How to measure the distance between elements?
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| Jun 7th 2019, 13:23 | |
KO2FTotal Topics: 0 Total Posts: 0 |
When constructing an antenna with elements of any significant size, where is the distance between elements measured? For example... If I am constructing a Yagi with 1 inch tubing and the design calls for 16 inches between 2 elements, does this mean: a) 16 inches between the outer element surfaces? Meaning that the two elements are 17 inches apart on center... b) 16 inches on center? x...) something else? If I am constructing a 10 foot diameter double loop for 160 meters, this 1 inch question could mean a difference of more than 6 inches in length. Bob KO2F |
| Jun 7th 2019, 13:32 | |
W1VTSuper Moderator Total Topics: 0 Total Posts: 0 |
All the computer modeling programs that I have seen use the center to center distance. Very few people have a test range for optimizing 2M antennas via trial and error. This article attempts to explain Yagi dimensions http://www.arrl.org/vhf-beams Homebrewing a 6-Meter Yagi (from QEX RF column) QEX January/February 1998, p. 52-57 Enlarged Figure 6 with key dimensions. Zipped file with all figures and photos. In the past I've measured distances off a photo to see which option seemed most reasonable. These days imported dial calipers are inexpensive measuring tools. Zak W1VT ARRL Senior Lab Engineer |
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