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22

For an antenna, a gain of 22 dBi means a gain of 22 dB with respect to a theoretical isotropic antenna. If an isotrpoic antenna radiates 1 watt, it would radiate that power uniformly over the 4π steradians around it, so at a power density of about 80 mW per steradian. For your antenna with 22 dBi gain, 22 dB is a power ratio of 158, the emitted power density ...


12

The USB Wifi adapter you mentioned has two antennas. Each of these operates on both 2.4 and 5GHz bands per the specification-"2.4G/5GHz Dual-Band 5dBi dipole antenna". The reason you have 2 antennas is to enable the MIMO/beamforming/multiple concurrent transmissions capabilities as defined by 802.11ac


7

Say you have a source of 0 dBm power. If you hook it up to an antenna with 22 dBi gain, then in the direction of the main lobe, your source appears to be 22 dB stronger than it would if it were connected to an ideal, isotropic radiator.


3

I am the creator of the dipole animation above. There have been some excellent points made above. I think the reason there is still confusion over the question is that there is some missing information due to a slight inaccuracy in the animation (which is also present in all drawings of dipole standing waves in textbooks). Yes, there are standing waves on ...


2

Generally speaking, the voltage at the output of an antenna is just a scalar function of time, so you of course don't need anything more. You can connect each antenna input to a suitably fast wideband digitizer, and you'll be able to receive the signals directly. But such digitizers, of sufficient performance, may either not exist, or cost way too much, or ...


2

The environment for MIMO does not consist simply of N transmitters and M receivers, it also consists of R reflectors of signal creating multipath signal dispersion. These reflectors between the Tx and Rx, and close to them, consist of things like buildings, walls, trees, filing cabinets, cars, people etc. Any communication that takes place other than on an ...


2

If your drone has analog imaging, then with more that 30 dB SNR, you will not see any improvement in the reception. The frame and line sync are much more robust (much further distance) than the pixels. Thus even for very weak video, with lots of snow (black/white pixels), your image will still be stable on the display.


2

In antenna deisgn, you have something called standing wavelengths where you have a zero crossing at each wavelength. 2.4Ghz is close to 2.5 or half of 5Ghz and an antenna can be tuned to operate at both frequencies. There are many antennas though that can't do both so I'd look at the datasheet to make sure. From what you showed that antenna should be able to ...


2

I'll admit the Wikipedia explanation makes my head spin too. Let's keep the antennas still. Think of a pair of crossed dipole antennas just above the earth's surface. One oriented North-South, the other East-West. Connect the same transmitter to both, but use an extra piece of transmission line so the current in the E-W dipole is 90 degrees delayed relative ...


1

Even if you are only downloading files, there needs to be both TX and RX, its not a one way communication like an AM radio. The router is probably using some sort of duplexer for TX and RX, you would basically need another duplexer and 2 amplifiers tuned at different frequencies, most likely an LNA and a PA, I'm sorry but there is no easy solution if you use ...


1

I think one of the most suitable choice would be a telescopic antenna since the market offers lots of telescopic antennas. I don't think it works like that. There's a lot of cheap sand on the market. If you want to bake a cake, flour and sugar would still be a better choice... Also, telescope antennas are extendable, and monopoles, and thus not multi-band ...


1

Does it have something to do with MIMO? Yes, it could do. MIMO (multiple-input multiple-output) can use different polarizations to transmit two data streams in the same space. Lowest link loss occurs when the transmitting and receiving antennas are aligned to the same polarization. At 90° the signal strength is reduced (theoretically to nothing, but in ...


1

Those connectors are for GPS, WiFi, Bluetooth, Cellular -- none of them are connected to the FM radio input pad on the radio chip. If you don't want to plug in a headphone, you could use this antenna which is designed to plug into the headphone jack. Or solder a wire into a headphone plug (use the shell contact) and you're there. If there's no room to insert ...


1

A ferrite rod antenna generates a voltage in series with the coil. After all, the signal is coming from free-space and gets concentrated magnetically by the ferrite to produce maybe 2 or 3 times more induced voltage in the coil. However, that induced voltage is in series with the rod's coil-inductance and can, therefore form a very effective voltage ...


1

All of these components are nominally 50 Ohms. For a receiver, improving the impedance match doesn't have a big payoff, so if you're not experienced, you are probably better off putting a DC blocking capacitor between the each stage and moving on. I'd suggest this, because the LNA may be biased internally in such a way as to have a DC voltage at either the ...


1

Technically, yes, the radiation pattern is the sum of the individual element radiation patterns, adjusted for geometric differences in distance to the receiving point. But you're mixing together several fundamental antenna concepts: The size of individual antenna elements (you've suggested 𝜆/2 and 𝜆/4 as examples). The arrangement of several antenna ...


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