Hi
Here is some actual RF data on a number of antennas:
http://www.ngs.noaa.gov/ANTCAL/
There also is a pretty good document on how the calibration is performed.
It appears that if you are after ps or mm then a calibration file on the
antenna type being used is needed. Pointing north to be ab
Hi
> On Dec 17, 2014, at 8:49 AM, Jim Lux wrote:
>
> On 12/17/14, 4:36 AM, Bob Camp wrote:
>> HI
>>
>>> On Dec 17, 2014, at 1:07 AM, Chuck Harris wrote:
>>>
>>> I would venture that the extent of the magic was to note the physical
>>> center of the array, and call that the phase center.
>>>
>
On 12/17/14, 4:36 AM, Bob Camp wrote:
HI
On Dec 17, 2014, at 1:07 AM, Chuck Harris wrote:
I would venture that the extent of the magic was to note the physical
center of the array, and call that the phase center.
As long as you always orient the antenna in the same direction, any
errors that
HI
> On Dec 17, 2014, at 1:07 AM, Chuck Harris wrote:
>
> I would venture that the extent of the magic was to note the physical
> center of the array, and call that the phase center.
>
> As long as you always orient the antenna in the same direction, any
> errors that might exist in the real ph
I would venture that the extent of the magic was to note the physical
center of the array, and call that the phase center.
As long as you always orient the antenna in the same direction, any
errors that might exist in the real phase center will be consistent,
and could be corrected for by noting
Inquiring minds surely are in high gear!! And to think, all I
wanted to know was how close I needed to to point to north!!
The need to point north is a legitimate question. There is a chance
that they designed some magic into it to deliberately shape the response.
Having taken a few apart,
Hi
> On Dec 16, 2014, at 9:15 PM, Dave M wrote:
>
> Jim Lux wrote:
>> On 12/16/14, 5:59 AM, Tom Van Baak wrote:
Clever idea, but..
Most rotary joints have more phase and amplitude variability than
the antenna.
So you're stuck with rotating back and forth with a ca
Jim Lux wrote:
On 12/16/14, 5:59 AM, Tom Van Baak wrote:
Clever idea, but..
Most rotary joints have more phase and amplitude variability than
the antenna.
So you're stuck with rotating back and forth with a cable that's
flexing and now you get to measure the phase variability of the
coax.
I
On 12/16/14, 5:59 AM, Tom Van Baak wrote:
Clever idea, but..
Most rotary joints have more phase and amplitude variability than
the antenna.
So you're stuck with rotating back and forth with a cable that's
flexing and now you get to measure the phase variability of the
coax.
I was thinking of
> Clever idea, but..
>
> Most rotary joints have more phase and amplitude variability than the
> antenna.
>
> So you're stuck with rotating back and forth with a cable that's flexing
> and now you get to measure the phase variability of the coax.
I was thinking of some sort of non-contact RF b
On 12/15/14, 8:10 PM, Tom Van Baak wrote:
But to prove us wrong, put the antenna on a 17 hour turn-table, collect data
for 6 months, and then see if you see any 17h peaks in the FFT!
Clever idea, but..
Most rotary joints have more phase and amplitude variability than the
antenna.
So you'
Hi
> On Dec 15, 2014, at 11:20 PM, Dave M wrote:
>
> Jim Lux wrote:
>> On 12/15/14, 5:46 PM, Dave M wrote:
>>> With all the discussion about surveys & position accuracy, I have a
>>> question about my choke ring antenna. There is an arrow marked "N"
>>> on the underside of the rings. How accura
To answer which "North", it is True North, not Magnetic. Orbits,
including GPS, are specified relative to the geographic pole. Magnetic
North moves noticeably over time and place. True North moves somewhat
over time but only very slightly.
David
On 12/15/14 9:05 PM, Jim Lux wrote:
On 12/1
Jim Lux wrote:
On 12/15/14, 5:46 PM, Dave M wrote:
With all the discussion about surveys & position accuracy, I have a
question about my choke ring antenna. There is an arrow marked "N"
on the underside of the rings. How accurately does the alignment
need to be to "N"orth? True north or magnet
> With all the discussion about surveys & position accuracy, I have a question
> about my choke ring antenna. There is an arrow marked "N" on the underside
> of the rings. How accurately does the alignment need to be to "N"orth?
> True north or magnetic north (my thinking says True North)?
>
On 12/15/14, 5:46 PM, Dave M wrote:
With all the discussion about surveys & position accuracy, I have a question
about my choke ring antenna. There is an arrow marked "N" on the underside
of the rings. How accurately does the alignment need to be to "N"orth?
True north or magnetic north (my thi
Hi
If:
1) You are doing a survey of a number of points in an area
2) You want to hit the “1/5 mm accuracy” that your system is rated to :)
3) You really do care
Then:
You point the arrow north to the best of your ability to make all the antenna
errors show up in the same direction. It becom
With all the discussion about surveys & position accuracy, I have a question
about my choke ring antenna. There is an arrow marked "N" on the underside
of the rings. How accurately does the alignment need to be to "N"orth?
True north or magnetic north (my thinking says True North)?
Does the d
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