Polar plot for antenna measurement

Hi,
I have LabVIEW 8.2 (Full) and I could make a polar plot in LabVIEW from the 'Polar Plot.vi'. However, I realized that I don't have the option to use 'Create Annotation' on the front panel to get the value of certain point of interest on the plot itself (since the plot itself is a picture). My point of interest is -3dB from the peak of the plot, and is there anyway to extract the corresponding information from the polar plot? Eg, peak point is -20dB, my point of interest would be -23dB, and I would like to retrieve the angle of -23dB.
Attachments:
polar.vi ‏32 KB

I must have attached the old file. I did use the 'Array Max & Min.vi' to look for the highest point in dB, and then get the corresponding angle. From the max point, I subtracted 3dB and obtained the -3dB point, but there is no corresponding value for the -3dB point. Eg: -20dB is the highest peak, -23dB is the point of interest, and there is not -23dB in my data set. In other words, I might have -22dB, -22.5dB, -23.3dB etc
I am assuming that the 'Polar Plot.vi' will connect all those points together and form the polar picture. And I would like to obtain the -23dB angle from the plot.
Attachments:
Polar 2.vi ‏35 KB
antenna.xls ‏9 KB

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Solved!
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www.mcm-electronics.com
PS: Don't forget to rate a good anwser ; )
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Mensaje editado por Special K
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Very nice unclebump,
You get 5 stars for that one To help people new with LabVIEW I decided to attach a picture showing you where to navigate to make the change. You need to change the logic constant from false to true in the Polar Plot Data.vi (Labeled Polar Data) under the Polar Plot.vi (No Label just a picture of a polar plot). The plot comes out filled because it is a multiple line graph drawn in a picture node with the line fill option on.
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Message Edited by ShotSimon on 08-27-2008 09:25 AM
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Solved!
Go to Solution.

robin533,
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Polar plot for antenna measurement

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