Hi Neo.

This is up one of my favorite ally's, I studied antenna theory say 20 years ago, very interesting to say the least, I look at radio waves as a cool source of potential energy, I like an antenna design in the shape of a full band slice of pie, hexagonal antenna with 6 individual slices that form a radial and omni-directional antenna.

if you need an idea of the design, imagine 3 bow tie antenna's that form a hexagon, pretty simple.

looking forward to your next post.

Jerry

Hi onthecuttingedge2005

Im sorry to say, i have no interest in constructing fractal antenna but I love that movie "The Cutting Edge"... 

@Wings: I am afraid, the antennas you mentioned (for sure the fractal antenna and the plasma antenna) still have to be designed or at least tuned into a specific narrow band (narrow range of frequencies). And the frequency range of the Lakhovsky antenna is not clear.

What I want is to receive alle frequencies from 60 MHz to 10 GHz at once or together (seems it is difficult to make myself understood). Not only the station which is the most powerful at a given location, but also all other stations or transmitters weak or strong. So, I want to receive the whole elctromagnetic smog souurounding us with one antenna.

There are some FM radio stations in every area, there are some TV stations, there are a few cell phone towers everywhere, and there are some WLANs everywhere. In Vienna one sees 20 or more WLANS in an aparement building and I see the WLAN in the houses of my neighbour. And I want to receive all that "electromegnetic smog" with one antenna and I want to rectify the whole lot into DC.

The contribuition of each transmitter might be low, but in sum there could be useful power to be fed into a rechargable battery over time.

Whenever I talk to a specialist about antennas I end up with something that is not "very broad band". The specialists just naturally think in "adapting the antenna to the frequency" and think that this is the only thing required. And normaly that is the case, we are normaly only receiving the transmission from one transmitter. And the specialist always has this situation in mind. "What do you want to recieve?" they ask me (meaning "At what frequency does the transmitter transmit"?). And I say "I want to receive everything", and then the specialists "switch of mentally".

Greetings, Conrad

like this
http://hackaday.com/2011/07/11/scavenging-ambient-electromagnetic-energy/

http://www.sciencedaily.com/releases/2011/07/110707131545.htm

http://blogs.discovermagazine.com/80beats/2011/07/15/inkject-printed-antenna-gathers-ambient-energy-from-tv-transmissions/#.UO5Z4Inm6wM


http://gtresearchnews.gatech.edu/device-captures-ambient-energy/

I will change my design into non-inductive antenna so no need for tunning and capacitor.

@Neo-X:  The "very long vertical antenna and its problems" is the kind of information I was looking for. Thank you, that was a helpful reply.


@Wings:  Thank you for posting the links to the four articles about the antennas printed by ink jet printers at Georgia Tech School. These articles triggered my thoughts about two years ago.

When reading through the articles (e.g. http://gtresearchnews.gatech.edu/device-captures-ambient-energy/ ) one sees sentences like "The scavenging technology can take advantage presently of frequencies from FM radio to radar, a range spanning 100 megahertz (MHz) to 15 gigahertz (GHz) or higher."

But still, I get the strong impression that each antenna shown is only useful for a rather small frequency band. As I understand these articles: one can "print" many different antennas, each for a different rather narrow band. They mention a successful experiment where they go for the TV band.


@Madebymonkeys:  in my "long cable receiver for the 50 Hz hum" (see my last post) one measures or rather estimates "power received" by observing how long it takes to charge the 10µF capacitor to a certain Voltage.

First one looks how high the Voltage over the capacitor rises. In my house I most often can reach about 1.2 Volt. In case I place the long cable at certain locations (e.g. near the 220V mains distribution cabinet) the Voltage rises to about 2 Volt. Once this "highest possible Voltage" is established one can look how long it takes to reach it. From these three numbers, "Voltage reached", "time it takes to reach it" and "capacitance e.g. 10µF" one can calculate Wattage; of course it is µWatt. The time it takes to reach the highest Voltage is in the order of minutes.


@Onthecuttingedge 2005:  http://www.cv.nrao.edu/ntcweb/Pictures/GBSRBSantenna.jpg looks interesting, but it seems to be strongly directional (because of the parabolic dish). An antenna for receiving ambient electromagnetic waves should be good in all directions. Conventional wisdom says, that in order to increase the "gain" of an antenna, one gives it a strong directional orientation towards the transmitter. And this is exactly what one does NOT want to do when going for "all transmitters wherever they are".

My conclusion:

A very long vertical antenna would be the best but poses practical problems (expensive tower, lighning strikes, building codes will not allow it in most regions). So, one has to come up with something that has the same "properties" but is not as long and high. One should think about "electronic extension" of a vertical antenna.

Greetings, Conrad

Hi Conrad.

actually the antenna I linked you to is a broad band receiver unit that sit in the focal spot of a 45ft radio dish. the antenna was designed for optimum reception.
the dish you saw was simply a support for the antenna.

the antenna itself is what I was pointing out since the broad band design can be arrayed in any direction.

Jerry

I tried the antenna as shown in the photo, but total failure. The circuit is shown in Reply #14 in this thread.

Greetings, Conrad

Wouldnt a broadband ant pull in a bunch of mixed signals, of which producing a lot of mush?

Unless the receiver it were connected to were able to tune in to viable signals.

If the receiver is wide band, receiving multiple distant signals, the mix is probably not stronger than tuning into 1 good signal producing a consistent oscillation.

I think it would be better to make many different tuned antenna, each with their own tuned receivers. But dont make receivers/ant that are tuned to freq that are not viable. That would depend on the area you might be in geographically.

Pretty much the ant isnt that critical as compared to the tuning of the receiver. Like say CB radio. 40 ch, 1 ant.  But one would usually be only working 1 channel at a time.
So if you have 1 CB ant and 40 tuned receivers. Would the receivers produce more output with each having their own ant(even of the same type) than drawing off of 1 ant?

Just some of my thoughts. 

Mags

I think that conrad was looking for an antenna that picked up all radio noise at the same time and in an omni-directional receiver antenna. and you are also right, CETI antenna did it all the time listening in on thousands of channels at the same time. but he just wants to convert the good signals and junk signals into electrical energy.

Jerry

@Jerry (onthecuttingedge2005): Yes, exactly! Why is it so difficult to understand for radio specialists?

@Radio and Antenna Specialists:

Just consider all electromagnetic waves in the air. In sum all electromagnetic waves have a certain energy content (of course the energy, even all electromagnetic waves summed up, is rather small). And now one can try to harvest this total energy content (some call it ambient energy).

The most simple idea is to rectify all electromagnet waves by help of a diode rectifier. Just one diode, because a full wave rectifier has a higher Voltage threshold.

See the drawing for the most simple circuit which depends on the "gain" of the antenna. The antenna should have a "high gain" in all frequencies (ideally from 45 Hz to 1000 GHz) and in all directions. And the diode should be a HF Diode also for all frequencies.

Of course one will not be able to build the "ideal electromagnetic wave catcher", but may be 60 MHz to 10 GHz is possible?

Most electromagnetic waves in the air are between 60 MHz and 10 GHz (FM Radio, TV, cell phones, WLANs), radar would be higher towards 1000 GHz, and the hum from the AC mains would be 45 Hz or 50 Hz. So, may be three antennas? The AM radio stations are shutting down and short wave radio and long wave radio are on the decline as well.

Application: a super cap is slowly charged to a certain Voltage (e.g. 2 Volt) over a day or a week (by the "ambient energy receiver") and then one can use the super cap as a battery for a clock or a cell phone or a flash light. Well, not very exciting, but why not?

May be it is not possible to build an "universal omnidirectional antenna". If this is the case, I want to know from the specialists why it should not be possible.

The best antenna should be a very high (hundreds of meters) vertical wire. This poses practical problems (expensive tower, lightning strikes, building codes). So, the question boils down to: "is there something else than a long vertical wire?"

Greetings, Conrad

P.S.: I know, what I write is trivial, but I want to get the idea across to radio and antenna specialists who always want to select a frequency or at least a frequency band. They also want to "direct" the antenna towards the transmitter and they want to do "something" with the received frequency. Just consider the "content" of all transmissions in the air as "energy" and not as "information". And one does not know which transmitter will be received, one wants to receive all transmitters there are around a certain place on earth (may be in a radius of 1000 miles, also from satellits).