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Preliminary measurements of the new loop are now complete. The stock loop assembly without the main radiator attached has a resonant frequency of 22 MHz. when placed directly over a 1/4 wave ground plane. I suspect this frequency is lower then expected because I had to place it over the 1/4 wave ground plane in order to take stable readings with a counterpoise. In either event, the new loop dimensions work out to be 129 inches in diameter with four 80 inch support rods. This design exactly duplicates the resonant frequency of the stock loop. The four stock black PVC braces will have to be extended to support the new loop.

I'm sure you're probably questioning why the loop is actually over a 1/4 wavelength. The answer is simple. The entire diameter of the loop does not add to the electrical wavelength. RF looks at this arrangement as the loop adding to the electrical wavelength by only half the distance between each of the four support rods. So basically the diameter of the loop adds to the support rod length by approximately 1/8 of it total diameter. I must say the design of this loop has exceptionally wide bandwidth in comparison to a simple 1/4 wave straight element. The loop makes a big difference here.

Soon I will install the main radiator and tune the entire assembly for maximum gain. Today I was just concerned with getting the loop in the ballpark. I'll have to set up the field strength receiver and a remote TX with 100% duty cycle in order to complete the antenna. With the main radiator about 28 feet I should be able to extract that last db of performance out of this antenna in due time.

<blockquote data-quote="Shockwave" data-source="post: 156300" data-attributes="member: 10882">Preliminary measurements of the new loop are now complete. The stock loop assembly without the main radiator attached has a resonant frequency of 22 MHz. when placed directly over a 1/4 wave ground plane. I suspect this frequency is lower then expected because I had to place it over the 1/4 wave ground plane in order to take stable readings with a counterpoise. In either event, the new loop dimensions work out to be 129 inches in diameter with four 80 inch support rods. This design exactly duplicates the resonant frequency of the stock loop. The four stock black PVC braces will have to be extended to support the new loop.I&#039;m sure you&#039;re probably questioning why the loop is actually over a 1/4 wavelength. The answer is simple. The entire diameter of the loop does not add to the electrical wavelength. RF looks at this arrangement as the loop adding to the electrical wavelength by only half the distance between each of the four support rods. So basically the diameter of the loop adds to the support rod length by approximately 1/8 of it total diameter. I must say the design of this loop has exceptionally wide bandwidth in comparison to a simple 1/4 wave straight element. The loop makes a big difference here.Soon I will install the main radiator and tune the entire assembly for maximum gain. Today I was just concerned with getting the loop in the ballpark. I&#039;ll have to set up the field strength receiver and a remote TX with 100% duty cycle in order to complete the antenna. With the main radiator about 28 feet I should be able to extract that last db of performance out of this antenna in due time.</blockquote>

[QUOTE="Shockwave, post: 156300, member: 10882"] Preliminary measurements of the new loop are now complete. The stock loop assembly without the main radiator attached has a resonant frequency of 22 MHz. when placed directly over a 1/4 wave ground plane. I suspect this frequency is lower then expected because I had to place it over the 1/4 wave ground plane in order to take stable readings with a counterpoise. In either event, the new loop dimensions work out to be 129 inches in diameter with four 80 inch support rods. This design exactly duplicates the resonant frequency of the stock loop. The four stock black PVC braces will have to be extended to support the new loop. I'm sure you're probably questioning why the loop is actually over a 1/4 wavelength. The answer is simple. The entire diameter of the loop does not add to the electrical wavelength. RF looks at this arrangement as the loop adding to the electrical wavelength by only half the distance between each of the four support rods. So basically the diameter of the loop adds to the support rod length by approximately 1/8 of it total diameter. I must say the design of this loop has exceptionally wide bandwidth in comparison to a simple 1/4 wave straight element. The loop makes a big difference here. Soon I will install the main radiator and tune the entire assembly for maximum gain. Today I was just concerned with getting the loop in the ballpark. I'll have to set up the field strength receiver and a remote TX with 100% duty cycle in order to complete the antenna. With the main radiator about 28 feet I should be able to extract that last db of performance out of this antenna in due time. [/QUOTE]

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