As I understand it, the GPS signals are circularly polarised, and so
surely reflections will reverse the sense of that polarisation such
that the antenna will be insensitive to them? Maybe Warren's simple
pie dish is working by shielding the antenna from the true MULTI-path
reflections, and any
Peter Vince wrote:
As I understand it, the GPS signals are circularly polarised, and so
surely reflections will reverse the sense of that polarisation such
that the antenna will be insensitive to them? Maybe Warren's simple
pie dish is working by shielding the antenna from the true MULTI-path
Peter Vince wrote:
As I understand it, the GPS signals are circularly polarised, and so
surely reflections will reverse the sense of that polarisation such
that the antenna will be insensitive to them?
Yes, as a first degree analysis. However, cancellation will not be 100%
since neither the
Hi
That's one of the many things that makes this all a bit tough to work out.
Even without a choke ring, a pie plate, or a ground sheet involved you can move
a cheap GPS timing antenna 5 feet and see a very real change in plots. Up /
down / left / right often the move does not make much
Does someone know which commercial antennas are 3D designs? Sounds like
the $200 AeroAntenna version mentioned previously might be a 3d design,
although it's a little tough to guess by simply looking at the enclosure
and a single drawing. An evaluation of some 3D antennas:
What I have found is if you have a decent view of the sky or even when
indoors on an upper shelf,
by turning the pie pan lip up, it helps the antenna location placement
sensitivity issue.
I'll leave it to the antenna Experts speculate on why that is.
ws
***
Hi
That's one of the
Warren,
I'm not trying to be a wise guy, but what direction is right other than up?
Steve
At 08:46 PM 3/13/2010, WarrenS wrote:
All true,
BUT...
Just put an 8 inch pie pan in the right place, facing the right direction.
ws
***
___
Hi
Down would be a lot better for rain draining off.
Of course most people don't get a lot of rain in the living room
Bob
On Mar 14, 2010, at 3:14 PM, steve gunsel wrote:
Warren,
I'm not trying to be a wise guy, but what direction is right other than up?
Steve
At 08:46 PM
/ant_cals.html
John WA4WDL
--
From: WarrenS warrensjmail-...@yahoo.com
Sent: Saturday, March 13, 2010 7:46 PM
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Subject: Re: [time-nuts] Choke Ring Design for L1
Steve
I tried several Positions and directions and sizes of antennas and pie pans.
Usually best was with antenna sitting on the pan with lip up,
But not always.
Attached is the RIGHT position for one of the best cheap ones I tried.
My earlier recommendation for a cheap good working GPS PiePan
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
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
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
, 2010 7:46 PM
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Subject: Re: [time-nuts] Choke Ring Design for L1
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
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
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
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
21 matches
Mail list logo
