Planet Fox > Microwaves > My Antennas > Fiberglass Ku Band Antenna

Fiberglass Ku Band Antenna, ca. 1987

I actually have no idea who made this, since it's so old any identifying marks have long since worn away. I got this when a local business closed down. I think they were using it for in-store music, and it was probably aimed at AMC 1 at 101°W, although it wasn't connected to anything when I took it down, so it's hard to tell how long it's been since it was used.

This dish was in really rough shape, completely covered in almost 30 years worth of filth, and the feed support struts and bracket were really rusty, but everything was definitely salvageable.

I started by pressure washing the reflector, then scrubbing it down with a wire brush and hot TSP in preparation for painting. Painting an antenna like this helps preserve it; the smooth surface layer of plastic has worn away, exposing the fiberglass strands underneath, and the paint will seal it back up. I used the same type of paint I used on my old Primestar dish: Rustoleum Universal, but in flat white. This paint is expensive, but I really can't recommend it enough. I painted my Primestar dish years ago and it still looks brand new.

I had to use an angle grinder with a wire brush to get all of the rust off of the metal parts. Once I had them stripped I thoroughly cleaned them. These parts were originally galvanized, so rather than paint them gloss gray like I normally do, I decided to try something new and spray them down with Rustoleum's bright galvanizing compound which is kind of a lacquer with loads of zinc particles suspended in it. I've never used it before, but hopefully it'll keep everything from corroding better than normal paint. Commscope recommends a "chlorinated, rubber-based paint" for the glavanized parts on their antennas, but I could only find that in gallon cans.

Like my Primestar antenna, I had to replace all of the hardware. In this case, that only consisted of four carriage bolts, two hex bolts, washers, and stop nuts. This antenna had a fine adjuster too, but I'll just leave it off for now since I don't feel like welding up a new one. The feed supports and elevation bracket are held to the antenna the with double ended screws that have a coarse thread that screws directly into the fiberglass on one side and a machine threaded screw on the other side. I don't think you can buy these anywhere, but if I ever need to replace them I can just drill all the way through and use carriage bolts.

This dish has the most unique mounting bracket I've ever seen. Where most antennas have a collar that gets tightened around the mounting pole, this one has an eye bolt that hooks around a large bolt driven through the mounting pole, and is tightened by tightening the eye bolt's nut. It's kind of weird, but it seems as secure as any other mount I've ever used.

The feed that came with this dish was in good shape, in that it didn't have any corrosion, but like most feeds this age the plastic cover had all but disintegrated from exposure to sunlight. I'm going to expoxy some new clear plastic over it eventually, any plastic will do but the clear polystyrene used for food packaging is especially well-suited. For now I'm going to use my Chaparral Ku feed. I was really surprised to find that the LNB, a Norsat model 9000A covering 11.7-12.2 GHz with an 0.8dB noise figure still works, and quite well I might add. Old Japanese manufactured LNBs like this are legendarily reliable, but since the feedhorn's weather cover was shattered and there was no cable or protective cap on it's output I expected some water damage. Local oscillator drift measured a respectable +/- 300kHz. The LNB provided the only indication of this dish's age, the serial number indicated it was made in 1987, making it 27 years old when I got it. I wish everything was this reliable.

For now I'm using this dish, combined with the Chaparral Ku feed and an old Primestar LNB to receive the PBS channels on AMC 21.

Photo Album

Before cleaning

Before Cleaning

After cleaning and repainting

The original LNB, a Norsat model 9000A, manufactured in 1987. It looks terrible, but works perfectly.

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