favorite :) Don't start spending what little money you have until you know what
Re: [time-nuts] Standard Resistor oil
Plain old mineral oil, also known as paraffin oil, as can be found in any drugstore. They should be filled above the element, but not quite full. Maybe 3/4 to 7/8 full. It isn't really important. -Chuck Harris Chris Erickson wrote: I bought some old Leeds Northrup standard resistors on ebay and and seller dumped the oil out before sending them. Does anyone know what the correct kind of oil to put back in these? How full should they be? ___ 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] Zero dead time and average frequency estimation
Bruce, Bruce Griffiths wrote: There are some excellent papers on the subject; start with the one by Rubiola: http://www.femto-st.fr/~rubiola/pdf-articles/journal/2005rsi-hi-res-freq-counters.pdf There are additional papers (perhaps Bruce can locate them). In particular, there is one paper that corrects some mistakes of Rubiola, Australian if I remember correctly. Yes, the paper by Dawkins, McFerran and Luiten: http://ieeexplore.ieee.org/Xplore/login.jsp?url=http%3A%2F%2Fieeexplore.ieee.org%2Fiel5%2F4318993%2F4318994%2F04319178.pdf%3Farnumber%3D4319178authDecision=-203 http://ieeexplore.ieee.org/Xplore/login.jsp?url=http%3A%2F%2Fieeexplore.ieee.org%2Fiel5%2F4318993%2F4318994%2F04319178.pdf%3Farnumber%3D4319178authDecision=-203 Yes, many thanks. This article by J.J. Snyder, An Ultra-High Resolution Frequency Meter, FCS #35, is very useful: http://www.ieee-uffc.org/main/publications/fcs/proceed/1981/s8110464.pdf It describes an hardware implementation of a zero dead-time counter (crude!) implementing the algorithm. It performs the averaging in the way I described earlier. The above paper by Snyder is the inspiration to the original MDEV paper published in for the same conference and directly following: David W. Allan and James A. Barnes, A modified Allan Variance with increased oscillator characterization ability, FCS #35. http://www.ieee-uffc.org/main/publications/fcs/proceed/1981/s8110470.pdf From the same conference exists a summary paper of Howe, Allan and Barnes on measurements, spending time on comparing over-lapping and non-overlapping estimators, effective use of data, DF/EDF, chi-square etc. etc. 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] Standard Resistor oil
Hi Some drug store mineral oil has extra stuff in it. This is one case where you want the cheap generic version rather than the improved name brand. Bob On Feb 1, 2010, at 5:56 PM, Chuck Harris wrote: Plain old mineral oil, also known as paraffin oil, as can be found in any drugstore. They should be filled above the element, but not quite full. Maybe 3/4 to 7/8 full. It isn't really important. -Chuck Harris Chris Erickson wrote: I bought some old Leeds Northrup standard resistors on ebay and and seller dumped the oil out before sending them. Does anyone know what the correct kind of oil to put back in these? How full should they be? ___ 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] Zero dead time and average frequency estimation
Unfortunately can't download these On Mon, Feb 1, 2010 at 6:06 PM, Magnus Danielson mag...@rubidium.dyndns.org wrote: Bruce, Bruce Griffiths wrote: There are some excellent papers on the subject; start with the one by Rubiola: http://www.femto-st.fr/~rubiola/pdf-articles/journal/2005rsi-hi-res-freq-counters.pdf There are additional papers (perhaps Bruce can locate them). In particular, there is one paper that corrects some mistakes of Rubiola, Australian if I remember correctly. Yes, the paper by Dawkins, McFerran and Luiten: http://ieeexplore.ieee.org/Xplore/login.jsp?url=http%3A%2F%2Fieeexplore.ieee.org%2Fiel5%2F4318993%2F4318994%2F04319178.pdf%3Farnumber%3D4319178authDecision=-203 http://ieeexplore.ieee.org/Xplore/login.jsp?url=http%3A%2F%2Fieeexplore.ieee.org%2Fiel5%2F4318993%2F4318994%2F04319178.pdf%3Farnumber%3D4319178authDecision=-203 Yes, many thanks. This article by J.J. Snyder, An Ultra-High Resolution Frequency Meter, FCS #35, is very useful: http://www.ieee-uffc.org/main/publications/fcs/proceed/1981/s8110464.pdf It describes an hardware implementation of a zero dead-time counter (crude!) implementing the algorithm. It performs the averaging in the way I described earlier. The above paper by Snyder is the inspiration to the original MDEV paper published in for the same conference and directly following: David W. Allan and James A. Barnes, A modified Allan Variance with increased oscillator characterization ability, FCS #35. http://www.ieee-uffc.org/main/publications/fcs/proceed/1981/s8110470.pdf From the same conference exists a summary paper of Howe, Allan and Barnes on measurements, spending time on comparing over-lapping and non-overlapping estimators, effective use of data, DF/EDF, chi-square etc. etc. 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] Zero dead time and average frequency estimation
paul swed wrote: Unfortunately can't download these You need the IEEE UFFC account. Now you know why I have mine. Those two articles is fairly short, so getting an UFFC account for those alone is kind of meaningless. 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] Test Equipment
Hi Bob. Display shows use, definitely, but I can see info over the whole tube. I have a couple of things to do before I can start the learning curve, but am looking forward to using it. I'll have a bunch of test stuff for sale if this thing works out ;-) Don Bob Camp Hi I *suspect* that any size that was common in 2003 will be ok. I have no basis for that claim. That likely will limit you to 2 gig and down. Each time I called Amtronix, Rick answered on the first ring. It's definitely someplace I would recommend dealing with. How's the display on your unit? That sees to be the weakness of a lot of test gear these days. Can't wait to measure -100 dbc/Hz phase noise with mine :) Bob On Feb 1, 2010, at 5:34 PM, Don Latham wrote: Just bought one last week. As advertised, came with a cal and checkout sheet. BTW, cost another $150 to have manuals printed out. But, I'm old fashioned and have a hard time using manuals onscreen... I also got the feeling (phone order) that I can call Amtronix and at least reach a Real Person who will talk to me. I think the E8285A will replace at least three present instruments with better, once I master Instrument Basic :-). Does anyone know which low-cost PCMCIA memory card will work? They're on Epay for as little as $10 Don Bob Camp Hi I do believe the last (or maybe next to last) of the Amtronix E8285A's is now on it's way to a basement in Pennsylvania. If anybody else here is looking for one, I'd sure call Rick pretty quick. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of John Ackermann N8UR Sent: Thursday, January 21, 2010 4:14 PM To: john.fo...@gmail.com; Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Test Equipment If RF measurement is your bag, and you're able to spend a couple of $K (actually, $2K if what I've seen recently holds), consider a communications service monitor like the HP 8920A/8920B/8921/8924/8935/E8285 (all pretty much the same thing). You get an RF generator, RF power meter, RX frequency meter and modulation analyzer, audio generator, audio analyzer, digital o'scope, and in most units a spectrum analyzer (many have a tracking generator, too) in one box. And I've probably forgotten a few things. If you get one with spec analyzer and tracking generator, there's software that lets you do swept insertion/return loss and cable fault finding. None of its capabilities are as good as those of a dedicated box performing a single function, but they're good enough for the vast majority of uses. An 8920 was the first significant piece of test gear I bought, and if I ever have to sell out, it'll be the last one to go. The prices came down a lot when Lucent surplused hundreds (thousands?) of them from their portable and cell phone production lines. I saw an 8935 with spec an, fully functional (as far as I could tell) for about $1500 this summer. A guy who sells and services a lot of these boxes is Rick at http://www.amtronix.com -- that web site will give you lots of info about the various versions and options. (I just noticed he has some Agilent 8285As as a hobbyist special with spec an and tracking generator for $650. That looks like a deal.) John john.fo...@gmail.com said the following on 01/21/2010 03:43 PM: Just that John, I'm looking to setup a general purpose lab. I'd lean towards RF type stuff since I'm a HAM. Sent via BlackBerry by ATT -Original Message- From: J. Forster j...@quik.com Date: Thu, 21 Jan 2010 12:22:11 To: did...@cox.net; Discussion of precise time and frequency measurementtime-nuts@febo.com Subject: Re: [time-nuts] Test Equipment I made the mistake of setting up a purpose-built lab once, and soon discovered to do most things, you really need at least a basic general purpose lab. The only exception is, I suppose, if you are going to repair a specific instrument and do nothing else. Also, as others have pointed out, you really need to define what are your area(s) of interest. Specialized gear gets $$$ pretty quickly. -John John, That sounds like asking what is the best vehicle for you to buy. If you do not know what you want to do with it, I am not sure we can help you all that much. However, if you have a specific objective, I am sure you will get a lot of valuable information here. You have a (good) analog scope, you may want a power supply or two, a soldering iron and maybe a desoldering station if you do surface mount. You also want a good hand-held multimeter. Some sort of signal or function generator may be useful too. These vary widely depending on frequency range and features. There is no good single answer to any of these questions without knowing more about what you do with it. Many of us on this list have more than one of pretty much everything (I am guilty of that too)
Re: [time-nuts] More IKEA hardware...
Hi Brooke... Ah, so I see. Curious that they have 200+ in stock at the store 40 minutes away from me. Maybe they don't ship cheaply or without high risk of breakage. But enough conjecture for this reflector; on to the fun stuff! Thanks! Regards, Tom Holmes, N8ZM Tipp City, OH EM79xx -Original Message- From: Brooke Clarke [mailto:bro...@pacific.net] Sent: Monday, February 01, 2010 3:55 PM To: thol...@woh.rr.com; Discussion of precise time and frequency measurement Subject: Re: [time-nuts] More IKEA hardware... Hi Tom: You can NOT order lamps in the U.S on line. Have Fun, Brooke Clarke http://www.PRC68.com Tom Holmes, N8ZM wrote: While we are briefly back on the subject of IKEA, I recall someone commenting that IKEA does not do web sales. According to the catalog my better half received a couple of weeks ago, in the States it is www.ikea-usa.com for web sales. But I admit I haven't tried it out, yet. Regards, Tom Holmes, N8ZM Tipp City, OH EM79xx -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Poul-Henning Kamp Sent: Monday, February 01, 2010 7:17 AM To: Discussion of precise time and frequency measurement Subject: [time-nuts] More IKEA hardware... http://wiki.eth-0.nl/index.php/LackRack (Please try to avoid a long wandering thread on this one...) ___ 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] Test Equipment
Hi The big question in my mind about these is how well they do below 30 MHz. Until I know I can trust them it down there, I'm not selling very much stuff. I have yet to find a data sheet from before 2000 when they shipped with the sub-800 MHz stuff enabled. I get the impression that the E8285's never quite did as well below 30 MHz as the 8920's do. Bob On Feb 1, 2010, at 7:29 PM, Don Latham wrote: Hi Bob. Display shows use, definitely, but I can see info over the whole tube. I have a couple of things to do before I can start the learning curve, but am looking forward to using it. I'll have a bunch of test stuff for sale if this thing works out ;-) Don Bob Camp Hi I *suspect* that any size that was common in 2003 will be ok. I have no basis for that claim. That likely will limit you to 2 gig and down. Each time I called Amtronix, Rick answered on the first ring. It's definitely someplace I would recommend dealing with. How's the display on your unit? That sees to be the weakness of a lot of test gear these days. Can't wait to measure -100 dbc/Hz phase noise with mine :) Bob On Feb 1, 2010, at 5:34 PM, Don Latham wrote: Just bought one last week. As advertised, came with a cal and checkout sheet. BTW, cost another $150 to have manuals printed out. But, I'm old fashioned and have a hard time using manuals onscreen... I also got the feeling (phone order) that I can call Amtronix and at least reach a Real Person who will talk to me. I think the E8285A will replace at least three present instruments with better, once I master Instrument Basic :-). Does anyone know which low-cost PCMCIA memory card will work? They're on Epay for as little as $10 Don Bob Camp Hi I do believe the last (or maybe next to last) of the Amtronix E8285A's is now on it's way to a basement in Pennsylvania. If anybody else here is looking for one, I'd sure call Rick pretty quick. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of John Ackermann N8UR Sent: Thursday, January 21, 2010 4:14 PM To: john.fo...@gmail.com; Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Test Equipment If RF measurement is your bag, and you're able to spend a couple of $K (actually, $2K if what I've seen recently holds), consider a communications service monitor like the HP 8920A/8920B/8921/8924/8935/E8285 (all pretty much the same thing). You get an RF generator, RF power meter, RX frequency meter and modulation analyzer, audio generator, audio analyzer, digital o'scope, and in most units a spectrum analyzer (many have a tracking generator, too) in one box. And I've probably forgotten a few things. If you get one with spec analyzer and tracking generator, there's software that lets you do swept insertion/return loss and cable fault finding. None of its capabilities are as good as those of a dedicated box performing a single function, but they're good enough for the vast majority of uses. An 8920 was the first significant piece of test gear I bought, and if I ever have to sell out, it'll be the last one to go. The prices came down a lot when Lucent surplused hundreds (thousands?) of them from their portable and cell phone production lines. I saw an 8935 with spec an, fully functional (as far as I could tell) for about $1500 this summer. A guy who sells and services a lot of these boxes is Rick at http://www.amtronix.com -- that web site will give you lots of info about the various versions and options. (I just noticed he has some Agilent 8285As as a hobbyist special with spec an and tracking generator for $650. That looks like a deal.) John john.fo...@gmail.com said the following on 01/21/2010 03:43 PM: Just that John, I'm looking to setup a general purpose lab. I'd lean towards RF type stuff since I'm a HAM. Sent via BlackBerry by ATT -Original Message- From: J. Forster j...@quik.com Date: Thu, 21 Jan 2010 12:22:11 To: did...@cox.net; Discussion of precise time and frequency measurementtime-nuts@febo.com Subject: Re: [time-nuts] Test Equipment I made the mistake of setting up a purpose-built lab once, and soon discovered to do most things, you really need at least a basic general purpose lab. The only exception is, I suppose, if you are going to repair a specific instrument and do nothing else. Also, as others have pointed out, you really need to define what are your area(s) of interest. Specialized gear gets $$$ pretty quickly. -John John, That sounds like asking what is the best vehicle for you to buy. If you do not know what you want to do with it, I am not sure we can help you all that much. However, if you have a specific objective, I am sure you will get a lot of valuable information here. You have a (good) analog scope, you may want a power supply or two, a
Re: [time-nuts] Strange event on my Z3805A [REVISED to correct links]
On 2 February 2010 11:11, Matt Osborn kc0...@msosborn.com wrote: I've seen similar results when the receiver switches satellites. Multipath?? It does that all the time as sats come in and out of view but I've never seen an event of this magnitude before. If you look at the trace for the preceeding 36h you can see peaks where the unit switches stats but those peaks are decades less than this peak. I also see that the EFC voltage changes very significantly, is this perhaps one of the infamous crystal jumps we have spoken about I wonder. The area of interest is that it appears somewhat unstable after the event but is improving now. Multipath, I don't think so as nothing has changed here and I live in an urban area well outside the city. Nothing has been errected or changed as far as I can see. Cheers, Steve -- Steve Rooke - ZL3TUV G8KVD A man with one clock knows what time it is; A man with two clocks is never quite sure. ___ 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] Zero dead time and average frequency estimation
Go to your public library and request the articles via interlibrary loan. I recently got Oliver Collins paper on Low Jitter Hard Limiters that way. Depending on your library's policies it might be free or cost a few dollars. It cost me $2.50 for photocopying. I'm not sure if you can get the actual journal. Ed paul swed wrote: Unfortunately can't download these On Mon, Feb 1, 2010 at 6:06 PM, Magnus Danielson mag...@rubidium.dyndns.org wrote: Bruce, Bruce Griffiths wrote: There are some excellent papers on the subject; start with the one by Rubiola: http://www.femto-st.fr/~rubiola/pdf-articles/journal/2005rsi-hi-res-freq-counters.pdf There are additional papers (perhaps Bruce can locate them). In particular, there is one paper that corrects some mistakes of Rubiola, Australian if I remember correctly. Yes, the paper by Dawkins, McFerran and Luiten: http://ieeexplore.ieee.org/Xplore/login.jsp?url=http%3A%2F%2Fieeexplore.ieee.org%2Fiel5%2F4318993%2F4318994%2F04319178.pdf%3Farnumber%3D4319178authDecision=-203 http://ieeexplore.ieee.org/Xplore/login.jsp?url=http%3A%2F%2Fieeexplore.ieee.org%2Fiel5%2F4318993%2F4318994%2F04319178.pdf%3Farnumber%3D4319178authDecision=-203 Yes, many thanks. This article by J.J. Snyder, An Ultra-High Resolution Frequency Meter, FCS #35, is very useful: http://www.ieee-uffc.org/main/publications/fcs/proceed/1981/s8110464.pdf It describes an hardware implementation of a zero dead-time counter (crude!) implementing the algorithm. It performs the averaging in the way I described earlier. The above paper by Snyder is the inspiration to the original MDEV paper published in for the same conference and directly following: David W. Allan and James A. Barnes, A modified Allan Variance with increased oscillator characterization ability, FCS #35. http://www.ieee-uffc.org/main/publications/fcs/proceed/1981/s8110470.pdf From the same conference exists a summary paper of Howe, Allan and Barnes on measurements, spending time on comparing over-lapping and non-overlapping estimators, effective use of data, DF/EDF, chi-square etc. etc. 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] Triangle Waves
Hi Ok, next up on the dual mixer stuff is checking the limiter chain. To do that with any chance of the results meaning anything you need a good triangle wave. You certainly can build some pretty complex gizmos to make them. There also appears to be a fairly simple approach. If I take a fairly good 16 bit DAC that will accept a clock a bit above 1 MHz, I can feed a simple count up / count down into it. That should give me a triangle wave at (clock rate) / 2^32. Simply put, 1.3 MHz data gives me a 10 Hz triangle wave. The digital crud should be almost entirely up around the clock rate or higher and 90 db down. That assumes that the DAC is a low clock feed through version and that it's got good linearity. A reasonable dual mixer or heterodyne system should have some kind of low pass filter built into it. Even a 150 Hz lowpass should knock the digital stuff down into a -160 noise floor. The gotcha seems to be flicker noise out of the DAC. There's no guarantee that the gizmo will have a 1nV/Hz class noise floor. The same sort of audio spectrum analyzers used for phase noise should be able to measure the noise coming out under various conditions. The nice thing about this gizmo is that it does not have to *only* put out a triangle wave. If you drive it with a micro, you can tell it to do all sorts of things. You might try a number of DC levels as you check for noise. You might also try various triangle wave levels to see how everything matches up. Slew rate limited square waves also sound interesting. There are a couple of other details like DC level shifting and driving it all with a decent clock. Both need to be done properly, but they don't appear to be the limiting factors in this kind of setup. I suspect this approach has been tried before. Any record of it out there? Bob ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Triangle Waves
Bob Camp wrote: Hi Ok, next up on the dual mixer stuff is checking the limiter chain. To do that with any chance of the results meaning anything you need a good triangle wave. You certainly can build some pretty complex gizmos to make them. There also appears to be a fairly simple approach. If I take a fairly good 16 bit DAC that will accept a clock a bit above 1 MHz, I can feed a simple count up / count down into it. That should give me a triangle wave at (clock rate) / 2^32. Simply put, 1.3 MHz data gives me a 10 Hz triangle wave. The digital crud should be almost entirely up around the clock rate or higher and 90 db down. That assumes that the DAC is a low clock feed through version and that it's got good linearity. A reasonable dual mixer or heterodyne system should have some kind of low pass filter built into it. Even a 150 Hz lowpass should knock the digital stuff down into a -160 noise floor. The gotcha seems to be flicker noise out of the DAC. There's no guarantee that the gizmo will have a 1nV/Hz class noise floor. The same sort of audio spectrum analyzers used for phase noise should be able to measure the noise coming out under various conditions. The nice thing about this gizmo is that it does not have to *only* put out a triangle wave. If you drive it with a micro, you can tell it to do all sorts of things. You might try a number of DC levels as you check for noise. You might also try various triangle wave levels to see how everything matches up. Slew rate limited square waves also sound interesting. There are a couple of other details like DC level shifting and driving it all with a decent clock. Both need to be done properly, but they don't appear to be the limiting factors in this kind of setup. I suspect this approach has been tried before. Any record of it out there? Bob ___ Bob You arent going to find a DAC with a 1nV/rtHz noise floor off the shelf due to the reference noise. Heroic filtering measures will be necessary to reduce the reference noise, then you will have to deal with the DAC component noise which will almost invariably be greater than 1nV/rtHz. If it has an external reference capability you could try using a series stack of leds as in this application the reference tempco shouldnt be too important. A Josephson junction stack would work as a DAC well with very low noise. NIST uses such JJ stacks as sigma delta DACs to calibrate the Johnson noise thermometers. Why can't you just use a sinewave test source? Only the part near the zero crossings is of any importance. Another effect to consider with diode mixers/phase detectors is that at 10MHz the amplitude sensitivity may be as high as 256ps/dB with both inputs ports saturated. Reducing the input port VSWR with a series resistor and attenuator pad can reduce this effect by a factor of 10 or more. Bruce ___ 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] Test Equipment
If goggle HP 8285a spec, you will get HP spec which say this unit is 800 Mhz up. The 8920, 8921, 8025 will go down to ham freq. Regards, Dr. Joseph G. Palsa P.E. Director, Sales Marketing Clary Corporation Phone: 888-442-5279 Phone: 804-674-0364 Fax: 804-674-0714 Cell: 804-350-2665 jpa...@clary.com djpa...@yahoo.com k3...@aol.com k3...@arrl.net This e-mail (including any attachments) is intended only for the use of the individual or entity named above and may contain privileged, proprietary, or confidential information. The information may also contain technical data subject to export control laws. In a message dated 2/1/2010 8:42:56 P.M. Eastern Standard Time, li...@cq.nu writes: Hi The big question in my mind about these is how well they do below 30 MHz. Until I know I can trust them it down there, I'm not selling very much stuff. I have yet to find a data sheet from before 2000 when they shipped with the sub-800 MHz stuff enabled. I get the impression that the E8285's never quite did as well below 30 MHz as the 8920's do. Bob On Feb 1, 2010, at 7:29 PM, Don Latham wrote: Hi Bob. Display shows use, definitely, but I can see info over the whole tube. I have a couple of things to do before I can start the learning curve, but am looking forward to using it. I'll have a bunch of test stuff for sale if this thing works out ;-) Don Bob Camp Hi I *suspect* that any size that was common in 2003 will be ok. I have no basis for that claim. That likely will limit you to 2 gig and down. Each time I called Amtronix, Rick answered on the first ring. It's definitely someplace I would recommend dealing with. How's the display on your unit? That sees to be the weakness of a lot of test gear these days. Can't wait to measure -100 dbc/Hz phase noise with mine :) Bob On Feb 1, 2010, at 5:34 PM, Don Latham wrote: Just bought one last week. As advertised, came with a cal and checkout sheet. BTW, cost another $150 to have manuals printed out. But, I'm old fashioned and have a hard time using manuals onscreen... I also got the feeling (phone order) that I can call Amtronix and at least reach a Real Person who will talk to me. I think the E8285A will replace at least three present instruments with better, once I master Instrument Basic :-). Does anyone know which low-cost PCMCIA memory card will work? They're on Epay for as little as $10 Don Bob Camp Hi I do believe the last (or maybe next to last) of the Amtronix E8285A's is now on it's way to a basement in Pennsylvania. If anybody else here is looking for one, I'd sure call Rick pretty quick. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of John Ackermann N8UR Sent: Thursday, January 21, 2010 4:14 PM To: john.fo...@gmail.com; Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Test Equipment If RF measurement is your bag, and you're able to spend a couple of $K (actually, $2K if what I've seen recently holds), consider a communications service monitor like the HP 8920A/8920B/8921/8924/8935/E8285 (all pretty much the same thing). You get an RF generator, RF power meter, RX frequency meter and modulation analyzer, audio generator, audio analyzer, digital o'scope, and in most units a spectrum analyzer (many have a tracking generator, too) in one box. And I've probably forgotten a few things. If you get one with spec analyzer and tracking generator, there's software that lets you do swept insertion/return loss and cable fault finding. None of its capabilities are as good as those of a dedicated box performing a single function, but they're good enough for the vast majority of uses. An 8920 was the first significant piece of test gear I bought, and if I ever have to sell out, it'll be the last one to go. The prices came down a lot when Lucent surplused hundreds (thousands?) of them from their portable and cell phone production lines. I saw an 8935 with spec an, fully functional (as far as I could tell) for about $1500 this summer. A guy who sells and services a lot of these boxes is Rick at http://www.amtronix.com -- that web site will give you lots of info about the various versions and options. (I just noticed he has some Agilent 8285As as a hobbyist special with spec an and tracking generator for $650. That looks like a deal.) John john.fo...@gmail.com said the following on 01/21/2010 03:43 PM: Just that John, I'm looking to setup a general purpose lab. I'd lean towards RF type stuff since I'm a HAM. Sent via BlackBerry by ATT -Original Message- From: J. Forster j...@quik.com Date: Thu, 21 Jan 2010 12:22:11 To: did...@cox.net; Discussion of precise time and frequency measurementtime-nuts@febo.com Subject: Re:
Re: [time-nuts] Triangle Waves
Hi At least from the last time I tried it: If you use a sine wave input source, it's got to be an amazingly good 10 Hz sine wave. A normal audio generator will not produce a 10 Hz output with good enough short term stability / noise to give you useful data. Audio generators may be out there that will do the job, but I certainly don't have one, and have never come across one. Since the output of the mixer is basically a triangle wave, it makes sense to use that as your test source. A triangle wave also has the nice property that it's easy on the math. You don't have any approximation issues with the integers going into the DAC. That shoves the inevitable digital crud higher in frequency. Another nice thing about a pure digital approach is that it provides a clean trigger for the start channel of the counter you are testing things with. You can even set up the DAC to put out square waves to see just how good various bits of the chain are. Tough to do that with anything other than another arbitrary function generator. I agree that the reference is going to be an issue and that a LED stack may be the way to go. No matter how you generate the test tone, power supply noise will be an issue. The output amplifier on the DAC is my biggest worry. I could go with a current out DAC and something like an OP-27. That won't give me 1nV/Hz either, but it will at least be within shouting distance of it. Sigma deltas might be a third option. I have no idea what their low frequency flicker noise looks like. So, other than the noise issue (which obviously needs to be analyzed / tested / pounded on) any other issues with the approach? At least from what I have seen in the past, level sensitivity on the inputs shows up pretty fast in the output beat note as you vary the input signals that are supposed to be saturating the mixer. If they are doing their job, a 2 db level change produces a very small change in the output. If you have something amiss in that department, you will see it pretty fast. On that I'm pretty much in agreement with Rubiola's stuff. Since I intend to mate the isolation amps up directly on the same board as the mixer, there is no real need for a 50 ohm interface between them. If the mixer looks like 18.26 ohms, the amp output can be transformed to that level rather than 50 ohms. Everything is matched (over a 1/8 trace) and you don't burn up power in a bunch of resistors. How well that idea works - time will tell. It's easy to put the resistors in if it flunks out. So many things to try Bob On Feb 1, 2010, at 9:48 PM, Bruce Griffiths wrote: Bob Camp wrote: Hi Ok, next up on the dual mixer stuff is checking the limiter chain. To do that with any chance of the results meaning anything you need a good triangle wave. You certainly can build some pretty complex gizmos to make them. There also appears to be a fairly simple approach. If I take a fairly good 16 bit DAC that will accept a clock a bit above 1 MHz, I can feed a simple count up / count down into it. That should give me a triangle wave at (clock rate) / 2^32. Simply put, 1.3 MHz data gives me a 10 Hz triangle wave. The digital crud should be almost entirely up around the clock rate or higher and 90 db down. That assumes that the DAC is a low clock feed through version and that it's got good linearity. A reasonable dual mixer or heterodyne system should have some kind of low pass filter built into it. Even a 150 Hz lowpass should knock the digital stuff down into a -160 noise floor. The gotcha seems to be flicker noise out of the DAC. There's no guarantee that the gizmo will have a 1nV/Hz class noise floor. The same sort of audio spectrum analyzers used for phase noise should be able to measure the noise coming out under various conditions. The nice thing about this gizmo is that it does not have to *only* put out a triangle wave. If you drive it with a micro, you can tell it to do all sorts of things. You might try a number of DC levels as you check for noise. You might also try various triangle wave levels to see how everything matches up. Slew rate limited square waves also sound interesting. There are a couple of other details like DC level shifting and driving it all with a decent clock. Both need to be done properly, but they don't appear to be the limiting factors in this kind of setup. I suspect this approach has been tried before. Any record of it out there? Bob ___ Bob You arent going to find a DAC with a 1nV/rtHz noise floor off the shelf due to the reference noise. Heroic filtering measures will be necessary to reduce the reference noise, then you will have to deal with the DAC component noise which will almost invariably be greater than 1nV/rtHz. If it has an external reference capability you could try using a series stack of leds as in this
Re: [time-nuts] Test Equipment
The early production E8285A units operate all RF functions down to 100KHz. You have to ask the seller to verify what he's offering operates this way. Pete Rawson On Feb 1, 2010, at 8:18 PM, k3...@aol.com wrote: If goggle HP 8285a spec, you will get HP spec which say this unit is 800 Mhz up. The 8920, 8921, 8025 will go down to ham freq. Regards, Dr. Joseph G. Palsa P.E. Director, Sales Marketing Clary Corporation Phone: 888-442-5279 Phone: 804-674-0364 Fax: 804-674-0714 Cell: 804-350-2665 jpa...@clary.com djpa...@yahoo.com k3...@aol.com k3...@arrl.net This e-mail (including any attachments) is intended only for the use of the individual or entity named above and may contain privileged, proprietary, or confidential information. The information may also contain technical data subject to export control laws. In a message dated 2/1/2010 8:42:56 P.M. Eastern Standard Time, li...@cq.nu writes: Hi The big question in my mind about these is how well they do below 30 MHz. Until I know I can trust them it down there, I'm not selling very much stuff. I have yet to find a data sheet from before 2000 when they shipped with the sub-800 MHz stuff enabled. I get the impression that the E8285's never quite did as well below 30 MHz as the 8920's do. Bob On Feb 1, 2010, at 7:29 PM, Don Latham wrote: Hi Bob. Display shows use, definitely, but I can see info over the whole tube. I have a couple of things to do before I can start the learning curve, but am looking forward to using it. I'll have a bunch of test stuff for sale if this thing works out ;-) Don Bob Camp Hi I *suspect* that any size that was common in 2003 will be ok. I have no basis for that claim. That likely will limit you to 2 gig and down. Each time I called Amtronix, Rick answered on the first ring. It's definitely someplace I would recommend dealing with. How's the display on your unit? That sees to be the weakness of a lot of test gear these days. Can't wait to measure -100 dbc/Hz phase noise with mine :) Bob On Feb 1, 2010, at 5:34 PM, Don Latham wrote: Just bought one last week. As advertised, came with a cal and checkout sheet. BTW, cost another $150 to have manuals printed out. But, I'm old fashioned and have a hard time using manuals onscreen... I also got the feeling (phone order) that I can call Amtronix and at least reach a Real Person who will talk to me. I think the E8285A will replace at least three present instruments with better, once I master Instrument Basic :-). Does anyone know which low-cost PCMCIA memory card will work? They're on Epay for as little as $10 Don Bob Camp Hi I do believe the last (or maybe next to last) of the Amtronix E8285A's is now on it's way to a basement in Pennsylvania. If anybody else here is looking for one, I'd sure call Rick pretty quick. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of John Ackermann N8UR Sent: Thursday, January 21, 2010 4:14 PM To: john.fo...@gmail.com; Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Test Equipment If RF measurement is your bag, and you're able to spend a couple of $K (actually, $2K if what I've seen recently holds), consider a communications service monitor like the HP 8920A/8920B/8921/8924/8935/E8285 (all pretty much the same thing). You get an RF generator, RF power meter, RX frequency meter and modulation analyzer, audio generator, audio analyzer, digital o'scope, and in most units a spectrum analyzer (many have a tracking generator, too) in one box. And I've probably forgotten a few things. If you get one with spec analyzer and tracking generator, there's software that lets you do swept insertion/return loss and cable fault finding. None of its capabilities are as good as those of a dedicated box performing a single function, but they're good enough for the vast majority of uses. An 8920 was the first significant piece of test gear I bought, and if I ever have to sell out, it'll be the last one to go. The prices came down a lot when Lucent surplused hundreds (thousands?) of them from their portable and cell phone production lines. I saw an 8935 with spec an, fully functional (as far as I could tell) for about $1500 this summer. A guy who sells and services a lot of these boxes is Rick at http://www.amtronix.com -- that web site will give you lots of info about the various versions and options. (I just noticed he has some Agilent 8285As as a hobbyist special with spec an and tracking generator for $650. That looks like a deal.) John john.fo...@gmail.com said the following on 01/21/2010 03:43 PM: Just that John, I'm looking to setup a general purpose lab. I'd lean towards RF type stuff since I'm a
Re: [time-nuts] Test Equipment
HI I agree. The 800 MHz spec was all I could find. That's the only spec that Google seems to know about. Back before some point like mid 2001, there was a different spec on these boxes. They went down to much lower frequencies. That information is still preserved in the repair manual. Unfortunately, it does not give a full detail set of specifications for the earlier box. The boxes Amtronix is / was selling have the old firmware and modules in them. They will go to the old wider frequency range. Bob On Feb 1, 2010, at 10:18 PM, k3...@aol.com wrote: If goggle HP 8285a spec, you will get HP spec which say this unit is 800 Mhz up. The 8920, 8921, 8025 will go down to ham freq. Regards, Dr. Joseph G. Palsa P.E. Director, Sales Marketing Clary Corporation Phone: 888-442-5279 Phone: 804-674-0364 Fax: 804-674-0714 Cell: 804-350-2665 jpa...@clary.com djpa...@yahoo.com k3...@aol.com k3...@arrl.net This e-mail (including any attachments) is intended only for the use of the individual or entity named above and may contain privileged, proprietary, or confidential information. The information may also contain technical data subject to export control laws. In a message dated 2/1/2010 8:42:56 P.M. Eastern Standard Time, li...@cq.nu writes: Hi The big question in my mind about these is how well they do below 30 MHz. Until I know I can trust them it down there, I'm not selling very much stuff. I have yet to find a data sheet from before 2000 when they shipped with the sub-800 MHz stuff enabled. I get the impression that the E8285's never quite did as well below 30 MHz as the 8920's do. Bob On Feb 1, 2010, at 7:29 PM, Don Latham wrote: Hi Bob. Display shows use, definitely, but I can see info over the whole tube. I have a couple of things to do before I can start the learning curve, but am looking forward to using it. I'll have a bunch of test stuff for sale if this thing works out ;-) Don Bob Camp Hi I *suspect* that any size that was common in 2003 will be ok. I have no basis for that claim. That likely will limit you to 2 gig and down. Each time I called Amtronix, Rick answered on the first ring. It's definitely someplace I would recommend dealing with. How's the display on your unit? That sees to be the weakness of a lot of test gear these days. Can't wait to measure -100 dbc/Hz phase noise with mine :) Bob On Feb 1, 2010, at 5:34 PM, Don Latham wrote: Just bought one last week. As advertised, came with a cal and checkout sheet. BTW, cost another $150 to have manuals printed out. But, I'm old fashioned and have a hard time using manuals onscreen... I also got the feeling (phone order) that I can call Amtronix and at least reach a Real Person who will talk to me. I think the E8285A will replace at least three present instruments with better, once I master Instrument Basic :-). Does anyone know which low-cost PCMCIA memory card will work? They're on Epay for as little as $10 Don Bob Camp Hi I do believe the last (or maybe next to last) of the Amtronix E8285A's is now on it's way to a basement in Pennsylvania. If anybody else here is looking for one, I'd sure call Rick pretty quick. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of John Ackermann N8UR Sent: Thursday, January 21, 2010 4:14 PM To: john.fo...@gmail.com; Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Test Equipment If RF measurement is your bag, and you're able to spend a couple of $K (actually, $2K if what I've seen recently holds), consider a communications service monitor like the HP 8920A/8920B/8921/8924/8935/E8285 (all pretty much the same thing). You get an RF generator, RF power meter, RX frequency meter and modulation analyzer, audio generator, audio analyzer, digital o'scope, and in most units a spectrum analyzer (many have a tracking generator, too) in one box. And I've probably forgotten a few things. If you get one with spec analyzer and tracking generator, there's software that lets you do swept insertion/return loss and cable fault finding. None of its capabilities are as good as those of a dedicated box performing a single function, but they're good enough for the vast majority of uses. An 8920 was the first significant piece of test gear I bought, and if I ever have to sell out, it'll be the last one to go. The prices came down a lot when Lucent surplused hundreds (thousands?) of them from their portable and cell phone production lines. I saw an 8935 with spec an, fully functional (as far as I could tell) for about $1500 this summer. A guy who sells and services a lot of these boxes is Rick at http://www.amtronix.com -- that web site will give you lots of info about the
Re: [time-nuts] Test Equipment
Don, Funny thing I bought a HP E8285A non-SA from Amtronix for $250 + shipping as a RF source and spare parts for my $1200 HP 8935A... Do you by any chance have a HP 8620A/B/C (or HP 8350B/11869A) and HP 8709A/H10 and some 862xx RF plug-ins...(poor man's TG from .01 Mhz to 18 Ghz with the right plug-ins with 3 kHz RBW, and a 21.4 Mhz IF SA)? I have some Cisco cards I need to try floating around my desk somewhere... I will let you know what I find. Jim Cotton, N8QOH| jim.cot...@wmich.edu Western Michigan University | Phone: (269) 387-6421 Network Systems Group| Fax: (269) 387-5473 On Feb 1, 2010 at 15:34 -0700, Don Latham wrote: Date: Mon, 01 Feb 2010 15:34:57 -0700 (MST) From: Don Latham d...@montana.com Reply-To: Discussion of precise time and frequency measurement time-nuts@febo.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] Test Equipment Just bought one last week. As advertised, came with a cal and checkout sheet. BTW, cost another $150 to have manuals printed out. But, I'm old fashioned and have a hard time using manuals onscreen... I also got the feeling (phone order) that I can call Amtronix and at least reach a Real Person who will talk to me. I think the E8285A will replace at least three present instruments with better, once I master Instrument Basic :-). Does anyone know which low-cost PCMCIA memory card will work? They're on Epay for as little as $10 Don Bob Camp Hi I do believe the last (or maybe next to last) of the Amtronix E8285A's is now on it's way to a basement in Pennsylvania. If anybody else here is looking for one, I'd sure call Rick pretty quick. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of John Ackermann N8UR Sent: Thursday, January 21, 2010 4:14 PM To: john.fo...@gmail.com; Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Test Equipment If RF measurement is your bag, and you're able to spend a couple of $K (actually, $2K if what I've seen recently holds), consider a communications service monitor like the HP 8920A/8920B/8921/8924/8935/E8285 (all pretty much the same thing). You get an RF generator, RF power meter, RX frequency meter and modulation analyzer, audio generator, audio analyzer, digital o'scope, and in most units a spectrum analyzer (many have a tracking generator, too) in one box. And I've probably forgotten a few things. If you get one with spec analyzer and tracking generator, there's software that lets you do swept insertion/return loss and cable fault finding. None of its capabilities are as good as those of a dedicated box performing a single function, but they're good enough for the vast majority of uses. An 8920 was the first significant piece of test gear I bought, and if I ever have to sell out, it'll be the last one to go. The prices came down a lot when Lucent surplused hundreds (thousands?) of them from their portable and cell phone production lines. I saw an 8935 with spec an, fully functional (as far as I could tell) for about $1500 this summer. A guy who sells and services a lot of these boxes is Rick at http://www.amtronix.com -- that web site will give you lots of info about the various versions and options. (I just noticed he has some Agilent 8285As as a hobbyist special with spec an and tracking generator for $650. That looks like a deal.) John john.fo...@gmail.com said the following on 01/21/2010 03:43 PM: Just that John, I'm looking to setup a general purpose lab. I'd lean towards RF type stuff since I'm a HAM. Sent via BlackBerry by ATT -Original Message- From: J. Forster j...@quik.com Date: Thu, 21 Jan 2010 12:22:11 To: did...@cox.net; Discussion of precise time and frequency measurementtime-nuts@febo.com Subject: Re: [time-nuts] Test Equipment I made the mistake of setting up a purpose-built lab once, and soon discovered to do most things, you really need at least a basic general purpose lab. The only exception is, I suppose, if you are going to repair a specific instrument and do nothing else. Also, as others have pointed out, you really need to define what are your area(s) of interest. Specialized gear gets $$$ pretty quickly. -John John, That sounds like asking what is the best vehicle for you to buy. If you do not know what you want to do with it, I am not sure we can help you all that much. However, if you have a specific objective, I am sure you will get a lot of valuable information here. You have a (good) analog scope, you may want a power supply or two, a soldering iron and maybe a desoldering station if you do surface mount. You also want a good hand-held multimeter. Some sort of signal or function generator may
[time-nuts] Check out RE: [Repeater-Builder] HP E-8285A Service Monitor
_Click here: RE: [Repeater-Builder] HP E-8285A Service Monitor_ (http://www.mail-archive.com/repeater-buil...@yahoogroups.com/msg59646.html) Additional info on monitor history. Joe k3wry This e-mail (including any attachments) is intended only for the use of the individual or entity named above and may contain privileged, proprietary, or confidential information. The information may also contain technical data subject to export control laws. ___ 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] Strange event on my Z3805A [REVISED to correct links]
Steve, I'm much more wizened than wise, but my understanding is that crystal jumps do not come back. They stay at their new frequency. I did notice on your graph of the event that there were changes in the sat. constellation at the beginning and end of the anomaly. I've seen similar moves on both my Thunderbolt and Fury GPSDOs. All seem to be related to satellite switching. One was so repetitive I was able to identify the offending satellite. On Tue, 2 Feb 2010 15:00:50 +1300, Steve Rooke sar10...@gmail.com wrote: On 2 February 2010 11:11, Matt Osborn kc0...@msosborn.com wrote: I've seen similar results when the receiver switches satellites. Multipath?? It does that all the time as sats come in and out of view but I've never seen an event of this magnitude before. If you look at the trace for the preceeding 36h you can see peaks where the unit switches stats but those peaks are decades less than this peak. I also see that the EFC voltage changes very significantly, is this perhaps one of the infamous crystal jumps we have spoken about I wonder. The area of interest is that it appears somewhat unstable after the event but is improving now. Multipath, I don't think so as nothing has changed here and I live in an urban area well outside the city. Nothing has been errected or changed as far as I can see. Cheers, Steve -- kc0ukk at msosborn dot 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.
Re: [time-nuts] Standard Resistor oil
The stuff in the store generally has Vitamin E in there as a stabilizer, and sometimes fragrance if marketed as baby lotion. Get the stuff for use as a laxative and it *should* be okay. I had to buy tens of gallons of this stuff from the local pharmacies because the local national laboratory saw mineral oil as a hazard when it came in 5 gallon carbouys. It's toxic, flammable, and causes skin irritation unless it's sold as baby lotion or laxative! Always take the MSDS sheets with a grain of salt. -Bob On Mon, Feb 1, 2010 at 6:02 PM, Bob Camp li...@cq.nu wrote: Hi Some drug store mineral oil has extra stuff in it. This is one case where you want the cheap generic version rather than the improved name brand. Bob On Feb 1, 2010, at 5:56 PM, Chuck Harris wrote: Plain old mineral oil, also known as paraffin oil, as can be found in any drugstore. They should be filled above the element, but not quite full. Maybe 3/4 to 7/8 full. It isn't really important. -Chuck Harris Chris Erickson wrote: I bought some old Leeds Northrup standard resistors on ebay and and seller dumped the oil out before sending them. Does anyone know what the correct kind of oil to put back in these? How full should they be? ___ 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] Triangle Waves
Bob Camp wrote: Hi At least from the last time I tried it: If you use a sine wave input source, it's got to be an amazingly good 10 Hz sine wave. A normal audio generator will not produce a 10 Hz output with good enough short term stability / noise to give you useful data. Audio generators may be out there that will do the job, but I certainly don't have one, and have never come across one. Since the output of the mixer is basically a triangle wave, it makes sense to use that as your test source. A triangle wave also has the nice property that it's easy on the math. You don't have any approximation issues with the integers going into the DAC. That shoves the inevitable digital crud higher in frequency. When both the RF and LO ports are saturated, the mixer output waveform depends on how the IF port is terminated. The output is indeed approximately triangular with your IF port termination method when both the RF and LO ports are saturated. With the IF port terminated in a capacitor when both RF and LO ports are saturated the output waveform is quasi trapezoidal. When only the LO port is saturated the IF output is sinusoidal. Another nice thing about a pure digital approach is that it provides a clean trigger for the start channel of the counter you are testing things with. You can even set up the DAC to put out square waves to see just how good various bits of the chain are. Tough to do that with anything other than another arbitrary function generator. I agree that the reference is going to be an issue and that a LED stack may be the way to go. No matter how you generate the test tone, power supply noise will be an issue. The output amplifier on the DAC is my biggest worry. I could go with a current out DAC and something like an OP-27. That won't give me 1nV/Hz either, but it will at least be within shouting distance of it. Sigma deltas might be a third option. I have no idea what their low frequency flicker noise looks like. Producing a high amplitude (eg 20V pp) output and attenuating it down to say 2V pp or so typical of a mixer will significantly reduce the noise due to the output amplifier. So, other than the noise issue (which obviously needs to be analyzed / tested / pounded on) any other issues with the approach? At least from what I have seen in the past, level sensitivity on the inputs shows up pretty fast in the output beat note as you vary the input signals that are supposed to be saturating the mixer. If they are doing their job, a 2 db level change produces a very small change in the output. If you have something amiss in that department, you will see it pretty fast. On that I'm pretty much in agreement with Rubiola's stuff. Yes but NIST used a saturated mixer and still found that the mixer phase shift depended on how hard you drive the diodes. Long term variations in isolation amplifier output due to temperature variations may be significant. Since I intend to mate the isolation amps up directly on the same board as the mixer, there is no real need for a 50 ohm interface between them. If the mixer looks like 18.26 ohms, the amp output can be transformed to that level rather than 50 ohms. Everything is matched (over a 1/8 trace) and you don't burn up power in a bunch of resistors. How well that idea works - time will tell. It's easy to put the resistors in if it flunks out. So many things to try Bob You could also try driving the mixer ports from a highe impedance source (eg transistor collector). One early NIST paper advocated this. Bruce On Feb 1, 2010, at 9:48 PM, Bruce Griffiths wrote: Bob Camp wrote: Hi Ok, next up on the dual mixer stuff is checking the limiter chain. To do that with any chance of the results meaning anything you need a good triangle wave. You certainly can build some pretty complex gizmos to make them. There also appears to be a fairly simple approach. If I take a fairly good 16 bit DAC that will accept a clock a bit above 1 MHz, I can feed a simple count up / count down into it. That should give me a triangle wave at (clock rate) / 2^32. Simply put, 1.3 MHz data gives me a 10 Hz triangle wave. The digital crud should be almost entirely up around the clock rate or higher and 90 db down. That assumes that the DAC is a low clock feed through version and that it's got good linearity. A reasonable dual mixer or heterodyne system should have some kind of low pass filter built into it. Even a 150 Hz lowpass should knock the digital stuff down into a -160 noise floor. The gotcha seems to be flicker noise out of the DAC. There's no guarantee that the gizmo will have a 1nV/Hz class noise floor. The same sort of audio spectrum analyzers used for phase noise should be able to measure the noise coming out under various conditions. The nice thing about this gizmo is that it does not have to *only* put out a triangle wave. If you drive it with a micro, you can
Re: [time-nuts] Test Equipment
Amtronix did tell me that the power measurements were off, according to some folks who had compared them to Birds. Of course the E's could be calibrated. I don't have much below 30 MHz at present either. I sense that there may be enough around to warrant a Yahoo or Google group??? Don - Original Message - From: Bob Camp li...@cq.nu To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Monday, February 01, 2010 6:42 PM Subject: Re: [time-nuts] Test Equipment Hi The big question in my mind about these is how well they do below 30 MHz. Until I know I can trust them it down there, I'm not selling very much stuff. I have yet to find a data sheet from before 2000 when they shipped with the sub-800 MHz stuff enabled. I get the impression that the E8285's never quite did as well below 30 MHz as the 8920's do. Bob On Feb 1, 2010, at 7:29 PM, Don Latham wrote: Hi Bob. Display shows use, definitely, but I can see info over the whole tube. I have a couple of things to do before I can start the learning curve, but am looking forward to using it. I'll have a bunch of test stuff for sale if this thing works out ;-) Don Bob Camp Hi I *suspect* that any size that was common in 2003 will be ok. I have no basis for that claim. That likely will limit you to 2 gig and down. Each time I called Amtronix, Rick answered on the first ring. It's definitely someplace I would recommend dealing with. How's the display on your unit? That sees to be the weakness of a lot of test gear these days. Can't wait to measure -100 dbc/Hz phase noise with mine :) Bob On Feb 1, 2010, at 5:34 PM, Don Latham wrote: Just bought one last week. As advertised, came with a cal and checkout sheet. BTW, cost another $150 to have manuals printed out. But, I'm old fashioned and have a hard time using manuals onscreen... I also got the feeling (phone order) that I can call Amtronix and at least reach a Real Person who will talk to me. I think the E8285A will replace at least three present instruments with better, once I master Instrument Basic :-). Does anyone know which low-cost PCMCIA memory card will work? They're on Epay for as little as $10 Don Bob Camp Hi I do believe the last (or maybe next to last) of the Amtronix E8285A's is now on it's way to a basement in Pennsylvania. If anybody else here is looking for one, I'd sure call Rick pretty quick. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of John Ackermann N8UR Sent: Thursday, January 21, 2010 4:14 PM To: john.fo...@gmail.com; Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Test Equipment If RF measurement is your bag, and you're able to spend a couple of $K (actually, $2K if what I've seen recently holds), consider a communications service monitor like the HP 8920A/8920B/8921/8924/8935/E8285 (all pretty much the same thing). You get an RF generator, RF power meter, RX frequency meter and modulation analyzer, audio generator, audio analyzer, digital o'scope, and in most units a spectrum analyzer (many have a tracking generator, too) in one box. And I've probably forgotten a few things. If you get one with spec analyzer and tracking generator, there's software that lets you do swept insertion/return loss and cable fault finding. None of its capabilities are as good as those of a dedicated box performing a single function, but they're good enough for the vast majority of uses. An 8920 was the first significant piece of test gear I bought, and if I ever have to sell out, it'll be the last one to go. The prices came down a lot when Lucent surplused hundreds (thousands?) of them from their portable and cell phone production lines. I saw an 8935 with spec an, fully functional (as far as I could tell) for about $1500 this summer. A guy who sells and services a lot of these boxes is Rick at http://www.amtronix.com -- that web site will give you lots of info about the various versions and options. (I just noticed he has some Agilent 8285As as a hobbyist special with spec an and tracking generator for $650. That looks like a deal.) John john.fo...@gmail.com said the following on 01/21/2010 03:43 PM: Just that John, I'm looking to setup a general purpose lab. I'd lean towards RF type stuff since I'm a HAM. Sent via BlackBerry by ATT -Original Message- From: J. Forster j...@quik.com Date: Thu, 21 Jan 2010 12:22:11 To: did...@cox.net; Discussion of precise time and frequency measurementtime-nuts@febo.com Subject: Re: [time-nuts] Test Equipment I made the mistake of setting up a purpose-built lab once, and soon discovered to do most things, you really need at least a basic general purpose lab. The only exception is, I suppose, if you are going to repair a specific instrument and do nothing else. Also, as others have pointed out, you really need to define what are your area(s) of interest.
Re: [time-nuts] Test Equipment
Oh, forgot. My firmware appears to be something like A.02.4 or something like that, and the manuals are A.05.0 or so. another possible problem. Don - Original Message - From: Bob Camp li...@cq.nu To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Monday, February 01, 2010 6:42 PM Subject: Re: [time-nuts] Test Equipment Hi The big question in my mind about these is how well they do below 30 MHz. Until I know I can trust them it down there, I'm not selling very much stuff. I have yet to find a data sheet from before 2000 when they shipped with the sub-800 MHz stuff enabled. I get the impression that the E8285's never quite did as well below 30 MHz as the 8920's do. Bob On Feb 1, 2010, at 7:29 PM, Don Latham wrote: Hi Bob. Display shows use, definitely, but I can see info over the whole tube. I have a couple of things to do before I can start the learning curve, but am looking forward to using it. I'll have a bunch of test stuff for sale if this thing works out ;-) Don Bob Camp Hi I *suspect* that any size that was common in 2003 will be ok. I have no basis for that claim. That likely will limit you to 2 gig and down. Each time I called Amtronix, Rick answered on the first ring. It's definitely someplace I would recommend dealing with. How's the display on your unit? That sees to be the weakness of a lot of test gear these days. Can't wait to measure -100 dbc/Hz phase noise with mine :) Bob On Feb 1, 2010, at 5:34 PM, Don Latham wrote: Just bought one last week. As advertised, came with a cal and checkout sheet. BTW, cost another $150 to have manuals printed out. But, I'm old fashioned and have a hard time using manuals onscreen... I also got the feeling (phone order) that I can call Amtronix and at least reach a Real Person who will talk to me. I think the E8285A will replace at least three present instruments with better, once I master Instrument Basic :-). Does anyone know which low-cost PCMCIA memory card will work? They're on Epay for as little as $10 Don Bob Camp Hi I do believe the last (or maybe next to last) of the Amtronix E8285A's is now on it's way to a basement in Pennsylvania. If anybody else here is looking for one, I'd sure call Rick pretty quick. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of John Ackermann N8UR Sent: Thursday, January 21, 2010 4:14 PM To: john.fo...@gmail.com; Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Test Equipment If RF measurement is your bag, and you're able to spend a couple of $K (actually, $2K if what I've seen recently holds), consider a communications service monitor like the HP 8920A/8920B/8921/8924/8935/E8285 (all pretty much the same thing). You get an RF generator, RF power meter, RX frequency meter and modulation analyzer, audio generator, audio analyzer, digital o'scope, and in most units a spectrum analyzer (many have a tracking generator, too) in one box. And I've probably forgotten a few things. If you get one with spec analyzer and tracking generator, there's software that lets you do swept insertion/return loss and cable fault finding. None of its capabilities are as good as those of a dedicated box performing a single function, but they're good enough for the vast majority of uses. An 8920 was the first significant piece of test gear I bought, and if I ever have to sell out, it'll be the last one to go. The prices came down a lot when Lucent surplused hundreds (thousands?) of them from their portable and cell phone production lines. I saw an 8935 with spec an, fully functional (as far as I could tell) for about $1500 this summer. A guy who sells and services a lot of these boxes is Rick at http://www.amtronix.com -- that web site will give you lots of info about the various versions and options. (I just noticed he has some Agilent 8285As as a hobbyist special with spec an and tracking generator for $650. That looks like a deal.) John john.fo...@gmail.com said the following on 01/21/2010 03:43 PM: Just that John, I'm looking to setup a general purpose lab. I'd lean towards RF type stuff since I'm a HAM. Sent via BlackBerry by ATT -Original Message- From: J. Forster j...@quik.com Date: Thu, 21 Jan 2010 12:22:11 To: did...@cox.net; Discussion of precise time and frequency measurementtime-nuts@febo.com Subject: Re: [time-nuts] Test Equipment I made the mistake of setting up a purpose-built lab once, and soon discovered to do most things, you really need at least a basic general purpose lab. The only exception is, I suppose, if you are going to repair a specific instrument and do nothing else. Also, as others have pointed out, you really need to define what are your area(s) of interest. Specialized gear gets $$$ pretty quickly. -John John, That sounds like asking what is the best vehicle for you to buy. If
