Re: [time-nuts] Choke Ring Pictures
In a message dated 14/03/2010 04:24:10 GMT Standard Time,
kilodelta4foxmike@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
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
GandalfG8@aol.com wrote:
In a message dated 14/03/2010 04:24:10 GMT Standard Time,
kilodelta4foxmike@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
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and follow the instructions there.
definition of "pie"
3.1415926535 etc ?
Ooops
D.
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-bounces@febo.com [mailto:time-nuts-bounces@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.
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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)
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...
Check this out if you have not yet seen it _
http://www.cnn.com/2010/TECH/03/12/pi.day.math/index.html?hpt=C2
Some interesting facts-
Record for calculation: 2.7 trillion digits (by Fabrice Bellard, December
2009)
Record for memorization: 67,890 digits (by Chao Lu, 2005)
How random? There are no occurences of the sequence 123456 in the first
million digits of pi
They also have the first 10,000 digits shown. Enjoy - mike
Mike B. Feher, N4FS
89 Arnold Blvd.
Howell, NJ, 07731
732-886-5960
-----Original Message-----
From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On
Behalf Of Mike Feher
Sent: Sunday, March 14, 2010 12:10 PM
To: david.partridge@perdrix.co.uk; 'Discussion of precise time and frequency
measurement'
Subject: 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-bounces@febo.com [mailto:time-nuts-bounces@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.
At 01:05 PM 3/14/2010, Mike Feher wrote...
How random? There are no occurences of the sequence 123456 in the
first
million digits of pi
Isn't there basically a (e-1)/e (63%) chance of a given n digit
sequence occurring in a string of 10^n random digits? That 123456
doesn't occur would actually seem to be a (very weak) indication that
pi is non-random.
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
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
Something that I often find unasked is
a) How much difference does it make?
b) Are there simpler ways to get the same or better results.
Concerning the home made Choke ring antenna, Nice job for a survey nut
BUT for freq nuts
I'm wondering if placing an 8 inch PiePan with its lip up between the choke
ring assumable and the Puck antenna would:
- improve the performance when used as a GPSDO antenna
- Simplify the construction by eliminating the cake pans
Short summery of why I think that may be true:
A survey antenna and a GPSDO antenna have different Jobs.
Two different set of compromises can be used to best do their job.
A choke ring antenna's job is to determine its unknown location with sub cm
accuracy.
To do that, it need to pick up low horizon satellites signals but not pick
up any multipath reflections that add a mm or so error.
One of the ways they accomplish this is to add a sharp cut off at somewhere
around 10 deg above the horizon.
The goal is to reject signals below this, and pass signals that are above
this without adding any reflection errors of their own.
A GPSDO on the other hand is told its fixed location and its job is to pick
up satellites signals above around 30 deg elevation.
It needs to do this by reducing multipath signals without adding more than a
foot or so of reflected errors of its own.
What I have found is that a PiePan that serves as a ground plane / dish
reflector / low horizon attenuator,
seems to work pretty good for this. (if you don't mind the 1ns or so of
added phase noise it causes)
If you think a pie pan will not reduce a GPS reflected signal from below the
antenna, try placing the pie pan above the antenna.
I'm sure there are other even better ways to get the job done and NOT add
the 1 ns of noise.
Next on my list of things to try is a smaller open taco maker deep dish
metal pan.
I've only experimented using Tbolts, so I can not say if the same results
would be seen with other GPS units.
But
It is safe to think that I have more experimental experienced than anyone
out there when it comes to ways to make a Tbolt perform better.
I would be interested in hearing from anyone that could challenge that
assumsion.
PS. if the PiePan does not improve the cake pan antenna, try lowering the
position of the antenna, in relation to the choke rings.
For a survey antenna you want near zero horizon signals to come thru but for
a GPSDO a 30 deg lower limit seems to be the best compromise.
ws
----- Original Message -----
From: "Brian Kirby" kilodelta4foxmike@gmail.com
To: "Discussion of precise time and frequency measurement"
time-nuts@febo.com
Sent: Sunday, March 14, 2010 5:49 PM
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
Hi
Any idea what the funnel was made out of? Some plastics aren't real great at
microwaves...
Bob
-----Original Message-----
From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@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.
Next on my list of things to try is a smaller open taco maker deep dish
metal pan.
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
Previous subject: PiePan GPS Antenna
Have a 5065A with a RVFR that says the warranty ended in 1988.
Bought it from eBay in 2003, had a 1998 cal sticker.
Photo current is below normal, second harmonic is 9, but it works.
Been through the manual, ran an amp through the RVFR for five days
until the second harmonic improved, back in 2008.
Google is no help when looking for an RVFR package. Thinking about
using an LPRO to maintain the function within the classic HP package.
Is anyone else still using a 5065A?
Can the RVFR be replaced?
Bill Hawkins
Heck yes.
Mine is working just fine.
Not so sure how far you can get away with the actual levels but if it works
use it.
You are thinking the same way I would at end of life.
Nice rack mount unit and clock why not toss a modern rb into it if its dead.
On Mon, Mar 15, 2010 at 1:32 PM, Bill Hawkins bill@iaxs.net wrote:
Have a 5065A with a RVFR that says the warranty ended in 1988.
Bought it from eBay in 2003, had a 1998 cal sticker.
Photo current is below normal, second harmonic is 9, but it works.
Been through the manual, ran an amp through the RVFR for five days
until the second harmonic improved, back in 2008.
Google is no help when looking for an RVFR package. Thinking about
using an LPRO to maintain the function within the classic HP package.
Is anyone else still using a 5065A?
Can the RVFR be replaced?
Bill Hawkins
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.
Didn't Corby Dawson rebuild these?"
-John
===============
Heck yes.
Mine is working just fine.
Not so sure how far you can get away with the actual levels but if it
works
use it.
You are thinking the same way I would at end of life.
Nice rack mount unit and clock why not toss a modern rb into it if its
dead.
On Mon, Mar 15, 2010 at 1:32 PM, Bill Hawkins bill@iaxs.net wrote:
Have a 5065A with a RVFR that says the warranty ended in 1988.
Bought it from eBay in 2003, had a 1998 cal sticker.
Photo current is below normal, second harmonic is 9, but it works.
Been through the manual, ran an amp through the RVFR for five days
until the second harmonic improved, back in 2008.
Google is no help when looking for an RVFR package. Thinking about
using an LPRO to maintain the function within the classic HP package.
Is anyone else still using a 5065A?
Can the RVFR be replaced?
Bill Hawkins
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.
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-bounces@febo.com [mailto:time-nuts-bounces@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.
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
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-bounces@febo.com [mailto:time-nuts-bounces@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-bounces@febo.com [mailto:time-nuts-bounces@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
and follow the instructions there.
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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
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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" kilodelta4foxmike@gmail.com
To: "Discussion of precise time and frequency measurement"
time-nuts@febo.com
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
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
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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"
kilodelta4foxmike@gmail.com
To: "Discussion of precise time and frequency measurement"
time-nuts@febo.com
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
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and follow the instructions there.
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"
kilodelta4foxmike@gmail.com
To: "Discussion of precise time and frequency measurement"
time-nuts@febo.com
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
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and follow the instructions there.
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
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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 bruce.griffiths@xtra.co.nz wrote:
From: Bruce Griffiths bruce.griffiths@xtra.co.nz
Subject: Re: [time-nuts] Choke Ring Pictures
To: "Discussion of precise time and frequency measurement" time-nuts@febo.com
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-bounces@febo.com [mailto:time-nuts-bounces@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
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My aluminum frying pan ground plane does a nice job.
The nut welded on for the handle is a convenient
place to attach the lightning ground wire.
Snow accumulation hasn't been a problem yet.
The non-stick underside seems to discourage insects.
You should have seen the look on my wife's face when
I told her that I would like to bolt a frying pan
on the peak of the roof.
Mike - AA8K
WarrenS wrote:
Next on my list of things to try is a smaller open taco maker deep
dish metal pan.
A pity that the GPS receiver elevation mask can't generally be made to
be azimuth dependent.
You could then have a higher elevation limit in the direction of those
trees.
However, it is possible in principle with an M12+T, M12M T or similar
timing receiver which provides the relative timing contribution of each
SV to the solution, to back out the contribution of a given SV and
compute the corresponding timing correction for software correction of
the PPS pulse timing.
Bruce
Mike Naruta AA8K wrote:
My aluminum frying pan ground plane does a nice job.
The nut welded on for the handle is a convenient
place to attach the lightning ground wire.
Snow accumulation hasn't been a problem yet.
The non-stick underside seems to discourage insects.
You should have seen the look on my wife's face when
I told her that I would like to bolt a frying pan
on the peak of the roof.
Mike - AA8K
WarrenS wrote:
Next on my list of things to try is a smaller open taco maker deep
dish metal pan.
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True Bruce. Alas, those trees to the West are matched by
trees to the East. Power lines run in front of the house
to the South. And the towers, guy wires, and wire antennae
are to the North in the back yard. It's like looking up
a funnel to see the satellites.
I have another Motorola patch under the roof that also works.
What is the dielectric of wood sheathing and asphalt shingles?
I may try the cake pans on the inside one; not much snow
inside the attic. :)
Mike - AA8K
Bruce Griffiths wrote:
A pity that the GPS receiver elevation mask can't generally be made to
be azimuth dependent.
You could then have a higher elevation limit in the direction of those
trees.
However, it is possible in principle with an M12+T, M12M T or similar
timing receiver which provides the relative timing contribution of each
SV to the solution, to back out the contribution of a given SV and
compute the corresponding timing correction for software correction of
the PPS pulse timing.
Bruce
Below 600C the only significant source of microwave absorption in wood
is the water content:
http://pubs.acs.org/doi/abs/10.1021/ie901336k
Bitumen has very low microwave loss so if the asphalt doesnt have any
taconite in it its loss should be low.
http://www.nrri.umn.edu/egg/REPORTS/TR200419/CTS0510.pdf
You could always try the microwave oven test with some samples.
One thing to consider is the reflection loss from the roof due to its
non unity dielectric constant.
Bruce
Mike Naruta AA8K wrote:
True Bruce. Alas, those trees to the West are matched by
trees to the East. Power lines run in front of the house
to the South. And the towers, guy wires, and wire antennae
are to the North in the back yard. It's like looking up
a funnel to see the satellites.
I have another Motorola patch under the roof that also works.
What is the dielectric of wood sheathing and asphalt shingles?
I may try the cake pans on the inside one; not much snow
inside the attic. :)
Mike - AA8K
Bruce Griffiths wrote:
A pity that the GPS receiver elevation mask can't generally be made
to be azimuth dependent.
You could then have a higher elevation limit in the direction of
those trees.
However, it is possible in principle with an M12+T, M12M T or similar
timing receiver which provides the relative timing contribution of
each SV to the solution, to back out the contribution of a given SV
and compute the corresponding timing correction for software
correction of the PPS pulse timing.
Bruce
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