Re: [time-nuts] lawnmower robots may be the end of VLF timekeeping
Bill Hawkins wrote: Did the pictures have to be in SVG format? SVG is extremely available, and extremely useful because it allows you to scale the picture to any size you like, and retain all of the detail. It provides a lot more functionality than just that, but I am sure that you can use google to discover what that might be as well as most anyone. To quote the wiki entry for Scalable Vector Graphics: All major modern web browsers—including Mozilla Firefox, Internet Explorer, Google Chrome, Opera, and Safari—have at least some degree of SVG rendering support. My Mozilla based browser came with full support out of the box, so to speak. I expect that whatever browser you are using either natively supports SVG, or can pull in a plugin. If not, prudence dictates that it might be time for an upgrade... if only to gain the benefit of the latest security patches. Is this only a problem for those who routinely use SVG? Maybe. I expect that the solver of this problem will be someone who is flexible enough to embrace a wide variety of new techniques, and processes. -Chuck Harris -Original Message- From: Poul-Henning Kamp Sent: Saturday, May 09, 2015 7:16 AM I spent some time capturing some data today. The measurements is from my $20 loop-antenna in the attic, which is something like 8 meters up and 10 meters besides the lawn-mower loop: http://phk.freebsd.dk/time/20150509.html ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] lawnmower robots may be the end of VLF timekeeping
In message 45C7C6B09BC548C19241E4E0673E9E9F@system072, Bill Hawkins writes: Did the pictures have to be in SVG format? Is this only a problem for those who routinely use SVG? A problem how ? I *like* SVG since you can zoom without pixellation effects, and spent an afternoon writing code to screen-dump the HP8568 into SVG format for the very same reason. -- 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] Greek clocks - planets rather than seconds
Michael Wright talking about the Antikythera http://www.the-eg.com/videos/michael-wright-antikythera-resurrector-eg8 The video is 1/2 hour. I thought it was good. He's a colorful speaker. Anybody know how they made gears back then? Or machinery in general? What did they use for a file? How did they make files? The Computer History Museum is having an event: May 13, 2015 10:30 AM Secrets of the Antikythera Mechanism http://www.computerhistory.org/events/upcoming/ In 1900, sponge divers off the coast of the tiny Greek island of Antikythera made an astonishing discovery: the wreck of an ancient Roman ship lay 200 feet beneath the water, its dazzling cargo spread out over the ocean floor. Among the life-size statues and amphorae was an encrusted piece of metal, which after nearly a century of investigation, is finally revealing its secrets -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] EMI and CE certification
yes for transmitter antennas, but not for receiver antennas in Austria Germany Switzerland France Hungary one could have receiver antenna as long as he want, but the height is limited similarly as in the US 73 KJ6UHN Alex On 5/10/2015 7:15 AM, Chuck Harris wrote: My recollection is that in the US, certain requirements exist for antenna length on the so called free bands. I have no idea what the European requirements might be, but, perhaps they can be foiled by their allowing their minuscule amounts of power to flow into an over length antenna? -Chuck Harris Magnus Danielson wrote: ... Depends. If they use approved frequencies and powerlevels it may be fine. In this case it doesn't look like it. There are telemetry frequencies allocated, they should use those. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HPGL and SVG (was Re: lawnmower robots may be the end of VLF timekeeping)
In message caj_qrvafz6dnihttst7_-fag_q0g2vdmf5e3jdvsopwm_90...@mail.gmail.com , Tim Shoppa writes: I love Poul-Henning's SVG scope plots. [...] I wonder if he actually uses a piece of HP equipment and then converts the output from HPGL to SVG? The HP8568 was dumped using my Pylt' code https://github.com/bsdphk/pylt Which reads the display memory over HPIB and spits out SVG from it. The TDS504 I cheated and dumped EPS over HPIB and used a random web-service to convert to SVG. -- 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] EMI and CE certification
Is it driven as an inductive loop? That might put it under different regulations. On 11 May 2015 17:47, Chuck Harris cfhar...@erols.com wrote: Yes, but in the case of the lawnmower fence, and the invisible dog fence, the transmitter drives the fence as an antenna. In the US, the antenna size for free bands is seriously limited. As an example, the so called Lowfer band at 136KHz is limited to antennas no larger than 15m in length. And, that is one of the larger limitations. 15m would encircle only a very small lawn. OBTW, I realized on reading my post below, that I was very unclear on what could be foiled. I meant that the operating permission for the lawnmower system could probably be foiled by looking into the maximum antenna lengths for unlicensed services of this sort, in this frequency range. I would quite imagine that any certification they may have is for the transmitter and receiver, without an antenna. -Chuck Harris Alex Pummer wrote: yes for transmitter antennas, but not for receiver antennas in Austria Germany Switzerland France Hungary one could have receiver antenna as long as he want, but the height is limited similarly as in the US 73 KJ6UHN Alex On 5/10/2015 7:15 AM, Chuck Harris wrote: My recollection is that in the US, certain requirements exist for antenna length on the so called free bands. I have no idea what the European requirements might be, but, perhaps they can be foiled by their allowing their minuscule amounts of power to flow into an over length antenna? -Chuck Harris ___ time-nuts mailing 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] Greek clocks - planets rather than seconds
Hal, Gear wheels have been cut by hand for many a century. A simple dividing head made from wood and fixed to a mandrel would index a blank wheel and allow the teeth to be cut by a saw and then rounded up to a cycloidal shape with a file. As time progressed shaped files were used and later simple fly cutters with the cycloidal shape. Files were made by hand in a similar way as that are made today. Once the correct material was chosen, originally iron and later steel, a blank was shaped and the teeth cut using a chisel. The file would then be hardened by heating and quenching followed by straightening and warping before it set. As with most tasks machines either speed up the process or take the skill out of it. As an aside only use new files on brass until they have the edge taken off them then they can be used on harder materials. There is somewhat more to the above but it would take up too much bandwidth. Regards Peter On 11/05/2015 00:32, Hal Murray wrote: Michael Wright talking about the Antikythera http://www.the-eg.com/videos/michael-wright-antikythera-resurrector-eg8 The video is 1/2 hour. I thought it was good. He's a colorful speaker. Anybody know how they made gears back then? Or machinery in general? What did they use for a file? How did they make files? The Computer History Museum is having an event: May 13, 2015 10:30 AM Secrets of the Antikythera Mechanism http://www.computerhistory.org/events/upcoming/ In 1900, sponge divers off the coast of the tiny Greek island of Antikythera made an astonishing discovery: the wreck of an ancient Roman ship lay 200 feet beneath the water, its dazzling cargo spread out over the ocean floor. Among the life-size statues and amphorae was an encrusted piece of metal, which after nearly a century of investigation, is finally revealing its secrets ___ time-nuts mailing 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] Greek clocks - planets rather than seconds
Good question. I intrigued me so I researched it. To make gears the Greek craftsmen made a circular blank, then marked it out for the correct number of teeth, probably using dividers, then filed the teeth with a triangular needle file Analysis of the Antikythera Mechanism shows the sort of irregularities that this method would give, Michael Wright made gears this way to prove it. The teeth have a 60 degree angle and are triangular in profile, which is not very efficient, but good enough for a clock. I made a pair of gears this way, it took half a day but it worked. Thanks for the link. Tom Harris celephi...@gmail.com On 11 May 2015 at 10:32, Hal Murray hmur...@megapathdsl.net wrote: Michael Wright talking about the Antikythera http://www.the-eg.com/videos/michael-wright-antikythera-resurrector-eg8 The video is 1/2 hour. I thought it was good. He's a colorful speaker. Anybody know how they made gears back then? Or machinery in general? What did they use for a file? How did they make files? The Computer History Museum is having an event: May 13, 2015 10:30 AM Secrets of the Antikythera Mechanism http://www.computerhistory.org/events/upcoming/ In 1900, sponge divers off the coast of the tiny Greek island of Antikythera made an astonishing discovery: the wreck of an ancient Roman ship lay 200 feet beneath the water, its dazzling cargo spread out over the ocean floor. Among the life-size statues and amphorae was an encrusted piece of metal, which after nearly a century of investigation, is finally revealing its secrets -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] lawnmower robots may be the end of VLF timekeeping
Yes, flexibility is the key. Once upon a time I could hack hardware and software using Unix and C, starting in 1982. I can no longer keep up with the bright ideas of millions of programmers. Bought some Windows 7 machines a year ago before they gave way to 8. Still use XP because I can do what I need to do with it, and it has become more stable since MS stopped supporting it. But I can't go to each new browser with better customer tracking tools. Tried Chrome briefly. Hate to be told what I might like to buy. So when an intriguing new mystery is presented with good data from one of the best members of this group, and all I get is empty boxes with red Xs at the top left, I am annoyed. Chasing the file name reveals SVG type. Chasing that reveals its purpose and some possible download sites. But the sites are not known to me, and I do not want to install unknown software, let alone learn how to use it. I'm sorry I expressed my annoyance, but I'm fighting an unknown infection, and that makes me testy. If someone could send me a reliable link to download SVG, I could try it after a full system backup. That's all extra work, but there's got to be a pony in there somewhere. Bill Hawkins -Original Message- From: Chuck Harris Sent: Monday, May 11, 2015 12:09 AM Bill Hawkins wrote: Did the pictures have to be in SVG format? Is this only [should have been NOT] a problem for those who routinely use SVG? Maybe. I expect that the solver of this problem will be someone who is flexible enough to embrace a wide variety of new techniques, and processes. -Chuck Harris ___ time-nuts mailing 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] 53132A Polish UHS Time Base Option Interesting Ovservation
I recently obtained a 53132A and added the HP Opt 010 High Stability Time Base option with a 10811 variant OCXO. I left it on for over a week and it, ultimately, seemed to slow down in its drift, with the displayed frequency, as it 'read' my GPSDO, slowly decreasing, suggesting that the Time Base was, slowly, increasing in frequency. I then removed the HP option and installed a Polish UHS Time Base option with a Morion DOCXO. After about 72 hours, it seemed to stabilize. I then 'calibrated' the 53132A by connecting my GPSDO to Channel 1. The displayed frequency was +/- 1 to 2 mHz of 10.000 000 000 MHz for the past week or so, with no drift noticeable. I had 'calibrated' the 53132A with it sitting at about +30 degrees, propped up on its 'handle' in a 'vertical' position. I then had occasion to move the 'handle' under the unit whereby the unit was 'flat', at which point the displayed frequency dropped to 9.999 999 997 MHz, +/- 1 to 2 mHz. The displayed frequency was the same this evening when I came home. When I again 'elevated' the unit by moving the handle to its more 'vertical' position, the displayed frequency moved to 10.000 000 000 MHz +/- 1 to 2 mHz. I'm not sure what this means. It is a 'repeatable' observation. It displayed the lower frequency all day and when I 'elevated' the 53132A this evening, the frequency again went to 10.000 000 000 Mhz. Is this a 'gravity' effect? Is this an issue with the DOCXO? Is this an issue with the 53132A? If I am correct in my calculations, the displayed frequency is +/- 1 to 2 parts in 10E-10 of 10 MHz, assuming my GPSDO is accurate and stable. Otherwise, the GPSDO and 53132A 'drift' is exactly the same. I would appreciate anyone's thoughts regarding this analysis and observation and how to go about 'quantifying' it in a more scientific method, assuming it's worth pursuing. Thanks in advance. Joe ___ time-nuts mailing 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] EMI and CE certification
Hi On most of these “buried” systems, the *intended* output is an audio ( 15 KHz) signal. Since the carrier is below the bottom end of the regulations, you are in “who cares” territory. That’s the intent. The problem comes from the fact that they modulate the carrier in ways the reg’s never envisioned (back in 1926). On top of that, there is a “it’s not RF, it’s audio” design approach that ignores the need for filtering or EMI protection. As we bemoan the death of the various low frequency services. EMI from all these systems is what is really killing them. You may be able to pick stuff up out in the middle of nowhere. If it’s jammed to death where 95% of the population lives, the service is dead. You may not *like* the political process that shuts down a service when 5% of the population can access it. That does not make it any less real. Without some sort of push to get the EMI situation under control, it will happen to all of these systems. Bob On May 11, 2015, at 3:52 PM, Adrian Godwin artgod...@gmail.com wrote: Is it driven as an inductive loop? That might put it under different regulations. On 11 May 2015 17:47, Chuck Harris cfhar...@erols.com wrote: Yes, but in the case of the lawnmower fence, and the invisible dog fence, the transmitter drives the fence as an antenna. In the US, the antenna size for free bands is seriously limited. As an example, the so called Lowfer band at 136KHz is limited to antennas no larger than 15m in length. And, that is one of the larger limitations. 15m would encircle only a very small lawn. OBTW, I realized on reading my post below, that I was very unclear on what could be foiled. I meant that the operating permission for the lawnmower system could probably be foiled by looking into the maximum antenna lengths for unlicensed services of this sort, in this frequency range. I would quite imagine that any certification they may have is for the transmitter and receiver, without an antenna. -Chuck Harris Alex Pummer wrote: yes for transmitter antennas, but not for receiver antennas in Austria Germany Switzerland France Hungary one could have receiver antenna as long as he want, but the height is limited similarly as in the US 73 KJ6UHN Alex On 5/10/2015 7:15 AM, Chuck Harris wrote: My recollection is that in the US, certain requirements exist for antenna length on the so called free bands. I have no idea what the European requirements might be, but, perhaps they can be foiled by their allowing their minuscule amounts of power to flow into an over length antenna? -Chuck Harris ___ time-nuts mailing 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] TymServe 2100 1995 Issue - A Kludgy Fix
Hi The only definitive statement I have seen for implementation of the 13 bit week is that it will be part of the Block III deployment process. Anything going on now is “testing only”. Block III now looks like a 2017 sort of thing. There may be people out there with fancy simulators that are 100% perfect. They *could* have coded and tested a 13 bit solution a few years ago. My observation is that *very* few people do this. The normal approach seems to be to wait until there are on the air signals and then test against them. That way you can cope with any odd last minute adjustments in the transmitted format. Bob On May 10, 2015, at 8:26 PM, Henry Hallam he...@pericynthion.org wrote: Is the 13-bit week number somewhere in the L1 C/A message? I see it in the CNAV definition for broadcast on L2C and L5 (and eventually, with GPS III, L1C), but I don't see any indication of a 13-bit week number in the LNAV section of IS-GPS-200H. So as far as I can tell, it is not being and will not be broadcast on L1 any time soon. Please correct me if I'm wrong :) Henry On Sat, May 9, 2015 at 1:14 PM, Bob Camp kb...@n1k.org wrote: Hi As far as I can see, the 13 bit week stuff is still very much in the “testing” phase. I’d say that counting on it working on anything made before 2013 is a bit of a stretch. I would also bet that roughly 90% of the “current” timing GPS chip set designs do not yet fully support it. That might change with a firmware upgrade (if one ever comes out for your chip set etc.). Based on how well things like leap years seem to get taken care of, we’ll really only know in 20 years or so. Yes it’s a bit confusing, it’s all snarled up in the “block III will be here in 2008” ... err…2014 … err …2017 …errr... confusion. Bob On May 6, 2015, at 12:04 PM, Brian Inglis brian.ing...@systematicsw.ab.ca wrote: On 2015-05-05 11:32, Alan Ambrose wrote: It's not that simple. First, it's not 20 years, but 1024 weeks (19.6 years). And not UTC weeks (which may have leap seconds) but GPS weeks (which do not, and are always 604800 seconds long). etc Don't think it's _that_ much code though. There's some open source ACM date algorithms, and it would be easy enough to implement a quick and dirty fix, adding a number of days offset, while the rest of the algorithm is tested. See http://www.leapsecond.com/notes/gpswnro.htm This was first noted in 1996 and has been happening since the first rollover in August 1999 so some affected NTP GPS drivers have been patched to add 1024 weeks while the input is more than 512 weeks in the past. Will the next time this problem reoccurs be another 20 years? The next rollover is about April 2019, but this can happen any time an older receiver's internal date representation used for GPS to UTC conversion overflows. Looks like Tymserve 2100 picked about Sep 1995 for its date epoch so it hits now. Newer GPS receivers support the extra 3 bits added to GPS extended week allowing 8192 weeks (157 years) between rollovers - 2137 is the next big rollover problem, but NavStar will likely not be sending the same data on the same frequency then. -- Take care. Thanks, Brian Inglis ___ time-nuts mailing 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] EMI and CE certification
On 5/11/15 12:52 PM, Adrian Godwin wrote: Is it driven as an inductive loop? That might put it under different regulations. On 11 May 2015 17:47, Chuck Harris cfhar...@erols.com wrote: Yes, but in the case of the lawnmower fence, and the invisible dog fence, the transmitter drives the fence as an antenna. In the US, the antenna size for free bands is seriously limited. As an example, the so called Lowfer band at 136KHz is limited to antennas no larger than 15m in length. And, that is one of the larger limitations. 15m would encircle only a very small lawn. OBTW, I realized on reading my post below, that I was very unclear on what could be foiled. I meant that the operating permission for the lawnmower system could probably be foiled by looking into the maximum antenna lengths for unlicensed services of this sort, in this frequency range. I would quite imagine that any certification they may have is for the transmitter and receiver, without an antenna. The US FCC Part 15 limit is probably 2400/f(kHz) uV/m field strength at 300m distance. It's probably pretty easy to meet that. https://transition.fcc.gov/Bureaus/Engineering_Technology/Documents/bulletins/oet63/oet63rev.pdf ___ time-nuts mailing 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] SVG Re: lawnmower robots may be the end of VLF timekeeping
On 5/10/15 11:40 PM, Poul-Henning Kamp wrote: In message 45C7C6B09BC548C19241E4E0673E9E9F@system072, Bill Hawkins writes: Did the pictures have to be in SVG format? Is this only a problem for those who routinely use SVG? A problem how ? I *like* SVG since you can zoom without pixellation effects, and spent an afternoon writing code to screen-dump the HP8568 into SVG format for the very same reason. I like SVG for the same reason.. Not all browsers provide the same flexibility in viewing the data, or are as smart when plotting a very dense set of lines: say you've got 30,000 datapoints which are individual vectors... if you were displaying this in a tiny window that is a few hundred pixels, a smart rendering engine would do some collapsing of the vectors, which would make rendering faster. There are smart and less smart renderers of .eps and .pdf too.. I wish that some of the more popular tools (Matlab, Octave) would directly export their plots as svg. For all I know the latest version might do that, I should check. ___ time-nuts mailing 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] HPGL and SVG (was Re: lawnmower robots may be the end of VLF timekeeping)
I am a huge fan of SVG. I love Poul-Henning's SVG scope plots. The resemblance to the HP Pen Plotter output that was the standard of excellence in the 70's is remarkable. The pens themselves were obsoleted by HP in the 1990's and then I had to start hoarding them, but I think third-party equivalents are still available today. I wonder if he actually uses a piece of HP equipment and then converts the output from HPGL to SVG? Tim N3QE On Sun, May 10, 2015 at 4:33 PM, Bill Hawkins b...@iaxs.net wrote: Did the pictures have to be in SVG format? Is this only a problem for those who routinely use SVG? -Original Message- From: Poul-Henning Kamp Sent: Saturday, May 09, 2015 7:16 AM I spent some time capturing some data today. The measurements is from my $20 loop-antenna in the attic, which is something like 8 meters up and 10 meters besides the lawn-mower loop: http://phk.freebsd.dk/time/20150509.html ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] EMI and CE certification
Yes, but in the case of the lawnmower fence, and the invisible dog fence, the transmitter drives the fence as an antenna. In the US, the antenna size for free bands is seriously limited. As an example, the so called Lowfer band at 136KHz is limited to antennas no larger than 15m in length. And, that is one of the larger limitations. 15m would encircle only a very small lawn. OBTW, I realized on reading my post below, that I was very unclear on what could be foiled. I meant that the operating permission for the lawnmower system could probably be foiled by looking into the maximum antenna lengths for unlicensed services of this sort, in this frequency range. I would quite imagine that any certification they may have is for the transmitter and receiver, without an antenna. -Chuck Harris Alex Pummer wrote: yes for transmitter antennas, but not for receiver antennas in Austria Germany Switzerland France Hungary one could have receiver antenna as long as he want, but the height is limited similarly as in the US 73 KJ6UHN Alex On 5/10/2015 7:15 AM, Chuck Harris wrote: My recollection is that in the US, certain requirements exist for antenna length on the so called free bands. I have no idea what the European requirements might be, but, perhaps they can be foiled by their allowing their minuscule amounts of power to flow into an over length antenna? -Chuck Harris ___ time-nuts mailing 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] lawnmower robots may be the end of VLF timekeeping
In practice it seems to be hard to fight interference issues at lower frequencies. A local 50,000 watt AM (medium wave) broadcaster, put up a FM (VHF) transmitter several years ago. One of the reasons they gave for going to FM were the interference issues on the AM band. I noticed the newer electric trolly busses were significant sources of interference on my drive home from work. I've largely stopped using my HF amateur radios in the city, and even at VHF the noise floor is noticeably lower in the country side. Reception for my WWVB clock is also rather hit or miss from south western Canada but it does work on occasion.I was however pleased that my 1.2 Ghz amateur radio activities don't seem to disrupt my own GPS reception despite less 15 feet of antenna separation. Sent from my iPad On 2015-05-09, at 12:48 PM, Bob Camp kb...@n1k.org wrote: Hi The real questions: 1) Are they breaking any laws with their pollution? 2) Is there a regulatory body that is charged with enforcing those laws? 3) Is the cost (hours / dollars / hassle) of taking action prohibitive? Often it’s a combination of more than one that gets you … This is fundamentally no different than the boys setting up their system right next to GPS. The main difference is that they had to go through the licensing process and not all these devices do that. I do know that when every radio clock within 1/2 Km goes dead, there are towns that will have a lot of people scratching their heads …. Bob On May 9, 2015, at 2:15 PM, Björn b...@lysator.liu.se wrote: The same has been observed by the lightning listeners at blitzortnung.org -- Björn div Originalmeddelande /divdivFrån: Poul-Henning Kamp p...@phk.freebsd.dk /divdivDatum:2015-05-09 14:15 (GMT+01:00) /divdivTill: time-nuts@febo.com /divdivRubrik: [time-nuts] lawnmower robots may be the end of VLF timekeeping /divdiv /divI spent some time capturing some data today. The measurements is from my $20 loop-antenna in the attic, which is something like 8 meters up and 10 meters besides the lawn-mower loop: http://phk.freebsd.dk/time/20150509.html -- 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. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
