The Story of my Dish Antenna

(C) DL4MEA 04/2010

Click on the pictures to get them in larger size

My dish is made in Italy, and we picked it up there by ourselfes. It was the first time that I was at the adriatic beach in January, and it was wonderful.
I took this dish because it was flat and therewith it was extendable up to, what I expected, above 4m.

At home, the dish was built up in a friendly company's hall and is hanging at the crane here

My first plannings were to make my own rotor

With a lot of luck - you only get such an offer once in your life - I got asked if I could make use of an old Rohde&Schwarz "Drehstand", made 1965. It was used by DLR in order to track the first weather satellites previously.

After some work, the rotor was ready to move the dish. Also visible in this picture is the feed mount that I had to add to the dish. I first wanted to rotate the feeds through the focus, like a revolver head.

A solid construction that can even carry the owner

The old controller was based on pre-pepared stitched tapes and the dish rotated in 5° steps, which is on 137MHz quite sufficient. And the control was made with relays only, so I had to make my own controller.

A flying dish
The dish while on its way to its first outside test

My first operation on 23cm, using a diagonal waveguide feed.
At this time I was not aware about feed properties, especially that feed has to provide a clean pattern and match to the f/D of the dish.
You see that the dish is free standing, as it still is today (year 2010).

My shack during the first operation was placed in an office container - the hall meanwhile was rented to a company dealing with such-

The feed assembly in detail
At this time I also still believed that DJ9BV preamps really reach their proposed noise figure.

Some time later, I meanwhile rented a house with some garden, I moved the dish to Vierkirchen. DL4MUP/G4HUP helped me a much, I was busy with my own's house construction and Dave was the main operator during this phase.
(Picture taken facing north)

Another picture of the dish during this time.

Suddenly, one of the original motors became overheatened and broken since one of the solid state relays that I used for powering got short.
I then decided to replace the motor with a speed controlled 3 phase motor.
You see that I used some equipment from the ongoing house construction for getting access to the motor.

Dave, DL4MUP (G4HUP) while operating.
TH347 amplifier, FT847, dish controller, NOVA as tracking source and spectran waterfall.

Another fligth of the dish.
Our house was ready, we had to leave, and this time I got a truck helping me to move the whole dish in one piece.

At the beginning, I used the dish only to hold a 4wl 144MHz antenna, since I was more interested in 144MHz Meteor Scatter at this time, and setting up the cables for 23cm was not possible across the construction ground.

In the background: The dish in the far south-west corner of my garden.
In the foreground: A frame for a 1.8m Prodelin offset dish (meanwhile all are sold)

The dish's early morning shadow on the neighbour house, seen from my shack window.

Winter impressions

The cable run from the cable's exit at the house to the dish had to be lawn mower friendly and easy accessible for maintenance. I am using boxes with a removable cover that are also used during for example railway constructions.

I had meanwile removed the revolver feed and shifted the two for 23cm and 13cm with a screw jack.

I started expanding the dish to 4.5m.
The expansion ribs are, as the dish is, from stainless steel and I got them made for EUR 15,- each from a company which has a laser cutter and a professional folding machine.

Florian and I while fixing the mesh to the dish. All had to be done on a 1.8m high schuffold.

Again a view from the street, but now the dish has 4.5m diameter

During sunset
Some additional weight had to be added to the rear of the dish.
Here you also see the round septum feed (here: 23cm) with chaparral choke and the new feed mount on a rail that I am using today (2010). The screwjack is used to shift the feed into best focal position.

Very late, I found a picture of how the Rohde&Schwarz "Drehstand" was originally used.

Behind the dish is a box that contains the 13cm equipment and a power supply for 9cm and 6cm.

[HOME]Last updated 14.04.2010 06:30 (( ) home (X) Munich, Rosenheimer Platz, S-Bahn station) by DL4MEA