Antenna Identification

emsflyer84

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Hey guys, just driving in my town the other day and I noticed this antenna on top of a pole next to an older train station that is no longer used, since the 60’s or 70’s I believe. There is still an amature rail car club that uses the buildings. The wire from the antenna (coax?) comes down the pole but just just cut and coiled up so it’s not connected to anything. Just curious what this is and what it might have been used for at an older train station. Thanks guys!
 

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mmckenna

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My eyes may be playing tricks on me, but it looks like it's horizontally polarized, which would make it a poor performer for most things except for point to point use. Maybe for a remote link, remote control, etc.
 

prcguy

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Its vertical. For horizontal you would rotate the entire antenna including reflector so it looks like this < from the side.

My eyes may be playing tricks on me, but it looks like it's horizontally polarized, which would make it a poor performer for most things except for point to point use. Maybe for a remote link, remote control, etc.
 

mmckenna

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Its vertical. For horizontal you would rotate the entire antenna including reflector so it looks like this < from the side.
Yeah, I know that. It's an optical illusion, first time I looked at it it looked horizontal. Looking at it again, I can see vertical.
 

kruser

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Yeah, I know that. It's an optical illusion, first time I looked at it it looked horizontal. Looking at it again, I can see vertical.
Ha, I can see the illusion as well. After your post, my second view of the picture made it look horizontal while my first glance, it looked vertical.
I can now stare at the pic and see it both ways. Kinda weird.
 

Ubbe

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It looks to be one driven dipole element and one director element on that boom. But what are that in the middle of the reflector boom that points away? Looks like another dipole at the other side of the reflector?

/Ubbe
 

kruser

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It looks to be one driven dipole element and one director element on that boom. But what are that in the middle of the reflector boom that points away? Looks like another dipole at the other side of the reflector?

/Ubbe
I saw that also.
Maybe someone's experiment with reception from the backside of the reflector. I can't say I've ever seen that before though.
 

Ubbe

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Maybe it was used for a relaying repeater that received signal from one direction up the track and relayed down the other direction?

/Ubbe
 

kruser

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Interesting idea and sounds reasonable.

I may need to study this and see how it was designed to work without cancellation of any signals arriving from the front.
 

Ubbe

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Interesting idea and sounds reasonable. I may need to study this and see how it was designed to work without cancellation of any signals arriving from the front.
I was thinking more of that they use one frequency from one direction and another out the outer direction. Then the next repeater reused that first frequency and both repeaters needs to isolate that frequency as much as possible to each other and also having a ground plane 1/4 wave behind a dipole will inrease its gain. It would probably be a 2 frequency duplex system to be able to operate in both TX and RX directions.

/Ubbe
 
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