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Antenna plots

Jun 10th 2016, 00:38

mikeh

Joined: Oct 16th 2014, 01:13
Total Topics: 0
Total Posts: 0
Can anyone describe how to read an antenna polar plot diagram? I am pretty new to all of this. I understand the basic look of the thing, but don't understand why the dB start at negative 30 dB and go out to 0 dB. I'm reading through the ARRL book and it doesn't explain it at all; and surprisingly the internet is no help. Thanks.
Jun 10th 2016, 00:48

W1VT

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
Jul 1980 - QST (Pg. 26)
New Look For QST's Antenna Patterns, The

Author: Hall, Jerry, K1TD
Article: http://p1k.arrl.org/pubs_archive/73749
Jun 10th 2016, 21:30

mikeh

Joined: Oct 16th 2014, 01:13
Total Topics: 0
Total Posts: 0
So the values on the chart are only applied where the concentric circles meet the plotted lines? e.g.- the 0 db straight out, the -2 db line meets at 30 deg off of the centerline, -4 at 40 deg, -20 db at 80 deg, etc?
Jun 11th 2016, 02:47

W1VT

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
Yes, though I see the intersections at 45 degrees for -4 and 82 for -20.

Zack W1VT
Jun 11th 2016, 17:54

mikeh

Joined: Oct 16th 2014, 01:13
Total Topics: 0
Total Posts: 0
Ok, thanks so much for the help.

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