Ham Radio Antenna Design Notes: Difference between revisions
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=== 492 / Freq in MHz === | === 492 / Freq in MHz === | ||
Calculate length for an inverted V antenna. | |||
=== 1005 / MHz === | === 1005 / MHz === | ||
Revision as of 20:55, 29 July 2017
Considerations in Design
resonance / swr
Q
Impedance
Common Mode Current
Velocity Factor
Math
492 / Freq in MHz
Calculate length for an inverted V antenna.
1005 / MHz
Talking Points of Experience
Loading coil to simulate length, but inefficient and generates heat, doesn't handle high power well.
DC grounded antennas are ideal: prevents static build up on antenna
Precision in element length becomes more significant at higher frequency
Understand how capacity hats impact resonance
Impedance Dipole vs Inverted V
A dipole in free space should have about 72 ohms of input impedance. As you move the poles down to form and inverted V the impedance lowers.
A folded dipole needs a 4:1 balun