Polar Plot: What do the x and y axis represent?

[Neil in West Jersey]

I love the Polar Plot feature of the V3i. I like it so much that I have replaced the Analyze screen, preferring the Polar Plot as my default setting. While the target size indication of the Analyze screen is useful, I think the audio in pinpoint mode along with VCO give a more accurate indication of target size.

A couple of things I have observed in my short time using the V3i are:

1) EMI from a nearby single frequency detector shows up on the Polar Plot as one continuous concentric circle originating from the center and spiraling out in the 7.5 KHz range.

2) Coins on edge will sometimes have a gentle curve downward.

3) The lower quadrants generally do not show any data at all, except curved lines or circles leading to points above the center "equator".

My question is that strong targets show high in the NW corner (upper right), but sometimes targets show more pointing to the east (right) side of the screen. What determines how far N or S the line is? Is it target strength, or conductivity?

 

[Pocketfisherman]

I believe it is showing the phase difference between the transmitted and received signals.

 

[gilfordberry]

The phase angle shift of the returned signal in each of the three frequencies. The angle between the horizontal axis the the returned signal is representative of the phase shift. A non-ferrous target will normally produce a signal in the upper right quadrant. A vertical response (overlaying the "y" axis) would, I believe, indicate a 90 degree phase shift which would be consistent with a very high VDI number (a plus 95??). Iron targets would most likely show up in the upper left quadrant. I'm not sure about this, but it does seem that way to me. Experts?

 

[Larry (IL)]

Phase angle and intensity.

Here is a good thread on Polar Plot. http://www.findmall.com/read.php?66,1192324,1201550#msg-1201550

 

[ak_1234]

...A vertical response (overlaying the "y" axis) would, I believe, indicate a 90 degree phase shift which would be consistent with a very high VDI number (a plus 95??)

0, not 95