That's a dramatic and impressive difference Mark! Were the other
choke-rings similarly better than the ordinary conical, or was this
one heads and shoulders better than the rest? I was just wondering if
it was the choke-ring concept that gave the major improvement, with
this one just being
I'm considering getting another batch of PCBs made up for the frequency
divider design I sold a number of the other year.
The basic target is low jitter, 10MHz sine in, square wave outputs at 10MHz,
5MHz, 1MHz, and one other output that is switchable from 100kHz down to 1Hz.
These are four layer
I'm in the middle of switching email addresses.
Old email: david.partri...@dsl.pipex.com
New email: david.partri...@perdrix.co.uk
Mail to either address will get through, but the new email address is
preferred. I'm still sending as the old email address for now, but will
change over soon.
My
Hi
Depending on just what sort of DMTD you are after, there are an enormous number
of JPL reports on their system. They range from papers that are basically
operating manuals (when this happens that shows up on the screen) to deep dives
on obscure math. If you are not after a 100 Hz system
From KO4BB page
http://www.ko4bb.com/Timing/FAQ-1.php
What exactly would we be measuring unless we compare our standards to a perfect
standard ?
Maybe be a jittery oscillator with a slow drifter on a walkabout. :-)
The Allan Deviation is typically computed from a series of Time Interval (TI)
Hello,
Do people on the list have a preference for using a specific version
of FreeBSD
for a ntpd/ntpns server running on a Soekris net4501 board?
I finally ordered (and promptly received) the Soekris net4501 board
that I wanted to connect to my Thunderbolt.
Having to start fresh (not
All the choke ring antennas were similar in performance. The Aero/Leica one
is optimized for the L1 freq only.
All the other choke rings that I tested did L1/L2 which compromises performance
a bit which did show up in the data (but at a level that could just have been
random luck of the
In message 9b81a82e-b5a5-45ba-a36d-c2f6e4fb0...@tenpierick.com, Pieter ten Pi
erick writes:
Hello,
Do people on the list have a preference for using a specific version
of FreeBSD
for a ntpd/ntpns server running on a Soekris net4501 board?
Any recent version will do.
I would take a 7.x or 8.x
Hello The Net:
Is there a design for a choke ring to add to my existing L1 GPS antenna ?
While there may be some variations to the exact dimensions of a choke
ring to a specific
type of L1 antenna, either patch, helical, etc.,
I suspect there is some commonality to the design dimensions.
I
Hi Stan,
Hello The Net:
Is there a design for a choke ring to add to my existing L1 GPS antenna ?
While there may be some variations to the exact dimensions of a choke
ring to a specific
type of L1 antenna, either patch, helical, etc.,
I suspect there is some commonality to the design
Hi
One real world application is or an autonomous box is supplied with many clock
signals., The task is to select the one that's best. The standard of comparison
may be far from perfect in this case.
Bob
On Mar 13, 2010, at 10:23 AM, Raj wrote:
From KO4BB page
Hi
A lot depends on just how bleeding edge you happen to want to be. Both 8.0 and
7.2 run ok on the 4501.
Bob
On Mar 13, 2010, at 10:59 AM, Pieter ten Pierick wrote:
Hello,
Do people on the list have a preference for using a specific version of
FreeBSD
for a ntpd/ntpns server running
Good information to know, if one is doing survey work.
But some NON-Nut needs to ask, SO WHAT?
A 3 foot error may cause + - 3ns of additional phase time error, which is
well below the short term GPS noise level.
If that is averaged over the 500 or so second TC loop or the 48 hrs supper
survey
Hello,
I am placing my TADD-2 into the TAPR TADD enclosure, and I need to know the
size / threads of the fixed mounting posts.
Anyone know?
Thanks,
Dave
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Is there a design for a choke ring to add to my existing L1 GPS antenna ?
Yeah
If you are using it for GPSDO work where a ns is good enough and you don't need
cm accuracy,
It is called a pie pan with its Lip turned up.
A choke rings blocks reflected signals from below the antenna from
Any one of the counters listed above can do this measurement,
A decent time nut Allan Deviation needs to have noise floor of below 1e-12.
To do this for a 1sec ADEV, it needs a resolution of under 1ps, so NO not all
the counters can do that.
ws
On Mar 13, 2010, at 10:23
Dave, the standoffs are threaded for a 4-40 screw, but I'll tell you a
secret -- if you use the nuts and washers on the BNC connectors, the
board is held very securely without any need for the mounting screws;
I've frankly never bothered with them.
John
Dave hartzell said the following
Hi
Ok, I got enough time to play a bit more with the 5370B today. Here's what I
found (all running on the internal standard):
If I take the gate time out to 1 second, the frequency display reads as it
should.
If I look at the standard deviation on various samples of period I get some
Fellow members of time-nuts,
I have recently acquired an Oscilloquartz 8650S var. 00 5MHz oscillator.
Now i am looking for some information about this oscillator, i could
find no information about it on the site of Oscilloquartz, so i am
hoping that someone on this list has some data for this
Hi there,
just to prevent from making mistakes ...
You can have two different accessories for GNSS antennas:
1) a ground plane
it prevents the antenna from receiving signals from beneath the
antenna (from the ground, roof or whatever is beneath)
... so this could be your pie
All true,
BUT
Just to keep from being mislead,
I said what a choke ring antenna does,
You have described how it is so good at its job.
The Main purpose of the choke ring's, hi impedance, 1/4 wave, tuned
thingies, around the antenna is to keep reflected Signals from BELOW the
antenna from
For detailed measurements of six different choke ring GPS antennas, see;
http://facility.unavco.org/project_support/permanent/equipment/antennas/ant_cals.html
John WA4WDL
--
From: WarrenS warrensjmail-...@yahoo.com
Sent: Saturday, March 13,
WarrenS wrote:
All true,
BUT
Just to keep from being mislead,
I said what a choke ring antenna does,
You have described how it is so good at its job.
The Main purpose of the choke ring's, hi impedance, 1/4 wave, tuned
thingies, around the antenna is to keep reflected Signals from BELOW
the
Thanks, Nice set of references as always.
OK, so its not 100db, But you may of missed my point yet again.
If you think I said that a 10 cent pie pan is a good substitute for a $1000
survey antenna in all applications,
I think we all know that would be Nonsense.
BUT what may not be known is:
WarrenS wrote:
Thanks, Nice set of references as always.
OK, so its not 100db, But you may of missed my point yet again.
If you think I said that a 10 cent pie pan is a good substitute for a $1000
survey antenna in all applications,
I think we all know that would be Nonsense.
BUT what may not
WarrenS wrote:
Bruce wrote:
ws response
Only for your particular location and antenna.
True, My location is under the sky indoors or outdoors, and I used
severl cheap car type antennas and a pole mounted timing antenna.
May not work as well in other locations or with other types of
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
Bruce wrote
Those plots give little information about the antenna response to
variations in SV elevation directly as the signal strength from theSV also
varies with
elevation. No account is taken of the SV signal variation with elevation.
ws) Correct, but a really Silly comment. Of course for
Thanks John.
I picked some screws up at the local hardware store. I see what you mean
about the BNC mounting...
FYI, I had to bend the vertical nut ears a bit to be able to get the board
in, and screwed in.
I'm probably going to be operating open lid for a while just to see the
LED status.
The major flaw in that method is that it doesn't actually make
measurements over the entire sphere.
Unless you have an independent method of showing that the effective
response to signals incident from underneath the antenna are small it
also fails to measure the true response in the upper
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
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
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