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Ravaner
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Hello. I use a group of 4 helix antennas in the band of 1420 MHz. It works fine but by nature directivity is very poor ( around 50° at -3 dB). Is there a way to improve directivity using mechanical, electrical ... devices ?
Ravaner said:Hello. I use a group of 4 helix antennas in the band of 1420 MHz. It works fine but by nature directivity is very poor ( around 50° at -3 dB). Is there a way to improve directivity using mechanical, electrical ... devices ?
Drag your pictures.jpg onto the PF reply window and they will appear in your post.Ravaner said:Sorry but it's too difficult (URL !)
A nice construction, congratulations.Ravaner said:Seems to work ! Here is my "Amateur" radiotelescope. All data and command transfers are made through radio connection.
No tricks for reducing beamwidth I am afraid, other than using wide spaced antennas as an interferometer. I was thinking that you might not actually be achieving the theoretical beamwidth.Ravaner said:All this is interesting, but very far from my original question. Some formulas give the gain and directivity for this kind of antenna. Based on these formulas directivity is necessary poor, but may be is there a trick for reducing beam width ...
A helix antenna directivity is a measure of the antenna's ability to focus or concentrate its energy in a specific direction. It is a ratio of the power radiated in the direction of maximum radiation to the average power radiated in all directions.
Helix antenna directivity is calculated using the formula D = 4πA/λ^2, where D is the directivity, A is the effective aperture, and λ is the wavelength of the signal.
The main factors that affect helix antenna directivity are the number of turns in the helix, the spacing between the turns, and the diameter of the helix. The length of the helix and the frequency of the signal also play a role in determining the directivity.
Directivity and gain are often used interchangeably, but they have slightly different meanings. Directivity is a measure of the antenna's ability to focus energy in a specific direction, while gain is a measure of the increase in signal strength achieved by using the antenna compared to a reference antenna.
The higher the directivity of a helix antenna, the stronger the signal will be in the desired direction. This can improve the performance of a communication system by increasing the range and reducing interference from other directions. However, a high directivity can also make the antenna more sensitive to changes in the orientation or position of the antenna.