Re: [time-nuts] Possible replacement for FE5680A
Le 09/03/2012 08:29, Roger Costello a écrit : I noticed this which could potentially be a very good thing. https://newsroom.unsw.edu.au/news/science/nuclear-clock-may-keep-time-universe Interesting. Thanks for the ref. I am afraid it will be a while before the price drops to $40 shipping included. ___ time-nuts mailing 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] Loran in the US
In message 9d1dabc0-ae63-4fb5-ad7d-d8c42f9fd...@gmail.com, Dennis Ferguson wr ites: If so, frequency stability is priority number one and time is probably just better than 100msec or so I could swear I saw something that said 50 ns, though I can You can _almost_ do that with loran, if you know your l/l coords. indicates they aren't just looking at Loran by itself. The MF dGPS bands and 500 kHz are also included in whatever they are doing. Which indicates to me that they are pretty damn serious, and not just catering to some recently discovered VIP Loran-C users. I'd be very surprised if LightSquared nuking GPS reliability doesn't have something to do with this. -- 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.
Re: [time-nuts] Solar Storm Effects?
Last evening I looked at my raw (but sawtooth corrected) GPS vs. Rb and didn't see anything noteworthy. John On 3/8/2012 10:20 PM, Mark Spencer wrote: Over last day and a half I've been comparing the 10Mhz output of my Jupiter based GPSDO (actually a G3RUH GPSDO) to a BVA OCXO. So far I don't see anything un expected. That being said I recognize that it would take a fairly significant disruption in the GPS signal for the affects to be noticeable in the 10 Mhz output. --- On Thu, 3/8/12, ALAN MELIAalan.me...@btinternet.com wrote: From: ALAN MELIAalan.me...@btinternet.com Subject: Re: [time-nuts] Solar Storm Effects? To: Discussion of precise time and frequency measurementtime-nuts@febo.com Received: Thursday, March 8, 2012, 10:24 AM From the look of it to me it is a non-event it looks like it bounced off and didnt reconnect. there is little increase in the ring current i.e. the charge in the van Allen belt according to the Dst index 1500z today..yesterdays event was bigger from that point of view Alan G3NYK --- On Thu, 8/3/12, John Ackermann N8URj...@febo.com wrote: From: John Ackermann N8URj...@febo.com Subject: Re: [time-nuts] Solar Storm Effects? To: j...@quikus.com, Discussion of precise time and frequency measurement time-nuts@febo.com Date: Thursday, 8 March, 2012, 15:20 On 3/8/2012 10:08 AM, J. Forster wrote: The media is reporting a large solar storm and saying it will upset GPS among other things. Has anybody see any effects? I won't be able to look at the data until I get home from work tonight, but last evening I started measuring the sawtooth-corrected output of a CNS2 clock vs. the PPS output of an Rb standard. Wondering if I'll see any glitches... if so I'll report back here. There was a major solar event in December, 2006 and at the time I was monitoring GPS signal strength. I got a very noticeable glitch at the time the blast hit the earth: http://febo.com/pages/gps_solar_flare/ Unfortunately, I didn't have an appropriate PPS measurement going on at the time. John ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing 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] Loran in the US
Hi A lot depends on weather it's 50 ns right out of the spout (1 second samples or what ever) or if it's a couple day average. There are a number of odd things that happen with the sunrise and sunset. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Poul-Henning Kamp Sent: Friday, March 09, 2012 3:16 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Loran in the US In message 9d1dabc0-ae63-4fb5-ad7d-d8c42f9fd...@gmail.com, Dennis Ferguson wr ites: If so, frequency stability is priority number one and time is probably just better than 100msec or so I could swear I saw something that said 50 ns, though I can You can _almost_ do that with loran, if you know your l/l coords. indicates they aren't just looking at Loran by itself. The MF dGPS bands and 500 kHz are also included in whatever they are doing. Which indicates to me that they are pretty damn serious, and not just catering to some recently discovered VIP Loran-C users. I'd be very surprised if LightSquared nuking GPS reliability doesn't have something to do with this. -- 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] Possible replacement for FE5680A
Hi The whole how do you do an ion standard thing is expensive even if you have a national government to fund you... Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of mike cook Sent: Friday, March 09, 2012 3:09 AM To: time-nuts@febo.com Subject: Re: [time-nuts] Possible replacement for FE5680A Le 09/03/2012 08:29, Roger Costello a écrit : I noticed this which could potentially be a very good thing. https://newsroom.unsw.edu.au/news/science/nuclear-clock-may-keep-time-univer se Interesting. Thanks for the ref. I am afraid it will be a while before the price drops to $40 shipping included. ___ time-nuts mailing 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] 5370B heatsink temperature
I just acquired my first HP 5370B off of ebay. After I had it running for 30 min to get it warm and start doing the checkout procedures in the manual i noticed that the heatsink was REALLY hot. I used my IR thermometer to check it and it read ~160F(71C). This seems excessively hot to me. What's normal? i didn't see it in the manual, but I might have missed it. -- --Eric _ Eric Garner ___ time-nuts mailing 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] 5370B heatsink temperature
On Fri, Mar 9, 2012 at 10:08 AM, Eric Garner garn...@gmail.com wrote: .. i noticed that the heatsink was REALLY hot. I used my IR thermometer to check it and it read ~160F(71C). What heat sink? Did you have the cover off and were measuring the internal bar they use as a sink or was your FE5680A screwed down to a large aluminum heat sink. Were all the dozen or so screws in place? Was in making good contact -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 5370B heatsink temperature
Check the archives on this one. There have been several discussions in the past about high heatsink temperatures. Some users have added external fans to them to get the temperature down. -John -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Eric Garner Sent: Friday, March 09, 2012 12:09 PM To: Discussion of precise time and frequency measurement Subject: [time-nuts] 5370B heatsink temperature I just acquired my first HP 5370B off of ebay. After I had it running for 30 min to get it warm and start doing the checkout procedures in the manual i noticed that the heatsink was REALLY hot. I used my IR thermometer to check it and it read ~160F(71C). This seems excessively hot to me. What's normal? i didn't see it in the manual, but I might have missed it. -- --Eric _ Eric Garner ___ time-nuts mailing 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] 5370B heatsink temperature
This is on my HP 5370B time interval counter. it's the external heatsink by the power inlet. -eric On Fri, Mar 9, 2012 at 10:16 AM, Chris Albertson albertson.ch...@gmail.com wrote: On Fri, Mar 9, 2012 at 10:08 AM, Eric Garner garn...@gmail.com wrote: .. i noticed that the heatsink was REALLY hot. I used my IR thermometer to check it and it read ~160F(71C). What heat sink? Did you have the cover off and were measuring the internal bar they use as a sink or was your FE5680A screwed down to a large aluminum heat sink. Were all the dozen or so screws in place? Was in making good contact -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- --Eric _ Eric Garner ___ time-nuts mailing 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] 5370B heatsink temperature
I believe so. I don't own a 5370B, but I remember the thread. What I was thinking of starts here: http://www.febo.com/pipermail/time-nuts/2010-September/050384.html Or the complete thread is available here: http://answerpot.com/showthread.php?1285452-Questions+about+HP+5370B -John -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Eric Garner Sent: Friday, March 09, 2012 12:22 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] 5370B heatsink temperature This is on my HP 5370B time interval counter. it's the external heatsink by the power inlet. -eric On Fri, Mar 9, 2012 at 10:16 AM, Chris Albertson albertson.ch...@gmail.com wrote: On Fri, Mar 9, 2012 at 10:08 AM, Eric Garner garn...@gmail.com wrote: .. i noticed that the heatsink was REALLY hot. I used my IR thermometer to check it and it read ~160F(71C). What heat sink? Did you have the cover off and were measuring the internal bar they use as a sink or was your FE5680A screwed down to a large aluminum heat sink. Were all the dozen or so screws in place? Was in making good contact -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- --Eric _ Eric Garner ___ time-nuts mailing 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] 5370B heatsink temperature
Both of mine get quite hot but I've never measured the temperature. I have placed mine in a cold drafty area of a cold room in my basement. I figure the heat output can help heat the room. I pull data from them via gpib (over ethernet) and distribute some of the signals being measured via cables from other rooms so I have some freedom as to their location. -- On Fri, 9 Mar, 2012 1:29 PM EST John Lofgren wrote: I believe so. I don't own a 5370B, but I remember the thread. What I was thinking of starts here: http://www.febo.com/pipermail/time-nuts/2010-September/050384.html Or the complete thread is available here: http://answerpot.com/showthread.php?1285452-Questions+about+HP+5370B -John -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Eric Garner Sent: Friday, March 09, 2012 12:22 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] 5370B heatsink temperature This is on my HP 5370B time interval counter. it's the external heatsink by the power inlet. -eric On Fri, Mar 9, 2012 at 10:16 AM, Chris Albertson albertson.ch...@gmail.com wrote: On Fri, Mar 9, 2012 at 10:08 AM, Eric Garner garn...@gmail.com wrote: .. i noticed that the heatsink was REALLY hot. I used my IR thermometer to check it and it read ~160F(71C). What heat sink? Did you have the cover off and were measuring the internal bar they use as a sink or was your FE5680A screwed down to a large aluminum heat sink. Were all the dozen or so screws in place? Was in making good contact -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- --Eric _ Eric Garner ___ time-nuts mailing 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] Mike Key Swap Meet
This is directed primarily at those in the Pacific Northwest region of the States. The 31st Annual Mike Key radio club electronics swap meet will take place this Saturday, March 10th, at the Puyallup Fairgrounds Pavilion Exhibition Hall, 110 9th Ave. SW, Puyallup, WA, from 09:00 to 15:00 local time. This is a big event, typically drawing over 300 vendor tables, all crammed into 44,000 square feet on two floors. SHAMELESS SELF-PROMOTION ALERT: I will be there, selling and buying, and among my other goodies up for grabs this year are a Unisite programmer with MSM, PinSite, PPI adapter, PLCC52 PPI socket adapter, and a UV EPROM eraser. I'll also have some nice Weller soldering stations, and a Pace 'Hot Tweezer' station for desoldering chip components. For the hamateurs among us: Talk-in is on the club repeater, 146.820, negative offset, transmit PL only 103.5 (1A). Keep the peace(es). -=-=-=-=-=-=-=-=-=-=-=- Bruce Lane, Owner Head Hardware Heavy, Blue Feather Technologies -- http://www.bluefeathertech.com kyrrin (at) bluefeathertech do/t c=o=m Quid Malmborg in Plano... ___ time-nuts mailing 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] need a good oscillator
Hello guys, looking for a very good oscillator (OSA 8607 BVA or similar) with known-good STS from 0.1s to 100s and longer of a couple of parts in the E-13's. Does anyone have anything for sale? I would take a Hydrogen maser too if that's priced right :) Would prefer 10MHz, but 5MHz would work too. Phase noise should be good too, my FTS-1200 for example has good sts, but horrible phase noise floor of less than -140dBc/Hz, so I am not a big fan of those. Thanks, Said ___ time-nuts mailing 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] need a good oscillator
Forgot to mention: please contact me off-list so we don't bother the rest of the lot here. Thanks, Said In a message dated 3/9/2012 12:30:47 Pacific Standard Time, saidj...@aol.com writes: Hello guys, looking for a very good oscillator (OSA 8607 BVA or similar) with known-good STS from 0.1s to 100s and longer of a couple of parts in the E-13's. Does anyone have anything for sale? I would take a Hydrogen maser too if that's priced right :) Would prefer 10MHz, but 5MHz would work too. Phase noise should be good too, my FTS-1200 for example has good sts, but horrible phase noise floor of less than -140dBc/Hz, so I am not a big fan of those. Thanks, Said ___ time-nuts mailing 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] 5370B heatsink temperature
I have two 5370A and both run about the same temperature. It is high, but the heatink only supports a few power bipolar transistors used in the power supply that are designed to run hot. Other than the inconvenience of having blisters if you touch the heatsink, I would not worry about it. Its better to have the heat dissipated outside the unit than inside. Didier KO4BB Sent from my BlackBerry Wireless thingy while I do other things... -Original Message- From: Eric Garner garn...@gmail.com Sender: time-nuts-boun...@febo.com Date: Fri, 9 Mar 2012 10:08:56 To: Discussion of precise time and frequency measurementtime-nuts@febo.com Reply-To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: [time-nuts] 5370B heatsink temperature I just acquired my first HP 5370B off of ebay. After I had it running for 30 min to get it warm and start doing the checkout procedures in the manual i noticed that the heatsink was REALLY hot. I used my IR thermometer to check it and it read ~160F(71C). This seems excessively hot to me. What's normal? i didn't see it in the manual, but I might have missed it. -- --Eric _ Eric Garner ___ time-nuts mailing 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] pointers to information on ways to collect data, 5335, etc.
I've got a student intern (Undergrad Senior) who's doing a project for me where he's trying to synchronize (and syntonize) two 1 pps ticks, generated from different oscillators using some modules in an FPGA. One oscillator is a run of the mill 66 MHz clock oscillator the other is a 49.x MHz TCXO. (and, of course, because he's working in a breadboard, I can swap in a signal generator for either.. I've got a stack of 3325Bs and 8663s, etc.) The objective is to get two signals that are 1 pps (or 10 pps) ticks (each derived from a different oscillator) that align I'm looking for info to point him to on evaluating the performance of his implementation. I've got a HP 5335 (which works quite nicely with a Prologix and John Miles's tools... thanks John!). I've got oscilloscopes. I've got access to more exotic stuff if need be (although, since my intern budget is skinny, stuff I happen to have in the lab, like my uncalibrated 5335, is better) I also have a bunch of Wenzel 10 MHz OCXOs sitting around (although for this, why not use one of the instrument's internal oscillator and distribute it around) I do have a hydrogen maser derived reference in the lab, but I'm more interested in him measuring the two oscillators against each other. (that is, measuring the performance of the TCXO, by itself, isn't particularly interesting) What he needs is some suggestions on things that he can measure that would be meaningful figures of merit for the application. He's not doing a PhD dissertation, though.. And he has to be done before the end of the spring semester. No million second Allan Deviation measurements. ___ time-nuts mailing 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] pointers to information on ways to collect data, 5335, etc.
Hi Jim, On 03/09/2012 10:27 PM, Jim Lux wrote: I've got a student intern (Undergrad Senior) who's doing a project for me where he's trying to synchronize (and syntonize) two 1 pps ticks, generated from different oscillators using some modules in an FPGA. One oscillator is a run of the mill 66 MHz clock oscillator the other is a 49.x MHz TCXO. (and, of course, because he's working in a breadboard, I can swap in a signal generator for either.. I've got a stack of 3325Bs and 8663s, etc.) The objective is to get two signals that are 1 pps (or 10 pps) ticks (each derived from a different oscillator) that align I'm looking for info to point him to on evaluating the performance of his implementation. I've got a HP 5335 (which works quite nicely with a Prologix and John Miles's tools... thanks John!). I've got oscilloscopes. I've got access to more exotic stuff if need be (although, since my intern budget is skinny, stuff I happen to have in the lab, like my uncalibrated 5335, is better) For the application, the 5335 will be more than adequate. I also have a bunch of Wenzel 10 MHz OCXOs sitting around (although for this, why not use one of the instrument's internal oscillator and distribute it around) I do have a hydrogen maser derived reference in the lab, but I'm more interested in him measuring the two oscillators against each other. (that is, measuring the performance of the TCXO, by itself, isn't particularly interesting) What he needs is some suggestions on things that he can measure that would be meaningful figures of merit for the application. He should measure: - Lock-in transient - Lock-in time/time-constant - Lock-in overshot - Estimate control loop bandwidth and Q-value/resonance He should then also have a lock detector, possibly several lock levels and illustrate them in the transient waveform. Then, he should measure the lock-in deviation pattern and measure bias and RMS noise. Maybe even do a nice ADEV/TDEV set of plots. MTIE plots is always nice as well. Showing good control of model parameters and actual performance remains a good thing. It is usually good to attempt to improve things. A good exercise is trying to figure out ways to get quick and dead safe lock-in while also get good in-lock performance. :) I strongly recommend having a digital scope in parallel with the counter. He's not doing a PhD dissertation, though.. And he has to be done before the end of the spring semester. No million second Allan Deviation measurements. Should be a good project for him. Keep me posted on the progress. 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] WWVB phase modulation format?
Interesting that WWVB is running a phase-modulation test---thanks for the links. Is the signal format known? A quick search shows nothing specific, just we're testing. Could someone record a few minutes of the broadband signal so that those of us without ready-to-hand LF receivers can have a look? Cheers, Peter ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] FCC Chair Talks Spectrum, Gets GPS Letter
Here's the link to the white paper: http://javad.com/downloads/javadgnss/publications/20112312.pdf. It was originally linked from GPS World's news email. It was originally posted as a technical white paper. I don't recall the 'Political Noise' lead in, but then, I'm a technical person and try to avoid political noise anyway. After rereading it, it seems more like a 'I love me' piece. Mike On 3/8/2012 12:53 AM, Hal Murray wrote: mbla...@satx.rr.com said: I read a white paper Javad put out touting their new (and cheaper to build) front end filter. Of course it is patented. So guess where everyone has to go should LS get the green light. Was that filter included as part of the recent round of testing? Did it work? I don't remember seeing any grand press releases along the lines of just use our filter. ___ time-nuts mailing 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] Austron 2100 switch repair
Given the current Loran situation I know this might have come a bit late but thought it worth sharing in case it's of any benefit to others. If it's old news then apologies for that but I've not seen it documented elsewhere. Along with other equipment, the 2100 is known to suffer in the long term from keybounce problems with the front panel tactile switches. A common cure is to increase the keybounce time constant on the 74C923 keyboard encoders, the 1uF fitted to the 2100 is quite low and I've found that this can be increased to at least 10uF without adding any additional problems. However, there is likely to come a time when this is no longer an adequate fix and switches can become severely intermittent or even totally open circuit. Replacements are available from Mouser or Digikey, the current manufacturer is E-Switch, but with the numbered key caps not being a stock item I checked my faulty switches to see if the caps could be removed and the original numbered caps transferred to new switches. Having found that, with care, the caps can be removed, I also discovered that these switches are mechanically straightforward and physical failure is highly unlikely. Other than the cap itself, the only moving part in the switch is a metal clicker dome which when depressed shorts across the contacts formed by the internal ends of the solder pins used for mounting the switch. One of these pins is in the centre of the switch, directly below the centre of the dome, and the other is in one corner with a corner of the dome plate resting on it. I'm not sure what the plating is on these pins but, in my switches anyway, the contact surfaces were heavily tarnished and this was the source of all the problems. Prior to cleaning the contact surfaces were dark brown to black and looked very much like tarnished silver, albeit in this case seemingly non-conducting. This tarnishing also seems to have a knock on effect on the gold plating on the contact surface of the dome so this will need cleaning too. Given that the dome plate has four distinct corners it's easy enough to ensure that a fresh corner is used as this contact. A small drop of isopropyl alcohol with a folded offcut of cartridge or printer paper used for burnishing seems to do a good job of removing the tarnish and polishing the contact areas, I certainly wouldn't recommend anything more severe. After cleaning and reassembly all my switches have a contact resistance of 0.1 Ohms or less and the unit is fully functional again. I could probably now reduce the 10uF debounce capacitors but all is working ok so have left well alone. Practical tips It isn't necessary to remove the switches from the circuit board in order to remove the caps but it will need a very fine blade or hook to get in alongside the cap and lever it out. What I used has been in my tool kit for years and I'm not even sure what it is, some kind of sewing implement I think, with a plastic handle and a bent bent end with the bent section around 3/8 inch long, very hard and pointed, and not much thicker than a reasonably fine sewing needle. The black caps of the flat faced switches used on the numeric keypad and for the back light switch have a lug approx 1/8 wide protruding downwards from the centre of each side. These seem to be fairly rugged and careful leverage alongside the lugs should remove the caps without damage. The white caps with a raised tapered section, on the switches along the bottom of the front panel, have only two lugs, top and bottom, and these seem more fragile. I found it best to lever out the top of the cap first, top being defined as when viewed in the panel, having broken the end off a bottom lug when levering one out bottom first, thanks be for superglue:-), but offer no guarantees that what worked for me will be the best solution for anyone else. Given the cost of replacement switches, plus delivery charges, a few hours work has saved me over 50GBP, so again I hope this information may be of benefit to others. Unfortunately though, from this point on, you're on your own, you break it, you fix it:-) Regards Nigel GM8PZR ___ time-nuts mailing 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] FCC Chair Talks Spectrum, Gets GPS Letter
I see a big lack of details. Form factor? Insertion loss? Frequency change with temperature? How does it compare with a standard Murata filters? On Fri, 09 Mar 2012 19:32:10 -0600, Michael Blazer mbla...@satx.rr.com wrote: Here's the link to the white paper: http://javad.com/downloads/javadgnss/publications/20112312.pdf. It was originally linked from GPS World's news email. It was originally posted as a technical white paper. I don't recall the 'Political Noise' lead in, but then, I'm a technical person and try to avoid political noise anyway. After rereading it, it seems more like a 'I love me' piece. Mike On 3/8/2012 12:53 AM, Hal Murray wrote: mbla...@satx.rr.com said: I read a white paper Javad put out touting their new (and cheaper to build) front end filter. Of course it is patented. So guess where everyone has to go should LS get the green light. Was that filter included as part of the recent round of testing? Did it work? I don't remember seeing any grand press releases along the lines of just use our filter. ___ time-nuts mailing 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] FCC Chair Talks Spectrum, Gets GPS Letter
I'm sure it's way, way better. Just ask them, they'll tell you... Even if you could buy it of the shelf, how well would it perform in anything but the reference design? Their envelopes look very, very good. In my experience, the entire front end would need to be very carefully tuned. On 3/9/2012 8:11 PM, David wrote: I see a big lack of details. Form factor? Insertion loss? Frequency change with temperature? How does it compare with a standard Murata filters? On Fri, 09 Mar 2012 19:32:10 -0600, Michael Blazer mbla...@satx.rr.com wrote: Here's the link to the white paper: http://javad.com/downloads/javadgnss/publications/20112312.pdf. It was originally linked from GPS World's news email. It was originally posted as a technical white paper. I don't recall the 'Political Noise' lead in, but then, I'm a technical person and try to avoid political noise anyway. After rereading it, it seems more like a 'I love me' piece. Mike On 3/8/2012 12:53 AM, Hal Murray wrote: mbla...@satx.rr.com said: I read a white paper Javad put out touting their new (and cheaper to build) front end filter. Of course it is patented. So guess where everyone has to go should LS get the green light. Was that filter included as part of the recent round of testing? Did it work? I don't remember seeing any grand press releases along the lines of just use our filter. ___ time-nuts mailing 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] Austron 2100 switch repair
Good timing. I have just noticed that my 2 button has started acting up. Thanks Paul WB8TSL On Fri, Mar 9, 2012 at 8:48 PM, gandal...@aol.com wrote: Given the current Loran situation I know this might have come a bit late but thought it worth sharing in case it's of any benefit to others. If it's old news then apologies for that but I've not seen it documented elsewhere. Along with other equipment, the 2100 is known to suffer in the long term from keybounce problems with the front panel tactile switches. A common cure is to increase the keybounce time constant on the 74C923 keyboard encoders, the 1uF fitted to the 2100 is quite low and I've found that this can be increased to at least 10uF without adding any additional problems. However, there is likely to come a time when this is no longer an adequate fix and switches can become severely intermittent or even totally open circuit. Replacements are available from Mouser or Digikey, the current manufacturer is E-Switch, but with the numbered key caps not being a stock item I checked my faulty switches to see if the caps could be removed and the original numbered caps transferred to new switches. Having found that, with care, the caps can be removed, I also discovered that these switches are mechanically straightforward and physical failure is highly unlikely. Other than the cap itself, the only moving part in the switch is a metal clicker dome which when depressed shorts across the contacts formed by the internal ends of the solder pins used for mounting the switch. One of these pins is in the centre of the switch, directly below the centre of the dome, and the other is in one corner with a corner of the dome plate resting on it. I'm not sure what the plating is on these pins but, in my switches anyway, the contact surfaces were heavily tarnished and this was the source of all the problems. Prior to cleaning the contact surfaces were dark brown to black and looked very much like tarnished silver, albeit in this case seemingly non-conducting. This tarnishing also seems to have a knock on effect on the gold plating on the contact surface of the dome so this will need cleaning too. Given that the dome plate has four distinct corners it's easy enough to ensure that a fresh corner is used as this contact. A small drop of isopropyl alcohol with a folded offcut of cartridge or printer paper used for burnishing seems to do a good job of removing the tarnish and polishing the contact areas, I certainly wouldn't recommend anything more severe. After cleaning and reassembly all my switches have a contact resistance of 0.1 Ohms or less and the unit is fully functional again. I could probably now reduce the 10uF debounce capacitors but all is working ok so have left well alone. Practical tips It isn't necessary to remove the switches from the circuit board in order to remove the caps but it will need a very fine blade or hook to get in alongside the cap and lever it out. What I used has been in my tool kit for years and I'm not even sure what it is, some kind of sewing implement I think, with a plastic handle and a bent bent end with the bent section around 3/8 inch long, very hard and pointed, and not much thicker than a reasonably fine sewing needle. The black caps of the flat faced switches used on the numeric keypad and for the back light switch have a lug approx 1/8 wide protruding downwards from the centre of each side. These seem to be fairly rugged and careful leverage alongside the lugs should remove the caps without damage. The white caps with a raised tapered section, on the switches along the bottom of the front panel, have only two lugs, top and bottom, and these seem more fragile. I found it best to lever out the top of the cap first, top being defined as when viewed in the panel, having broken the end off a bottom lug when levering one out bottom first, thanks be for superglue:-), but offer no guarantees that what worked for me will be the best solution for anyone else. Given the cost of replacement switches, plus delivery charges, a few hours work has saved me over 50GBP, so again I hope this information may be of benefit to others. Unfortunately though, from this point on, you're on your own, you break it, you fix it:-) Regards Nigel GM8PZR ___ time-nuts mailing 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.
