[MIL] Giant Yagi at McChord AFB

Actually two giant Yagi's at McChord. One way off on the other side of the airfields, and another also near Madigan Hosp side. These are Yagi, obviously not single channel and are huge.

The smaller of the two is about 80 feet up on a tower whose base is octagonal with each facet being over 9 feet in length, and the height of the tower is such that they could add at least two more of these critters. The smaller Yagi had 23 elements on each side with a non tradtional finish in that all elements reached clear to the back so that the Yagi looked similar to the feather end of an arrow. So the final, 23rd pair of elements were the shortest and were perhaps 10 feet in length. I was at the base and under the circumstances not too keen to show how interested I was in the Yagi. The lead elements were at least 60 feet long. They all appeared to be made of a very strange metal. Sort of looked like very dull stainless steel. Maybe tantalum? And the antenna had cable running down for each element and they were all collected into a bundle which was 50 running strands of 02 wire. The bundle was as big around as say a PC monitor m/l and ran for miles off into the woods on the Mr Rainier side. I have never seen so much heavy cable in my life. It was all copper too, no aluminium according to the descriptor on the bundle. I would estimate several hundreds of thousands of dollars worth of cable easily.


I could not get as close to the other Yagi. So I am guessing that it was 100 feet in length as it appeared to be twice as big as the one I was under. It was also on a tower that would have supported several huge water tanks. Its cables also ran off into the same patch of woods.

Now some one with EE knowledge will have to chime in here. What freq would a Yagi that size collect? Could it be used as a transmitter antenna???? If so, of what form of radiation.

By the way, while the smaller Yagi was horizontal like a tv version, the larger was at a distinct, say 50 degree off the horizon rake. Also quite strange.

No guards that I could see, but still one had to be escorted through several observed checkpoints.


Curiouser and curiouser....

also lots of heavy chemtrails today. It seemed that the planes were coming out of McChord and not portland like usual...
 

Coast Watcher

Membership Revoked
I hate to sound stupid, but -- what's a Yagi? When I first read the header, I thought it said Yeti! Whew, had me going there for a minute.
 
Sorry. Yagis are antennas, like the old style one might have to tune your tv where you had to point the bugger toward the direction of the station(s) you were after. If you have always had sat or cable this will not mean much but I am pretty sure you have seen one. Usually though, they are about 5 feet long maximum, not 50!
 
H

Huntersun

Guest
Pliny,
Could you get a idea in which direction
they were pointed? Thanks.
 
HunterSun,
the small one is directed north by noreast. Sort of slightly to the left of the mountain. The large one was generally the same in alignment except had that skyward skew.
 

eXe

Techno Junkie
_______________
23 Element Yagi? Wow.. thats probably a HF antenna or some kind.. Any way to get a pic of it..

I do know that the Air Force uses a Global High Frequency network to pass traffic to other bases. Might want to listen in to 4.724, 6.712, 6.739, 8.992 (this is the best freq often referred to as eight niner), 9.025, 11.175, 11.181, 13.200, 13.212, 15.016, and 20.390 All upper side band all voice.

Take a listen around and see if these are very strong in your area. This could be what that antenna is all about.

About those cables running down in into bundles these could have been radials for the antenna not sure would have to see it.

See if somehow you can get a pic. I can help you better that way.
 

Dean Miller

Archaic Member
Hi Pliney,

Yagis are very definitely single band antennas. Multi-band yagis have shorter length elements mixed in with longer length elements, or the elements have coils (traps) in them to electrically change the element length.

Usually, wide-band directional antennas (such as most home TV antennas) are log-periodic designs.

(Collins Radio in Cedar Rapids Iowa used to have some amazing, huge log-periodics and other rotating antennas, where the entire tower rotated.)
 

Jay Urban

Inactive
How about two parallel cubical quad arrays, 30 feet apart, one reflector and seven director elements each? 500' foot elevation, rotatable.
 
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