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651 views

### How to derive antenna gain from radiation pattern

I need to calculate the antenna gain in both dimensions: azimuth and elevation. The datasheet of the antennas I am using has two different radiation patterns, one for the elevation and one for the ...
711 views

### Phased Array Pattern

I'm working on a passively scanned phased array radar project, as a concept and hopefully design. One of the things that bugs me is that antenna patterning used. The vast majority of radar arrays I'...
417 views

### Dipole antenna radiation field equation

Can anybody provide me with an idealised formula that describes the radiation pattern of an omnidirectional dipole antenna? In particular I am interested in the formula that creates a plot similar to ...
119 views

### what is main reason for formation of side lobes in directional antennas?

I would like to know why are side lobes formed along with main beam in an antenna. I asked one of my colleague and he explained me that its due to radiation of frequencies near to the required center ...
164 views

### Ham operators often tell me that comparing gain to an isotropic radiator isn't much use because it's only a theoretical antenna, is this true?

When you look down on an isotropic radiator from above, ie : the azimuth view radiation pattern, it's a circle. The same as looking down on any omni directional antenna. So when comparing the gain of ...
436 views

### What are the effects of a ground plane under a horizontal dipole?

What are the effects on signal propagation if this ground plane is just a metal object and what are the effects if the ground plane is actually grounded? I am asking this question because someone ...
99 views

### Antenna Patterns and Multipath Effect

It's said that in order to decrease multi-path effects on receiving antennas that your antenna pattern should have a sharp slope near the horizon. Why? for example this is article mentioned it.(...
521 views

### What is the easiest way to eliminate a beam antenna's backward radiation (rear lobe)?

I tried a metallic reflector which works well in terms of radiation, but considerably degrades the return loss and adds more complexity to the design.
147 views

142 views

### Do Far-Field Radiation Patterns/Gains of NEC Software Accurately and Always Show the E-M Fields "Launched" by Vertical Monopoles?

Judging from posts on the Internet, this belief commonly is considered to be valid. But what is the correct answer?
83 views

### What's the general difference between radiation patterns of stationary and adaptive aerials in mobile communication systems?

I am trying to find general difference between radiation patterns of adaptive and stationary antennas (common difference, calculation difference and any other). I am interesting in any example and ...
241 views

### Rhombic Polarization Question, provided radiation maps

I am trying to engineer my first antenna to get on the air. I need to hit a repeater 50 miles away at a lower elevation than me so that I can use its IRLP nodes. Would this mean I am looking for low ...
302 views

### Can you place reflective material near to an antenna without interfering with the radiation pattern?

So I'm trying to understand how radiation pattern are calculated and it's going well (so far!). I've come across a bit of an issue when it comes to the following situation: If we have a ...
89 views

### Antenna Q vs pattern shape

Is there any reason to think that changing the Q of an antenna would affect the directional pattern, assuming that is the only variable that changes? Restricting to values of Q say less than 1000. ...
67 views

### Total radiation pattern in antenna arrays

let's consider a simple linear uniform spaced array: We know that, from elementary array theory, the total pattern (for instance in terms of E-field) may be evaluated, in case no phase shift is ...
286 views

### How Does the Performance of an Inverted V Dipole Compare to a Linear Dipole?

The NEC4.2 comparison in the answer below shows one example, for a practical set of installation conditions.
136 views

### How Much Does the Radiation Pattern of an "EFHW" Antenna System Vary Across its Bands?

This NEC4.2 analysis shows one example of such variation.
137 views

### How Does the Low-Angle Radiation of a Horizontal Dipole Compare to That of a Vertical Monopole?

Conventional wisdom based on the far-field (only) patterns calculated by M-o-M software such as NEC show that low-angle radiation from a horizontal dipole is very low, and zero in the horizontal plane....
67 views

### How Might Nearby Re-Radiators Affect the Radiation Patterns of a Transmit Antenna?

Here is one example of such, based on a NEC study...
105 views

### Half wave dipole with parasitic element, (Gain calculation)

good morning all, I have difficulties to find the correct formula that allows me to calculate the gain of half wave dipole in parallel with another parasitic half wave dipole. I'm trying to calculate ...
218 views

### Would a covering like aluminised kapton effect antenna radiation pattern?

I'm looking at using a 1/4 wave whip antenna for a transmitter. If possible I'd like to cover the antenna in very thin (0.02 mm) aluminised kapton for reasons unrelated to the radio system; to be ...
816 views

Consider the radiation pattern of a horizontal dipole mounted at a height of 1.75λ. Is it possible for a receiving station's antenna to be mounted at a certain height such that the radiation of the ...
1k views

### Radiation pattern for a 1/4th wave 2 meter antenna used on 70cm

What would the radiation pattern look like if I used a 1/4th wave 2 meter mag-mount antenna on 70cm with an HT.
237 views

### How to calculate/estimate the effect of having conductive material nearby an antenna

I have a system with a 1/4 wave whip antenna and above the antenna there is a mess of aluminium they're not connected but are nearby. I would like to figure out what effect this would have on the ...
184 views

### How to plot transmitter coverage area?

As an Extra class licensee, I should probably know this... I am working on a web application for repeater owners. I would like to include an estimated coverage area, provided they have entered all of ...
132 views

### Need help understanding the gain on antenna pattern plots

My understanding is that the value of the axis (like -10 / 0 dB) refers to the maximum antenna gain (e.g. 12dbi). So, if a ...
117 views

### Directional antenna overlapping main lobes

In a 2-Rx by 2-Tx directional antenna system, say both transmitters are transmitting concurrently as in Fig. The main lobes from the two transmitters overlap. How does this affect the resultant signal ...