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Dome on Tower

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#1
I am wondering what the purpose of the dome on the left side of the tower is (in the attached photo). I don't know a lot about radio towers but was just wondering what the function of this device is. Thanks.
 

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#4
As stated, that's a microwave antenna used for point to point communications.
The microwave systems provide a high bandwidth connection. Depending on what's residing on the tower, it could mean anything:
If it's a cellular tower, they use the microwave links to tie the cell site back to the mobile switching center.
If it's a broadcast tower, it's used as a studio <-> transmitter link. The link could be carrying broadcast audio, TV signal as well as system control. They often operate in both directions, hauling engineering data streams back to the studio.
If it's the phone company, it's providing services between central offices.
If it's a LMR/Public safety tower, then it can be used for carrying transmit and receive audio between dispatch centers and the radios sites.

As for the antenna, the back (right) half is the parabolic reflector like what you would normally think of on a satellite or microwave dish. The other half (left side) is the protective cover. Under that cover is the feed horn that feeds the signal to/from the focal point of the parabolic dish.
Since these feed horns can be fragile and can be affected by weather (think ice), the are often protected with these covers. The covers are an RF transparent material, like plastic, fiberglass, fabric, etc.

There are online tools where you can enter the location of the tower and it will show you what links are there, where they go and who the belong to, but only if they are FCC licensed. Not all microwave links require licensing with the FCC, some frequencies are "license by rule".
 

n0nhp

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#8
The fun times begin when a chunk of ice falls from above and puts a small hole in the dome.
We were losing signal on both ends of a hop and were at about wits end trying to fix the electronics.
I finally climbed the tower, found the hole (leaning way, way out on my harness). We started the none too fun procedure to remove the old radome and install a replacement. About the time the one with the hole started moving, so did the techs as the wasp nest inside was disturbed!
A trip to town for a couple cans of wasp spray and another couple of trips up and down the tower solved the path problems.

Bruce
 

n0nhp

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#10
That was the first and only ice damage that we saw (when I worked there), a warm pacific storm blew in after a cold spell and iced the tower. We did replace the plastic radome with fiberglass and as far as I know it is still there.
 
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#12
Misinformation? Technically speaking - yes, what he is seeing there on the exterior is the radome. It does not give attention to the actual equipment the radome is protecting.

The information given here is good and still stands.
 

buddrousa

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#13
Mike can you post a picture of an ice guard living in the middle of the US Tennessee Kentucky I have no idea what one would look like.
Thanks Charles
 
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#14
An ice guard or ice shield looks like a platform mounted above an antenna.
There is another type sometimes called an ice bridge that is mounted over the transmission lines between the tower and building.
Google "antenna ice shield" and you should be able to find lots of pictures.
 

mikewazowski

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#15
nd5y nailed it although we refer to an ice bridge as a waveguide bridge since it serves to support the waveguides and other cables as well as protect them from ice.

Ice shields only serve to protect a dish from falling ice although sometimes Osprey will use them to support their nests.
 

buddrousa

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#16
Thanks Mike and ND5Y when I was doing antenna work in West Tennessee and West Kentucky I would find 110 volt heat tape mounted to the tube built dishes that linked FM Radio Stations to Remote Tower Sites.
Thanks Charles
 

mfn002

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#17
Not all radio stations use those dishes for their studio to transmitter (STL) links. I interned for a local company that owned several radio stations (both AM and FM) and all of the STL stuff was transmitted and received using 900 MHz yagis. These signals are highly directional, and each of the STL antennas on the roof of the station had to be aimed directly at each of the tower sites.

I just thought I would add some of what I know to this discussion.
 

milf

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#19
Some of the ones here need those but don't have them as bad ice is not that often but is real bad when it hits

Sent from my LG-K330 using Tapatalk
 
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#20
Back in the middle to late 60's I worked for Indiana Bell. We installed and maintained STLs for radio and TV stations as well as remote links for high school and college ball games. We also handled the video link that the Indianapolis Motor Speedway used for the closed circuit TV coverage of the Indy 500. It was very hard to get a license for a microwave link back then but Bell had a bunch of them. Most of the permanent video circuits ran on coax cable but the audio was carried on equalized phone lines.
 
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