Broadcast waveguide antenna

[dr pepper]

While out I noticed an unusual antenna on a broadcast station.
it looks like a waveguide, its a horn shape about 5 foot square at the radiating end down to around 4 inch at the radiator.
The unusual thing is that the horn points upwards, there's some kind of reflector at the top directing the beam outwards.
What Is this kind of aerial called, and what sort of freq is it going to be operating at, the opening would kind of suggest the high end of th fm band.

 

[4pyros]

Sounds like a microwave link to a satellite.

 

[dr pepper]

I just did some research, I think its a hogg horn or 'sugar scoop'
And yes probably microwave, however the apperture is pointing down so probably a link to a fairly close relay station.
Must have been there a while.
Apparently these were very effecient but were replaced by the popular shrouded dish.

 

[4pyros]

Its old technology from the military.
I thought you said it was pointing up.
How about a pic?

 

[JimB]

Anything like the antennas in this video from the 1960s?
Have a look at about 4:20 onwards.

https://www.youtube.com/watch?v=jtn2XFmMtrI

They are horn antennas mounted vertically, with a parabolic plate on top to deflect the signal out horizontally.

JimB

 

[dr pepper]

Yep thats is Jim, sorry 4pyros I didnt explain that all that well, I should have said reflects the beam horizontally rather than out.

Surprisingly they are still in use here in the uk, heres a couple that are being used for dab radio in bedfordshire:

https://www.google.co.uk/imgres?img...fxUPHbJcTT0QX1l4CgAw&ved=0CE4Q9QEwBg&dur=2153

And you can buy them for operating at really high frequencies:

https://www.google.co.uk/imgres?img...afxUPHbJcTT0QX1l4CgAw&ved=0CEsQ9QEwBQ&dur=733

Seems they were popular as they have a narrow directivity so you can have several on the same mast without issues.

I've liked the look of the one I mentioned in the first post since I was a kid.

 

[MikeMl]

Those are Horn antennas for point-to-point GHz links of several tens to hundreds of miles, not for "broadcast". Very narrow beam-width.

 

[dr pepper]

Dr pepper quote: Seems they were popular as they have a narrow directivity so you can have several on the same mast without issues.

I was thinking they'd be used for a link back to the studio rather than a broadcast antenna.

 

[4pyros]

Yes thay are mostly for links. One facing the other over miles of distance.

 

[dr pepper]

Interesting.
I looked at a project on the web a while back where you repurposed a marconi bluecap lnb as a microwave modem.