00:01
Hello students, first we find the number of lengths, number of elements.
00:07
So the desired gain is 12 .35 dbi.
00:11
The gain of a yagi -yuda antenna is directly related to the number of elements.
00:18
A rough estimate is that each additional element adds about 1 .5 db of gain.
00:26
So a three element yagi has a gain of about 7 dbi.
00:54
So we can calculate the number of elements needed as desired gain minus three element yagi gain that is equal to 12 .35 minus 7 which is equal to 5 .35.
01:24
Now 5 .35 divided by 3 that is equal to 1 .5 db.
01:35
5 .35 divided by 1 .5 db per element that is 3 .57 which is approximately 4.
01:49
Since we can't have a fraction of an element, we will round up to four additional elements for a total of seven elements.
02:01
Therefore, four elements, this is the total number of elements for the next part.
02:15
The lengths can be calculated using lengths is equal to 150 divided by frequency in mhz.
02:29
So, de is 150 by 108 that is 1 .39 meters and 1 .39 into 1 .05 equal to 1 .46 meter.
02:52
This is ref.
02:55
Similarly, d1 is 1 .39 into 0 .95 is equal to 1 .32 meter.
03:10
D2 is 1 .32 into 0 .95 that is 1 .25 meter and d3 is equal to 1 .25 into 0 .95 that is 1 .19...