Welcome of my homemade loop antenna pages. All the loops described here were designed and built by myself. The features are not real different from loop to loop. These loops are made to enhance radio reception in the broadcast band range. Some of the loops are just one coil, some have tuning capacitors and some have an extra coupling coil. Read on and discover the fantasy of loop antennas. Or fetish in my case.

The loop shown above is my first loop and it has only one winding. This ended up connected to my 4 tube radio. I used pine wood cut to 5/8 inches by 3/4 inches. There are three pieces 12 inches long and another 16 inches long. The squares in the center are about 3x3 inches and are 3/16 inches thick.

The wire is 23 gauge enameled magnet wire, but you can use what you have and what looks cool. There are 15 full turns of wire. I drilled 15 small holes starting 3/8 inch in and at 3/8 inch intervals. The bottom leg (the 16 inch long) has an extra hole at the bottom so the winding will start and end on that section of the loop. You will have to spool out 70 feet of wire and thread it all the way through. Be careful that the wire doesn't kink and you should have a big enough space and two people to do this job. I did it by myself, but it took a long time to wind this loop.

After the loop is done, take a piece of wood, or some left over garolite like I did and drill two countersink holes to attach to the frame and two more holes for the connection hardware.

I made the base with two pieces of oak wood. One is about 7 inches square and the other is 4 inches square. Use what you have. Sand, stain and shellac the wood, then attach them together with 4 flathead wood screws. Drill a 1/4 inch hole in both the base and the loop and put in a dowel rod to attach both together. If the dowel doesn't easily go in, sand it until you get a better fit.

Check out my crystal loop antenna/receiver.

Here it is friends. I made a loop specifically for one radio. This my loop #6. I was using my "test" loop (which is shown below) to see how my Sparton radio would perform. I was impressed and since I use that my Sparton a lot, it deserved it's own loop.

I decided that this antenna had to be lightened up a little. The two garolite squares had to go. I cut a notch in both pieces of wood so that they would interlock. The pieces are glued and fastened with a single flat head wood screw.

The wire is wound with some litz wire. Litz isn't really necessary but the wire is more flexible than the magnet wire. This makes a nice looking wiring job when finished. You will need 70 feet of wire for the tuning coil and about 14 feet for the outer coil. I thread the wire for my loops outside where there is room to pull the wire. The drilling and other details are contained in the drawing shown below.

I used litz wire between the loop terminals and the base box. Earlier I had used 18 gauge PVC covered wire. This was too stiff and the loop would not stay in the position it was turned to. Just one of those little learning things.

A base box isn't necessary. All the parts could be mounted on the loop itself, or a small board could hold the loop with a small panel for the other parts. But I like those basswood boxes that I have.

The Sparton radio is a multi band set and the shortwave bands require a different antenna. I added a switch and some terminals to accommodate this need. The radio antenna is switched between the loop coupling coil, or an external antenna and ground. The other switch is a high low band switch and adds a 300 pf capacitor across the 365 pf variable capacitor. A larger value of variable capacitor would tune the whole band in one chunk.

This loop is not real expensive to build, but they require a lot of building time. Use your imagination and you will be as proud of your loop as I am of mine.

Loop schematic

Hole drilling detail for my homemade loops.

This is my 4th loop. Sorry for leaving #2 and #3 off the site, but those were so much like my first that I decided I would wait for something worthwhile to offer. This is worthwhile. I wanted a loop with lots of bells and whistles to do my radio experiments. Look at what this loop has to offer.

This loop has two windings. The larger winding (15 turns) is connected to a variable capacitor for a large tuned circuit. Since a single 365 pf capacitor will not tune the entire broadcast band, more capacitance has to be added. In the case of my dad's loop (shown below), he switched a 300 pf fixed capacitor across the 365 to allow tuning down to 540 khz. I am using a ganged capacitor and a switch. Included is a third position of having no capacitor across the coil. I did this as some of my radios tune the antenna loop by a ganged capacitor inside the radio.

The other winding (2 turns) is to connect to the antenna input of the old BC radio. I picked two turns as that emulates the single turn that my dad had on his larger loop.

This loop has 3 wood pieces. The arms are 12-1/2 inches long, and the main pole (vertical part) is 30 inches tall. This is a little larger than my earlier loops so that I would have room for that extra winding. After the holes are drilled, I stained the oak with Minwax Red Mahogany stain. After the gloss deft dried, assembled the loop using two 3x3 inch square pieces of garolite. Thin wood, plastic or anything you have around will work. Before you mount everything, fit it together and take a look to see if it looks right.

Another change from my first loop is how the ends of the wires are handled. So that the wire wouldn't work loose, I drilled an extra hole close to each end hole on my loop. This makes 2 extra holes I had to drill. What the heck, holes are cheap so I splurged. The extra holes are about 3/16 inch from the end holes. The wire can be then looped around a couple of times. This holds the ends secure and looks neat too.

On the top of the mast pole and each side arm, I drilled 17 holes. I used a 3/32 inch drill but it isn't too important the size of the hole. Each hole is 3/8 inch from each other and I started 3/8 inch from each end.

Then measuring down from the top of the pole 25 inches, I drilled a series of 21 holes going back up the pole, 15 holes, one for each turn, one for the end winding. Then two extra holes close spaced for ending the tuned winding. . When the wire is wound on this loop, it will look like a square.

Three more holes are drilled for the untuned winding. I looped the both wires once through the middle hole as with this winding, having the ends so close wouldn't matter. I think that comes out to 21. Lets see.... 15+1+2 +3 = 21. Good thing I stayed awake in the first grade!

You with me so far? Good. After I wound the wire, I made a little 4 terminal connection block from another piece of garolite. I also drilled a 1/4 inch hole in the bottom of the pole and inserted a dowel rod in the hole. This is the weak point of the loop. If the loop falls over the dowel will break and need replacing.

Next I built the box that serves as a base for the loop and holds the capacitor. I used a cut down basswood box, a piece of 3/4 inch thick oak as a base and some 1/8 inch garolite as a panel. I took a 1x1x3 inch piece of wood and screwed it to the garolite. This is so the 1/4 inch dowel will be stable in the loop base.

Using that big thick 14 gauge wire, I make the connections to the capacitor and link switch. In my case, I used a 3 gang capacitor. That made it easy to use a single link switch to do what I wanted it to. You could make two spst link switches, one to add a fixed or second gang and the other to disconnect the capacitor from the circuit. I built mine the way I wanted, and you can build yours any way that is handy for you.

So I can use this loop several ways:

Connect a radio to the untuned 2 turn loop and tune the main coil with the capacitor.

Hook an antenna and ground to the two turns and a diode and earphone on the tuned side for a cool crystal set. Or if I was really close to the station, forget the antenna and ground.

Use the untuned winding as a tickler coil in a regenerative set.

Use only the large loop without the tuning to connect to a radio. This loop could be used to replace a built-in loop on a radio.

Connect the coupling loop between a wire antenna and a crystal set for a wave trap. Make sure the loop is turned to null the station you want to trap.

Maybe I could use this loop to strain my spaghetti. Anyway, below are some pictures of how I constructed the loop. If something is unclear or you have a better idea on something, please e-mail me. These loops are very cheap to build but take a long time to make. But they sure look cool sitting on top of your old radio. Best of luck with yours!
Dave

Top of panel with loop plugged in.

Underneath view with old time wiring.

The bottom base box.

Panel view with loop removed.

Bottom of pole showing end wire looping.

Left side arm showing 17 holes with wires.

Schematic

Hole drilling detail for my homemade loops.