Hello, what kind of antenna is this? I’ve been trying to figure it out for 14 years. None of my neighbors know. Whomever installed it either moved or passed away.
The antenna is a Yagi-Uda, or Yagi, antenna. It is a highly directional type of antenna (and this one has 4 director elements, making it particularly so). Yagi antennas are recognizable by the structure of having a series of parallel elements (rods) of slightly varying length, with the feed line (wiring) running to the element adjacent to the rear "reflector" element (the longest element).
A directional antenna with a fixed (not rotatable) mount is only useful for point-to-point communications; in other words, it's pointing at a specific other station with its own antenna (which may or may not be directional). Possible uses for this include:
- Point-to-point wireless networking (either to provide Internet access, or as a dedicated link between two buildings). However, this antenna looks a little lower in frequency range than I'd expect for that application.
- Voice communication (which could be amateur, public service, or commercial); talking to a repeater that is also used by handheld/mobile radios. The directional antenna and fixed radio installation is used to cover a longer distance, or be more reliable, than otherwise.
- Telemetry from remote stations (unlikely in an urban area).
- …and probably other uses I'm not familiar with.
Another common use of directional antennas mounted on poles is for television reception, but television antennas are generally horizontally polarized (the rods would be horizontal rather than vertical) and closer to the log-periodic design than Yagi-Uda (because they need to be able to receive many different stations and thus need a wider frequency range).