Hello, I have contstructed this wonderful loop antenna much like the early models found in the 20's and 30's. This is like the the cross with wires running in a diamond shape. I up graded it and added a sprial coil and a tunning capacitor out of a 20's Radiola. I was excited to use it and I was also getting funny looks from my wife on what I had built, proud of my master piece I have found that it does not help much at all. I found that just a 15" piece of speaker wire hanging from the celling works a lot better...LOL. What could I have done wrong with my loop antenna?????? On paper and in real life it looks like it would pick up station from outerspace. Any suggestions and input would be greatly appreciated.
Thanks
David

A long wire antenna will ALMOST always outperform a loop antenna. The loop antenna should be somewhat directional. Try turning it in several directions and see if it performs better.
MRO

Hang in there David. You may be picking up something from outer space. Just got to figure a way to detect it.

Bill VA

:Hello, I have contstructed this wonderful loop antenna much like the early models found in the 20's and 30's. This is like the the cross with wires running in a diamond shape. I up graded it and added a sprial coil and a tunning capacitor out of a 20's Radiola. I was excited to use it and I was also getting funny looks from my wife on what I had built, proud of my master piece I have found that it does not help much at all. I found that just a 15" piece of speaker wire hanging from the celling works a lot better...LOL. What could I have done wrong with my loop antenna?????? On paper and in real life it looks like it would pick up station from outerspace. Any suggestions and input would be greatly appreciated.
:Thanks
:David

Antenna construction is not as simple as some may think, loop diameter, length of wire, number of turns and the value of the capacitor are all very critical. There are a lot of good web sites for antenna construction, a well constructed loop performs very well.

Dave

:
::Hello, I have contstructed this wonderful loop antenna much like the early models found in the 20's and 30's. This is like the the cross with wires running in a diamond shape. I up graded it and added a sprial coil and a tunning capacitor out of a 20's Radiola. I was excited to use it and I was also getting funny looks from my wife on what I had built, proud of my master piece I have found that it does not help much at all. I found that just a 15" piece of speaker wire hanging from the celling works a lot better...LOL. What could I have done wrong with my loop antenna?????? On paper and in real life it looks like it would pick up station from outerspace. Any suggestions and input would be greatly appreciated.
::Thanks
::David

As Dave was saying, a loop must match the circuitry to which it is connected. If it doesn't match impedance wise, signals won't transfer properly. Certain size coils (such as your loop) respond to certain frequencies best. This would concern matching to that tuning condenser. Also, there must be current and voltage matching. This is the same as with matching a speaker to the output section of a radio. Most modern speaker voice coils are very low impedance. They require lots of current, not voltage. A tube is very high in impedance, and therefore works with high voltage, low current. If you put the speaker directly onto the tube, you'd easily load down the voltage with the very low impedance coil, and the tube wouldn't have enough current to drive the coil. It's a whole lot more complicated than this, but I don't care to type it all out right now. Anyway, your loop must match the antenna coil in your radio both impedance wise and frequency wise. If your radio was a single band radio, you'd almost be better off disconnecting the antenna coil and then wiring the loop directly to where the secondary of the antenna coil used to connect. The loop must then be matched to the antenna tuning condenser section. You cannot do this with a multi-band radio unless you have multiple taps on your loop for the different frequencies.

A very good long wire antenna can be found in the General Electric section of the Resources section of this web page. However, it requires that your radio have an antenna coil designed for a V-Doublet antenna. Look down the list for V-Doublet antenna. If constructed properly and wired to your radio properly, it will pick up signals strongly, and without static. This is because it is a balanced antenna, and it feeds the signal in through a balanced line. The signal is alternating current. Whenever the signal is flowing in through one of the leads (cable to be described), it is flowing out through the other. Interference that is picked up by the antenna or cable is cancelled since it is picked up by both halves of the antenna or cable equally, and will be out of phase with itself.

I use from 25 to 50 feet of wire suspended horizontally in one direction (never make bends or fold-backs with any long wire antenna..this ruins efficiency). Split the wire in the middle and insert an insulator. At about 3 feet from either side of this split solder a wire about 3 or 4 feet in length. Purchase about 100 feet of old 300 ohm flat twin lead television cable (usually brown and with the two wires on each edge of the flat cable--found at Radio Shack). Connect each of the wires you soldered on to each of the leads in the cable (one wire per lead). Connect the other end to the antenna terminals on your radio. Most radios have only one antenna terminal. This is the problem. What you must do in order to use this antenna properly is to disconnect your antenna coil primary from all internal chassis/ground connections. Connect each lead-in wire to each end of the antenna coil primary. An example of a radio built for such an antenna can be found here on this web site in the Resources section under Crosley--model 1117. I own this radio and use the V-Doublet with this radio. Its reception is static free even in the worst conditions. I can run the radio under the same conditions with a regular long wire antenna, and reception is terrible. The resistor found on the primary coils is to sort of balance the coils. This is a rather lazy way of balancing the different band coils so that they all perform about the same.

Thomas

How do you measure or check a tunning capacitor?

You can measure a tuning capacitor's minimum and maximum capacitance with a capacitance meter. Rotate capacitor and observe capacitance. To test for shorts, use the resistance setting of your multi-meter.

Thomas