The CAN is the back end of the horn antenna. The CAN is made up of two parts:
- a paint thinner can
- a feedthrough antenna
Making the Feedthrough Antenna
The feedthrough antenna is made up of two parts:
- a 5.25 cm length of 4 gauge copper wire
- a panel mount 4 hole male SMA connector
The two parts are soldered together. The simplest way of doing this is by placing each part horizontally in the clips of the helping hands of your soldering stand. A small drop of solder is melted onto the tip of the SMA connector and onto the tip of copper wire. The two soldered ends are brought together and then soldered together. Make sure that the SMA connector and the copper wire are aligned horizontally before soldering. Remember that the parts will be hot! Do not handle the parts too quickly after applying the solder to the tip of the SMA connector and the copper wire. Use tweezers or needle nose pliers to handle the hot parts. You can also let the parts cool before handling. Click on the video link to watch a demonstration of soldering the SMA connector to the copper wire.
https://youtu.be/lt63VYeqB38
Preparing the Can
Making the paint thinner can into the back end of the radio telescope requires four steps:
1. Removing the bottom of the paint thinner can
2. Drilling the hole for the antenna
3. Taping the spout of the paint thinner can
4. Attaching the antenna to the paint thinner can
Removing the Bottom of the Paint Thinner Can
Removing the bottom of the paint thinner can is best done with a smooth edge can opener. The OXO Smooth Edge Can Opener model number 2128100 works the best. This can opener cuts on the outside of the can instead of the inside and leaves a very smooth edge. This can opener also has a top turning knob. Do not get a side turning knob can opener. The side turning knob hits the side of the paint thinner can. A regular can opener will also not engage far enough down the inside edge of the paint thinner can to cut properly or at all. The rounded corners of a paint thinner can are also impossible for a regular can opener to navigate. Click on the video link to watch a demonstration of cutting the bottom off the paint thinner can.
https://youtu.be/IFm9_-f6lvQ
Drilling the Feedthrough Hole
A hole needs to be drilled in the paint thinner can for the feedthrough antenna. The hole is 1/4 of an inch in diameter and is located 5.25cm from the edge of the top of the paint thinner can (the uncut side) and 3.25 inches from the side (the centerline of the can). You should also place a snuggly fitting wooden support block in the can under the spot where the hole is to be drilled. This will insure a clean, smooth, and circular hole. Click on the video link to watch a demonstration of drilling the feedthrough hole.
https://youtu.be/nOl8OJEHZHQ
Taping the Spout
You should tape the spout opening of the can before attaching the feedthrough antenna. You will need two 2 inches long pieces of aluminum tape to cover the outside and inside of the spout. This is assuming that the roll of aluminum tape is 1.5 inches wide. Do your best to keep the tape smooth and flush with the edges of the spout. Click on the video link to watch a demonstration of taping the spout.
https://youtu.be/t-MNZw7UhMI
Attaching the Feedthrough Antenna
The feedthrough antenna is soldered onto the paint thinner can. First use the soldering iron or hot air gun to melt enough solder to surround the 1/4 inch hole and also be a pool of solder the size of the base of the SMA connector. Let the solder cool. Drop the feedthrough antenna into the hole copper wire side down. Look into the paint thinner can and center the feedthrough antenna in the 1/4 inch hole. You do not want the copper wire or solder touching the metal can. Use the hot air gun to heat up the SMA connector, ring of solder, and metal can. When all three pieces are at the correct temperature, the solder will liquify and pull the SMA connector down level with the metal can. This should be a solid connection between the metal can and the SMA connector. Click on the video link to watch a demonstration of attaching the feedthrough antenna.
https://youtu.be/dH5D2EP3ODM