[time-nuts] Choke Rings and Points North

Bob Camp kb8tq at n1k.org
Mon Dec 15 20:55:30 EST 2014



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 


You point the arrow north to the best of your ability to make all the antenna errors show up in the same direction. It becomes an offset to the entire grid of points rather than an error randomly added to each point. You do a correlation process at your stationary survey (DGPS) locations to remove the error. 

If you are not doing that sort of survey work … don’t worry about it. 

(Apologies to those who do this for a living, you do indeed care, it’s just the time side that does not care). I’m sure  that “best of your ability” is indeed quite good. 


> On Dec 15, 2014, at 8:46 PM, Dave M <dgminala at mediacombb.net> 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 thinking says True North)?
> Does the directional accuracy affect the precision survey?  I'm assuming 
> that it would have no effect on the accuracy of the 10 MHz frequency output. 
> Or am I completely off base?
> Dave M 
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