Re: [time-nuts] GPS Antenna on Tower.

[Wes]

Mark,

Excuse my ignorance but where do I find this version?

Wes

On 6/20/2017 9:34 AM, Mark Sims wrote:

I just added the ability to calculate solid earth tides and the vertical 
gravity offset due to the sun and moon to Lady Heather.   The lat/lon offset is 
typically around +/- 60 cm per day.Vertical offset is around  +/- 180mm.  
Depending upon the day and where you are, the swings are not symmetrical around 
0.0



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Re: [time-nuts] GPS Antenna on Tower.

[Attila Kinali]

On Tue, 20 Jun 2017 16:34:14 +
Mark Sims  wrote:

> I just added the ability to calculate solid earth tides and the vertical 
> gravity offset due to the sun and moon to Lady Heather.   

Cool! How do you calculate the displacement on a fixed position receiver?

> The lat/lon offset 
> is typically around +/- 60 cm per day.Vertical offset is around  +/- 
> 180mm.  Depending upon the day and where you are, the swings are not 
> symmetrical around 0.0   

This might be of interest:
http://www.unoosa.org/documents/pdf/psa/activities/2012/un-latvia/ppt/2-11.pdf
(more papers available upon request)

> Solid earth tides are a BIG factor in precision geodesy.   Gravity offset is 
> a big issue for precision pendulum nuts.  If your pendulum clock cannot
> detect gravity offsets (very few can) it's not nutty enough.

:-D

Attila Kinali

-- 
It is upon moral qualities that a society is ultimately founded. All 
the prosperity and technological sophistication in the world is of no 
use without that foundation.
 -- Miss Matheson, The Diamond Age, Neil Stephenson
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Re: [time-nuts] GPS Antenna on Tower.

[Hal Murray]

How do the GPS control/monitoring stations handle Earth tides?

My guess is they have another nearby antenna that they can link up to VLBI 
data.

-- 
These are my opinions.  I hate spam.



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Re: [time-nuts] GPS Antenna on Tower.

[Bob kb8tq]

Hi

Earth tides are at least as crazy a topic as time. There are formulas that will 
let you incorporate
the effect of Pluto on solid Earth tides.

Bob

> On Jun 20, 2017, at 7:21 PM, Peter Vince  wrote:
> 
> Hi Mark,
> 
> This is all new information to me - and fascinating!  Have you just
> "calculated" the offsets (using known values from somewhere), or "measured"
> it by very long term averaging of the GPS position information?
> 
> Peter Vince
> 
> 
> On 20 June 2017 at 17:34, Mark Sims  wrote:
> 
>> I just added the ability to calculate solid earth tides and the vertical
>> gravity offset due to the sun and moon to Lady Heather.   The lat/lon
>> offset is typically around +/- 60 cm per day.Vertical offset is around
>> +/- 180mm.  Depending upon the day and where you are, the swings are not
>> symmetrical around 0.0
>> 
>> Solid earth tides are a BIG factor in precision geodesy.   Gravity offset
>> is a big issue for precision pendulum nuts.  If your pendulum clock cannot
>> detect gravity offsets (very few can) it's not nutty enough.
>> 
>> The attached plot shows around 5 days of data.
>> 
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Re: [time-nuts] GPS Antenna on Tower.

[Peter Vince]

Hi Mark,

 This is all new information to me - and fascinating!  Have you just
"calculated" the offsets (using known values from somewhere), or "measured"
it by very long term averaging of the GPS position information?

 Peter Vince


On 20 June 2017 at 17:34, Mark Sims  wrote:

> I just added the ability to calculate solid earth tides and the vertical
> gravity offset due to the sun and moon to Lady Heather.   The lat/lon
> offset is typically around +/- 60 cm per day.Vertical offset is around
> +/- 180mm.  Depending upon the day and where you are, the swings are not
> symmetrical around 0.0
>
> Solid earth tides are a BIG factor in precision geodesy.   Gravity offset
> is a big issue for precision pendulum nuts.  If your pendulum clock cannot
> detect gravity offsets (very few can) it's not nutty enough.
>
> The attached plot shows around 5 days of data.
>
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Re: [time-nuts] GPS Antenna on Tower.

[Bryan _]

I have wondered how geologists are able to measure tectonic plate movements in 
the earths surface to a couple cm's when the sensors from what I see/read they 
are nothing more than sensors in concrete boxes?. I believe they use various 
technologies such as Very Long Baseline 
Interferometry<http://www.see.leeds.ac.uk/structure/dynamicearth/plates_move/active_tectonics/vlbi.htm>
 (VLBI) and Satellite Laser 
Ranging<http://www.see.leeds.ac.uk/structure/dynamicearth/plates_move/active_tectonics/slr1.htm>
 (SLR)


All fascinating stuff




-=Bryan=-



From: time-nuts <time-nuts-boun...@febo.com> on behalf of Thorbjørn Pedersen 
<thorbjorn.peder...@ikm.no>
Sent: June 19, 2017 9:42 PM
To: time-nuts@febo.com
Subject: Re: [time-nuts] GPS Antenna on Tower.

http://www.sp.se/en/index/resources/GNSS/Sidor/default.aspx
[http://www.sp.se/sv/index/resources/GNSS/PublishingImages/pelare.jpg]<http://www.sp.se/en/index/resources/GNSS/Sidor/default.aspx>

GNSS-equipment - SP<http://www.sp.se/en/index/resources/GNSS/Sidor/default.aspx>
www.sp.se
GNSS-equipment RISE has equipment for GNSS (Global Navigation Satellite 
Systems) for applications in Time and Frequency, Positioning and Atmospheric 
Studies.



Have a look at the best receiving antenna I know about.

The tower must have cooling tubes coiled around it because of the sun heating 
one side will make it bend away from the sun, and turn this way all day.
The cable and doom is also temperature controlled.

Best Regards

Thorbjørn W. Pedersen


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Re: [time-nuts] GPS Antenna on Tower.

[Clay Autery]

I thought there was kind of a rule about EXCLUDING sats on or near the
horizon...

__
Clay Autery, KY5G

On 6/20/2017 8:27 AM, "Björn Gabrielsson" wrote:
> Hi Thorbjörn,
>
> To bad this particula antenna has surrounding buildings (and maybe trees)
> that mask low elevation satellites.
>
> --
>
>Björn
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Re: [time-nuts] GPS Antenna on Tower.

[Björn Gabrielsson]

Hi Thorbjörn,

To bad this particula antenna has surrounding buildings (and maybe trees)
that mask low elevation satellites.

--

   Björn

> http://www.sp.se/en/index/resources/GNSS/Sidor/default.aspx
> Have a look at the best receiving antenna I know about.
>
> The tower must have cooling tubes coiled around it because of the sun
> heating one side will make it bend away from the sun, and turn this way
> all day.
> The cable and doom is also temperature controlled.
>
> Best Regards
>
> Thorbjørn W. Pedersen
>
>
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Re: [time-nuts] GPS Antenna on Tower.

[Michael Wouters]

Try again ...,

Since 1cm of motion is equivalent to 30 ps, there's probably not much point
in putting your GNSS antenna on a geodetic monument if all you care about
is timing. But it does matter if you're trying to track continental drift.

Michael

On Tue, 20 Jun 2017 at 10:44 pm, Michael Wouters 
wrote:

> Since 1cm of motion is equivalent to 30ps, there's probably not
>
> On Tue, 20 Jun 2017 at 10:11 pm, Didier Juges  wrote:
>
>> If that is not time-nutty, I do not know what will :)
>>
>> On Jun 20, 2017 7:04 AM, "jimlux"  wrote:
>>
>> >
>> > for geodetic measurements, they drill a hole down to bedrock, and run a
>> > pipe down to anchor the antenna to the bedrock.
>> >
>> > "All holes shall be drilled straight enough so that PVC casing can be
>> > installed in the top 15.5 ft of each hole, and that the steel pipe can
>> be
>> > freely lowered, not forced, for its entire 35 ft length."
>> >
>> > http://kb.unavco.org/kb/article/deep-drilled-braced-monument
>> > -overview-300.html
>> > http://www.scign.org/arch/sdb_monument.htm
>> >
>> >
>> > Google for Ken Hudnutt's or Frank Webb's papers
>> >
>> >
>> > or a 3m tall monument for a CORS station
>> >
>> > http://www.mwrtk.net/support_docs/corsinstallprocedures.pdf
>> >
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>> > ailman/listinfo/time-nuts
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Re: [time-nuts] GPS Antenna on Tower.

[Michael Wouters]

Since 1cm of motion is equivalent to 30ps, there's probably not

On Tue, 20 Jun 2017 at 10:11 pm, Didier Juges  wrote:

> If that is not time-nutty, I do not know what will :)
>
> On Jun 20, 2017 7:04 AM, "jimlux"  wrote:
>
> >
> > for geodetic measurements, they drill a hole down to bedrock, and run a
> > pipe down to anchor the antenna to the bedrock.
> >
> > "All holes shall be drilled straight enough so that PVC casing can be
> > installed in the top 15.5 ft of each hole, and that the steel pipe can be
> > freely lowered, not forced, for its entire 35 ft length."
> >
> > http://kb.unavco.org/kb/article/deep-drilled-braced-monument
> > -overview-300.html
> > http://www.scign.org/arch/sdb_monument.htm
> >
> >
> > Google for Ken Hudnutt's or Frank Webb's papers
> >
> >
> > or a 3m tall monument for a CORS station
> >
> > http://www.mwrtk.net/support_docs/corsinstallprocedures.pdf
> >
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Re: [time-nuts] GPS Antenna on Tower.

[Wes]

It was bright sunshine and 46 degrees C here in the desert near Tucson, Arizona 
yesterday.  It would take a lot of cooling to keep that solar collector (radome) 
cool.


Wes Stewart

 On 6/19/2017 9:42 PM, Thorbjørn Pedersen wrote:

http://www.sp.se/en/index/resources/GNSS/Sidor/default.aspx
Have a look at the best receiving antenna I know about.

The tower must have cooling tubes coiled around it because of the sun heating 
one side will make it bend away from the sun, and turn this way all day.
The cable and doom is also temperature controlled.

Best Regards

Thorbjørn W. Pedersen


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Re: [time-nuts] GPS Antenna on Tower.

[Clay Autery]

LOL!!!  My first reaction to reading the drill for sub-subterranean GPS
mast was...

Wonder if I could borrow Shappell's little drilling rig to do THAT hole
and the vertical wells for the geo-thermal cooling loops?

Followed closely by...

Wonder what kind and number of Sorbothan, et al. dampers required to
damp the locally generated vibrations that would resonate in that length
"tuning fork" hooked to the bedrock?

  Even we non-scientists on this reflector reserve the right
to be equally nutty.  

PS - I have a master map of my back yard in order to manage the
available square footage and its use and to de-conflict the
sub-subterranean "air space".

__
Clay Autery, KY5G

On 6/20/2017 7:21 AM, jimlux wrote:
> On 6/20/17 5:11 AM, Didier Juges wrote:
>> If that is not time-nutty, I do not know what will :)
>
> if you're a "real time-nut" you drill your own holes - you buy a
> surplus drilling rig, refurbish it, figure out how to work it (maybe
> there's a "drill-nuts" list?), etc.
>
> But at least the station will probably fit in your backyard.
>

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Re: [time-nuts] GPS Antenna on Tower.

[jimlux]

On 6/20/17 5:11 AM, Didier Juges wrote:

If that is not time-nutty, I do not know what will :)


if you're a "real time-nut" you drill your own holes - you buy a surplus 
drilling rig, refurbish it, figure out how to work it (maybe there's a 
"drill-nuts" list?), etc.


But at least the station will probably fit in your backyard.



On Jun 20, 2017 7:04 AM, "jimlux"  wrote:



for geodetic measurements, they drill a hole down to bedrock, and run a
pipe down to anchor the antenna to the bedrock.

"All holes shall be drilled straight enough so that PVC casing can be
installed in the top 15.5 ft of each hole, and that the steel pipe can be
freely lowered, not forced, for its entire 35 ft length."

http://kb.unavco.org/kb/article/deep-drilled-braced-monument
-overview-300.html
http://www.scign.org/arch/sdb_monument.htm


Google for Ken Hudnutt's or Frank Webb's papers


or a 3m tall monument for a CORS station

http://www.mwrtk.net/support_docs/corsinstallprocedures.pdf

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Re: [time-nuts] GPS Antenna on Tower.

[Didier Juges]

If that is not time-nutty, I do not know what will :)

On Jun 20, 2017 7:04 AM, "jimlux"  wrote:

>
> for geodetic measurements, they drill a hole down to bedrock, and run a
> pipe down to anchor the antenna to the bedrock.
>
> "All holes shall be drilled straight enough so that PVC casing can be
> installed in the top 15.5 ft of each hole, and that the steel pipe can be
> freely lowered, not forced, for its entire 35 ft length."
>
> http://kb.unavco.org/kb/article/deep-drilled-braced-monument
> -overview-300.html
> http://www.scign.org/arch/sdb_monument.htm
>
>
> Google for Ken Hudnutt's or Frank Webb's papers
>
>
> or a 3m tall monument for a CORS station
>
> http://www.mwrtk.net/support_docs/corsinstallprocedures.pdf
>
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Re: [time-nuts] GPS Antenna on Tower.

[jimlux]

for geodetic measurements, they drill a hole down to bedrock, and run a 
pipe down to anchor the antenna to the bedrock.


"All holes shall be drilled straight enough so that PVC casing can be 
installed in the top 15.5 ft of each hole, and that the steel pipe can 
be freely lowered, not forced, for its entire 35 ft length."


http://kb.unavco.org/kb/article/deep-drilled-braced-monument-overview-300.html
http://www.scign.org/arch/sdb_monument.htm


Google for Ken Hudnutt's or Frank Webb's papers


or a 3m tall monument for a CORS station

http://www.mwrtk.net/support_docs/corsinstallprocedures.pdf

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Re: [time-nuts] GPS Antenna on Tower.

[Thorbjørn Pedersen]

http://www.sp.se/en/index/resources/GNSS/Sidor/default.aspx
Have a look at the best receiving antenna I know about.

The tower must have cooling tubes coiled around it because of the sun heating 
one side will make it bend away from the sun, and turn this way all day.
The cable and doom is also temperature controlled.

Best Regards

Thorbjørn W. Pedersen


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Re: [time-nuts] GPS Antenna on Tower.

[Attila Kinali]

On Mon, 19 Jun 2017 08:52:37 -0400
Dan Kemppainen  wrote:

> So, what sorts of things are done for high precision survey work? I 
> would guess a sturdy mount, good sky view, no reflections, good antenna, 
> no nearby radiators, etc. Those all seem like common sense stuff.

I don't know about survey work, but you can have a look at the EUREF[1]
stations. Most (all?) stations in the list[2] have pictures.

[1] https://en.wikipedia.org/wiki/EUREF_Permanent_Network
[2] http://www.epncb.oma.be/_networkdata/stationlist.php

> But for applications that really matter, what sorts of things might be 
> missing above. Obviously, really expensive silly things won't be done on 
> my site for a few GPSDO's, but it would be good to know what the issues 
> are.

You try to mount the antenna as sturdy as possible. The best is if
you have an open and level field and can put a nice block of concrete on
unmoving bedrock. If not, ontop of a well build building will do,
though the vibrations might not be negligible. People use also relatively
low towers (high towers tend to vibrate), of only 2-5m height. Again mounted
on a block of concrete, if the tower isn't itself a construction made
of concrete. The dome should be such, that you don't get a bird problem
and that snow does not stick. At the same time the dome should be
shaped in a way that does not cause any refraction. If your reference
station (which is in a nearby building in a temperature controlled room)
has any ultra stable reference oscillator (think of a Cs beam standard
or a hydrogen maser), then you also want to have the temperature and
humidity of the cable going to the antenna controlled. Ie. you put
the antenna cable into a tube and blow constant temperature/humidity
air through it.

Of course you can go even more crazy, but the temperature/humidity controlled
cable is about the most extreme I have heard of.


Attila Kinali
-- 
It is upon moral qualities that a society is ultimately founded. All 
the prosperity and technological sophistication in the world is of no 
use without that foundation.
 -- Miss Matheson, The Diamond Age, Neil Stephenson
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Re: [time-nuts] GPS Antenna on Tower.

[Bob kb8tq]

Hi

If you go totally insane, you build a 30’ tall concrete monolith in the middle 
of a wide open field. The antenna
and ground plane go on top of the monolith. You then grab your chain saw and 
start knocking down any trees,
towers, or homes that happen to obstruct your perfect view. :) Indeed this is a 
bit easier if you have a nice big 
budget and can buy (or already own) a giant open chunk of land already. Ex-air 
bases seem to be an excellent 
candidate. 

Bob

> On Jun 19, 2017, at 8:52 AM, Dan Kemppainen  wrote:
> 
> Hi Bob,
> 
> So, what sorts of things are done for high precision survey work? I would 
> guess a sturdy mount, good sky view, no reflections, good antenna, no nearby 
> radiators, etc. Those all seem like common sense stuff.
> 
> But for applications that really matter, what sorts of things might be 
> missing above. Obviously, really expensive silly things won't be done on my 
> site for a few GPSDO's, but it would be good to know what the issues are.
> 
> Thanks,
> Dan
> 
> 
> 
> On 6/16/2017 6:29 PM, time-nuts-requ...@febo.com wrote:
>> 
>> Hi
>> 
>> Will there be an effect? Yes. Are roughly 99% of all GPSDO’s run with 
>> antennas mounted that way
>> by “pros” ? Yes again.
>> 
>> If you are setting up a reference site for high precision survey work, don’t 
>> do it that way. For a GPSDO,
>> you should be fine.
>> 
>> Bob
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Re: [time-nuts] GPS Antenna on Tower.

[Dan Kemppainen]

Hi Bob,

So, what sorts of things are done for high precision survey work? I 
would guess a sturdy mount, good sky view, no reflections, good antenna, 
no nearby radiators, etc. Those all seem like common sense stuff.


But for applications that really matter, what sorts of things might be 
missing above. Obviously, really expensive silly things won't be done on 
my site for a few GPSDO's, but it would be good to know what the issues 
are.


Thanks,
Dan



On 6/16/2017 6:29 PM, time-nuts-requ...@febo.com wrote:


Hi

Will there be an effect? Yes. Are roughly 99% of all GPSDO’s run with antennas 
mounted that way
by “pros” ? Yes again.

If you are setting up a reference site for high precision survey work, don’t do 
it that way. For a GPSDO,
you should be fine.

Bob

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Re: [time-nuts] GPS Antenna on Tower.

[paul swed]

Good comments by Bob.
I run 100 ft of Rohn 45 and then have a stack of rotatable antennas at that
point.
I have the antenna some 3-4 ft off the tower at 90' feeding with 1/2"
line.(Because I had it) The trees have grown to 90' so that gives a nice
clean view south. Works totally fine. Reason to keep it a bit lower is to
allow other things to take the static that can build up. Most of the other
stuff is just metal.
I also have a backup antenna at the 50' level using 75 ohm hardline.
the great thing today is just about anything works pretty well.
Regards
Paul.
WB8TSL

On Fri, Jun 16, 2017 at 2:38 PM, Bob kb8tq  wrote:

> Hi
>
> Will there be an effect? Yes. Are roughly 99% of all GPSDO’s run with
> antennas mounted that way
> by “pros” ? Yes again.
>
> If you are setting up a reference site for high precision survey work,
> don’t do it that way. For a GPSDO,
> you should be fine.
>
> Bob
>
> > On Jun 16, 2017, at 1:17 PM, Dan Kemppainen 
> wrote:
> >
> > Hi All,
> >
> > Fair Warning: Nuts Mode Engaged.  :)
> >
> >
> > Recently we've moved to a new house and am in the process of getting the
> antennas back up for various things. One of these is the GPSDO(s), and an
> obvious location is somewhere on a Roan 25 tower set up just south of the
> house. At about half way up the tower, there is clear sky view in all
> directions and the GPS antenna is temporarily parked there about a foot off
> the tower. The GPS antenna is on the south side of the tower and we're
> ~47N, so most of the GPS birds should be visible. Single band GPS antenna,
> nothing special.
> >
> > My guess is this will be fine. However, I'm still wondering what sorts
> of multi-path or reflections could be expected off the tower itself. And
> are these enough to worry about? If there is multi-path what sorts of
> things would help prevent this? (Mounting the antenna further off the
> tower, etc.)
> >
> > Once I get the tower guy lines redone, I'm thinking about putting the
> GPS antenna on the tip of the mast (No rotator on this tower). That's at
> about 75 feet with nothing close by. That would be slightly above the tree
> line, with a 360 degree sky view.
> >
> > FYI, currently the GPS antenna wire is "Priority Wire and Cable" RG-6/U.
> Did some measurements last night. It measures as 85 Ohm, with a velocity
> factor of ~.86. It looks pretty lossy, but it should still work.
> >
> > Any ideas and comments welcome!
> >
> > Thanks,
> > Dan
> >
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Re: [time-nuts] GPS Antenna on Tower.

[Bob kb8tq]

Hi

Will there be an effect? Yes. Are roughly 99% of all GPSDO’s run with antennas 
mounted that way
by “pros” ? Yes again. 

If you are setting up a reference site for high precision survey work, don’t do 
it that way. For a GPSDO,
you should be fine.

Bob

> On Jun 16, 2017, at 1:17 PM, Dan Kemppainen  wrote:
> 
> Hi All,
> 
> Fair Warning: Nuts Mode Engaged.  :)
> 
> 
> Recently we've moved to a new house and am in the process of getting the 
> antennas back up for various things. One of these is the GPSDO(s), and an 
> obvious location is somewhere on a Roan 25 tower set up just south of the 
> house. At about half way up the tower, there is clear sky view in all 
> directions and the GPS antenna is temporarily parked there about a foot off 
> the tower. The GPS antenna is on the south side of the tower and we're ~47N, 
> so most of the GPS birds should be visible. Single band GPS antenna, nothing 
> special.
> 
> My guess is this will be fine. However, I'm still wondering what sorts of 
> multi-path or reflections could be expected off the tower itself. And are 
> these enough to worry about? If there is multi-path what sorts of things 
> would help prevent this? (Mounting the antenna further off the tower, etc.)
> 
> Once I get the tower guy lines redone, I'm thinking about putting the GPS 
> antenna on the tip of the mast (No rotator on this tower). That's at about 75 
> feet with nothing close by. That would be slightly above the tree line, with 
> a 360 degree sky view.
> 
> FYI, currently the GPS antenna wire is "Priority Wire and Cable" RG-6/U. Did 
> some measurements last night. It measures as 85 Ohm, with a velocity factor 
> of ~.86. It looks pretty lossy, but it should still work.
> 
> Any ideas and comments welcome!
> 
> Thanks,
> Dan
> 
> ___
> 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.

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