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It's likely that many people do not follow what I'm talking about when I say the model is off by 90 degrees or that the collinear EZNEZ model has two 1/4 wave sections of exposed radiator that have opposing phase as a result. However, there are other analogies that relate much the same way and are easier to understand.

Think of the 3/4 wave Sigma as 3 equal fans all blowing in the same direction to create a combined wind speed of 15 MPH. Each fan representing one 1/4 wavelength of the antenna. Now I have two more fans that represent the next 1/2 wave collinear section. I want to use these two fans to increase the MPH. What's the first thing I need to know in order to do this? The compass bearing or direction the original 3 fans are pointing in.

Think of that compass bearing being the phase delay required to add the top 1/2 wave in my collinear test. If I don't know what the other 3 fans are doing, I can't add two more in an effort to increase power. If I don't know the exact phase on each element of the Vector, I can't accurately predict the degree of phase shift required to stack the next collinear 1/2 wave either. That's the EZNEC problem.

Essentially the results show one of the two fans we added in the EZNEC model are blowing in the opposite direction and canceling one of the 3 below resulting in the same 15 MPH wind speed. Once we figure out the correct degree of phase delay on the antenna or compass bearing to point all 5 fans in, we get closer to 25 MPH in the field tests.

The concept is further complicated by the typical requirement of a 180 degree phase delay being needed to stack two 1/2 waves. Trouble is the Sigma is not a 1/2 wave and we didn't just stack one 1/2 wave on top of another. We are stacking one 1/2 wave onto an existing 3/4 wave that has already had the base currents phase shifted by 90 degrees inside the cone with respect to the source. Since the normal radial currents and the CMC one 1/4 wavelength from the source have had no change in phase, starting the center verticals radiation 90 degrees later creates the offset needed to make them constructive.

<blockquote data-quote="Shockwave" data-source="post: 496764" data-attributes="member: 10882">It&#039;s likely that many people do not follow what I&#039;m talking about when I say the model is off by 90 degrees or that the collinear EZNEZ model has two 1/4 wave sections of exposed radiator that have opposing phase as a result. However, there are other analogies that relate much the same way and are easier to understand.&nbsp;Think of the 3/4 wave Sigma as 3 equal fans all blowing in the same direction to create a combined wind speed of 15 MPH. Each fan representing one 1/4 wavelength of the antenna. Now I have two more fans that represent the next 1/2 wave collinear section. I want to use these two fans to increase the MPH. What&#039;s the first thing I need to know in order to do this? The compass bearing or direction the original 3 fans are pointing in.&nbsp;Think of that compass bearing being the phase delay required to add the top 1/2 wave in my collinear test. If I don&#039;t know what the other 3 fans are doing, I can&#039;t add two more in an effort to increase power. If I don&#039;t know the exact phase on each element of the Vector, I can&#039;t accurately predict the degree of phase shift required to stack the next collinear 1/2 wave either. That&#039;s the EZNEC problem.&nbsp;Essentially the results show one of the two fans we added in the EZNEC model are blowing in the opposite direction and canceling one of the 3 below resulting in the same 15 MPH wind speed. Once we figure out the correct degree of phase delay on the antenna or compass bearing to point all 5 fans in, we get closer to 25 MPH in the field tests.&nbsp;The concept is further complicated by the typical requirement of a 180 degree phase delay being needed to stack two 1/2 waves. Trouble is the Sigma is not a 1/2 wave and we didn&#039;t just stack one 1/2 wave on top of another. We are stacking one 1/2 wave onto an existing 3/4 wave that has already had the base currents phase shifted by 90 degrees inside the cone with respect to the source. Since the normal radial currents and the CMC one 1/4 wavelength from the source have had no change in phase, starting the center verticals radiation 90 degrees later creates the offset needed to make them constructive.</blockquote>

[QUOTE="Shockwave, post: 496764, member: 10882"] It's likely that many people do not follow what I'm talking about when I say the model is off by 90 degrees or that the collinear EZNEZ model has two 1/4 wave sections of exposed radiator that have opposing phase as a result. However, there are other analogies that relate much the same way and are easier to understand. Think of the 3/4 wave Sigma as 3 equal fans all blowing in the same direction to create a combined wind speed of 15 MPH. Each fan representing one 1/4 wavelength of the antenna. Now I have two more fans that represent the next 1/2 wave collinear section. I want to use these two fans to increase the MPH. What's the first thing I need to know in order to do this? The compass bearing or direction the original 3 fans are pointing in. Think of that compass bearing being the phase delay required to add the top 1/2 wave in my collinear test. If I don't know what the other 3 fans are doing, I can't add two more in an effort to increase power. If I don't know the exact phase on each element of the Vector, I can't accurately predict the degree of phase shift required to stack the next collinear 1/2 wave either. That's the EZNEC problem. Essentially the results show one of the two fans we added in the EZNEC model are blowing in the opposite direction and canceling one of the 3 below resulting in the same 15 MPH wind speed. Once we figure out the correct degree of phase delay on the antenna or compass bearing to point all 5 fans in, we get closer to 25 MPH in the field tests. The concept is further complicated by the typical requirement of a 180 degree phase delay being needed to stack two 1/2 waves. Trouble is the Sigma is not a 1/2 wave and we didn't just stack one 1/2 wave on top of another. We are stacking one 1/2 wave onto an existing 3/4 wave that has already had the base currents phase shifted by 90 degrees inside the cone with respect to the source. Since the normal radial currents and the CMC one 1/4 wavelength from the source have had no change in phase, starting the center verticals radiation 90 degrees later creates the offset needed to make them constructive. [/QUOTE]

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