3 votes

Minmum spacing between two receive-only omidirectional antennas

If antennas are end to end, they can be very close, nearly touching without any problem. If the antennas are side by side, they will not interfere with each other for receiving, but one antenna may ...
user10489's user avatar
  • 6,255
3 votes

How is the length of an inverted V affected by being too close to the ground?

Feed-point impedance of a capacitive antenna, like an Inverted V, is affected by four physical factors: Length of radiating elements. Adjusting the overall length so that the antenna is resonant on ...
Louis Seaman's user avatar
2 votes

How is the length of an inverted V affected by being too close to the ground?

Yes, somewhat. We could model the effect of height above ground on resonant length for an outdoor antenna. The effect I would expect to see is that lower height means more capacitance to ground, which ...
hobbs - KC2G's user avatar
  • 12.4k
2 votes

Converting a 470-694Mhz TV antenna for 433Mhz reception

It is not generally practical to convert an antenna for lower frequency operation. This is because, if you want to change the a given antenna design to a different frequency, what you do is scale it ...
Kevin Reid AG6YO's user avatar
  • 24.5k
1 vote

What core material would offer the highest sensitivity in the design of an ELF/VLF handheld rod antenna?

Another thing to consider is the strong background noise at these frequencies, caused by thunderstorms. Your antenna only needs to be sensitive enough to measure this noise, more sensitivity makes no ...
tomnexus's user avatar
  • 11.2k
1 vote

What core material would offer the highest sensitivity in the design of an ELF/VLF handheld rod antenna?

As said in the comments, I'm really not an expert on magnetic materials. But at ELF frequencies (3 to 30 Hz, definition of the ITU), as others have said, ferrites are unnecessarily lossy / low in $\...
Marcus Müller's user avatar
1 vote

What core material would offer the highest sensitivity in the design of an ELF/VLF handheld rod antenna?

For low frequencies and low field strengths (receiving only, similar to earth's magnetic field) you could also look into Mu metal or amorphous metals, which can have extremely high permeability. I've ...
tomnexus's user avatar
  • 11.2k
1 vote

Minmum spacing between two receive-only omidirectional antennas

For receive only, no real problem. If you had transmitters, you could not separate them far enough horizontally. You would blow out the receiver's front end in the adjacent antenna without some ...
Dereck's user avatar
  • 484

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