diff --git a/Antennas.md b/Antennas.md index d1d9dd5..fe40351 100644 --- a/Antennas.md +++ b/Antennas.md @@ -1,8 +1,11 @@ This section focuses on mobile antennas for the LoRa APRS Tracker +![image](https://user-images.githubusercontent.com/3480859/184908947-1e914613-b380-4967-a970-39bc011a7a97.png) +Photo courtesy Klaus Kitzmantel, OE5KKP DL9KX + # Technical terms ## Polarization -LoRa APRS uses vertical polarization exclusively. +LoRa APRS uses vertical polarization exclusively. Vertical antennas are the best way to get an omni-directional pattern. They're vertically polarized. Yagi antennas are very directional, meaning they can produce gain in a certain direction. They're generally horizontally polarized. There are large signal losses when the polarization of the transmit antenna and the receive antenna don't match. It does not make sense for mobile units to transmit horizontal polarization. Therefore iGates and Trackers have pretty much standardized on using vertical polarization ##Antenna gain dBi - Gain over isotropic, a point source