Re: [time-nuts] Choke Ring Pictures
bles. Its highly likely that a number of the better performance GPS timing receivers also use carrier phase smoothing. Thus whether one is aware of it or not the antenna carrier phase properties are likely to be of some importance. In the absence of complete information on how your particular GPS timing receiver uses carrier phase and code phase observables, the best you can do is compare the performance of a range of antennas using a given timing receiver. Such results will only apply to a particular site and receiver. Specifying the pertinent characteristics (eg isolated on a flat plain, surrounded by a set of hills, mountains which obscure the sky below 10 degrees, surrounded by trees that obscure everything below 40 degeees elevation, etc) of your antenna location and the particular GPS receiver used will be helpful to others in selecting an antenna that suits their budget, receiver, antenna location constraints, etc. Bruce ws * Bruce said: Which antenna performance metric do you have in mind? There are several, some of which are considered in the paper: http://www.novatel.com/Documents/Papers/effectofantenna.pdf Since the topography surrounding the antenna, its height and location on the Earth all affect measured performance any comparative measurements should use the same receiver and antenna location. Some estimates for the effect of multipath on code phase receivers can be found: http://bbcr.uwaterloo.ca/~wzhuang/papers/iee95_gps.pdf http://bbcr.uwaterloo.ca/%7Ewzhuang/papers/iee95_gps.pdf Since the better timing receivers use carrier phase smoothing of the code phase timing, both the carrier phase and code phase performance of the antenna are important. A phased array antenna like the one in the following papers may provide better performance than alternative antennae: http://www.navsys.com/Papers/0001002.pdf http://www.congrex.nl/07c12/papers/day1_s1_paper05_Konovaltsev.pdf Some measurements with geodetic antennae: http://www.fig.net/pub/fig2008/papers/ts05g/ts05g_03_eventzur_shaked_2816.pdf Comparison of code phase and carrier phase time transfer: http://tycho.usno.navy.mil/ptti/ptti2004/paper41.pdf Bruce ** WarrenS wrote: Brian wrote: "There were also comments about surveying and timing antennas." Those may of been from me, unsuccessfully trying to make a point of the difference between what is 'Best' and what is 'GOOD enough'. "about every national timing laboratory uses choke ring antennas. ... for timing stability reasons." Then again they also have multiple CS and Just their Antenna budget is likely more than the annual income of most time nuts. Can you do a test to show IF there is ANY improvement for the AVERAGE time nut when compared to a well setup (Tbolt) GPSDO using a TacoSalad antenna? Would be interesting to see a plot of cost vs. performance for the various antenna types, Scaled to show the performance improvement that the average Time nut would see. The TacoSalad antenna, originally cost me a total of $7.95, And took under 30 seconds to build. That cost should be discounted because those parts had been considered just throw away junk up until now. ws ** - Original Message - From: "Brian Kirby" To: "Discussion of precise time and frequency measurement" Sent: Monday, March 15, 2010 2:09 PM Subject: Re: [time-nuts] Choke Ring Pictures Dr. Clark passed on a tip that I used. Put the funnel in a microwave oven and run it and see if the funnel warms up. If it warms up, you do not use it. I do not know what type of plastic the funnel was made out of; it was white, semi-transparent. There were also comments about surveying and timing antennas. If you investigate about every national timing laboratory uses choke ring antennas. Some enclose the antenna unit and they temperature control it. They do this for timing stability reasons. The commercial timing antenna is bullet shaped and is operated without a ground plane. They are patch antennas. When there is not ground plane, the antenna picks up best from the overhead and less towards the horizon. These antennas usually have a lot more gain (30-50 db vs most normal antennas in the 15-25 db range). Also in surveying, we cut off the horizon at 15 degrees in software. A free Army Corp of Engineering manual on GPS Surveying is at http://140.194.76.129/publications/eng-manuals/em1110-1-1003/toc.htm The main difference in surveying and timing is in surveying they use the carrier phase method, were in timing most use a solution derived from the processing of the coarse acquisition code, in were the receiver is in a fixed over-determined position . Some timing labs are using carrier phase method, when they need more resolution. Brian - KD4FM
Re: [time-nuts] Choke Ring Pictures
t;>>> yeah, >>>>>> So many variables, ALL the more reasion to just see what the overall >>>>>> effect is on the more common type of GPSDO receviers at a few sites. >>>>>> So did you have a better plan? >>>>>> >>>>>> ws >>>>>> >>>>>> >>>>>> Bruce Griffiths Added: >>>>>> >>>>>> >>>>>> >>>>>>> WarrenS wrote: >>>>>>> >>>>>>> Bruce wrote: >>>>>>> >>>>>>> >>>>>>>> "Which antenna performance metric do you have in mind?" >>>>>>>> >>>>>>>> >>>>>>> Could do GPSDO hold over performance, but that would not be much of >>>>>>> a test of the antenna. >>>>>>> How about the antenna's effect on the ADEV Osc noise and Phase noise. >>>>>>> What else does the Time Nut care about? >>>>>>> >>>>>>> >>>>>>> >>>>>>>> Since the better timing receivers use carrier phase ... >>>>>>>> >>>>>>>> >>>>>>> I don't remember you ever finding ANY Time Nut that is now using one. >>>>>>> So may be simpler for now to just stick to the more common type of >>>>>>> GPSDO in use. >>>>>>> >>>>>>> >>>>>>> >>>>>> The Motorola M12+T and iLotus M12M use carrier phase smoothing of the >>>>>> code phase observables. >>>>>> >>>>>> Its highly likely that a number of the better performance GPS timing >>>>>> receivers also use carrier phase smoothing. >>>>>> >>>>>> Thus whether one is aware of it or not the antenna carrier phase >>>>>> properties are likely to be of some importance. >>>>>> >>>>>> In the absence of complete information on how your particular GPS timing >>>>>> receiver uses carrier phase and code phase observables, the best you can >>>>>> do is compare the performance of a range of antennas using a given >>>>>> timing receiver. >>>>>> >>>>>> Such results will only apply to a particular site and receiver. >>>>>> Specifying the pertinent characteristics (eg isolated on a flat plain, >>>>>> surrounded by a set of hills, mountains which obscure the sky below 10 >>>>>> degrees, surrounded by trees that obscure everything below 40 degeees >>>>>> elevation, etc) of your antenna location and the particular GPS receiver >>>>>> used will be helpful to others in selecting an antenna that suits their >>>>>> budget, receiver, antenna location constraints, etc. >>>>>> >>>>>> Bruce >>>>>> >>>>>> >>>>>> >>>>>>> ws >>>>>>> >>>>>>> * >>>>>>> Bruce said: >>>>>>> >>>>>>> Which antenna performance metric do you have in mind? >>>>>>> There are several, some of which are considered in the paper: >>>>>>> http://www.novatel.com/Documents/Papers/effectofantenna.pdf >>>>>>> >>>>>>> Since the topography surrounding the antenna, its height and location on >>>>>>> the Earth all affect measured performance any comparative measurements >>>>>>> should use the same receiver and antenna location. >>>>>>> >>>>>>> Some estimates for the effect of multipath on code phase receivers can >>>>>>> be found: >>>>>>> >>>>>>> http://bbcr.uwaterloo.ca/~wzhuang/papers/iee95_gps.pdf >>>>>>> >>>>>>> http://bbcr.uwaterloo.ca/%7Ewzhuang/papers/iee95_gps.pdf >>>>>>> >>>>>>> Since the better timing receivers use carrier phase smoothing of the >>>>>>> code phase timing, both the carrier phase and code phase performance of >>>>>>> the antenna are important. >>>>&g
Re: [time-nuts] Choke Ring Pictures
c antennae: http://www.fig.net/pub/fig2008/papers/ts05g/ts05g_03_eventzur_shaked_2816.pdf Comparison of code phase and carrier phase time transfer: http://tycho.usno.navy.mil/ptti/ptti2004/paper41.pdf Bruce ** WarrenS wrote: Brian wrote: "There were also comments about surveying and timing antennas." Those may of been from me, unsuccessfully trying to make a point of the difference between what is 'Best' and what is 'GOOD enough'. "about every national timing laboratory uses choke ring antennas. ... for timing stability reasons." Then again they also have multiple CS and Just their Antenna budget is likely more than the annual income of most time nuts. Can you do a test to show IF there is ANY improvement for the AVERAGE time nut when compared to a well setup (Tbolt) GPSDO using a TacoSalad antenna? Would be interesting to see a plot of cost vs. performance for the various antenna types, Scaled to show the performance improvement that the average Time nut would see. The TacoSalad antenna, originally cost me a total of $7.95, And took under 30 seconds to build. That cost should be discounted because those parts had been considered just throw away junk up until now. ws ** - Original Message - From: "Brian Kirby" To: "Discussion of precise time and frequency measurement" Sent: Monday, March 15, 2010 2:09 PM Subject: Re: [time-nuts] Choke Ring Pictures Dr. Clark passed on a tip that I used. Put the funnel in a microwave oven and run it and see if the funnel warms up. If it warms up, you do not use it. I do not know what type of plastic the funnel was made out of; it was white, semi-transparent. There were also comments about surveying and timing antennas. If you investigate about every national timing laboratory uses choke ring antennas. Some enclose the antenna unit and they temperature control it. They do this for timing stability reasons. The commercial timing antenna is bullet shaped and is operated without a ground plane. They are patch antennas. When there is not ground plane, the antenna picks up best from the overhead and less towards the horizon. These antennas usually have a lot more gain (30-50 db vs most normal antennas in the 15-25 db range). Also in surveying, we cut off the horizon at 15 degrees in software. A free Army Corp of Engineering manual on GPS Surveying is at http://140.194.76.129/publications/eng-manuals/em1110-1-1003/toc.htm The main difference in surveying and timing is in surveying they use the carrier phase method, were in timing most use a solution derived from the processing of the coarse acquisition code, in were the receiver is in a fixed over-determined position . Some timing labs are using carrier phase method, when they need more resolution. Brian - KD4FM warrens wrote: ... Preliminary results for the Taco Dish GPS antenna as an indoor antenna are looking good. Certainly worth considering if your GPS antenna is stuck indoors, 'Out of the rain in the living room'. I find it best to rise it up near the ceiling such as on an upper shelf with nothing above it. It would be hard to tell the difference between the GPSDO performance obtained from this or the Best outdoor antenna if using a Tbolt set to the standard default settings. Picture attached ws ** ___ 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] Choke Ring Pictures
rything below 40 degeees elevation, etc) of your antenna location and the particular GPS receiver used will be helpful to others in selecting an antenna that suits their budget, receiver, antenna location constraints, etc. Bruce ws * Bruce said: Which antenna performance metric do you have in mind? There are several, some of which are considered in the paper: http://www.novatel.com/Documents/Papers/effectofantenna.pdf Since the topography surrounding the antenna, its height and location on the Earth all affect measured performance any comparative measurements should use the same receiver and antenna location. Some estimates for the effect of multipath on code phase receivers can be found: http://bbcr.uwaterloo.ca/~wzhuang/papers/iee95_gps.pdf http://bbcr.uwaterloo.ca/%7Ewzhuang/papers/iee95_gps.pdf Since the better timing receivers use carrier phase smoothing of the code phase timing, both the carrier phase and code phase performance of the antenna are important. A phased array antenna like the one in the following papers may provide better performance than alternative antennae: http://www.navsys.com/Papers/0001002.pdf http://www.congrex.nl/07c12/papers/day1_s1_paper05_Konovaltsev.pdf Some measurements with geodetic antennae: http://www.fig.net/pub/fig2008/papers/ts05g/ts05g_03_eventzur_shaked_2816.pdf Comparison of code phase and carrier phase time transfer: http://tycho.usno.navy.mil/ptti/ptti2004/paper41.pdf Bruce ** WarrenS wrote: Brian wrote: "There were also comments about surveying and timing antennas." Those may of been from me, unsuccessfully trying to make a point of the difference between what is 'Best' and what is 'GOOD enough'. "about every national timing laboratory uses choke ring antennas. ... for timing stability reasons." Then again they also have multiple CS and Just their Antenna budget is likely more than the annual income of most time nuts. Can you do a test to show IF there is ANY improvement for the AVERAGE time nut when compared to a well setup (Tbolt) GPSDO using a TacoSalad antenna? Would be interesting to see a plot of cost vs. performance for the various antenna types, Scaled to show the performance improvement that the average Time nut would see. The TacoSalad antenna, originally cost me a total of $7.95, And took under 30 seconds to build. That cost should be discounted because those parts had been considered just throw away junk up until now. ws ** - Original Message - From: "Brian Kirby" To: "Discussion of precise time and frequency measurement" Sent: Monday, March 15, 2010 2:09 PM Subject: Re: [time-nuts] Choke Ring Pictures Dr. Clark passed on a tip that I used. Put the funnel in a microwave oven and run it and see if the funnel warms up. If it warms up, you do not use it. I do not know what type of plastic the funnel was made out of; it was white, semi-transparent. There were also comments about surveying and timing antennas. If you investigate about every national timing laboratory uses choke ring antennas. Some enclose the antenna unit and they temperature control it. They do this for timing stability reasons. The commercial timing antenna is bullet shaped and is operated without a ground plane. They are patch antennas. When there is not ground plane, the antenna picks up best from the overhead and less towards the horizon. These antennas usually have a lot more gain (30-50 db vs most normal antennas in the 15-25 db range). Also in surveying, we cut off the horizon at 15 degrees in software. A free Army Corp of Engineering manual on GPS Surveying is at http://140.194.76.129/publications/eng-manuals/em1110-1-1003/toc.htm The main difference in surveying and timing is in surveying they use the carrier phase method, were in timing most use a solution derived from the processing of the coarse acquisition code, in were the receiver is in a fixed over-determined position . Some timing labs are using carrier phase method, when they need more resolution. Brian - KD4FM warrens wrote: ... Preliminary results for the Taco Dish GPS antenna as an indoor antenna are looking good. Certainly worth considering if your GPS antenna is stuck indoors, 'Out of the rain in the living room'. I find it best to rise it up near the ceiling such as on an upper shelf with nothing above it. It would be hard to tell the difference between the GPSDO performance obtained from this or the Best outdoor antenna if using a Tbolt set to the standard default settings. Picture attached ws ** __
Re: [time-nuts] Choke Ring Pictures
t;>>> In the absence of complete information on how your particular GPS timing >>>> receiver uses carrier phase and code phase observables, the best you can >>>> do is compare the performance of a range of antennas using a given >>>> timing receiver. >>>> >>>> Such results will only apply to a particular site and receiver. >>>> Specifying the pertinent characteristics (eg isolated on a flat plain, >>>> surrounded by a set of hills, mountains which obscure the sky below 10 >>>> degrees, surrounded by trees that obscure everything below 40 degeees >>>> elevation, etc) of your antenna location and the particular GPS receiver >>>> used will be helpful to others in selecting an antenna that suits their >>>> budget, receiver, antenna location constraints, etc. >>>> >>>> Bruce >>>> >>>> >>>>> ws >>>>> >>>>> * >>>>> Bruce said: >>>>> >>>>> Which antenna performance metric do you have in mind? >>>>> There are several, some of which are considered in the paper: >>>>> http://www.novatel.com/Documents/Papers/effectofantenna.pdf >>>>> >>>>> Since the topography surrounding the antenna, its height and location on >>>>> the Earth all affect measured performance any comparative measurements >>>>> should use the same receiver and antenna location. >>>>> >>>>> Some estimates for the effect of multipath on code phase receivers can >>>>> be found: >>>>> >>>>> http://bbcr.uwaterloo.ca/~wzhuang/papers/iee95_gps.pdf >>>>> >>>>> http://bbcr.uwaterloo.ca/%7Ewzhuang/papers/iee95_gps.pdf >>>>> >>>>> Since the better timing receivers use carrier phase smoothing of the >>>>> code phase timing, both the carrier phase and code phase performance of >>>>> the antenna are important. >>>>> >>>>> A phased array antenna like the one in the following papers may provide >>>>> better performance than alternative antennae: >>>>> >>>>> http://www.navsys.com/Papers/0001002.pdf >>>>> http://www.congrex.nl/07c12/papers/day1_s1_paper05_Konovaltsev.pdf >>>>> >>>>> Some measurements with geodetic antennae: >>>>> http://www.fig.net/pub/fig2008/papers/ts05g/ts05g_03_eventzur_shaked_2816.pdf >>>>> >>>>> >>>>> Comparison of code phase and carrier phase time transfer: >>>>> http://tycho.usno.navy.mil/ptti/ptti2004/paper41.pdf >>>>> >>>>> Bruce >>>>> >>>>> ** >>>>> WarrenS wrote: >>>>> >>>>>> Brian wrote: >>>>>> >>>>>> >>>>>>> "There were also comments about surveying and timing antennas." >>>>>>> >>>>>> Those may of been from me, unsuccessfully trying to make a point of >>>>>> the difference between what is 'Best' and what is 'GOOD enough'. >>>>>> >>>>>> >>>>>>> "about every national timing laboratory uses choke ring antennas. >>>>>>> ... for timing stability reasons." >>>>>>> >>>>>> Then again they also have multiple CS and Just their Antenna budget is >>>>>> likely more than the annual income of most time nuts. >>>>>> Can you do a test to show IF there is ANY improvement for the AVERAGE >>>>>> time nut when compared to a well setup (Tbolt) GPSDO using a TacoSalad >>>>>> antenna? >>>>>> >>>>>> Would be interesting to see a plot of cost vs. performance for the >>>>>> various antenna types, >>>>>> Scaled to show the performance improvement that the average Time nut >>>>>> would see. >>>>>> The TacoSalad antenna, originally cost me a total of $7.95, And took >>>>>> under 30 seconds to build. >>>>>> That cost should be discounted because those parts had been considered >>>>>> just throw away junk up until now. >>>>>> >>>>>> ws >>>>>> >>>>>> **
Re: [time-nuts] Choke Ring Pictures
g stability reasons." Then again they also have multiple CS and Just their Antenna budget is likely more than the annual income of most time nuts. Can you do a test to show IF there is ANY improvement for the AVERAGE time nut when compared to a well setup (Tbolt) GPSDO using a TacoSalad antenna? Would be interesting to see a plot of cost vs. performance for the various antenna types, Scaled to show the performance improvement that the average Time nut would see. The TacoSalad antenna, originally cost me a total of $7.95, And took under 30 seconds to build. That cost should be discounted because those parts had been considered just throw away junk up until now. ws ** - Original Message - From: "Brian Kirby" To: "Discussion of precise time and frequency measurement" Sent: Monday, March 15, 2010 2:09 PM Subject: Re: [time-nuts] Choke Ring Pictures Dr. Clark passed on a tip that I used. Put the funnel in a microwave oven and run it and see if the funnel warms up. If it warms up, you do not use it. I do not know what type of plastic the funnel was made out of; it was white, semi-transparent. There were also comments about surveying and timing antennas. If you investigate about every national timing laboratory uses choke ring antennas. Some enclose the antenna unit and they temperature control it. They do this for timing stability reasons. The commercial timing antenna is bullet shaped and is operated without a ground plane. They are patch antennas. When there is not ground plane, the antenna picks up best from the overhead and less towards the horizon. These antennas usually have a lot more gain (30-50 db vs most normal antennas in the 15-25 db range). Also in surveying, we cut off the horizon at 15 degrees in software. A free Army Corp of Engineering manual on GPS Surveying is at http://140.194.76.129/publications/eng-manuals/em1110-1-1003/toc.htm The main difference in surveying and timing is in surveying they use the carrier phase method, were in timing most use a solution derived from the processing of the coarse acquisition code, in were the receiver is in a fixed over-determined position . Some timing labs are using carrier phase method, when they need more resolution. Brian - KD4FM warrens wrote: ... Preliminary results for the Taco Dish GPS antenna as an indoor antenna are looking good. Certainly worth considering if your GPS antenna is stuck indoors, 'Out of the rain in the living room'. I find it best to rise it up near the ceiling such as on an upper shelf with nothing above it. It would be hard to tell the difference between the GPSDO performance obtained from this or the Best outdoor antenna if using a Tbolt set to the standard default settings. Picture attached ws ** ___ 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] Choke Ring Pictures
All you can conclude from that is that the Thunderbolt GPS receiver doesn't output carrier phase measures. There's no way to tell if the GPS receiver itself uses carrier phase data internally. For example the M12+T and M12M_T GPS receivers use carrier phase smoothing internally but unlike some earlier Motorola GPS timing receivers due not make carrier phase data available to the user. Bruce Mark Sims wrote: At one time I thought the Thunderbolt had some carrier phase capabilities... it does not. I found a couple of undocumented (for the Thunderbolt) status messages that indicate that the Thunderbolt firmware does not have the carrier phase routines installed. It does output the code phase in a message (but in a form that is just about impossible to use for anything). If you dig back far enough in the archives, you can find information that suggests the Thunderbolt uses carrier phase data. _ Hotmail has tools for the New Busy. Search, chat and e-mail from your inbox. http://www.windowslive.com/campaign/thenewbusy?ocid=PID27925::T:WLMTAGL:ON:WL:en-US:WM_HMP:032010_1 ___ 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] Choke Ring Pictures
the following papers may provide >>> better performance than alternative antennae: >>> >>> http://www.navsys.com/Papers/0001002.pdf >>> http://www.congrex.nl/07c12/papers/day1_s1_paper05_Konovaltsev.pdf >>> >>> Some measurements with geodetic antennae: >>> http://www.fig.net/pub/fig2008/papers/ts05g/ts05g_03_eventzur_shaked_2816.pdf >>> >>> >>> >>> Comparison of code phase and carrier phase time transfer: >>> http://tycho.usno.navy.mil/ptti/ptti2004/paper41.pdf >>> >>> Bruce >>> >>> ** >>> WarrenS wrote: >>>> Brian wrote: >>>> >>>>> "There were also comments about surveying and timing antennas." >>>> Those may of been from me, unsuccessfully trying to make a point of >>>> the difference between what is 'Best' and what is 'GOOD enough'. >>>> >>>>> "about every national timing laboratory uses choke ring antennas. >>>>> ... for timing stability reasons." >>>> Then again they also have multiple CS and Just their Antenna budget is >>>> likely more than the annual income of most time nuts. >>>> Can you do a test to show IF there is ANY improvement for the AVERAGE >>>> time nut when compared to a well setup (Tbolt) GPSDO using a TacoSalad >>>> antenna? >>>> >>>> Would be interesting to see a plot of cost vs. performance for the >>>> various antenna types, >>>> Scaled to show the performance improvement that the average Time nut >>>> would see. >>>> The TacoSalad antenna, originally cost me a total of $7.95, And took >>>> under 30 seconds to build. >>>> That cost should be discounted because those parts had been considered >>>> just throw away junk up until now. >>>> >>>> ws >>>> >>>> ** >>>> >>>> - Original Message - From: "Brian Kirby" >>>> >>>> To: "Discussion of precise time and frequency measurement" >>>> >>>> Sent: Monday, March 15, 2010 2:09 PM >>>> Subject: Re: [time-nuts] Choke Ring Pictures >>>> >>>> >>>>> Dr. Clark passed on a tip that I used. Put the funnel in a microwave >>>>> oven and run it and see if the funnel warms up. If it warms up, you >>>>> do not use it. I do not know what type of plastic the funnel was >>>>> made out of; it was white, semi-transparent. >>>>> >>>>> There were also comments about surveying and timing antennas. If you >>>>> investigate about every national timing laboratory uses choke ring >>>>> antennas. Some enclose the antenna unit and they temperature control >>>>> it. They do this for timing stability reasons. >>>>> >>>>> The commercial timing antenna is bullet shaped and is operated >>>>> without a ground plane. They are patch antennas. When there is not >>>>> ground plane, the antenna picks up best from the overhead and less >>>>> towards the horizon. These antennas usually have a lot more gain >>>>> (30-50 db vs most normal antennas in the 15-25 db range). >>>>> Also in surveying, we cut off the horizon at 15 degrees in software. >>>>> A free Army Corp of Engineering manual on GPS Surveying is at >>>>> http://140.194.76.129/publications/eng-manuals/em1110-1-1003/toc.htm >>>>> The main difference in surveying and timing is in surveying they use >>>>> the carrier phase method, were in timing most use a solution derived >>>>> from the processing of the coarse acquisition code, in were the >>>>> receiver is in a fixed over-determined position . Some timing labs >>>>> are using carrier phase method, when they need more resolution. >>>>> >>>>> Brian - KD4FM >>>>> >>>> >>>>>> warrens wrote: >>>> ... >>>>>> Preliminary results for the Taco Dish GPS antenna as an indoor >>>>>> antenna are looking good. >>>>>> Certainly worth considering if your GPS antenna is stuck indoors, >>>>>> 'Out of the rain in the living room'. >>>>>> I find it best to rise it up near the ceiling such as on an upper >>>>>> shelf with nothing above it. >>>>>> It would be hard to tell the difference between the GPSDO >>>>>> performance obtained from this or the Best outdoor antenna if using >>>>>> a Tbolt set to the standard default settings. >>>>>> Picture attached >>>>>> >>>>>> ws >>>>>> >>>>> ** >>>> >>> >> >> >> ___ >> 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] Choke Ring Pictures
Hi The real question is weather Trimble uses the data that's there to help their algorithm stabilize the oscillator. I suspect there is a way for them to extract the information without the full firmware set being present. I agree that without being able to access the data properly, you would have a hard time using it for stuff like time transfer. Bob On Mar 15, 2010, at 9:32 PM, Mark Sims wrote: > > At one time I thought the Thunderbolt had some carrier phase capabilities... > it does not. I found a couple of undocumented (for the Thunderbolt) status > messages that indicate that the Thunderbolt firmware does not have the > carrier phase routines installed. > > It does output the code phase in a message (but in a form that is just about > impossible to use for anything). > > If you dig back far enough in the archives, you can find information that > suggests the Thunderbolt uses carrier phase data. > > > _ > Hotmail has tools for the New Busy. Search, chat and e-mail from your inbox. > http://www.windowslive.com/campaign/thenewbusy?ocid=PID27925::T:WLMTAGL:ON:WL:en-US:WM_HMP:032010_1 > ___ > 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] Choke Ring Pictures
ime transfer: http://tycho.usno.navy.mil/ptti/ptti2004/paper41.pdf Bruce ** WarrenS wrote: Brian wrote: "There were also comments about surveying and timing antennas." Those may of been from me, unsuccessfully trying to make a point of the difference between what is 'Best' and what is 'GOOD enough'. "about every national timing laboratory uses choke ring antennas. ... for timing stability reasons." Then again they also have multiple CS and Just their Antenna budget is likely more than the annual income of most time nuts. Can you do a test to show IF there is ANY improvement for the AVERAGE time nut when compared to a well setup (Tbolt) GPSDO using a TacoSalad antenna? Would be interesting to see a plot of cost vs. performance for the various antenna types, Scaled to show the performance improvement that the average Time nut would see. The TacoSalad antenna, originally cost me a total of $7.95, And took under 30 seconds to build. That cost should be discounted because those parts had been considered just throw away junk up until now. ws ** - Original Message - From: "Brian Kirby" To: "Discussion of precise time and frequency measurement" Sent: Monday, March 15, 2010 2:09 PM Subject: Re: [time-nuts] Choke Ring Pictures Dr. Clark passed on a tip that I used. Put the funnel in a microwave oven and run it and see if the funnel warms up. If it warms up, you do not use it. I do not know what type of plastic the funnel was made out of; it was white, semi-transparent. There were also comments about surveying and timing antennas. If you investigate about every national timing laboratory uses choke ring antennas. Some enclose the antenna unit and they temperature control it. They do this for timing stability reasons. The commercial timing antenna is bullet shaped and is operated without a ground plane. They are patch antennas. When there is not ground plane, the antenna picks up best from the overhead and less towards the horizon. These antennas usually have a lot more gain (30-50 db vs most normal antennas in the 15-25 db range). Also in surveying, we cut off the horizon at 15 degrees in software. A free Army Corp of Engineering manual on GPS Surveying is at http://140.194.76.129/publications/eng-manuals/em1110-1-1003/toc.htm The main difference in surveying and timing is in surveying they use the carrier phase method, were in timing most use a solution derived from the processing of the coarse acquisition code, in were the receiver is in a fixed over-determined position . Some timing labs are using carrier phase method, when they need more resolution. Brian - KD4FM warrens wrote: ... Preliminary results for the Taco Dish GPS antenna as an indoor antenna are looking good. Certainly worth considering if your GPS antenna is stuck indoors, 'Out of the rain in the living room'. I find it best to rise it up near the ceiling such as on an upper shelf with nothing above it. It would be hard to tell the difference between the GPSDO performance obtained from this or the Best outdoor antenna if using a Tbolt set to the standard default settings. Picture attached ws ** ___ 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] Choke Ring Pictures
WarrenS wrote: Magnus wrote: "Multipath rejection, antenna selectivity, antenna amplifier gain, antenna noise factor... all weigh in." And Your point is? Their effects would all be included in as much as they effect ADEV Osc noise and Phase noise. They would show up on the ADEV and phase-noise curve yes, but you can actually combat them by better antenna. "Several of us have carrier phase and dual frequency receivers. I lack a good double-frequency antenna, choke-ring with sufficient amplifier gain." You're not the Average Time nut and sounds like you're saying even you aren't using a choke ring with a carrier phase receiver? For the simple reason that I just didn't find one at a nice price just yet. While I may not be the average time-nut, I still run that lab on a fairly small budget. Otherwise there would be more cesiums and H-masers here for sure. Sounds like to keep it simple, still don't not need to test for that yet. I know that my antennas have severly multipath issues, and my L1/L2 antenna has way to little ompf in the amplifier gain to both cause me big headaches. I can't do the drastic changes (pull down the TV-antenna overhead) that a good sitting would require. 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] Choke Ring Pictures
Unless you have a CSO or a hydrogen maser absolute measures of ADEV and phase noise arent feasible for the range of Tau of interest. Even an indirect method such as measuring the location of the apparent minimum in ADEV between the GPS SV constellation observables and the OCXO when it is undisciplined depend heavily on the ADEV characteristics of the OCXO being used. Bruce WarrenS wrote: yeah, So many variables, ALL the more reasion to just see what the overall effect is on the more common type of GPSDO receviers at a few sites. So did you have a better plan? ws Bruce Griffiths Added: WarrenS wrote: Bruce wrote: "Which antenna performance metric do you have in mind?" Could do GPSDO hold over performance, but that would not be much of a test of the antenna. How about the antenna's effect on the ADEV Osc noise and Phase noise. What else does the Time Nut care about? Since the better timing receivers use carrier phase ... I don't remember you ever finding ANY Time Nut that is now using one. So may be simpler for now to just stick to the more common type of GPSDO in use. The Motorola M12+T and iLotus M12M use carrier phase smoothing of the code phase observables. Its highly likely that a number of the better performance GPS timing receivers also use carrier phase smoothing. Thus whether one is aware of it or not the antenna carrier phase properties are likely to be of some importance. In the absence of complete information on how your particular GPS timing receiver uses carrier phase and code phase observables, the best you can do is compare the performance of a range of antennas using a given timing receiver. Such results will only apply to a particular site and receiver. Specifying the pertinent characteristics (eg isolated on a flat plain, surrounded by a set of hills, mountains which obscure the sky below 10 degrees, surrounded by trees that obscure everything below 40 degeees elevation, etc) of your antenna location and the particular GPS receiver used will be helpful to others in selecting an antenna that suits their budget, receiver, antenna location constraints, etc. Bruce ws * Bruce said: Which antenna performance metric do you have in mind? There are several, some of which are considered in the paper: http://www.novatel.com/Documents/Papers/effectofantenna.pdf Since the topography surrounding the antenna, its height and location on the Earth all affect measured performance any comparative measurements should use the same receiver and antenna location. Some estimates for the effect of multipath on code phase receivers can be found: http://bbcr.uwaterloo.ca/~wzhuang/papers/iee95_gps.pdf http://bbcr.uwaterloo.ca/%7Ewzhuang/papers/iee95_gps.pdf Since the better timing receivers use carrier phase smoothing of the code phase timing, both the carrier phase and code phase performance of the antenna are important. A phased array antenna like the one in the following papers may provide better performance than alternative antennae: http://www.navsys.com/Papers/0001002.pdf http://www.congrex.nl/07c12/papers/day1_s1_paper05_Konovaltsev.pdf Some measurements with geodetic antennae: http://www.fig.net/pub/fig2008/papers/ts05g/ts05g_03_eventzur_shaked_2816.pdf Comparison of code phase and carrier phase time transfer: http://tycho.usno.navy.mil/ptti/ptti2004/paper41.pdf Bruce ** WarrenS wrote: Brian wrote: "There were also comments about surveying and timing antennas." Those may of been from me, unsuccessfully trying to make a point of the difference between what is 'Best' and what is 'GOOD enough'. "about every national timing laboratory uses choke ring antennas. ... for timing stability reasons." Then again they also have multiple CS and Just their Antenna budget is likely more than the annual income of most time nuts. Can you do a test to show IF there is ANY improvement for the AVERAGE time nut when compared to a well setup (Tbolt) GPSDO using a TacoSalad antenna? Would be interesting to see a plot of cost vs. performance for the various antenna types, Scaled to show the performance improvement that the average Time nut would see. The TacoSalad antenna, originally cost me a total of $7.95, And took under 30 seconds to build. That cost should be discounted because those parts had been considered just throw away junk up until now. ws ** - Original Message - From: "Brian Kirby" To: "Discussion of precise time and frequency measurement" Sent: Monday, March 15, 2010 2:09 PM Subject: Re: [time-nuts] Choke Ring Pictures Dr. Clark passed on a tip that I used. Put the funnel in a microwave oven and run it and see if the funnel warms up. If it warms up, you do not use it. I do not know what type of plastic the funnel was made out of; it was white, semi-transparent. There were also comments abou
Re: [time-nuts] Choke Ring Pictures
yeah, So many variables, ALL the more reasion to just see what the overall effect is on the more common type of GPSDO receviers at a few sites. So did you have a better plan? ws Bruce Griffiths Added: WarrenS wrote: Bruce wrote: "Which antenna performance metric do you have in mind?" Could do GPSDO hold over performance, but that would not be much of a test of the antenna. How about the antenna's effect on the ADEV Osc noise and Phase noise. What else does the Time Nut care about? Since the better timing receivers use carrier phase ... I don't remember you ever finding ANY Time Nut that is now using one. So may be simpler for now to just stick to the more common type of GPSDO in use. The Motorola M12+T and iLotus M12M use carrier phase smoothing of the code phase observables. Its highly likely that a number of the better performance GPS timing receivers also use carrier phase smoothing. Thus whether one is aware of it or not the antenna carrier phase properties are likely to be of some importance. In the absence of complete information on how your particular GPS timing receiver uses carrier phase and code phase observables, the best you can do is compare the performance of a range of antennas using a given timing receiver. Such results will only apply to a particular site and receiver. Specifying the pertinent characteristics (eg isolated on a flat plain, surrounded by a set of hills, mountains which obscure the sky below 10 degrees, surrounded by trees that obscure everything below 40 degeees elevation, etc) of your antenna location and the particular GPS receiver used will be helpful to others in selecting an antenna that suits their budget, receiver, antenna location constraints, etc. Bruce ws * Bruce said: Which antenna performance metric do you have in mind? There are several, some of which are considered in the paper: http://www.novatel.com/Documents/Papers/effectofantenna.pdf Since the topography surrounding the antenna, its height and location on the Earth all affect measured performance any comparative measurements should use the same receiver and antenna location. Some estimates for the effect of multipath on code phase receivers can be found: http://bbcr.uwaterloo.ca/~wzhuang/papers/iee95_gps.pdf http://bbcr.uwaterloo.ca/%7Ewzhuang/papers/iee95_gps.pdf Since the better timing receivers use carrier phase smoothing of the code phase timing, both the carrier phase and code phase performance of the antenna are important. A phased array antenna like the one in the following papers may provide better performance than alternative antennae: http://www.navsys.com/Papers/0001002.pdf http://www.congrex.nl/07c12/papers/day1_s1_paper05_Konovaltsev.pdf Some measurements with geodetic antennae: http://www.fig.net/pub/fig2008/papers/ts05g/ts05g_03_eventzur_shaked_2816.pdf Comparison of code phase and carrier phase time transfer: http://tycho.usno.navy.mil/ptti/ptti2004/paper41.pdf Bruce ** WarrenS wrote: Brian wrote: "There were also comments about surveying and timing antennas." Those may of been from me, unsuccessfully trying to make a point of the difference between what is 'Best' and what is 'GOOD enough'. "about every national timing laboratory uses choke ring antennas. ... for timing stability reasons." Then again they also have multiple CS and Just their Antenna budget is likely more than the annual income of most time nuts. Can you do a test to show IF there is ANY improvement for the AVERAGE time nut when compared to a well setup (Tbolt) GPSDO using a TacoSalad antenna? Would be interesting to see a plot of cost vs. performance for the various antenna types, Scaled to show the performance improvement that the average Time nut would see. The TacoSalad antenna, originally cost me a total of $7.95, And took under 30 seconds to build. That cost should be discounted because those parts had been considered just throw away junk up until now. ws ** - Original Message - From: "Brian Kirby" To: "Discussion of precise time and frequency measurement" Sent: Monday, March 15, 2010 2:09 PM Subject: Re: [time-nuts] Choke Ring Pictures Dr. Clark passed on a tip that I used. Put the funnel in a microwave oven and run it and see if the funnel warms up. If it warms up, you do not use it. I do not know what type of plastic the funnel was made out of; it was white, semi-transparent. There were also comments about surveying and timing antennas. If you investigate about every national timing laboratory uses choke ring antennas. Some enclose the antenna unit and they temperature control it. They do this for timing stability reasons. The commercial timing antenna is bullet shaped and is operated without a ground plane. They are patch antennas. When there is not ground plane, the antenna picks up best from t
Re: [time-nuts] Choke Ring Pictures
Magnus wrote: "Multipath rejection, antenna selectivity, antenna amplifier gain, antenna noise factor... all weigh in." And Your point is? Their effects would all be included in as much as they effect ADEV Osc noise and Phase noise. "Several of us have carrier phase and dual frequency receivers. I lack a good double-frequency antenna, choke-ring with sufficient amplifier gain." You're not the Average Time nut and sounds like you're saying even you aren't using a choke ring with a carrier phase receiver? Sounds like to keep it simple, still don't not need to test for that yet. ws ** WarrenS wrote: Bruce wrote: "Which antenna performance metric do you have in mind?" Could do GPSDO hold over performance, but that would not be much of a test of the antenna. How about the antenna's effect on the ADEV Osc noise and Phase noise. What else does the Time Nut care about? Multipath rejection, antenna selectivity, antenna amplifier gain, antenna noise factor... all weigh in. Even for a simple Thunderbolt. Since the better timing receivers use carrier phase ... I don't remember you ever finding ANY Time Nut that is now using one. So may be simpler for now to just stick to the more common type of GPSDO in use. Several of us have carrier phase and dual frequency receivers. I have several myself. I lack a good double-frequency antenna, choke-ring with sufficient amplifier gain. 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] Choke Ring Pictures
Hi If you dig back far enough in the archives, you can find information that suggests the Thunderbolt uses carrier phase data. Bob On Mar 15, 2010, at 8:15 PM, Bruce Griffiths wrote: > WarrenS wrote: >> >> Bruce wrote: >>> "Which antenna performance metric do you have in mind?" >> Could do GPSDO hold over performance, but that would not be much of a test >> of the antenna. >> How about the antenna's effect on the ADEV Osc noise and Phase noise. >> What else does the Time Nut care about? >> >>> Since the better timing receivers use carrier phase ... >> I don't remember you ever finding ANY Time Nut that is now using one. >> So may be simpler for now to just stick to the more common type of GPSDO in >> use. >> > The Motorola M12+T and iLotus M12M use carrier phase smoothing of the code > phase observables. > > Its highly likely that a number of the better performance GPS timing > receivers also use carrier phase smoothing. > > Thus whether one is aware of it or not the antenna carrier phase properties > are likely to be of some importance. > > In the absence of complete information on how your particular GPS timing > receiver uses carrier phase and code phase observables, the best you can do > is compare the performance of a range of antennas using a given timing > receiver. > > Such results will only apply to a particular site and receiver. > Specifying the pertinent characteristics (eg isolated on a flat plain, > surrounded by a set of hills, mountains which obscure the sky below 10 > degrees, surrounded by trees that obscure everything below 40 degeees > elevation, etc) of your antenna location and the particular GPS receiver used > will be helpful to others in selecting an antenna that suits their budget, > receiver, antenna location constraints, etc. > > Bruce > >> ws >> >> * >> Bruce said: >> >> Which antenna performance metric do you have in mind? >> There are several, some of which are considered in the paper: >> http://www.novatel.com/Documents/Papers/effectofantenna.pdf >> >> Since the topography surrounding the antenna, its height and location on >> the Earth all affect measured performance any comparative measurements >> should use the same receiver and antenna location. >> >> Some estimates for the effect of multipath on code phase receivers can >> be found: >> >> http://bbcr.uwaterloo.ca/~wzhuang/papers/iee95_gps.pdf >> >> http://bbcr.uwaterloo.ca/%7Ewzhuang/papers/iee95_gps.pdf >> >> Since the better timing receivers use carrier phase smoothing of the >> code phase timing, both the carrier phase and code phase performance of >> the antenna are important. >> >> A phased array antenna like the one in the following papers may provide >> better performance than alternative antennae: >> >> http://www.navsys.com/Papers/0001002.pdf >> http://www.congrex.nl/07c12/papers/day1_s1_paper05_Konovaltsev.pdf >> >> Some measurements with geodetic antennae: >> http://www.fig.net/pub/fig2008/papers/ts05g/ts05g_03_eventzur_shaked_2816.pdf >> >> >> Comparison of code phase and carrier phase time transfer: >> http://tycho.usno.navy.mil/ptti/ptti2004/paper41.pdf >> >> Bruce >> >> ** >> WarrenS wrote: >>> Brian wrote: >>> >>>> "There were also comments about surveying and timing antennas." >>> Those may of been from me, unsuccessfully trying to make a point of >>> the difference between what is 'Best' and what is 'GOOD enough'. >>> >>>> "about every national timing laboratory uses choke ring antennas. >>>> ... for timing stability reasons." >>> Then again they also have multiple CS and Just their Antenna budget is >>> likely more than the annual income of most time nuts. >>> Can you do a test to show IF there is ANY improvement for the AVERAGE >>> time nut when compared to a well setup (Tbolt) GPSDO using a TacoSalad >>> antenna? >>> >>> Would be interesting to see a plot of cost vs. performance for the >>> various antenna types, >>> Scaled to show the performance improvement that the average Time nut >>> would see. >>> The TacoSalad antenna, originally cost me a total of $7.95, And took >>> under 30 seconds to build. >>> That cost should be discounted because those parts had been considered >>> just throw away junk up until now. >>> >>> ws >>> &g
Re: [time-nuts] Choke Ring Pictures
WarrenS wrote: Bruce wrote: "Which antenna performance metric do you have in mind?" Could do GPSDO hold over performance, but that would not be much of a test of the antenna. How about the antenna's effect on the ADEV Osc noise and Phase noise. What else does the Time Nut care about? Since the better timing receivers use carrier phase ... I don't remember you ever finding ANY Time Nut that is now using one. So may be simpler for now to just stick to the more common type of GPSDO in use. The Motorola M12+T and iLotus M12M use carrier phase smoothing of the code phase observables. Its highly likely that a number of the better performance GPS timing receivers also use carrier phase smoothing. Thus whether one is aware of it or not the antenna carrier phase properties are likely to be of some importance. In the absence of complete information on how your particular GPS timing receiver uses carrier phase and code phase observables, the best you can do is compare the performance of a range of antennas using a given timing receiver. Such results will only apply to a particular site and receiver. Specifying the pertinent characteristics (eg isolated on a flat plain, surrounded by a set of hills, mountains which obscure the sky below 10 degrees, surrounded by trees that obscure everything below 40 degeees elevation, etc) of your antenna location and the particular GPS receiver used will be helpful to others in selecting an antenna that suits their budget, receiver, antenna location constraints, etc. Bruce ws * Bruce said: Which antenna performance metric do you have in mind? There are several, some of which are considered in the paper: http://www.novatel.com/Documents/Papers/effectofantenna.pdf Since the topography surrounding the antenna, its height and location on the Earth all affect measured performance any comparative measurements should use the same receiver and antenna location. Some estimates for the effect of multipath on code phase receivers can be found: http://bbcr.uwaterloo.ca/~wzhuang/papers/iee95_gps.pdf http://bbcr.uwaterloo.ca/%7Ewzhuang/papers/iee95_gps.pdf Since the better timing receivers use carrier phase smoothing of the code phase timing, both the carrier phase and code phase performance of the antenna are important. A phased array antenna like the one in the following papers may provide better performance than alternative antennae: http://www.navsys.com/Papers/0001002.pdf http://www.congrex.nl/07c12/papers/day1_s1_paper05_Konovaltsev.pdf Some measurements with geodetic antennae: http://www.fig.net/pub/fig2008/papers/ts05g/ts05g_03_eventzur_shaked_2816.pdf Comparison of code phase and carrier phase time transfer: http://tycho.usno.navy.mil/ptti/ptti2004/paper41.pdf Bruce ** WarrenS wrote: Brian wrote: "There were also comments about surveying and timing antennas." Those may of been from me, unsuccessfully trying to make a point of the difference between what is 'Best' and what is 'GOOD enough'. "about every national timing laboratory uses choke ring antennas. ... for timing stability reasons." Then again they also have multiple CS and Just their Antenna budget is likely more than the annual income of most time nuts. Can you do a test to show IF there is ANY improvement for the AVERAGE time nut when compared to a well setup (Tbolt) GPSDO using a TacoSalad antenna? Would be interesting to see a plot of cost vs. performance for the various antenna types, Scaled to show the performance improvement that the average Time nut would see. The TacoSalad antenna, originally cost me a total of $7.95, And took under 30 seconds to build. That cost should be discounted because those parts had been considered just throw away junk up until now. ws ** - Original Message - From: "Brian Kirby" To: "Discussion of precise time and frequency measurement" Sent: Monday, March 15, 2010 2:09 PM Subject: Re: [time-nuts] Choke Ring Pictures Dr. Clark passed on a tip that I used. Put the funnel in a microwave oven and run it and see if the funnel warms up. If it warms up, you do not use it. I do not know what type of plastic the funnel was made out of; it was white, semi-transparent. There were also comments about surveying and timing antennas. If you investigate about every national timing laboratory uses choke ring antennas. Some enclose the antenna unit and they temperature control it. They do this for timing stability reasons. The commercial timing antenna is bullet shaped and is operated without a ground plane. They are patch antennas. When there is not ground plane, the antenna picks up best from the overhead and less towards the horizon. These antennas usually have a lot more gain (30-50 db vs most normal antennas in the 15-25 db range). Also in surveying, we cut off the horizon at 15 degrees
Re: [time-nuts] Choke Ring Pictures
WarrenS wrote: Bruce wrote: "Which antenna performance metric do you have in mind?" Could do GPSDO hold over performance, but that would not be much of a test of the antenna. How about the antenna's effect on the ADEV Osc noise and Phase noise. What else does the Time Nut care about? Multipath rejection, antenna selectivity, antenna amplifier gain, antenna noise factor... all weigh in. Even for a simple Thunderbolt. Since the better timing receivers use carrier phase ... I don't remember you ever finding ANY Time Nut that is now using one. So may be simpler for now to just stick to the more common type of GPSDO in use. Several of us have carrier phase and dual frequency receivers. I have several myself. I lack a good double-frequency antenna, choke-ring with sufficient amplifier gain. 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] Choke Ring Pictures
Great resource and timing , I just finished ' Tuxedo Park ' and now know where the L in Loran came from Steve --- On Mon, 3/15/10, Bruce Griffiths wrote: From: Bruce Griffiths Subject: Re: [time-nuts] Choke Ring Pictures To: "Discussion of precise time and frequency measurement" Date: Monday, March 15, 2010, 1:34 PM For some idea of the considerations involved in selecting materials for and designing a radome see: http://ia331316.us.archive.org/0/items/radarscannersand033384mbp/radarscannersand033384mbp.pdf A list of the properties of some dielectrics at microwave frequencies in inluded. Bruce Bob Camp wrote: > Hi > > Any idea what the funnel was made out of? Some plastics aren't real great at > microwaves... > > Bob > > -Original Message- > From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On > Behalf Of Brian Kirby > Sent: Sunday, March 14, 2010 8:50 PM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] Choke Ring Pictures > > The home made choke ring was calculated and the pie/cake pans came > close. I think somebody all ready pointed at it, but Unavco or NASA had > the dimensions to about 6 or 8 common choke ring reflectors on line. > > They are aluminum cake pans - I bought them in a crafts store. They are > one inch apart between the rings. They are 2 inches deep at the rims. > The outside pan is 12 inches (measured inside). Next is 10 inch, then > 8 inch, then 6 inch, and 4 inch. > > When making them, I found the center of each pan and then drilled them. > Then I used a bolt to hold them all together except for the very center > unit. Then I drilled two holes about and inch from the center and used > thin long bolts to attach them to a piece of square tubing on the > bottom. The alignment bolt was removed from the center hole and > drilled out larger to pass the antenna coax thru. The very center > pan, I used epoxies to glue the antenna too and I used a clamp to hold > it in place. Then the coax was pass thru a hole I drilled out thru > the center holes of the other pans. Then I glued the antenna pan to > the other pans and used several blocks of wood to center the pan and a > big piece of pipe and weights as a clamp to hold it down while it was > curing. The square tubing was aligned into a laser level mount and > epoxied and that allows the unit to be attached to a tripod. The mount > has three adjusting screws that allows the antenna to be leveled. I > used the units in pairs when surveying and always aligned then north in > an attempt to bias out centering differences. > > The first unit mounted on the house roof did have a drainage problem the > first time it rained. I drilled 1/8 holes inside of each ring to let it > run out. That was not the worst problem. A bird decided it would make > a good home and started building a nest on it when I went on vacation. > I bought a large plastic funnel and inverted it and glued it inside of > the outer ring to stop that. > > The antenna is the common Antenna97 from Motorola, the coax was cut at > about one foot (I think it was originally 18 feet long) and a connector > was attached. I then used a very low loss coax (1/2 inch heliax) about > 40 feet long to bring it into the basement. > > Brian - KD4FM > > > > ___ > 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] Choke Ring Pictures
Bruce wrote: "Which antenna performance metric do you have in mind?" Could do GPSDO hold over performance, but that would not be much of a test of the antenna. How about the antenna's effect on the ADEV Osc noise and Phase noise. What else does the Time Nut care about? Since the better timing receivers use carrier phase ... I don't remember you ever finding ANY Time Nut that is now using one. So may be simpler for now to just stick to the more common type of GPSDO in use. ws * Bruce said: Which antenna performance metric do you have in mind? There are several, some of which are considered in the paper: http://www.novatel.com/Documents/Papers/effectofantenna.pdf Since the topography surrounding the antenna, its height and location on the Earth all affect measured performance any comparative measurements should use the same receiver and antenna location. Some estimates for the effect of multipath on code phase receivers can be found: http://bbcr.uwaterloo.ca/~wzhuang/papers/iee95_gps.pdf http://bbcr.uwaterloo.ca/%7Ewzhuang/papers/iee95_gps.pdf Since the better timing receivers use carrier phase smoothing of the code phase timing, both the carrier phase and code phase performance of the antenna are important. A phased array antenna like the one in the following papers may provide better performance than alternative antennae: http://www.navsys.com/Papers/0001002.pdf http://www.congrex.nl/07c12/papers/day1_s1_paper05_Konovaltsev.pdf Some measurements with geodetic antennae: http://www.fig.net/pub/fig2008/papers/ts05g/ts05g_03_eventzur_shaked_2816.pdf Comparison of code phase and carrier phase time transfer: http://tycho.usno.navy.mil/ptti/ptti2004/paper41.pdf Bruce ** WarrenS wrote: Brian wrote: "There were also comments about surveying and timing antennas." Those may of been from me, unsuccessfully trying to make a point of the difference between what is 'Best' and what is 'GOOD enough'. "about every national timing laboratory uses choke ring antennas. ... for timing stability reasons." Then again they also have multiple CS and Just their Antenna budget is likely more than the annual income of most time nuts. Can you do a test to show IF there is ANY improvement for the AVERAGE time nut when compared to a well setup (Tbolt) GPSDO using a TacoSalad antenna? Would be interesting to see a plot of cost vs. performance for the various antenna types, Scaled to show the performance improvement that the average Time nut would see. The TacoSalad antenna, originally cost me a total of $7.95, And took under 30 seconds to build. That cost should be discounted because those parts had been considered just throw away junk up until now. ws ** - Original Message - From: "Brian Kirby" To: "Discussion of precise time and frequency measurement" Sent: Monday, March 15, 2010 2:09 PM Subject: Re: [time-nuts] Choke Ring Pictures Dr. Clark passed on a tip that I used. Put the funnel in a microwave oven and run it and see if the funnel warms up. If it warms up, you do not use it. I do not know what type of plastic the funnel was made out of; it was white, semi-transparent. There were also comments about surveying and timing antennas. If you investigate about every national timing laboratory uses choke ring antennas. Some enclose the antenna unit and they temperature control it. They do this for timing stability reasons. The commercial timing antenna is bullet shaped and is operated without a ground plane. They are patch antennas. When there is not ground plane, the antenna picks up best from the overhead and less towards the horizon. These antennas usually have a lot more gain (30-50 db vs most normal antennas in the 15-25 db range). Also in surveying, we cut off the horizon at 15 degrees in software. A free Army Corp of Engineering manual on GPS Surveying is at http://140.194.76.129/publications/eng-manuals/em1110-1-1003/toc.htm The main difference in surveying and timing is in surveying they use the carrier phase method, were in timing most use a solution derived from the processing of the coarse acquisition code, in were the receiver is in a fixed over-determined position . Some timing labs are using carrier phase method, when they need more resolution. Brian - KD4FM warrens wrote: ... Preliminary results for the Taco Dish GPS antenna as an indoor antenna are looking good. Certainly worth considering if your GPS antenna is stuck indoors, 'Out of the rain in the living room'. I find it best to rise it up near the ceiling such as on an upper shelf with nothing above it. It would be hard to tell the difference between the GPSDO performance obtained from this or the Best outdoor antenna if using a Tbolt set to the standard default settings. Picture attached ws ** __
Re: [time-nuts] Choke Ring Pictures
Hi The helix was the original "NBS" antenna for GPS. Lucent's antenna dates back to the early 80's. The patch came along later. There are some significant differences between them, few of which matter in normal time nut applications. It's pretty easy to translate surveying units into timing units as far as just the antenna is concerned. All you really need to know is the speed of light. For quick calculations 30 cm = 1 ns. If you are moving around an extra +/- 1 M with antenna X, then you have ~ +/- 3.3 ns flopping around that you otherwise would not have. Bob On Mar 15, 2010, at 7:12 PM, Brian Kirby wrote: > And the Andrew , Motorola and Pansonic have patches > > Brooke Clarke wrote: >> Hi Brian: >> >> The Lucent bullet antenna has a quad helix antenna structure, photos at: >> http://www.prc68.com/I/DAGR.shtml#Ant and scroll down, >> or maybe faster go to: >> http://www.prc68.com/I/DAGR.shtml#DC >> and scroll up. >> >> Have Fun, >> >> Brooke Clarke >> http://www.PRC68.com >> >> >> Brian Kirby wrote: >>> Dr. Clark passed on a tip that I used. Put the funnel in a microwave oven >>> and run it and see if the funnel warms up. If it warms up, you do not use >>> it. I do not know what type of plastic the funnel was made out of; it was >>> white, semi-transparent. >>> >>> There were also comments about surveying and timing antennas. If you >>> investigate about every national timing laboratory uses choke ring >>> antennas. Some enclose the antenna unit and they temperature control it. >>> They do this for timing stability reasons. >>> >>> The commercial timing antenna is bullet shaped and is operated without a >>> ground plane. They are patch antennas. When there is not ground plane, >>> the antenna picks up best from the overhead and less towards the horizon. >>> These antennas usually have a lot more gain (30-50 db vs most normal >>> antennas in the 15-25 db range). >>> Also in surveying, we cut off the horizon at 15 degrees in software. A >>> free Army Corp of Engineering manual on GPS Surveying is at >>> http://140.194.76.129/publications/eng-manuals/em1110-1-1003/toc.htm >>> The main difference in surveying and timing is in surveying they use the >>> carrier phase method, were in timing most use a solution derived from the >>> processing of the coarse acquisition code, in were the receiver is in a >>> fixed over-determined position . Some timing labs are using carrier phase >>> method, when they need more resolution. >>> >>> Brian - KD4FM >>> >>> >>> >>> Bob Camp wrote: Hi Any idea what the funnel was made out of? Some plastics aren't real great at microwaves... 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. >>> >>> >> >> >> ___ >> 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] Choke Ring Pictures
Which antenna performance metric do you have in mind? There are several, some of which are considered in the paper: http://www.novatel.com/Documents/Papers/effectofantenna.pdf Since the topography surrounding the antenna, its height and location on the Earth all affect measured performance any comparative measurements should use the same receiver and antenna location. Some estimates for the effect of multipath on code phase receivers can be found: http://bbcr.uwaterloo.ca/~wzhuang/papers/iee95_gps.pdf <http://bbcr.uwaterloo.ca/%7Ewzhuang/papers/iee95_gps.pdf> Since the better timing receivers use carrier phase smoothing of the code phase timing, both the carrier phase and code phase performance of the antenna are important. A phased array antenna like the one in the following papers may provide better performance than alternative antennae: http://www.navsys.com/Papers/0001002.pdf http://www.congrex.nl/07c12/papers/day1_s1_paper05_Konovaltsev.pdf Some measurements with geodetic antennae: http://www.fig.net/pub/fig2008/papers/ts05g/ts05g_03_eventzur_shaked_2816.pdf Comparison of code phase and carrier phase time transfer: http://tycho.usno.navy.mil/ptti/ptti2004/paper41.pdf Bruce WarrenS wrote: Brian wrote: "There were also comments about surveying and timing antennas." Those may of been from me, unsuccessfully trying to make a point of the difference between what is 'Best' and what is 'GOOD enough'. "about every national timing laboratory uses choke ring antennas. ... for timing stability reasons." Then again they also have multiple CS and Just their Antenna budget is likely more than the annual income of most time nuts. Can you do a test to show IF there is ANY improvement for the AVERAGE time nut when compared to a well setup (Tbolt) GPSDO using a TacoSalad antenna? Would be interesting to see a plot of cost vs. performance for the various antenna types, Scaled to show the performance improvement that the average Time nut would see. The TacoSalad antenna, originally cost me a total of $7.95, And took under 30 seconds to build. That cost should be discounted because those parts had been considered just throw away junk up until now. ws ** - Original Message - From: "Brian Kirby" To: "Discussion of precise time and frequency measurement" Sent: Monday, March 15, 2010 2:09 PM Subject: Re: [time-nuts] Choke Ring Pictures Dr. Clark passed on a tip that I used. Put the funnel in a microwave oven and run it and see if the funnel warms up. If it warms up, you do not use it. I do not know what type of plastic the funnel was made out of; it was white, semi-transparent. There were also comments about surveying and timing antennas. If you investigate about every national timing laboratory uses choke ring antennas. Some enclose the antenna unit and they temperature control it. They do this for timing stability reasons. The commercial timing antenna is bullet shaped and is operated without a ground plane. They are patch antennas. When there is not ground plane, the antenna picks up best from the overhead and less towards the horizon. These antennas usually have a lot more gain (30-50 db vs most normal antennas in the 15-25 db range). Also in surveying, we cut off the horizon at 15 degrees in software. A free Army Corp of Engineering manual on GPS Surveying is at http://140.194.76.129/publications/eng-manuals/em1110-1-1003/toc.htm The main difference in surveying and timing is in surveying they use the carrier phase method, were in timing most use a solution derived from the processing of the coarse acquisition code, in were the receiver is in a fixed over-determined position . Some timing labs are using carrier phase method, when they need more resolution. Brian - KD4FM warrens wrote: ... Preliminary results for the Taco Dish GPS antenna as an indoor antenna are looking good. Certainly worth considering if your GPS antenna is stuck indoors, 'Out of the rain in the living room'. I find it best to rise it up near the ceiling such as on an upper shelf with nothing above it. It would be hard to tell the difference between the GPSDO performance obtained from this or the Best outdoor antenna if using a Tbolt set to the standard default settings. Picture attached ws ** ___ 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] Choke Ring Pictures
I can't do any antenna comparisons. The choke ring was at my house - I now live in a apartment and the landlord allowed me to put a patch antenna on the edge of the roof (and his rules are no external antenna - got his permission before moving in). I would expect the average patch antenna with a ground plane would be good enough for any gps receiver as long as the antenna has enough gain and transmission line loss is acceptable. I showed the pictures, because somebody ask me about them a couple of years ago and I forgot. And they were made for a multi path problem, and it stopped it. The reason I made the other two was for testing carrier phase surveying with the Motorola Oncore VPZ receiver. I was able to get down to the inch level with these units - maybe if they were commercial they may have done better. It was an experiment for myself. As with any hobby, you can spend what you want, your choice. WarrenS wrote: Brian wrote: "There were also comments about surveying and timing antennas." Those may of been from me, unsuccessfully trying to make a point of the difference between what is 'Best' and what is 'GOOD enough'. "about every national timing laboratory uses choke ring antennas. ... for timing stability reasons." Then again they also have multiple CS and Just their Antenna budget is likely more than the annual income of most time nuts. Can you do a test to show IF there is ANY improvement for the AVERAGE time nut when compared to a well setup (Tbolt) GPSDO using a TacoSalad antenna? Would be interesting to see a plot of cost vs. performance for the various antenna types, Scaled to show the performance improvement that the average Time nut would see. The TacoSalad antenna, originally cost me a total of $7.95, And took under 30 seconds to build. That cost should be discounted because those parts had been considered just throw away junk up until now. ws ** - Original Message - From: "Brian Kirby" To: "Discussion of precise time and frequency measurement" Sent: Monday, March 15, 2010 2:09 PM Subject: Re: [time-nuts] Choke Ring Pictures Dr. Clark passed on a tip that I used. Put the funnel in a microwave oven and run it and see if the funnel warms up. If it warms up, you do not use it. I do not know what type of plastic the funnel was made out of; it was white, semi-transparent. There were also comments about surveying and timing antennas. If you investigate about every national timing laboratory uses choke ring antennas. Some enclose the antenna unit and they temperature control it. They do this for timing stability reasons. The commercial timing antenna is bullet shaped and is operated without a ground plane. They are patch antennas. When there is not ground plane, the antenna picks up best from the overhead and less towards the horizon. These antennas usually have a lot more gain (30-50 db vs most normal antennas in the 15-25 db range). Also in surveying, we cut off the horizon at 15 degrees in software. A free Army Corp of Engineering manual on GPS Surveying is at http://140.194.76.129/publications/eng-manuals/em1110-1-1003/toc.htm The main difference in surveying and timing is in surveying they use the carrier phase method, were in timing most use a solution derived from the processing of the coarse acquisition code, in were the receiver is in a fixed over-determined position . Some timing labs are using carrier phase method, when they need more resolution. Brian - KD4FM warrens wrote: ... Preliminary results for the Taco Dish GPS antenna as an indoor antenna are looking good. Certainly worth considering if your GPS antenna is stuck indoors, 'Out of the rain in the living room'. I find it best to rise it up near the ceiling such as on an upper shelf with nothing above it. It would be hard to tell the difference between the GPSDO performance obtained from this or the Best outdoor antenna if using a Tbolt set to the standard default settings. Picture attached ws ** ___ 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] Choke Ring Pictures
And the Andrew , Motorola and Pansonic have patches Brooke Clarke wrote: Hi Brian: The Lucent bullet antenna has a quad helix antenna structure, photos at: http://www.prc68.com/I/DAGR.shtml#Ant and scroll down, or maybe faster go to: http://www.prc68.com/I/DAGR.shtml#DC and scroll up. Have Fun, Brooke Clarke http://www.PRC68.com Brian Kirby wrote: Dr. Clark passed on a tip that I used. Put the funnel in a microwave oven and run it and see if the funnel warms up. If it warms up, you do not use it. I do not know what type of plastic the funnel was made out of; it was white, semi-transparent. There were also comments about surveying and timing antennas. If you investigate about every national timing laboratory uses choke ring antennas. Some enclose the antenna unit and they temperature control it. They do this for timing stability reasons. The commercial timing antenna is bullet shaped and is operated without a ground plane. They are patch antennas. When there is not ground plane, the antenna picks up best from the overhead and less towards the horizon. These antennas usually have a lot more gain (30-50 db vs most normal antennas in the 15-25 db range). Also in surveying, we cut off the horizon at 15 degrees in software. A free Army Corp of Engineering manual on GPS Surveying is at http://140.194.76.129/publications/eng-manuals/em1110-1-1003/toc.htm The main difference in surveying and timing is in surveying they use the carrier phase method, were in timing most use a solution derived from the processing of the coarse acquisition code, in were the receiver is in a fixed over-determined position . Some timing labs are using carrier phase method, when they need more resolution. Brian - KD4FM Bob Camp wrote: Hi Any idea what the funnel was made out of? Some plastics aren't real great at microwaves... 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. ___ 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] Choke Ring Pictures
Brian wrote: "There were also comments about surveying and timing antennas." Those may of been from me, unsuccessfully trying to make a point of the difference between what is 'Best' and what is 'GOOD enough'. "about every national timing laboratory uses choke ring antennas. ... for timing stability reasons." Then again they also have multiple CS and Just their Antenna budget is likely more than the annual income of most time nuts. Can you do a test to show IF there is ANY improvement for the AVERAGE time nut when compared to a well setup (Tbolt) GPSDO using a TacoSalad antenna? Would be interesting to see a plot of cost vs. performance for the various antenna types, Scaled to show the performance improvement that the average Time nut would see. The TacoSalad antenna, originally cost me a total of $7.95, And took under 30 seconds to build. That cost should be discounted because those parts had been considered just throw away junk up until now. ws ** - Original Message - From: "Brian Kirby" To: "Discussion of precise time and frequency measurement" Sent: Monday, March 15, 2010 2:09 PM Subject: Re: [time-nuts] Choke Ring Pictures Dr. Clark passed on a tip that I used. Put the funnel in a microwave oven and run it and see if the funnel warms up. If it warms up, you do not use it. I do not know what type of plastic the funnel was made out of; it was white, semi-transparent. There were also comments about surveying and timing antennas. If you investigate about every national timing laboratory uses choke ring antennas. Some enclose the antenna unit and they temperature control it. They do this for timing stability reasons. The commercial timing antenna is bullet shaped and is operated without a ground plane. They are patch antennas. When there is not ground plane, the antenna picks up best from the overhead and less towards the horizon. These antennas usually have a lot more gain (30-50 db vs most normal antennas in the 15-25 db range). Also in surveying, we cut off the horizon at 15 degrees in software. A free Army Corp of Engineering manual on GPS Surveying is at http://140.194.76.129/publications/eng-manuals/em1110-1-1003/toc.htm The main difference in surveying and timing is in surveying they use the carrier phase method, were in timing most use a solution derived from the processing of the coarse acquisition code, in were the receiver is in a fixed over-determined position . Some timing labs are using carrier phase method, when they need more resolution. Brian - KD4FM warrens wrote: ... Preliminary results for the Taco Dish GPS antenna as an indoor antenna are looking good. Certainly worth considering if your GPS antenna is stuck indoors, 'Out of the rain in the living room'. I find it best to rise it up near the ceiling such as on an upper shelf with nothing above it. It would be hard to tell the difference between the GPSDO performance obtained from this or the Best outdoor antenna if using a Tbolt set to the standard default settings. Picture attached ws ** ___ 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] Choke Ring Pictures
Hi Brian: The Lucent bullet antenna has a quad helix antenna structure, photos at: http://www.prc68.com/I/DAGR.shtml#Ant and scroll down, or maybe faster go to: http://www.prc68.com/I/DAGR.shtml#DC and scroll up. Have Fun, Brooke Clarke http://www.PRC68.com Brian Kirby wrote: Dr. Clark passed on a tip that I used. Put the funnel in a microwave oven and run it and see if the funnel warms up. If it warms up, you do not use it. I do not know what type of plastic the funnel was made out of; it was white, semi-transparent. There were also comments about surveying and timing antennas. If you investigate about every national timing laboratory uses choke ring antennas. Some enclose the antenna unit and they temperature control it. They do this for timing stability reasons. The commercial timing antenna is bullet shaped and is operated without a ground plane. They are patch antennas. When there is not ground plane, the antenna picks up best from the overhead and less towards the horizon. These antennas usually have a lot more gain (30-50 db vs most normal antennas in the 15-25 db range). Also in surveying, we cut off the horizon at 15 degrees in software. A free Army Corp of Engineering manual on GPS Surveying is at http://140.194.76.129/publications/eng-manuals/em1110-1-1003/toc.htm The main difference in surveying and timing is in surveying they use the carrier phase method, were in timing most use a solution derived from the processing of the coarse acquisition code, in were the receiver is in a fixed over-determined position . Some timing labs are using carrier phase method, when they need more resolution. Brian - KD4FM Bob Camp wrote: Hi Any idea what the funnel was made out of? Some plastics aren't real great at microwaves... 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. ___ 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] Choke Ring Pictures
Hi If I ever need to duplicate the raydome on a B-29 I now know right where to look. === Lots of math and some crazy looking plots of what happens as you start going at off angles to the material. The problem certainly isn't just one of loss since the raydome acts as sort of a lens over the antenna. No matter what, raydome is a better thing than a bird sitting on top of the antenna. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Bruce Griffiths Sent: Monday, March 15, 2010 4:35 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Choke Ring Pictures For some idea of the considerations involved in selecting materials for and designing a radome see: http://ia331316.us.archive.org/0/items/radarscannersand033384mbp/radarscanne rsand033384mbp.pdf A list of the properties of some dielectrics at microwave frequencies in inluded. Bruce Bob Camp wrote: > Hi > > Any idea what the funnel was made out of? Some plastics aren't real great at > microwaves... > > Bob > > -Original Message- > From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On > Behalf Of Brian Kirby > Sent: Sunday, March 14, 2010 8:50 PM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] Choke Ring Pictures > > The home made choke ring was calculated and the pie/cake pans came > close. I think somebody all ready pointed at it, but Unavco or NASA had > the dimensions to about 6 or 8 common choke ring reflectors on line. > > They are aluminum cake pans - I bought them in a crafts store. They are > one inch apart between the rings. They are 2 inches deep at the rims. > The outside pan is 12 inches (measured inside). Next is 10 inch, then > 8 inch, then 6 inch, and 4 inch. > > When making them, I found the center of each pan and then drilled them. > Then I used a bolt to hold them all together except for the very center > unit. Then I drilled two holes about and inch from the center and used > thin long bolts to attach them to a piece of square tubing on the > bottom. The alignment bolt was removed from the center hole and > drilled out larger to pass the antenna coax thru.The very center > pan, I used epoxies to glue the antenna too and I used a clamp to hold > it in place. Then the coax was pass thru a hole I drilled out thru > the center holes of the other pans. Then I glued the antenna pan to > the other pans and used several blocks of wood to center the pan and a > big piece of pipe and weights as a clamp to hold it down while it was > curing. The square tubing was aligned into a laser level mount and > epoxied and that allows the unit to be attached to a tripod. The mount > has three adjusting screws that allows the antenna to be leveled. I > used the units in pairs when surveying and always aligned then north in > an attempt to bias out centering differences. > > The first unit mounted on the house roof did have a drainage problem the > first time it rained. I drilled 1/8 holes inside of each ring to let it > run out. That was not the worst problem. A bird decided it would make > a good home and started building a nest on it when I went on vacation. > I bought a large plastic funnel and inverted it and glued it inside of > the outer ring to stop that. > > The antenna is the common Antenna97 from Motorola, the coax was cut at > about one foot (I think it was originally 18 feet long) and a connector > was attached. I then used a very low loss coax (1/2 inch heliax) about > 40 feet long to bring it into the basement. > > Brian - KD4FM > > > > ___ > 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] Choke Ring Pictures
Dr. Clark passed on a tip that I used. Put the funnel in a microwave oven and run it and see if the funnel warms up. If it warms up, you do not use it. I do not know what type of plastic the funnel was made out of; it was white, semi-transparent. There were also comments about surveying and timing antennas. If you investigate about every national timing laboratory uses choke ring antennas. Some enclose the antenna unit and they temperature control it. They do this for timing stability reasons. The commercial timing antenna is bullet shaped and is operated without a ground plane. They are patch antennas. When there is not ground plane, the antenna picks up best from the overhead and less towards the horizon. These antennas usually have a lot more gain (30-50 db vs most normal antennas in the 15-25 db range). Also in surveying, we cut off the horizon at 15 degrees in software. A free Army Corp of Engineering manual on GPS Surveying is at http://140.194.76.129/publications/eng-manuals/em1110-1-1003/toc.htm The main difference in surveying and timing is in surveying they use the carrier phase method, were in timing most use a solution derived from the processing of the coarse acquisition code, in were the receiver is in a fixed over-determined position . Some timing labs are using carrier phase method, when they need more resolution. Brian - KD4FM Bob Camp wrote: Hi Any idea what the funnel was made out of? Some plastics aren't real great at microwaves... 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] Choke Ring Pictures
For some idea of the considerations involved in selecting materials for and designing a radome see: http://ia331316.us.archive.org/0/items/radarscannersand033384mbp/radarscannersand033384mbp.pdf A list of the properties of some dielectrics at microwave frequencies in inluded. Bruce Bob Camp wrote: Hi Any idea what the funnel was made out of? Some plastics aren't real great at microwaves... Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Brian Kirby Sent: Sunday, March 14, 2010 8:50 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Choke Ring Pictures The home made choke ring was calculated and the pie/cake pans came close. I think somebody all ready pointed at it, but Unavco or NASA had the dimensions to about 6 or 8 common choke ring reflectors on line. They are aluminum cake pans - I bought them in a crafts store. They are one inch apart between the rings. They are 2 inches deep at the rims. The outside pan is 12 inches (measured inside). Next is 10 inch, then 8 inch, then 6 inch, and 4 inch. When making them, I found the center of each pan and then drilled them. Then I used a bolt to hold them all together except for the very center unit. Then I drilled two holes about and inch from the center and used thin long bolts to attach them to a piece of square tubing on the bottom. The alignment bolt was removed from the center hole and drilled out larger to pass the antenna coax thru.The very center pan, I used epoxies to glue the antenna too and I used a clamp to hold it in place. Then the coax was pass thru a hole I drilled out thru the center holes of the other pans. Then I glued the antenna pan to the other pans and used several blocks of wood to center the pan and a big piece of pipe and weights as a clamp to hold it down while it was curing. The square tubing was aligned into a laser level mount and epoxied and that allows the unit to be attached to a tripod. The mount has three adjusting screws that allows the antenna to be leveled. I used the units in pairs when surveying and always aligned then north in an attempt to bias out centering differences. The first unit mounted on the house roof did have a drainage problem the first time it rained. I drilled 1/8 holes inside of each ring to let it run out. That was not the worst problem. A bird decided it would make a good home and started building a nest on it when I went on vacation. I bought a large plastic funnel and inverted it and glued it inside of the outer ring to stop that. The antenna is the common Antenna97 from Motorola, the coax was cut at about one foot (I think it was originally 18 feet long) and a connector was attached. I then used a very low loss coax (1/2 inch heliax) about 40 feet long to bring it into the basement. Brian - KD4FM ___ 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] Choke Ring Pictures
Hi Any idea what the funnel was made out of? Some plastics aren't real great at microwaves... Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Brian Kirby Sent: Sunday, March 14, 2010 8:50 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Choke Ring Pictures The home made choke ring was calculated and the pie/cake pans came close. I think somebody all ready pointed at it, but Unavco or NASA had the dimensions to about 6 or 8 common choke ring reflectors on line. They are aluminum cake pans - I bought them in a crafts store. They are one inch apart between the rings. They are 2 inches deep at the rims. The outside pan is 12 inches (measured inside). Next is 10 inch, then 8 inch, then 6 inch, and 4 inch. When making them, I found the center of each pan and then drilled them. Then I used a bolt to hold them all together except for the very center unit. Then I drilled two holes about and inch from the center and used thin long bolts to attach them to a piece of square tubing on the bottom. The alignment bolt was removed from the center hole and drilled out larger to pass the antenna coax thru.The very center pan, I used epoxies to glue the antenna too and I used a clamp to hold it in place. Then the coax was pass thru a hole I drilled out thru the center holes of the other pans. Then I glued the antenna pan to the other pans and used several blocks of wood to center the pan and a big piece of pipe and weights as a clamp to hold it down while it was curing. The square tubing was aligned into a laser level mount and epoxied and that allows the unit to be attached to a tripod. The mount has three adjusting screws that allows the antenna to be leveled. I used the units in pairs when surveying and always aligned then north in an attempt to bias out centering differences. The first unit mounted on the house roof did have a drainage problem the first time it rained. I drilled 1/8 holes inside of each ring to let it run out. That was not the worst problem. A bird decided it would make a good home and started building a nest on it when I went on vacation. I bought a large plastic funnel and inverted it and glued it inside of the outer ring to stop that. The antenna is the common Antenna97 from Motorola, the coax was cut at about one foot (I think it was originally 18 feet long) and a connector was attached. I then used a very low loss coax (1/2 inch heliax) about 40 feet long to bring it into the basement. Brian - KD4FM ___ 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] Choke Ring Pictures
The home made choke ring was calculated and the pie/cake pans came close. I think somebody all ready pointed at it, but Unavco or NASA had the dimensions to about 6 or 8 common choke ring reflectors on line. They are aluminum cake pans - I bought them in a crafts store. They are one inch apart between the rings. They are 2 inches deep at the rims. The outside pan is 12 inches (measured inside). Next is 10 inch, then 8 inch, then 6 inch, and 4 inch. When making them, I found the center of each pan and then drilled them. Then I used a bolt to hold them all together except for the very center unit. Then I drilled two holes about and inch from the center and used thin long bolts to attach them to a piece of square tubing on the bottom. The alignment bolt was removed from the center hole and drilled out larger to pass the antenna coax thru.The very center pan, I used epoxies to glue the antenna too and I used a clamp to hold it in place. Then the coax was pass thru a hole I drilled out thru the center holes of the other pans. Then I glued the antenna pan to the other pans and used several blocks of wood to center the pan and a big piece of pipe and weights as a clamp to hold it down while it was curing. The square tubing was aligned into a laser level mount and epoxied and that allows the unit to be attached to a tripod. The mount has three adjusting screws that allows the antenna to be leveled. I used the units in pairs when surveying and always aligned then north in an attempt to bias out centering differences. The first unit mounted on the house roof did have a drainage problem the first time it rained. I drilled 1/8 holes inside of each ring to let it run out. That was not the worst problem. A bird decided it would make a good home and started building a nest on it when I went on vacation. I bought a large plastic funnel and inverted it and glued it inside of the outer ring to stop that. The antenna is the common Antenna97 from Motorola, the coax was cut at about one foot (I think it was originally 18 feet long) and a connector was attached. I then used a very low loss coax (1/2 inch heliax) about 40 feet long to bring it into the basement. Brian - KD4FM ___ 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] Choke Ring Pictures
Hi Get a piece of polyethylene sheet (10 mill?). Cut a piece (or three) and put it under the bottom of each plate. Put the set of them in the oven to bake. Probably put some weight on the inner pan. At some magic temperature the poly will melt and flow to fill the gap between pans. It's got good enough dielectric properties at L1 to make a pretty good dielectric "plug" for the small gap. I suspect the same is true of the anodize on the pans. Once it's out of the oven, pop rivet or bolt it all to the mounting plate. I suspect this is one of those things you try for the first time while the rest of the family is conveniently away at the movies and there's a couple of hours available to air out the house before they get back .. Bob On Mar 14, 2010, at 5:42 PM, Magnus Danielson wrote: > Joe Gwinn wrote: >>> >>> Date: Sun, 14 Mar 2010 21:09:00 +0100 >>> From: Magnus Danielson >>> Subject: Re: [time-nuts] Choke Ring Pictures >>> To: Discussion of precise time and frequency measurement >>> >>> Message-ID: <4b9d425c.2050...@rubidium.dyndns.org> >>> Content-Type: text/plain; charset=ISO-8859-1; format=flowed >>> >>> Bob Camp wrote: >>>> Hi >>>> >>>> Wedding cake pans normally come in 1" increments and are either 2" or 3" >>>> deep. Sets are 2" increments on the diameter: >>>> >>>> http://cooksdream.com/store/wedding-round.html >>>> >>>> >>>> http://www.hubert.com/store/products.asp?CAWELAID=126235277&A=SB%2E58369%2E10738&Dn=0&An=966+966&Au=Presentation+Id&Ntt=10738&N=966+966&src=chanadv&Ntx=mode+matchall&D=10738&Ntk=SKU >>>> >>>> >>>> The height would be fairly easy to adjust. The diameter not so much so. >>>> >>>> Looks like 2 and 2.5" are typical dimensions for the depth. ~1" looks >>>> pretty typical for the width. A 2" deep / 2" diameter step set looks like >>>> it would do a pretty good job . It won't be accurate enough to be perfect. >>>> Without a 3D EM program it would be tough to figure out just what the >>>> errors would do to you. >>> >>> With 2.5" depth and 14", 12", 10", 8" and 6" diameter pans you are not >>> completely in a different world from some antennas: >>> >>> http://facility.unavco.org/project_support/permanent/equipment/antennas/ant_cals.html >>> >>> >>> Evaluating the performance may be a different thing. >>> >>> One thing to care about is the leakage between the pans if you just stick >>> them inside each other. >> I'd be tempted to use EMI gaskets between the pans, except that contact will >> soon be lost as the aluminum grows a nice oxide layer. But it may not be >> necessary to make DC electrical contact, as the capacitance between the >> metal layers may suffice to act as a short at 1.5 GHz. A thin sheet of >> mylar (or a heavy anodization layer) between would help this along, by >> increasing the capacitance. > > However it is done, you want it to be fairly stable. Evenly distributed > screws against a stable platform like a steel-plate should do it. > > An alternative is to TIG them together. > > 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] Choke Ring Pictures
Most light alloy cake tins are anodised, so getting consistent contact could be a problem. It's hard to remove the anodising and leave an even surface.. Robert G8RPI. --- On Sun, 14/3/10, Magnus Danielson wrote: From: Magnus Danielson Subject: Re: [time-nuts] Choke Ring Pictures To: "Discussion of precise time and frequency measurement" Date: Sunday, 14 March, 2010, 21:42 Joe Gwinn wrote: >> >> Date: Sun, 14 Mar 2010 21:09:00 +0100 >> From: Magnus Danielson >> Subject: Re: [time-nuts] Choke Ring Pictures >> To: Discussion of precise time and frequency measurement >> >> Message-ID: <4b9d425c.2050...@rubidium.dyndns.org> >> Content-Type: text/plain; charset=ISO-8859-1; format=flowed >> >> Bob Camp wrote: >>> Hi >>> >>> Wedding cake pans normally come in 1" increments and are either 2" or 3" >>>deep. Sets are 2" increments on the diameter: >>> >>> http://cooksdream.com/store/wedding-round.html >>> >>> >>> http://www.hubert.com/store/products.asp?CAWELAID=126235277&A=SB%2E58369%2E10738&Dn=0&An=966+966&Au=Presentation+Id&Ntt=10738&N=966+966&src=chanadv&Ntx=mode+matchall&D=10738&Ntk=SKU >>> >>> >>> The height would be fairly easy to adjust. The diameter not so much so. >>> >>> Looks like 2 and 2.5" are typical dimensions for the depth. ~1" looks >>>pretty typical for the width. A 2" deep / 2" diameter step set looks like it >>>would do a pretty good job . It won't be accurate enough to be perfect. >>>Without a 3D EM program it would be tough to figure out just what the errors >>>would do to you. >> >> With 2.5" depth and 14", 12", 10", 8" and 6" diameter pans you are not >> completely in a different world from some antennas: >> >> http://facility.unavco.org/project_support/permanent/equipment/antennas/ant_cals.html >> >> >> Evaluating the performance may be a different thing. >> >> One thing to care about is the leakage between the pans if you just stick >> them inside each other. > > I'd be tempted to use EMI gaskets between the pans, except that contact will > soon be lost as the aluminum grows a nice oxide layer. But it may not be > necessary to make DC electrical contact, as the capacitance between the metal > layers may suffice to act as a short at 1.5 GHz. A thin sheet of mylar (or a > heavy anodization layer) between would help this along, by increasing the > capacitance. However it is done, you want it to be fairly stable. Evenly distributed screws against a stable platform like a steel-plate should do it. An alternative is to TIG them together. 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] Choke Ring Pictures
Joe Gwinn wrote: Date: Sun, 14 Mar 2010 21:09:00 +0100 From: Magnus Danielson Subject: Re: [time-nuts] Choke Ring Pictures To: Discussion of precise time and frequency measurement Message-ID: <4b9d425c.2050...@rubidium.dyndns.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Bob Camp wrote: Hi Wedding cake pans normally come in 1" increments and are either 2" or 3" deep. Sets are 2" increments on the diameter: http://cooksdream.com/store/wedding-round.html http://www.hubert.com/store/products.asp?CAWELAID=126235277&A=SB%2E58369%2E10738&Dn=0&An=966+966&Au=Presentation+Id&Ntt=10738&N=966+966&src=chanadv&Ntx=mode+matchall&D=10738&Ntk=SKU The height would be fairly easy to adjust. The diameter not so much so. Looks like 2 and 2.5" are typical dimensions for the depth. ~1" looks pretty typical for the width. A 2" deep / 2" diameter step set looks like it would do a pretty good job . It won't be accurate enough to be perfect. Without a 3D EM program it would be tough to figure out just what the errors would do to you. With 2.5" depth and 14", 12", 10", 8" and 6" diameter pans you are not completely in a different world from some antennas: http://facility.unavco.org/project_support/permanent/equipment/antennas/ant_cals.html Evaluating the performance may be a different thing. One thing to care about is the leakage between the pans if you just stick them inside each other. I'd be tempted to use EMI gaskets between the pans, except that contact will soon be lost as the aluminum grows a nice oxide layer. But it may not be necessary to make DC electrical contact, as the capacitance between the metal layers may suffice to act as a short at 1.5 GHz. A thin sheet of mylar (or a heavy anodization layer) between would help this along, by increasing the capacitance. However it is done, you want it to be fairly stable. Evenly distributed screws against a stable platform like a steel-plate should do it. An alternative is to TIG them together. 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] Choke Ring Pictures
Bob Camp wrote: Hi Machining a chunk of Plexiglas sounds like more trouble that I would want to go to for a cheap choke ring setup. Maybe a hemispherical Plexiglass serving bowl take a look at inexpensive light fixtures with hemispherical or spherical plastic globes. Actually, hemispheres are made by softening the acrylic or polycarbonate or styrene sheet over a round hole, and then pulling a small vacuum on it (a vacuum cleaner is more than enough). Pretty easy to do at home.. sheet of plywood or particle board with the right sized hole in it, some heat lamps (or a steady hand with a moving propane torch and flame spreader) ___ 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] Choke Ring Pictures
Date: Sun, 14 Mar 2010 21:09:00 +0100 From: Magnus Danielson Subject: Re: [time-nuts] Choke Ring Pictures To: Discussion of precise time and frequency measurement Message-ID: <4b9d425c.2050...@rubidium.dyndns.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Bob Camp wrote: Hi Wedding cake pans normally come in 1" increments and are either 2" or 3" deep. Sets are 2" increments on the diameter: http://cooksdream.com/store/wedding-round.html http://www.hubert.com/store/products.asp?CAWELAID=126235277&A=SB%2E58369%2E10738&Dn=0&An=966+966&Au=Presentation+Id&Ntt=10738&N=966+966&src=chanadv&Ntx=mode+matchall&D=10738&Ntk=SKU The height would be fairly easy to adjust. The diameter not so much so. Looks like 2 and 2.5" are typical dimensions for the depth. ~1" looks pretty typical for the width. A 2" deep / 2" diameter step set looks like it would do a pretty good job . It won't be accurate enough to be perfect. Without a 3D EM program it would be tough to figure out just what the errors would do to you. With 2.5" depth and 14", 12", 10", 8" and 6" diameter pans you are not completely in a different world from some antennas: http://facility.unavco.org/project_support/permanent/equipment/antennas/ant_cals.html Evaluating the performance may be a different thing. One thing to care about is the leakage between the pans if you just stick them inside each other. I'd be tempted to use EMI gaskets between the pans, except that contact will soon be lost as the aluminum grows a nice oxide layer. But it may not be necessary to make DC electrical contact, as the capacitance between the metal layers may suffice to act as a short at 1.5 GHz. A thin sheet of mylar (or a heavy anodization layer) between would help this along, by increasing the capacitance. Joe Gwinn ___ 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] Choke Ring Pictures
Bob Camp wrote: Hi Wedding cake pans normally come in 1" increments and are either 2" or 3" deep. Sets are 2" increments on the diameter: http://cooksdream.com/store/wedding-round.html http://www.hubert.com/store/products.asp?CAWELAID=126235277&A=SB%2E58369%2E10738&Dn=0&An=966+966&Au=Presentation+Id&Ntt=10738&N=966+966&src=chanadv&Ntx=mode+matchall&D=10738&Ntk=SKU The height would be fairly easy to adjust. The diameter not so much so. Looks like 2 and 2.5" are typical dimensions for the depth. ~1" looks pretty typical for the width. A 2" deep / 2" diameter step set looks like it would do a pretty good job . It won't be accurate enough to be perfect. Without a 3D EM program it would be tough to figure out just what the errors would do to you. With 2.5" depth and 14", 12", 10", 8" and 6" diameter pans you are not completely in a different world from some antennas: http://facility.unavco.org/project_support/permanent/equipment/antennas/ant_cals.html Evaluating the performance may be a different thing. One thing to care about is the leakage between the pans if you just stick them inside each other. Wonder just how effective solution it would be. 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] Choke Ring Pictures
Hi Machining a chunk of Plexiglas sounds like more trouble that I would want to go to for a cheap choke ring setup. Maybe a hemispherical Plexiglass serving bowl Bob On Mar 14, 2010, at 3:42 PM, b...@lysator.liu.se wrote: > Hi, > > I have two AT575-90s - the Aeroantenna L1 chokering - resold by CMC, Leica > and others. They work really well as witnessed by others here. One nice > touch is that they - at least the CMC badged - come with a > "marine"-thread to 5/8" survey-mount adapter. > > However, this model is not present at > > http://www.ngs.noaa.gov/cgi-bin/query_cal_antennas.prl?Model=AER > > so it does not count as a true geodetic antenna. ;-) > > The cone cover is indeed good. Snow/ice-buildup would have been a > showstopper this year in Sweden. For real geodetic use "spike"-cones are > long out of fashion. From my understanding a thin plexiglas makes good > cone material. Combine a halfsphere (upper) with a suitable lenght "tube". > Make the center of the sphere as close to the phase center of the antenna > as possible. > > Here is an illustration. > > http://swepos.lmv.lm.se/stationer/opp.htm > > -- > > Björn > >> Hi >> >> All of these gizmos are going to work better outdoors than indoors. Coming >> up with a rainproof / bird proof / bug proof cover for the choke ring that >> also is rational at RF is one more "gotcha". Both loss and dielectric >> distortion effects are worth worrying about. >> >> Bob >> >> >> On Mar 14, 2010, at 1:23 PM, gandal...@aol.com wrote: >> >>> In a message dated 14/03/2010 15:46:55 GMT Standard Time, >>> cfhar...@erols.com writes: >>> >>> I would call those aluminum cake, not pie, pans. It looks like you >>> bought >>> a set for making wedding cakes. >>> >>> Is there a different definition of "pie" in G8 land? >>> - >>> Hi Chuck >>> >>> No other definition that I'm aware of, other than David's of course, but >>> I >>> was just replying to Brian, KD4FM, so I guess that makes it a US of A >>> definition:-) >>> >>> 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. >> > > > > ___ > 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] Choke Ring Pictures
Hi, I have two AT575-90s - the Aeroantenna L1 chokering - resold by CMC, Leica and others. They work really well as witnessed by others here. One nice touch is that they - at least the CMC badged - come with a "marine"-thread to 5/8" survey-mount adapter. However, this model is not present at http://www.ngs.noaa.gov/cgi-bin/query_cal_antennas.prl?Model=AER so it does not count as a true geodetic antenna. ;-) The cone cover is indeed good. Snow/ice-buildup would have been a showstopper this year in Sweden. For real geodetic use "spike"-cones are long out of fashion. From my understanding a thin plexiglas makes good cone material. Combine a halfsphere (upper) with a suitable lenght "tube". Make the center of the sphere as close to the phase center of the antenna as possible. Here is an illustration. http://swepos.lmv.lm.se/stationer/opp.htm -- Björn > Hi > > All of these gizmos are going to work better outdoors than indoors. Coming > up with a rainproof / bird proof / bug proof cover for the choke ring that > also is rational at RF is one more "gotcha". Both loss and dielectric > distortion effects are worth worrying about. > > Bob > > > On Mar 14, 2010, at 1:23 PM, gandal...@aol.com wrote: > >> In a message dated 14/03/2010 15:46:55 GMT Standard Time, >> cfhar...@erols.com writes: >> >> I would call those aluminum cake, not pie, pans. It looks like you >> bought >> a set for making wedding cakes. >> >> Is there a different definition of "pie" in G8 land? >> - >> Hi Chuck >> >> No other definition that I'm aware of, other than David's of course, but >> I >> was just replying to Brian, KD4FM, so I guess that makes it a US of A >> definition:-) >> >> 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. > ___ 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] Choke Ring Pictures
Hi Wedding cake pans normally come in 1" increments and are either 2" or 3" deep. Sets are 2" increments on the diameter: http://cooksdream.com/store/wedding-round.html http://www.hubert.com/store/products.asp?CAWELAID=126235277&A=SB%2E58369%2E10738&Dn=0&An=966+966&Au=Presentation+Id&Ntt=10738&N=966+966&src=chanadv&Ntx=mode+matchall&D=10738&Ntk=SKU The height would be fairly easy to adjust. The diameter not so much so. Looks like 2 and 2.5" are typical dimensions for the depth. ~1" looks pretty typical for the width. A 2" deep / 2" diameter step set looks like it would do a pretty good job . It won't be accurate enough to be perfect. Without a 3D EM program it would be tough to figure out just what the errors would do to you. Bob On Mar 14, 2010, at 1:57 PM, Chuck Harris wrote: > It would be nice to know where he got them, as they appear to make > a successful GPS choke ring. If they are US cake pans, they are > likely sized in 1 inch steps. > > In my world, a pie pan has sloped sides, and a cake pan has squared > sides... pie pans are always round, but cake pans can be a wide variety > of shapes, though are are usually round, or rectangular. > > -Chuck > > gandal...@aol.com wrote: >> In a message dated 14/03/2010 15:46:55 GMT Standard Time, >> cfhar...@erols.com writes: >> I would call those aluminum cake, not pie, pans. It looks like you bought >> a set for making wedding cakes. >> Is there a different definition of "pie" in G8 land? >> - >> Hi Chuck >> No other definition that I'm aware of, other than David's of course, but I >> was just replying to Brian, KD4FM, so I guess that makes it a US of A >> definition:-) >> 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. > ___ 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] Choke Ring Pictures
jimlux wrote: David C. Partridge wrote: definition of "pie" 3.1415926535 etc ? Ooops D. And, as my daughter reminds me, today is pi day (in the U.S. where we write the date month/year.. those of you in the rest of the world will have to wait a long time, as there is no April 31st) Nope. I would normally spend this evening at friends making home-made pi-zza at pi day... occuring every 3-14 (as in 2010-03-14). This year their festivities was cancelled since they have water-damages to their house. Remember to make it of radius z and heigth a so that the volume becomes pizza. ;) 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] Choke Ring Pictures
It would be nice to know where he got them, as they appear to make a successful GPS choke ring. If they are US cake pans, they are likely sized in 1 inch steps. In my world, a pie pan has sloped sides, and a cake pan has squared sides... pie pans are always round, but cake pans can be a wide variety of shapes, though are are usually round, or rectangular. -Chuck gandal...@aol.com wrote: In a message dated 14/03/2010 15:46:55 GMT Standard Time, cfhar...@erols.com writes: I would call those aluminum cake, not pie, pans. It looks like you bought a set for making wedding cakes. Is there a different definition of "pie" in G8 land? - Hi Chuck No other definition that I'm aware of, other than David's of course, but I was just replying to Brian, KD4FM, so I guess that makes it a US of A definition:-) 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.
Re: [time-nuts] Choke Ring Pictures
In a message dated 14/03/2010 17:35:24 GMT Standard Time, li...@rtty.us writes: All of these gizmos are going to work better outdoors than indoors. Coming up with a rainproof / bird proof / bug proof cover for the choke ring that also is rational at RF is one more "gotcha". Both loss and dielectric distortion effects are worth worrying about. --- Oh, that's an easy fix, just turn the whole thing upside down:-) ___ 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] Choke Ring Pictures
Hi All of these gizmos are going to work better outdoors than indoors. Coming up with a rainproof / bird proof / bug proof cover for the choke ring that also is rational at RF is one more "gotcha". Both loss and dielectric distortion effects are worth worrying about. Bob On Mar 14, 2010, at 1:23 PM, gandal...@aol.com wrote: > In a message dated 14/03/2010 15:46:55 GMT Standard Time, > cfhar...@erols.com writes: > > I would call those aluminum cake, not pie, pans. It looks like you bought > a set for making wedding cakes. > > Is there a different definition of "pie" in G8 land? > - > Hi Chuck > > No other definition that I'm aware of, other than David's of course, but I > was just replying to Brian, KD4FM, so I guess that makes it a US of A > definition:-) > > 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.
Re: [time-nuts] Choke Ring Pictures
In a message dated 14/03/2010 15:46:55 GMT Standard Time, cfhar...@erols.com writes: I would call those aluminum cake, not pie, pans. It looks like you bought a set for making wedding cakes. Is there a different definition of "pie" in G8 land? - Hi Chuck No other definition that I'm aware of, other than David's of course, but I was just replying to Brian, KD4FM, so I guess that makes it a US of A definition:-) 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] Choke Ring Pictures
Easy as pi: Take the first three odd digits 1,3, and 5. Use two of each as 113355. Put a division sign in the middle 113 )355 And you get pretty close... ___ 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] Choke Ring Pictures
David C. Partridge wrote: definition of "pie" 3.1415926535 etc ? Ooops D. And, as my daughter reminds me, today is pi day (in the U.S. where we write the date month/year.. those of you in the rest of the world will have to wait a long time, as there is no April 31st) ___ 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] Choke Ring Pictures
Very appropriate for today - international pi day. Talk about "time nuts", we are not even close. - 73 - Mike Mike B. Feher, N4FS 89 Arnold Blvd. Howell, NJ, 07731 732-886-5960 -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of David C. Partridge Sent: Sunday, March 14, 2010 12:05 PM To: 'Discussion of precise time and frequency measurement' Subject: Re: [time-nuts] Choke Ring Pictures >definition of "pie" 3.1415926535 etc ? Ooops D. ___ 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] Choke Ring Pictures
>definition of "pie" 3.1415926535 etc ? Ooops D. ___ 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] Choke Ring Pictures
I would call those aluminum cake, not pie, pans. It looks like you bought a set for making wedding cakes. Is there a different definition of "pie" in G8 land? -Chuck Harris gandal...@aol.com wrote: In a message dated 14/03/2010 04:24:10 GMT Standard Time, kilodelta4foxm...@gmail.com writes: I made 3 sets using pie plates. I promised somebody the pictures and forgot it until now. The pictures are hosted at http://kc0onr.com/Brian/_MG_0668.jpg http://kc0onr.com/Brian/_MG_0669.jpg Hi Brian Thanks for the photos, that looks interesting. Were the dimensions checked to see if they were anywhere close to calculated values or did you just have to go with what was available and keep your fingers crossed? 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.
Re: [time-nuts] Choke Ring Pictures
In a message dated 14/03/2010 04:24:10 GMT Standard Time, kilodelta4foxm...@gmail.com writes: I made 3 sets using pie plates. I promised somebody the pictures and forgot it until now. The pictures are hosted at http://kc0onr.com/Brian/_MG_0668.jpg http://kc0onr.com/Brian/_MG_0669.jpg Hi Brian Thanks for the photos, that looks interesting. Were the dimensions checked to see if they were anywhere close to calculated values or did you just have to go with what was available and keep your fingers crossed? 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] Choke Ring Pictures
Hi Brian! Nice work! /Björn > Several years back we had the discussion about choke ring antennas. > > Dr Thomas Clark - retired NASA - Goddard Space Flight Center - I believe > he was head of the VLBI project - made a simple choke ring antenna with > an electrical junction box. > > I made 3 sets using pie plates. I promised somebody the pictures and > forgot it until now. The pictures are hosted at > > http://kc0onr.com/Brian/_MG_0668.jpg > http://kc0onr.com/Brian/_MG_0669.jpg > > I made these units because were I lived was surrounded by mountains 3/4 > around my property and I was at 720 feet elevation and the mountains > varied from 1000 to 1200 feet. I had a problem that my receivers jumped > positions several times and I suspected a multi path problem. I made > the first antenna using some RF adsorbent material around the antenna. > Helped. After making the choke rings, the problem went away. The other > two units were used for carrier phase surveying. With the Motorola > Oncore VPZ unit and Waypoint's GrafNav software I could get resolution > down to a little under an inch. > > Brian KD4FM > > > > > > ___ > 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] Choke Ring Pictures
Just curious. Is this antenna under a cover or are there drain holes to let out the water when it rains? Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Brian Kirby Sent: Saturday, March 13, 2010 10:24 PM To: Discussion of precise time and frequency measurement; Bill Clingan Subject: [time-nuts] Choke Ring Pictures Several years back we had the discussion about choke ring antennas. Dr Thomas Clark - retired NASA - Goddard Space Flight Center - I believe he was head of the VLBI project - made a simple choke ring antenna with an electrical junction box. I made 3 sets using pie plates. I promised somebody the pictures and forgot it until now. The pictures are hosted at http://kc0onr.com/Brian/_MG_0668.jpg http://kc0onr.com/Brian/_MG_0669.jpg I made these units because were I lived was surrounded by mountains 3/4 around my property and I was at 720 feet elevation and the mountains varied from 1000 to 1200 feet. I had a problem that my receivers jumped positions several times and I suspected a multi path problem. I made the first antenna using some RF adsorbent material around the antenna. Helped. After making the choke rings, the problem went away. The other two units were used for carrier phase surveying. With the Motorola Oncore VPZ unit and Waypoint's GrafNav software I could get resolution down to a little under an inch. Brian KD4FM ___ 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.
