B-006
Subelement B-006
Section B-006-013
Section B-006-013
What is a quad antenna?
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Four straight, parallel elements in line with each other, each approximately a half-wavelength long
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A quarter-wavelength vertical conductor fed at the bottom
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Correct AnswerTwo or more parallel four-sided wire loops, each approximately one wavelength long
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A centre-fed half-wavelength long wire
What is a delta loop antenna with parasitic elements?
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An antenna system made of three vertical antennas, arranged in a triangular shape
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Correct AnswerAn antenna consisting of multiple elements, each a triangular loop whose total length is approximately one wavelength
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An antenna made from several triangular coils of wire on an insulating form
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An antenna made of a large multi-turn triangular loop
A 'delta' has a triangular shape. A 'delta' with parasitic elements is an array made of one-wavelength LOOPS with a triangular shape.
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
Tags: none
What is the approximate length of the driven element of a quad antenna designed for 21.4 MHz?
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3.57 metres
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7.01 metres
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Correct Answer14.30 metres
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10.93 metres
Key word: QUAD. A four-sided loop. Loop antennas are roughly 1 wavelength long. Wavelength (lambda) in metres IN FREE SPACE is 300 divided by frequency in megahertz. The 'driven' element in a LOOP is 2% longer than a full wavelength in free space = '300 * 1.02' divided by frequency in megahertz. In this example, the quad measures (300 * 1.02) / 21.4 MHz = 14.3 metres.
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
Tags: none
What is the approximate length of the driven element of a quad antenna designed for 14.3 MHz?
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16.36 metres
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Correct Answer21.40 metres
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10.49 metres
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5.35 metres
Key word: QUAD. A four-sided loop. Loop antennas are roughly 1 wavelength long. Wavelength (lambda) in metres IN FREE SPACE is 300 divided by frequency in megahertz. The 'driven' element in a LOOP is 2% longer than a full wavelength in free space = '300 * 1.02' divided by frequency in megahertz. In this example, the quad measures (300 * 1.02) / 14.3 MHz / 4 = 21.4 metres.
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
Tags: none
What is the approximate length of a delta loop antenna designed for 28.7 MHz?
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4.98 metres
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Correct Answer10.66 metres
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3.55 metres
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8.15 metres
Key word: DELTA LOOP. A three-sided loop. Loop antennas are roughly 1 wavelength long. Wavelength (lambda) in metres IN FREE SPACE is 300 divided by frequency in megahertz. The 'driven' element in a LOOP is 2% longer than a full wavelength in free space = '300 * 1.02' divided by frequency in megahertz. In this example, the DELTA measures (300 * 1.02) / 28.7 MHz = 10.66 metres.
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
Tags: none
What is a major disadvantage of a quad antenna, as compared to a Yagi antenna with the same number of elements and boom length?
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Requires a more heavy-duty mast or tower
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Requires matching to the transmission line
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Correct AnswerMore susceptible to weather damage
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Lower gain
The quad antenna with parasitic elements is a more complex structure than a Yagi. High winds and icing can be problematic, especially on HF.
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
Tags: none
You are constructing an HF delta loop antenna. It is oriented with the bottom element parallel to the ground. Where should you locate the feed point for horizontal polarization?
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In the centre of a side element
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On a side element, one quarter wavelength from the top
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Correct AnswerIn the centre of the bottom element
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At a junction of the bottom element and a side element
In your head, squish the delta from the top down; it now looks like a Folded Dipole. If the Folded dipole is horizontal, it is polarized horizontally.
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
Tags: none
Moving the feed point of a quad antenna from a side parallel to the ground to a side perpendicular to the ground will have what effect?
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It will significantly decrease the antenna feed point impedance
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It will significantly increase the antenna feed point impedance
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It will change the antenna polarization from vertical to horizontal
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Correct AnswerIt will change the antenna polarization from horizontal to vertical
In your head, squish the quad from the top down; it now looks like a Folded Dipole. If the Folded dipole is horizontal, it is polarized horizontally. Flip it 90 degrees and it now has a vertical polarization.
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
Tags: none
What is the approximate length of the wire for a horizontal loop tuned at 7.15 MHz?
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41.96 metres
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Correct Answer42.80 metres
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20.00 metres
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10.49 metres
Key word: LOOP. Loop antennas are roughly 1 wavelength long. Wavelength (lambda) in metres IN FREE SPACE is 300 divided by frequency in megahertz. The radiating element is 2% longer than a full wavelength in free space = '300 * 1.02' divided by frequency in megahertz. In this example, the loop measures (300 * 1.02) / 7.15 MHz = 42.8 metres.
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
Tags: none
The quad antenna consists of two or more square loops of wire. The driven element has an approximate overall length of:
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one half wavelength
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Correct Answerone wavelength
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two wavelengths
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three quarters of a wavelength
What is the approximate overall length of a delta loop antenna?
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One quarter of a wavelength
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Correct AnswerOne wavelength
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Two wavelengths
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One half of a wavelength
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