Flying around the area, I noticed this from the air - I have tried doing some searching but have been unable to find the name of the design or its specific use;

What is this massive antenna, and what is it used for?

picture of antenna

There is also what appears to be a giant Yagi in the same field, see below StreetView image with both antennas visible.

enter image description here

Specifically, what would these types of antennas be used for? This is somewhat near the coast, (Seattle, WA) [47.493135, -122.253059] and also somewhat near an airport.

Are these somehow related to aviation? Early warning defense systems? General comms?

click the pictures for closeups, I can take actual pictures if requested


From the view shown it appears to be an HF discone antenna. Characterized by sloping elements beginning at the top of the structure spaced radially around the vertical support, and topped with a capacitance hat.


The second photo shows a Log Periodic antenna which is large enough for wide coverage of most of the HF bands. I know that FEMA stations have these types of antennas and are primarily used for emergency communications nation wide when there is some catastrophic event. There is such a FEMA station in Bothell Washington which several antennas including a Log Periodic. There is also a FEMA station similarly equipped in Salem, Oregon.

  • $\begingroup$ I used to live in a condo right next to the Malaysian embassy here in Bangkok, and they had a log-periodic antenna that looked very similar to the one in the photo, on the roof of the embassy. It was fixed, and pointing at Kuala Lumpur. I did not have any radio gear when I lived there, so I don't know if it was used for transmitting, or just receiving $\endgroup$ – Scott Earle Nov 23 '18 at 9:27

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