"Scope-in-a-box" antenna feed modification

[Conrad Cardano]

Hi

At the last RTOP meeting, I mentioned that I made some modifications to my "scope-in-a-box".  Basically, the modification is moving the antenna feed closer to the antenna.

The antenna is in the shape of a parabola; however, the focus of the parabola does not match the position of the antenna feed.

Distance from center of feed to antenna base = 300 mm

The top of the antenna feed is removable.  You have to carefully shimmy it back and forth.  After you remove it, you can remove the coax cable.  You are then left with just the Al rod and base.

You will need two 5" x ¼" bolts, 6 nuts, and 4 lock washers.

I was able to thread the 5" bolts thru the antenna, and attach them securely to the frame.

Then, I attached the base of Al rod to the 5" bolts, with nuts on both sides.

You can adjust the nuts at the base to ensure that the rod is 90º to the antenna.

Finally, insert the coax cable and reattach the feed.

I hope the photos are helpful.

Conrad