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8 votes
3 answers
987 views

How would I calculate antenna gain?

The concept of antenna gain is pretty important for calculation of link budget and is something I've had contact with. I know that it tells me how focused the waves emitted by the antenna are and I ...
AndrejaKo's user avatar
  • 2,893
8 votes
2 answers
1k 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 ...
gabriel-shatana's user avatar
6 votes
4 answers
407 views

Why is gain used?

It always confused me why 100 watts out of your transmitter could radiate 200 watts coming from a high-gain antenna. Why is the term gain used instead of directionality?
Skyler 440's user avatar
  • 7,620
6 votes
2 answers
1k views

Is there any practical advantage to a parabolic reflector over a high-gain beam antenna?

I've been looking at options for a high-gain directional antenna recently, and I've noted that there are commercially available parabolic antennae for the shorter bands -- specifically 70 cm, with an ...
Zeiss Ikon's user avatar
  • 4,147
5 votes
6 answers
4k views

How does lowering the RF Gain help with SNR?

Let's say for sake of example we are in the 40m band. I've read articles and posts about riding the RF gain (or even just simply lowering it). And I can see how it is useful in overload situations. ...
Paul's user avatar
  • 791
4 votes
3 answers
1k views

What is the point of high gain antenna with respect to the maximum EIRP

OFCOM states that the maximum EIRP within the UK for 2.4 GHz is 100mW. Simply put, what is the point in being able to buy 2.4 GHz high gain antennas which can say do 24dBi, which already puts the ...
R4D4's user avatar
  • 141
4 votes
1 answer
113 views

Is there a technical reason to sell an LNA without advertising its gain?

I recently bought a couple SPF5189 low-noise amplifier boards via an online marketplace. One thing that struck me is that while nearly all the listings highlighted the LNA as having a noise figure of ...
natevw - AF7TB's user avatar
4 votes
2 answers
320 views

Use noise figure and gain to calculate weakest signal radio can receive?

An FM radio receiver, using a 1 kHz tone at 3 kHz deviation has a 12 dB SINAD (Signal To Noise and Distortion) of -116 dBm. I would like to increase the 12 dB SINAD sensitivity of the receiver to at ...
Skyler 440's user avatar
  • 7,620
3 votes
4 answers
3k views

Give vertical antenna directional gain?

So here is a strange thought. If a vertical electrically speaking is a half dipole with the other half as a ground plane to balance out. Perhaps there are ways to make equivalent director and ...
Matthew Wang's user avatar
3 votes
5 answers
2k views

Gain difference between half-wave and infinitesimal dipole?

In discussion around another Q&A here, Glenn W9IQ commented: The directive gain difference between a half wavelength dipole and an infinitesimal dipole is only 0.39 dB I'm curious where this ...
natevw - AF7TB's user avatar
3 votes
4 answers
830 views

Relation between antenna physical size and gain

I would like to know whether increasing the size of the antenna help increase its gain. Does this hold only for certain kinds of antennas like parabolic or horn antennas? And if it is true, can you ...
ResearcherW's user avatar
3 votes
2 answers
3k views

USRP Safe Gain Values

I am working with USRP N210 and USRP B200 radios with GNURadio. I have connected the TX/RX port of one radio to the RX2 port of the other with an RF cable as a simulated radio link. In GNURadio, I ...
rytse's user avatar
  • 33
2 votes
2 answers
824 views

Beamwidth of omni-directional antenna with gain

I am looking to buy a wifi antenna for a boat to connect to shore based wireless hotspots that may be "far" away. Due to the waves, I am assuming that the antenna mast sways +-15° from vertical. The ...
Mathias Schultz's user avatar
2 votes
1 answer
932 views

Calculating a real antenna gain from electric field strength?

Could someone please tell me if it is possible to measure the antenna gain simply by placing a field strength meter at a selected distance to my antenna, knowing the power applied to the antenna. ...
Icaros's user avatar
  • 23
2 votes
1 answer
249 views

Gain of Yagi turnstile?

I am currently working on a system to communicate with amateur CubeSats. I have decided to use the turnstile crossed-dipole style yagi because it is relatively easy to construct and uses circular ...
Caphlp22's user avatar
2 votes
1 answer
209 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 ...
Tarik L's user avatar
  • 45
1 vote
2 answers
281 views

Why is there so little difference in the gains of Yagi Uda antennas with omnidirectional antennas? Shouldn't the power at the back be at the front?

Consider an omnidirectional antenna with X dBi gain. Intuitively I understand that the power that would have been dispersed in now-dead directions is directed around the antenna. What I don't get is ...
Mister Mystère's user avatar
1 vote
1 answer
3k views

UV-5R High Gain Antenna Performance

My Baofeng UV-5R came with a shorter 6.5” antenna and a “high gain” 15.3” RH-771 antenna. In your experience, how much of a difference in range does the use of the longer antenna achieve?
plafratt's user avatar
  • 229
1 vote
1 answer
367 views

How to calculate passive repeater gain?

An active club in my area moved its repeater to a new location behind a big hill, and we can't join the regular social nets anymore. I'm not holding my breath that anyone in the gated HOA at the top ...
natevw - AF7TB's user avatar
1 vote
0 answers
88 views

Why does a peak remain at -10db gain and disappear at -50db gain?

I have a Pluto and an RTL-SDR both connected to a computer. On Matlab, I run such a script: ...
Count Zero's user avatar
0 votes
1 answer
415 views

Stacked Yagi Gain calculation

I had a quick look at a practice exam for the license in my country and had a question on stacked Yagi antenna. I have been looking around but the only thing I can find is the mention of an additional ...
ITChap's user avatar
  • 209
0 votes
1 answer
568 views

How would I calculate the diameter of an dish from antenna gain, or effective aperture?

So far I've calculated the effective aperture using an equation. However I was wondering how to calculate dish diameter using the gain calculated earlier and if there's an equation for this?
ijq12's user avatar
  • 1
0 votes
1 answer
1k views

Gain in long wire antennas

DARA (you know, Hamvention) TNG is looking for projects. Thursday, I will be proposing building and characterizing a vertically-polarized 1 wavelength on a side reentrant rhombic. Since in doing the ...
N6FXB's user avatar
  • 1