Just Sharing This Sat Dish Rescue - Andrew 3.0m

beavs2112

beavs2112

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I have rescued another dish from the metal scrappers. The previous owner was going to cut it up and sell it for the scrap aluminum since he thought no one used these things anymore. I was taking an alternate route home from one of my favorite Thai restaurants and noticed this 20170930_162203.jpg in someone's backyard. So I left a note one weekend giving my details and for the princely sum of $200 Canadian dollars he agreed to let me have it. I rented a trailer to get it home (it was only about 20 minutes drive away in the city) It did generate some curious looks on the weekend I brought it home. 20171029_155414.jpg

"Operation Rescue 3" was a success and it is now in my possession. It's a real beauty. It's an Andrew Corp. (ASC Signal, now CPI-ASC) 3.0m spun solid aluminum reflector. It's a TVRO model with diameter 119.5inches depth 25inches and a focal length of 35.7inches. Roughly a F/D ratio of 0.2987 so a fairly deep dish. The polar mount fits on a 4.5 inch diameter pole. The polar mount uses 1/2 inch thick plates in some places so I was not concerned about the rust it had accumulated after 30 years. For size comparison that is a regular c-band ring scalar resting in the polar mount.20180612_185842.jpg20180612_185914.jpg I think this is the model# of the entire unit. It looks like Andrew welded two sheets of aluminum together then spun the unit. I can make out a welded seam in it.
Of particular interest is the factory C-Band scalar (luckily still on the dish) Its much bigger than todays c-band scalars (shown here with a Chaparral on top and side by side) The 6 rings per side are only 12.5mm apart instead of the usual 15-16mm found on todays c-band flat scalars. Also its not entirely a flat scalar either. For some reason Andrew made the rings concave. I obtained a factory feedthroat for the scalar this week. It's a solid square block of aluminum that they machined out to make the round feed. They use what look like thin aluminum rods to convert the circular RF signal to linear RF signal for the LNB. And some sort of aluminum pin maybe to act as a tuned frequency cavity?

It's interesting that there is such an abrupt ridge about 1/3rd of the way down the throat. It was used to hold the Styrofoam feedthtroat plug in place. They used a one inch thick bit of Styrofoam to plug the throat. It looks just like the blue stuff used to insulate outside walls. I cut it out and want to use a plastic cap I have from an old LNBF. The blue chaparral cover doesn't fit over the thoat cause the throat is too wide. Its a nice snug fit now.
I thought abrupt ridges like that were a no-no in a waveguide due to the reflected energy they cause. But since the Andrew engineers probably knew what they were trying to accomplish much better than me I will leave it alone. It's also quite clean inside given it's age.
 

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John

John

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.. Thanks for sharing the information and pictures with some engineering detail there not seen before.
 
Channel Hopper

Channel Hopper

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I've not seen one of those in the flesh before. Thanks for the images.

The 1184 pictured is uplinking to who exactly ?
 
beavs2112

beavs2112

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