# Antenna (radio)
|  | In radio engineering, an antenna or aerial is the interface between radio waves propagating through space and electric currents moving in metal conductors, used with a transmitter or receiver. In transmission, a radio transmitter supplies an electric current to the antenna's terminals, and the antenna radiates the energy from the current as electromagnetic waves. In reception, an antenna intercepts some of the power of a radio wave in order to produce an electric current at its terminals, that is applied to a receiver to be amplified. Antennas are essential components of all radio equipment. |
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| | wikipedia:: [Antenna (radio)](https://en.wikipedia.org/wiki/Antenna_(radio)) |
> [!caution]+ Caution #v/caution: *Check every antenna you buy for correct frequency*
> Check the antenna you get that it is matched to the intended frequency because it's not uncommon to get a mismatched antenna from China/aliexpress, etc.
## Concepts
[[Decibel]]
- [[SWR]]
- how much energy is going out of the antenna
- how much is being reflected back to radio
- Resonance?
- dbm?
- [[Gain (antenna)]]
## Connectors
- [[SMA connector]]
- [[U.FL (I-PEX)]]
### Adapters
- pigtails
## Types
- Monopole
- Uses the ground plane of device. So the PCB or floor or car roof, etc.
- bad for [[Microcontroller|Single-board mirocontroller]]s
- [[Dipole]]
- 2 internal elements of equal length tuned to different parts of the spectrum
- Normally a circular extending range/omnidirectional
- Higher gain directional
- But the much higher Dbi range extends like an ellipsis
- [[Yagi]]
- Good for 2 fixed locations
- [[Omnidirectional]]
## LoRa Antennas
- [RicInNewMexico/Meshtastic-Antenna-Reports: Results of antenna testing by the meshtastic open source community.](https://github.com/RicInNewMexico/Meshtastic-Antenna-Reports)
## Sources
- [ ] [Getting More Range with Meshtastic - YouTube](https://www.youtube.com/watch?v=V3f-Y3EfsBU)
- Great video explaining antennas, connectors, range, etc.
- [LoRa Antenna Resources | Meshtastic](https://meshtastic.org/docs/hardware/antennas/resources/)
- [ ] [#188 Antenna Tutorial incl. cheap DIY Antenna Tester (LoRa, ESP32) - YouTube](https://www.youtube.com/watch?v=J3PBL9oLPX8)
- [ ] [HackadayU: Introduction to Antenna Basics - YouTube](https://www.youtube.com/playlist?list=PL_tws4AXg7authztKFg5ZN5qWGtq3N_nI)