Re: [time-nuts] nuts about position

Hi J: I had a number of survey stakes I placed using a manual transit and tape measure and hired a local surveyor to tell me where they were and also tell me where my GPS antenna was located. He setup a GPS antenna on one tripod and a (Trimble?) combined GPS-total station on another tripod

Re: [time-nuts] nuts about position

On 4/25/18 11:18 AM, Brooke Clarke wrote: Hi Tom: As part of a FireWise community mapping process I'd like to get GPS coordinates of the fire hydrants (Lat, Lon, Ele). Is there a civilian GPS receiver that makes use of WAAS and/or DGPS corrections? I think almost all handheld receivers

Re: [time-nuts] nuts about position

On 4/25/18 7:46 PM, Brooke Clarke wrote: Hi J: I had a number of survey stakes I placed using a manual transit and tape measure and hired a local surveyor to tell me where they were and also tell me where my GPS antenna was located. He setup a GPS antenna on one tripod and a (Trimble?)

Re: [time-nuts] nuts about position

It is true that most handheld GPS receivers have WAAS capability these days; however the accuracy is more like 3 to 4 meters even with several minutes of averaging. I've always been puzzled by why it is so much worse than good professional equipment can apparently achieve with similar "features".

Re: [time-nuts] nuts about position

Jim Lux writes: > But another poster did comment on "why not use the telescope" you could > precision point to a series of stars and calculate using celestial nav > where you are. Although, that might be painful to the 1 meter sort of > accuracy - the "tables" probably don't really account for

Re: [time-nuts] Cheap jitter measurements

Time-nuts! I went ahead and bought the TAPR-TICC, it is a very impressive instrument. For this setup it is combined with a Jackson Labs GPSTLXO as the 10MHz reference. The JL is a GPS disciplined temperature compensated crystal oscillator. The first setup uses the TAPR-TICC in Period mode,

Re: [time-nuts] Cheap jitter measurements

Hi Gary, > A little coding later and there are nice plots. They were compared to > the output of tvb's adev.c program. Results are similar. Whoa there cowboy. That doesn't mean it's right. Comments: > gps.png looks as expected. 1. No, it would appear something is wrong with your data. You

Re: [time-nuts] time-nuts Digest, Vol 165, Issue 48

Gary- Interesting. The TICC is spec'ed to have a 10e-10 AD floor at 1 sec. Your measurement is slightly better than the spec. How can we know whether you are measuring the test source (JL GPSTLXO) or the stability of the TICC itself? Jim At 03:10 AM 4/25/2018, you wrote: >Send time-nuts

[time-nuts] Low noise Oscillator

In the April Microwave Journal is an extensive article on a "Ultra-Low Phase Noise Oscillators with Attosecond Jitter"and measuring techniques. Bert Kehren ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to

Re: [time-nuts] Low noise Oscillator

Thanks Bert. They seem to have published it online too - see: http://www.microwavejournal.com/articles/30053-ultra-low-phase-noise-oscillators-with-attosecond-jitter Regards, Peter Vince On 25 April 2018 at 14:30, ew via time-nuts wrote: > In the April Microwave

[time-nuts] nuts about position

List -- I had a recent query by a researcher who would like to pinpoint the location of his telescope(s) within 0.3 meters. Also (he must be a true scientist) he wants to do this on-the-cheap. He may have timing requirements as well, but that's another posting. So I toss the GPS question to

Re: [time-nuts] Cheap jitter measurements

Hi Now that it is “free for all”, Stable-32 is another good program to run your data past. It will do nice plots and a *lot* of different statistics. Bob > On Apr 25, 2018, at 7:01 AM, Tom Van Baak wrote: > > Hi Gary, > >> A little coding later and there are nice

Re: [time-nuts] nuts about position

While I was at the Arecibo Observatory it became desirable to get a good surveyed position for a new GPS antenna we had installed for the NIST TMAS system. We found a resource at the Univ of Puerto Rico who had a Trimble (I think) unit. He set it up on the site, "turned on the bubble machine",

Re: [time-nuts] nuts about position

On Wed, Apr 25, 2018 at 7:56 AM, Tom Van Baak wrote: > List -- I had a recent query by a researcher who would like to pinpoint the > location of his telescope(s) within 0.3 meters. Also (he must be a true > scientist) he wants to do this on-the-cheap. He may have timing

Re: [time-nuts] nuts about position

Create your own DGPS? Trimble is good at this. George K. Watson K0IW > On Apr 25, 2018, at 10:56 AM, Tom Van Baak wrote: > > List -- I had a recent query by a researcher who would like to pinpoint the > location of his telescope(s) within 0.3 meters. Also (he must be a

[time-nuts] nuts about position

When in was developing Lady Heather's precision survey code I was comparing the calculated positions to those from an Ashtech Z12 dual freq GPS (with the position calculated by OPUS). Using the same survey grade antenna and a Thunderbolt the results were usually within a meter. I have not

Re: [time-nuts] nuts about position

Hi, Anecdotal response. A few years back we played with using handheld garmin units (GPSMAP 62st) for locating property lines and corners. We averaged for 6 to 12 hours at known standards (section corners). This data was used to subdivide the section for property corner locations, and these

Re: [time-nuts] nuts about position

Hi That sort of accuracy is pretty normal for a survey device. He needs to find a local surveyor who likes to look at stars :). I assume the telescope is not mobile and it’s a one time sort of thing. If he likes to romp around the question becomes how quickly he needs the location

Re: [time-nuts] nuts about position

This link seems to provide an overview of Differential GPS and some related techniques. https://www.e-education.psu.edu/geog862/node/1834 Building a system along these lines from "auction site purchases" and home brewed computer code might be a fun project but one would presumably need an

[time-nuts] Hat Creek observatory

Hi — Does anyone here have contacts with the Hat Creek Observatory? My partner and I will be in the area Jun 15 Fri afternoon through Jun 18 Mon morning. While reports state the site has a few kiosks for self-tourism, we’re geeky time/frequency, radio & astrophysics types that want to

Re: [time-nuts] Cheap jitter measurements

Tom! On Wed, 25 Apr 2018 04:01:10 -0700 "Tom Van Baak" wrote: > Hi Gary, > > > A little coding later and there are nice plots. They were compared > > to the output of tvb's adev.c program. Results are similar. > > Whoa there cowboy. That doesn't mean it's right.

Re: [time-nuts] Hat Creek observatory

Hi guys, I live in Auburn CA . About 2 miles from the Chief programmer/software engineer for Hat Creek. Hat Creek is east of Redding CA a LONG drive from here, but spectacular country. Apparently a world renowned Fly Fishing place. Fly fishermen have told me (I don't fish) that Hat Creek is on

[time-nuts] nuts about position

I don't know if you can easily see earth tides with a GPS... the post-processing services usually filter and correct them out. But, Lady Heather v6 can model and plot them (as lat/lon/alt displacements in mm). Also the vertical component of the gravity offset (in ugals)

Re: [time-nuts] nuts about position

Hi Tom: I have a friend who bought a house on a hill so that he could build an observatory with an excellent view of the sky.  The telescope mount is the Paramount by Software Bisque.  This mount is capable of pointing accuracy measured in a small number of arc seconds.  That implies the

Re: [time-nuts] nuts about position

Hi One of the “interesting features” of the ongoing bridge rebuilding process around here is the destruction of most of the benchmark locations. They were built into the old bridges and went away when the new ones went up. Now there are cute little brass disks on the new bridges. There is no

Re: [time-nuts] nuts about position

> How easy, how cheap, how possible is it to obtain 0.3 m accuracy in 3D > position? Elevation gets interesting. Earth has tides in solid rock that are ballpark of that scale peak-peak. It would be interesting to see if you could see the tides with low cost gear. -- These are my opinions.

[time-nuts] Cheap jitter measurements

Lady Heather v6 supports the TAPR TICC. It has most of the functionality of Timelab (but not as pretty), runs on Linux,etc, and can process both channel s(actually 4 channels if you have two TICCs). You can use it either as the main input device or as an auxiliary input device in

Re: [time-nuts] nuts about position

I think to really be confident about a position you really need the dual-frequency data (or that data from a nearby reference station), otherwise you could end up in a situation where you're consistent, but that consistency has a bias. IIRC, anyhow -- I'm not sure how the math actually works

Re: [time-nuts] Cheap jitter measurements

Hi Gary, > As requested, here is my raw data: http://pi5.rellim.com/1d.log.gz I'm having a close look. These are quite a few bad data points and that partly explains why your ADEV plots were off. Trim the file at, say, line 71000 and try again; the results will be much better. I'll post an

Re: [time-nuts] Question about frequency counter testing

Hi Unfortunately there is no “quick and dirty” way to come up with an accurate “number of digits” for a math intensive counter. There are a *lot* of examples of various counter architectures that have specific weak points in what they do. One sort of signal works one way, another signal works

[time-nuts] Question about frequency counter testing

Dear Ladies and Gentlemen, Let me tell a little story so you will be able to better understand what my question and what I am doing. I needed to check frequency in several GHz range from time to time. I do not need high absolute precision (anyway this is a reference oscillator problem, not