Re: [time-nuts] GPS simulator,
Hi One bit serial at 16 MHz isn't all that fancy any more. Sounds like a shift register feeding a couple filters. The money must be in the receive side. Bob On Nov 24, 2010, at 5:14 PM, erniepe...@aol.com wrote: Hi, found an interesting unit. I think it is not for the usual pocket money for a time-nuts. have a look... http://www.chronos.co.uk/pdfs/rac/labsat.pdf Rgds Ernie. -Original Message- From: John Green wpxs...@gmail.com To: time-nuts@febo.com Sent: Mon, Nov 22, 2010 6:43 pm Subject: [time-nuts] GPS jamming susceptibility Given that this is an extremely sensitive topic and completely illegal lso, let me just state at the outset that I have no interest in amming anyone's GPS. A while back, I was looking at one of those hinese discount electronics websites, I'm sure we all have, and oticed a GPS jammer for sale. I had been wanting to do some jamming usceptibility testing for quite some time but had never got around to uilding a generator to test with. The thing was cheap so I ordered t. After it arrived, I opened it up, first thing, to see how it was ade. It has a dual 555 oscillator, a couple of analog switches, a 1.9 Hz VCO, a single amplifier. It doesn't look capable of putting out ore than 50 milliwatts or so into a 2 inch antenna. I was somewhat ubious that it would do anything, so I took it to the bench where the 3801 lives and turned it on. Within 2 seconds, the holdover LED lit. immediately turned it off and within a few more seconds, the oldover LED was back off. The GPS antenna is perhaps 35 feet away ith a cinder block wall, a brick wall, and a metal roof in between. I lso put a 15 Db attenuator between it and the antenna with almost the ame result. I am going to do more testing with it wired into the GPS ownfeed an an adjustable attenuator in line just to see how much ignal it takes. That way, there will be little danger of messing with nyone's reception. It is just a simple sweeper so it must do its job y brute force. I am amazed that it took so little to shut my Z3801 own. Has anyone here had any actual experience testing GPS receivers or susceptibility? ___ ime-nuts mailing list -- time-nuts@febo.com o unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts nd 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] GPS simulator,
Agreed. The trick is to properly partition what is done in hardware ane what is done in software. This could eliminate a lot of logic hardware. Clearly, the RF stuff and modulator are hardware. Ditto PR code generation. Everything else in SW, I think. FWIW, -John === Hi One bit serial at 16 MHz isn't all that fancy any more. Sounds like a shift register feeding a couple filters. The money must be in the receive side. Bob On Nov 24, 2010, at 5:14 PM, erniepe...@aol.com wrote: Hi, found an interesting unit. I think it is not for the usual pocket money for a time-nuts. have a look... http://www.chronos.co.uk/pdfs/rac/labsat.pdf Rgds Ernie. -Original Message- From: John Green wpxs...@gmail.com To: time-nuts@febo.com Sent: Mon, Nov 22, 2010 6:43 pm Subject: [time-nuts] GPS jamming susceptibility Given that this is an extremely sensitive topic and completely illegal lso, let me just state at the outset that I have no interest in amming anyone's GPS. A while back, I was looking at one of those hinese discount electronics websites, I'm sure we all have, and oticed a GPS jammer for sale. I had been wanting to do some jamming usceptibility testing for quite some time but had never got around to uilding a generator to test with. The thing was cheap so I ordered t. After it arrived, I opened it up, first thing, to see how it was ade. It has a dual 555 oscillator, a couple of analog switches, a 1.9 Hz VCO, a single amplifier. It doesn't look capable of putting out ore than 50 milliwatts or so into a 2 inch antenna. I was somewhat ubious that it would do anything, so I took it to the bench where the 3801 lives and turned it on. Within 2 seconds, the holdover LED lit. immediately turned it off and within a few more seconds, the oldover LED was back off. The GPS antenna is perhaps 35 feet away ith a cinder block wall, a brick wall, and a metal roof in between. I lso put a 15 Db attenuator between it and the antenna with almost the ame result. I am going to do more testing with it wired into the GPS ownfeed an an adjustable attenuator in line just to see how much ignal it takes. That way, there will be little danger of messing with nyone's reception. It is just a simple sweeper so it must do its job y brute force. I am amazed that it took so little to shut my Z3801 own. Has anyone here had any actual experience testing GPS receivers or susceptibility? ___ ime-nuts mailing list -- time-nuts@febo.com o unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts nd 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] GPS simulator,
Hi It's not real clear that they do anything more than sample the RX and play it back for the TX. Bob Sent from my iPhone On Nov 25, 2010, at 9:39 AM, J. Forster j...@quik.com wrote: Agreed. The trick is to properly partition what is done in hardware ane what is done in software. This could eliminate a lot of logic hardware. Clearly, the RF stuff and modulator are hardware. Ditto PR code generation. Everything else in SW, I think. FWIW, -John === Hi One bit serial at 16 MHz isn't all that fancy any more. Sounds like a shift register feeding a couple filters. The money must be in the receive side. Bob On Nov 24, 2010, at 5:14 PM, erniepe...@aol.com wrote: Hi, found an interesting unit. I think it is not for the usual pocket money for a time-nuts. have a look... http://www.chronos.co.uk/pdfs/rac/labsat.pdf Rgds Ernie. -Original Message- From: John Green wpxs...@gmail.com To: time-nuts@febo.com Sent: Mon, Nov 22, 2010 6:43 pm Subject: [time-nuts] GPS jamming susceptibility Given that this is an extremely sensitive topic and completely illegal lso, let me just state at the outset that I have no interest in amming anyone's GPS. A while back, I was looking at one of those hinese discount electronics websites, I'm sure we all have, and oticed a GPS jammer for sale. I had been wanting to do some jamming usceptibility testing for quite some time but had never got around to uilding a generator to test with. The thing was cheap so I ordered t. After it arrived, I opened it up, first thing, to see how it was ade. It has a dual 555 oscillator, a couple of analog switches, a 1.9 Hz VCO, a single amplifier. It doesn't look capable of putting out ore than 50 milliwatts or so into a 2 inch antenna. I was somewhat ubious that it would do anything, so I took it to the bench where the 3801 lives and turned it on. Within 2 seconds, the holdover LED lit. immediately turned it off and within a few more seconds, the oldover LED was back off. The GPS antenna is perhaps 35 feet away ith a cinder block wall, a brick wall, and a metal roof in between. I lso put a 15 Db attenuator between it and the antenna with almost the ame result. I am going to do more testing with it wired into the GPS ownfeed an an adjustable attenuator in line just to see how much ignal it takes. That way, there will be little danger of messing with nyone's reception. It is just a simple sweeper so it must do its job y brute force. I am amazed that it took so little to shut my Z3801 own. Has anyone here had any actual experience testing GPS receivers or susceptibility? ___ ime-nuts mailing list -- time-nuts@febo.com o unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts nd follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Plastic covered OCXOs
I could tell you but... There's a lot of interesting IP in these little guys! Regards, Murray Greenman RAKON ___ 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] Plastic covered OCXOs
Got a URL handy? I'm interested in looking at a data sheet or two but couldn't find anything with Google. -Bob On Thu, Nov 25, 2010 at 4:33 PM, Murray Greenman murray.green...@rakon.comwrote: I could tell you but... There's a lot of interesting IP in these little guys! Regards, Murray Greenman RAKON ___ 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] Plastic covered OCXOs
Try: http://www.rakon.com/Products/Public%20Documents/Specifications/RFPO40.pdf ?? A link to this is on Rakon's website home page. Bruce Robert Darlington wrote: Got a URL handy? I'm interested in looking at a data sheet or two but couldn't find anything with Google. -Bob On Thu, Nov 25, 2010 at 4:33 PM, Murray Greenman murray.green...@rakon.comwrote: I could tell you but... There's a lot of interesting IP in these little guys! Regards, Murray Greenman RAKON ___ 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] First post - please disregard
Getting ready to make a post and wanted to see if this list supports html or only plain text and to see how urls are handled. (trying to avoid a mess of a first post) http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItemitem=270515147719ssPageName= STRK:MEWAX:IT item=270515147719ssPageName=STRK:MEWAX:IT 73 Eugene W2HX ___ 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] First post - please disregard yet again
Yikes. That didn't look so good. One last attempt to enclose the url in chevrons . If that doesn't work, I'll resort to tinyurl. http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItemitem=270515147719ssPageName= STRK:MEWAX:IT 73 Eugene W2HX -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of W2HX Sent: Thursday, November 25, 2010 11:12 PM To: time-nuts@febo.com Subject: [time-nuts] First post - please disregard Getting ready to make a post and wanted to see if this list supports html or only plain text and to see how urls are handled. (trying to avoid a mess of a first post) http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItemitem=270515147719ssPageName= STRK:MEWAX:IT item=270515147719ssPageName=STRK:MEWAX:IT 73 Eugene W2HX ___ 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] First post - please disregard
Go for it Gene - 73 - Mike Mike B. Feher, EOZ Inc. 89 Arnold Blvd. Howell, NJ, 07731 732-886-5960 office 908-901-9193 cell -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of W2HX Sent: Thursday, November 25, 2010 11:12 PM To: time-nuts@febo.com Subject: [time-nuts] First post - please disregard Getting ready to make a post and wanted to see if this list supports html or only plain text and to see how urls are handled. (trying to avoid a mess of a first post) http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItemitem=270515147719ssPageName= STRK:MEWAX:IT item=270515147719ssPageName=STRK:MEWAX:IT 73 Eugene W2HX ___ 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] First post - please disregard yet again
BTW - I have some of those Thunderbolts as well as the T-30B power supplies if that is what you are looking for - Mike Mike B. Feher, EOZ Inc. 89 Arnold Blvd. Howell, NJ, 07731 732-886-5960 office 908-901-9193 cell -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of W2HX Sent: Thursday, November 25, 2010 11:17 PM To: 'Discussion of precise time and frequency measurement' Subject: Re: [time-nuts] First post - please disregard yet again Yikes. That didn't look so good. One last attempt to enclose the url in chevrons . If that doesn't work, I'll resort to tinyurl. http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItemitem=270515147719ssPageName= STRK:MEWAX:IT 73 Eugene W2HX -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of W2HX Sent: Thursday, November 25, 2010 11:12 PM To: time-nuts@febo.com Subject: [time-nuts] First post - please disregard Getting ready to make a post and wanted to see if this list supports html or only plain text and to see how urls are handled. (trying to avoid a mess of a first post) http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItemitem=270515147719ssPageName= STRK:MEWAX:IT item=270515147719ssPageName=STRK:MEWAX:IT 73 Eugene W2HX ___ 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] ok, newbie questions
Hi all, I am sure my questions have been asked before. Unfortunately, the mailman style archives are so hard to search through. So forgive me my transgressions. Happy will I be to get a reference to an old thread that answers my questions. Don't need new answers if old ones suffice. (of course new answers always welcome!) I am looking for a 10 MHz standard for my lab. Accuracy/stability probably wouldn't make a hill of beans difference in the stuff I do, so my questions are more academic and it's just nice knowing I have a really good standard. 1. So from reading about this topic on KE5FX.com I understand that a better ocxo makes for better phase noise and near-term quality. I also understand that some later tbolts had a very good ocxo in them and therefore would not benefit significantly from an upgrade as ke5fx did using an HP 10811 unit. I am considering a thunderbolt advertised on ebay by flyingbest. I will be traveling to China (mainland, and Hong Kong) on business the last two weeks in December so I might save some shipping. Here is a photo. Can anyone tell me if this unit has a better 10811-class ocxo or not so good ocxo? I also understand that not all ocxo's are created equal, even if they are the same model number. http://tinyurl.com/2dg2dz3 2. Other GPS DO units seem to differ on the number of satellites they can receive from simultaneously (channels). What is the net effect of having a standard that can see 6,8 or 16 birds? Is noise averaged out? Is stability/phase noise improved? Here is an example of a 16 sat unit. Anyone have any experience with this unit? Good/bad indifferent? It seems they can be had for about $200. http://tinyurl.com/2ad5kls 3. And then there is the venerable HP units like this one. I understand this uses the 10811 ocxo. Other than the better ocxo, is there anything inherently superior about these HP units to warrant the additional cost? Or are we mostly just paying for the HP name? This one is 6 sats. http://tinyurl.com/24tkwdv Lastly, my use of a 10 MHz standard will be for use in equipment like microwave counters (EIP 548A), Spectrum analyzers (HP 8658B) VNA's (HP 3577A, 8753C to 6 GHz), synthesizer (HP 3326A and HP 8662A), premium receivers (Harris 590H), etc., etc. For these purposes, is a GPS DO advised, or perhaps a rubidium standard? For example, I don't need this to power a clock. Just a good, clean, stable signal with low noise, low spurs, etc. What's the overall opinion? THANKS (here's to hoping this message looks better than the first two tests I made) 73 Eugene W2HX ___ 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] temperature stability basics
In an attempt to educate myself about temperature stability, I put a temperature sensor in a 1 cube of brass wrapped in plastic packing-type bubble wrap, and compared that with another sensor outside the bubble wrap, with the whole combination in a thin nylon case just to slow down direct air drafts. I put it on the bench in the office where the ambient temperature varies up and down by a few degrees over the day. I recorded both temperatures with milli-degree resolution. Looking at the resulting plots, it looks like my thermal mass and thermal insulation on the inside sensor gives me only about a half hour lag at most relative to the outside sensor (hard to say exactly, it doesn't look like a simple one-pole filter). Note, I am not attempting any kind of ovenized control as yet, just measuring some time constants. I've read that plain bubble wrap has an R value of about 2 ft^2·°F·h/(BTU·in), while some types of rigid foam building insulation go up to R=8 (at least until the CFC gases used to blow the foam leak out). What is done in real instruments that need good thermal insulation? I assume dewar flasks are limited to aerospace applications. Photo of the block prior to bubble wrap: http://picasaweb.google.com/bealevideo/2010_11_18TempExperiment (live) plot of temperatures: http://www.pachube.com/feeds/12988 ___ 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.
