Sat Dish Rescue - Andrew 3.0m

[jamina68]

As originally posted in another thread 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.
"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 aluminum solid reflector. It's a TVRO model with a very heavy duty polar mount. View attachment 129054 View attachment 129058 View attachment 129060 I think this is the model# View attachment 129059 It looks like Andrew welded two sheets of aluminum together then spun the unit. I can make out a welded seam in it.
The actuator is a old Warner Electric 24" stroke Potentiometer model so I'll just use one of my Von-Wiese units as a replacement.
Of particular interest is the factory scalar (luckily still on the dish) View attachment 129061 View attachment 129066 Its much bigger than todays scalars (shown here with a Chaparral on top) View attachment 129062 View attachment 129064 The 6 rings per side are only 12.5mm apart instead of the usual 15-16mm. Also its not entirely a flat scalar. For some reason Andrew made the rings concave View attachment 129063 Titanium do you know why Andrew might have done this? The feed bore diameter is 70mm which is a coincidence because I wanted to use the dish on ku and the outer diameter of an Invacom ADF-120 prime focus feedhorn scalar View attachment 129065 is 70mm I think. So it should fit nicely inside the feed bore of the Andrew scalar.
So the plan is to paint the polar mount with grey rust paint. Its a reddish brown color now. Also the reflector will get a good cleaning then on a pole she goes It should make for some interesting testing. Since the model # of the dish basically turns up nothing on the internet & I don't have a manual for it I am curious whether it was originally designed to work in both the C&ku bands.

Hello!

I am wondering how much the outside diameter of Andrew is. I'm doing this one. I have a 3,0m Andrew PFA. I hope you send the size. Thanks!

 

[beavs2112]

Hello jamina68 My dish looks slightly different than yours. Yours looks like a fixed az/el type not a polar mount like mine. Also the back structure around the dish edge lip looks completely different than mine. Having said that if you measure your dish diameter,depth you can figure out the focal length. The formula is f = ( D times D ) / ( 16 times d ) where the Focal length = f, Depth = d, Diameter = D. You should measure your dish yourself to get the best results from your satellite antenna. Also read post #6 in this thread where I already mentioned the diameter and depth.

 

[jamina68]

Hello jamina68 My dish looks slightly different than yours. Yours looks like a fixed az/el type not a polar mount like mine. Also the back structure around the dish edge lip looks completely different than mine. Having said that if you measure your dish diameter,depth you can figure out the focal length. The formula is f = ( D times D ) / ( 16 times d ) where the Focal length = f, Depth = d, Diameter = D. You should measure your dish yourself to get the best results from your satellite antenna. Also read post #6 in this thread where I already mentioned the diameter and depth.

Hello beavs2112!
The type of antenna is Andrew HPX 10-107. Diameter: 3020 mm, depth: 628 mm, focal lenght: 908 mm, f/D: 0,3
I think, in KU band the Invacom ADF-120 does not see the entire surface. The situation is the same in "C" band. The Chaparral scalar ring does not see the entire surface. If I had a larger scalar ring would it be better?

 

[Titanium]

What makes you think that the ADF-120 and the Chaparral feeds are not illuminating the entire reflector?

A .3 FD is in the mid range setting for these units.

 

[beavs2112]

Hello beavs2112!
The type of antenna is Andrew HPX 10-107. Diameter: 3020 mm, depth: 628 mm, focal lenght: 908 mm, f/D: 0,3
I think, in KU band the Invacom ADF-120 does not see the entire surface. The situation is the same in "C" band. The Chaparral scalar ring does not see the entire surface. If I had a larger scalar ring would it be better?

So i googled your antenna model and found out it is NOT a satellite antenna. It is a terrestrial (land) fixed point to point ku band microwave antenna. So you are using it for something it was not designed or engineered for.

 

[jamina68]

What makes you think that the ADF-120 and the Chaparral feeds are not illuminating the entire reflector?

A .3 FD is in the mid range setting for these units.

Hello!
I've read on a forum, from Eduard Bach, Greenland. "If the dish is deep, this is possible". Then he attached a photo. Maybe this feed horn does not even see the entire surface.

 

[Titanium]

My point is... a standard flat scalar should properly illuminate a FD .30. Yes, you could optimize a scalar/feedhorn for a specific reflector.