Antenna polarization

[Golay]

The GM Machine

Gonna take a shot at answering my own question here. Site looks like it may be on the roof of the RenCen given that there does not appear to be any skyscrapers up river from the site and the roof edge looks to be curved or circular.

Anyway, nice pic, would like to see post from OP as to verification of site location.

These are the 2M and 440 antennas for the GM machines
Yes, they are on top of the Ren Cen. 145.21 and 442.075.
Since I originally posted this picture, the 440 antenna has been replaced with a 4 element.

 

[WA8ZTZ]

These are the 2M and 440 antennas for the GM machines
Yes, they are on top of the Ren Cen. 145.21 and 442.075.
Since I originally posted this picture, the 440 antenna has been replaced with a 4 element.

OK, thanks. Nice pic with Belle Isle in the background and the antennas framing the freighters passing in the channel.

For non-Detroiters, The RenCen is short for The Renaissance Center, a cluster of 4 office towers surrounding a central hotel tower. It opened in 1977. The intent of the project was to re-energize the downtown, riverfront, and economy of Detroit. The mover behind the project was Henry Ford II... interesting because it now is owned by General Motors and serves as GM world headquarters.

 

[prcguy]

Ok, now we need a picture of the new antenna so we can discuss its pattern and what its pointing at....
prcguy

These are the 2M and 440 antennas for the GM machines
Yes, they are on top of the Ren Cen. 145.21 and 442.075.
Since I originally posted this picture, the 440 antenna has been replaced with a 4 element.

 

[digitalanalog]

Yep, they look the same. lol

Yup, he might as well have said they are co-phased moonrakers.
prcguy

 

[mass-man]

I've never seen that before...always lusted for a Moonraker!

 

[Golay]

Ok, now we need a picture of the new antenna so we can discuss its pattern and what its pointing at....
prcguy

Here's the new 4-element. Elements on the north side of the mast, like the old one.

 

[wb6uqa]

New 4 element

It is more directional with 3 db more forward gain.

 

[Golay]

Thanks

It is more directional with 3 db more forward gain.

Thank you. This pretty much concurs with signal reports since the new antenna went up.

 

[WA8ZTZ]

Still somewhat lima bean shaped but with more bulge to the north and less towards Canadian side.
My guess is better coverage of the northern suburbs (good cpy Rochester... just ID, full quieting) still with good coverage Downriver and out to eastern Macomb, maybe less coverage beyond Windsor into Essex county. What do your signal reports say?

 

[prcguy]

The 4-bay should have the same basic horizontal pattern of the 2-bay but with a more squished vertical pattern at the horizon. If the new antenna is pointing in the exact same spot it should not loose any coverage off to the sides and if anything it should be better.
prcguy

Still somewhat lima bean shaped but with more bulge to the north and less towards Canadian side.
My guess is better coverage of the northern suburbs (good cpy Rochester... just ID, full quieting) still with good coverage Downriver and out to eastern Macomb, maybe less coverage beyond Windsor into Essex county. What do your signal reports say?