The Antenna Experiment.

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Introduction: The Antenna Experiment.

We are going to test the feasability of getting electricity from the atmosphere. We will use several kinds of antennas to put electricity to work. Just a simple dipole and unipolar antennas.. This is  intended this to be just a prototype for a much larger unit you would like to build. The antennas are meant for indoor use so that wet weather will not be a factor in preventing the experments in being completed.  Ages 10 and up.

Objective(s):

To teach that radio wavet can be captured create electricity.

To teach a basis alternating and direct current.

To educate that we can use natures own power instead of fossil fuel.

To compare student hypotheses with the actual results of the experiment

Step 1: Hypothesis

There is enough energy in the atmosphere to capture and put to work.

Step 2: What's Needed.

6 or more - rolls of cheap aluminium foil
1 - 10 -20 foot rope or other solid material such as a pvc pipe to hold the foil
Lots of tape

50 or so foot of copper wire

2 - ladders or something that can be used to hold up the antennas

Rectifiers (see circuit)
4 - gemanium diodes 1n34 or equivalent (or any diode if that is all you have)
2 - 0.2 uf 50v ceramic capacitors
2 - 100 uf 50v electrolytic capacitors

1 - rectifier bridge 50v or more

1 varialble capacitor form an old am radio,

25 or more 1n914 diodes (or equivalent)

Tv antenna transformer

Tools:

Voltmeter

Tv with dtv support

Dual ended alligatpr clip wires

Step 3: Strategy.

Each student is to take the materials and then put together various indoor antennas. They will need to use a bit of geometry to make the plates. By testing the coils with a compass they can see how magnetism works.  They will also see the force of wind can be put to work. They will get some experience at putting a project together as an engineer might do with a prototype. Lastly see the unit they have built create electricity. For younger students the soil and magnet platform could be pre-made.

Step 4: The Big Foil Dipole.

This test would have been best done outside, but the people who live around me have an aversion to anything foil.  The test was done inside with the little room to operate. the antenna sections were set so that they did not either touch the ground or each other.

Part 1: Non-efficient rectifier
Radio waves are alternating current (aka a.c.) based. Direct current does not go over the sky very well. My volt meter does a better job with d.c. converting from a.c. to d.c. needed to be done.  Just used a simple pre-made bridge to accomplish that.

Results.
Dipole antenna => bridge =. meter .01 volt
One side of dipole antenna and ground  => bridge => meter .02 volt
Both sides of antenna as one conductor and ground => meter .08 volt
Nothing dramatic there except to say, Yet you can get power from an antenna.

Part 2: Alternative rectifier
Using the famous circuit that is supposed to be an energy harvester, it yielded no measurable results. Then I thought about it and thought maybe the capacitors needed time to charge. Then after a while I did get a result that was about what I had in part 1.

Part 3:
Tried the foil wall as a tv antenna, but there were not enough benefits to use it all the time.

Taking down the antenna as it is getting in the way..

Step 5: The Long Wire.

We will try to use two of three of the tests as step 1 and see what happens.  Antenna is about twenty five feet long and was made of copper. Same wire used to test the earth battery in another instructable.

Part 1:Non-efficient rectifier.
Hybrid antenna We used ground instead of having a second antenna wing. The wire is about 25 feet long. and was grounded.
--------------------------
Results:
There was about .7 volt and noticed the wire was sagging. Made the line taut again and the voltage went to .08 volt.

Part 2 Alternative rectifier
Using the famous circuit that is supposed to be an energy harvester, it yielded no measurable results. Then I thought about it and thought maybe the capacitors needed time to charge. Then after a while I did get a result that was about what I had in part 1.

Part 3:
Tried the long wire as a tv antenna, Missed one major channel, but did get most of the others.

Step 6: Semi-aerial Antenna.

Using the same copper wire we used in the last step, but we tried to give it at least a little hieght.Not as much space so we had to fold the length in  half so to speak.

We will try to use two of three of the tests as step 1 and see what happens.  Antenna is about twenty five feet long and was made of copper. Same wire used to test the earth battery in another instructable.

Part 1:Non-efficient rectifier.
Hybrid antenna We used ground instead of having a second antenna wing. The wire is about 25 feet long. and was grounded.
--------------------------
Results:
There was about .11 volt a

Part 2 Alternative rectifier
Using the famous circuit that is supposed to be an energy harvester, it yielded .02 volts. Then I thought about it and thought maybe the capacitors needed time to charge. Then after a while I had the same result..

Part 3:
Best reception yet with this antenna. Sgnal waas stron and had only one of the mahor stations where the signal waivered a bit, but it is back to nortmal.

Step 7: Variation.

Update on results coming.

Instead of using the full wave rectifier or the special engergy circcuit,  lets use just a simple voltage doubler circuit we will use a special modified circuit to do voltage doubling. The traditional rectifier used in essense 4 diodes. To make a voltage double you will need to replace two fo the diodes with electrolytic capacitors. To make our circuit even more intersting, we will be using what is known aas a step up transformer to see what happens. A voltage meter will be added to the dc side to see what results we might get.Since the incoming signal is ac, the transformer should work fine within limitation. If you wer using incoming dc voltage, this circuit definately would not work. The Transformer might also help boots the voltage, but there might possibly be a power loss.

One other possible modification would be to add a tuning capacitor to the less coil side of the transformer to latch on to stronger signals.

Note: I know nothing about electronics, except what little I have read, so this experiment will be even more interesting.

Step 8: The Results.

Since the wall antenna was already taken down, we decided just to use a garden variety coat hanger antenna. Took the power transformer from a old radio, It had a ratio of 180 to 8 according to the ohm meter. I put the 8 side on the antenna. the 180 side when to the load circuit.  With the full wave rectifier circuit we saw a value of 2 to 7. with the voltage doubler we saw a value of 20. What a difference. The little magic power circuit that really did not work in earlier steps was really supposed to be some kind of voltage double for some reason that did not work well. Though the power was infinitesimal, we are still pleased with the results in this part of the experiment.

Diodes were the same kind as used  with the: https://www.instructables.com/id/Easy-home-made-wind-powered-generator/
Capacitors were .1uf 50 v electrolytic capacitors.

Step 9: Performance and Conclusions.

Performancewas considerting the crude setup we had was about what I expected. You can get energy from the air, but you will need better materials to work with. Probably do a followup with the correct materials to be use.

Step 10: Light Energy.

Light is a radio wave in it';s own way. So we took some silicon diodes (1n914) to see what would happen if we shed some light onn them. Yes we got some millivolts! Try some leds as an alternative too!

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3 Discussions

BE HAPPY.. I DELETED ALL OF MY "NASTY" POSTS.. NOW YOU HAVE NOTHING POSTED ABOUT THIS.. OTHERS SEE IT FOR WHAT IT IS..

Personally I thought the policy of instructables was not to be nasty. Just because you do not see it does not mean it is not valid. Sure hope no one poops on your instructables.

Funny, people tell me the opposite. One of these days we will be able to generate electricity from antennas. This is an extension of Volta's ideas.