m0ngoose
Electrical
- Jun 11, 2011
- 9
Hi guys,
Just started reading my new ARRL antenna book that came in... I have a few questions in reading Chapter 2 (fundamentals)
- when we say a 432-MHz half-wave dipole (for example):
- according to v = f*lambda: lambda = 3*10^8 / 432 * 10^6, correct?
- so is the length of the entire dipole antenna (not just one side) half of the lambda found above?
- what if I change the length of the antenna? that changes the resonant frequency to no longer be 432-MHz, right? therefore it is no longer a "432-MHz half-wave dipole antenna"?
- what does half-wave, full-wave, 3/2 wave... resonance mean? i.e., "I'm transmitting at the half-wave resonant frequency"?
- Let's say I measure the radiating peak power for a dipole antenna and wanted to find out the directivity.. I should be able to use Directivity = Peak Power measured from dipole / Average Power density.... what average power density is this? is that for an ideal isotropic antenna? If so, how do I know what value to use... is there a table or chart somewhere that has it?
Thanks in advance
Just started reading my new ARRL antenna book that came in... I have a few questions in reading Chapter 2 (fundamentals)
- when we say a 432-MHz half-wave dipole (for example):
- according to v = f*lambda: lambda = 3*10^8 / 432 * 10^6, correct?
- so is the length of the entire dipole antenna (not just one side) half of the lambda found above?
- what if I change the length of the antenna? that changes the resonant frequency to no longer be 432-MHz, right? therefore it is no longer a "432-MHz half-wave dipole antenna"?
- what does half-wave, full-wave, 3/2 wave... resonance mean? i.e., "I'm transmitting at the half-wave resonant frequency"?
- Let's say I measure the radiating peak power for a dipole antenna and wanted to find out the directivity.. I should be able to use Directivity = Peak Power measured from dipole / Average Power density.... what average power density is this? is that for an ideal isotropic antenna? If so, how do I know what value to use... is there a table or chart somewhere that has it?
Thanks in advance