SM7GVF


My new project;


A dish antenna
.



I am QRV on all bands from 1.8 MHz to 1.3 GHz, but only on 144 MHz I am able to hear my own
echoes from the moon. This should be corrected.

After working more than 500 initials on 144 MHz, I thought I had to find a new challenge.

I have started a slow process assembling and a erecting a dish antenna.

Skip the history, jump directly to status 2017!

2011-05-30

Below is a picture of the dish, used as a TVRO antenna many years ago.

3.2 m dish under construction.

I have to put the dish some where, so I started to dig a small hole.

Maybe this is the right place, there is already electricity!

After I had started to mount the dish, I thought it was too small.

The TVRO dish has been sold.

This looks better;

This dish is 8 m in diameter.

The dish was collected at OZ6OL, Hans, last summer. Hans thought it was too large
for his interest in frequencies above 3.4 GHz, where he already is using a 5 m dish.

The dish was built by OZ9AAR.

I made a first attempt to verify its shape;


It looks pretty much like a parabola.


Update 2017-05-28

I have finally made some progress, the dish tower is now on its rail, for rotation, the hydraulics for elevation works.


Below is a closer look at the base of the rotating tower in progress.



2017-05-29
I started mounting the 24 ribs to the hub, I will try to get them right.


2017-06-05
SM4IVE, and his wife Karin stopped by today. Lasse helped me put the ribs on the hub at the speed of light. I now have to adjust them so the focus is good, which will be a slower process for me, I want it as good as possible.



After that Lasse left, this is my garden situation.


2017-06-26
SM4IVE is here again and helping me adjusting the dish, doing that without help showed to be impossible.


Me turning the lower screws.


We are completing with mounting the concentric rings.


2017-06-27
I thought I should extend the dish diameter somewhat.


Two slices of mesh is mounted, I am now figuring how to avoid the mesh surface undulations that we see. A birds view below.



2017-07-24
Recent activities;
I have decided to use pop rivets in addition to cable ties for attaching the mesh to the parabola structure.


I have to find methods that I can handle myself. Below is shown how I stretch the mesh with the help of two buckets of water.
The rake is part of an old Wimo 23 cm yagi.


I have also decided to solder the joints between mesh slices, the idea is from G3LTF. It is very time consuming!


We test out the new axle on the gearbox, SM7EKU is happy as the axle with key fits exactly.


Prototype testing of the rotation.


Movie of the rotation, run at full speed (.mp4 file)

Today we had some socializing, resting from work.

Other VHF:ers; SA7CJO, SM7WSJ, SM7FWZ, SM7SJR and SM7THS.

2017-07-31
Today I finished hand mixing concrete.

To be continued.



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