Time to market? Cost? Any reason why the mobile companies can't spray all their masts and we wave goodbye to poor mobile reception?
Presenting at the new Google-backed talk fest "Solve for X", ChamTech Operations showed its nano tech-based antenna in a spray can, turning trees into antennas and connecting submarines by radio. The technology is easy to explain, but rather harder to realise. It comes in a aerosol with which one sprays nano-capacitors – onto …
Spray some of this on the antenna and boom, incinerated protesters, boost the power enough and you could just point it at a building and fry everyone inside... well we all knew it was coming, don't shoot the messenger, yadda yadda.
For the unenlightened: http://en.wikipedia.org/wiki/Active_Denial_System (microwave death trucks)
If you can boost the performance of an antenna by 100x by spraying this stuff on, then the antenna must have been at least 100x less efficient than a properly designed antenna in the first place. Maybe this stuff will help poorly designed and electrically small patch antennas but if you think it will make any kind of difference to radio/tv broadcast antennas or cellular antennas then you're wrong; these things are designed to operate with near 100% efficiency with very specific radiation patterns to optimise coverage, and applying any kind of coating will only be detrimental to the performance.
Antenna engineering is not a 'hit and miss' affair these days (to those who understand it) but an exacting science driven by the operators / broadcasters desire to squeeze every last drop of performance from their transmitters.
I have a couple of 15dBi gain antennas on my test masts outside; the path loss between them is around 30dB (in the UHF band). If I could spray this stuff on them and get 100x the range (an extra 20dB gain) then I'd get 10dB (10x) more power out of the receiving antenna than I put into the transmitting antenna and would be violating several laws of physics......
On the other hand, if your antenna is buried underground or inside equipment, just putting out in free space may give you even more than 20dB improvement.
It's pseudo science, or he's discovered how to violate the laws of physics.
Unless real info and specs are made available, then we'd best put this one in the 'perpetual motion' bag!
Light is just a high frequency radio wave. If we can use an aerosol to make photo voltaic panels 100x better then we'll get 2000% efficiency and solve the worlds energy probs while keeping our armpits fresh.
I'm sure though he'll make lots of sales to the people that think a Prius is powered by regenerative braking.
Typical geek, here's one the fashionistas made earlier:
"Spray-on T-shirt: 15 minutes and it's ready"*
Mine's the one with the spray can in the pocket...
* Warning, contains embedded advert.
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Either this guy is not telling us much about the details or most of it is bullshit. Maybe he's deliberately obfuscating what he's doing to deliberately mislead opponents (but then they'd recognize this from the BS).
!. Efficient antennas DO NOT get hot. Whip antennas on cars feel hot because the RF signals are absorbed into your hand, the metal itself isn't hot unless heat is generated by local RF absorption in some lossy/resistive material (your hand for instance) which in turn heats up the metal.
2. Metal antennas can be extremely low in loss. Loss (or I^2R losses) should NOT be confused with a low gain antenna. An antenna gets gain by being large -- having more elements. Essentially, hi-gain antennas don't give you something for nothing, all they do is point/beam/focus/concentrate the signals in a specific direction (i.e. send it where you want it to go).
3. There's nothing wrong the concept of spray-on capacitors that can be configured as an antenna. However, it won't work on metal surfaces and many surfaces are very lossy (i.e. absorb the RF before it's transmitted into space).
4. Transmitting 50MHz and above under lossy conductive salt water is fraught with problems (submarines use frequencies in the 10s of kHz and it's still marginal).
Reality check -- real facts and specifications please!
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3 meters is about the wavelength for 94 MHz radio waves, it's true. But ideal aerial length is one-quarter of wavelength because it makes an apparent delay line equivalent to one cycle. Here's how it works: travelling the length of the aerial and back is half a cycle. Then the radiation and re-absorption at the far end are each worth a 90 deg phase shift. Look it up. The whole adds up to a 360 deg. phase delay in the aerial so the signal returns exactly in phase.
Right, a simple antenna for 3 metres would be 1/4-lambda or about 0.75 metres. A dipole antenna however would be 1/2-lambda (1.5m). More complex antennae can be quite different lengths, electrically they can be tuned to 1/4 or 1/2 lambda with an inductor/tuned circuits but they can be odd non-resonant* lengths. Sometimes odd lengths can be a benefit as the radiation pattern can be more suitable to the job.
* Physically, they're not resonant lengths but they're made resonant by virtue of added reactances (capacitors inductors etc.).
No coating is going to reduce the power "consumption" of an antenna. And a coating to reduce heat....first of all, heat has nothing to do with an antenna's broadcasting/reception capability...but let's play along....since when does putting a coat of something on anything reduce heat? Unless it's water (which evaporates rapidly) or freeze spray (same issue as water).
Randomly spraying crap on a tree isn't going to help squat. This is the exact same things as those little stickers that you stick inside your battery compartment on your phone...just a complete waste of material/product.
While I am also highly dubious about the Wonder Spray, a coating certainly can "reduce heat", depending on what you mean by "reduce heat". If you just mean achieving less of a heat difference between the coated object and its environment, then any coating that improves thermal conductivity would. (So would an ablative coating that convects heat away, like your water and cooling-spray examples.)
If you mean reduces the heat *produced* by the coated object, then that's certainly possible too, depending on how it's dissipating energy in the first place. Consider a small-gauge wire that's conducting a current; it dissipates energy and produces heat in proportion to its resistance. Coat it in additional conductive material, and you've made a larger-gauge (lower gauge number, bigger diameter) wire, with lower resistance and greater conductive efficiency, which will thus produce less heat.
In effect, that's what this company claims to be doing for antennas; they say their "nano-capacitor" magic unicorn juice can improve the efficiency of an antenna and thus reduce the amount of energy lost as heat. As others have pointed out, this seems unlikely; but the basic idea that a coating can improve efficiency isn't wrong in itself.
This looks like it is converting a small antenna into a large antenna. No magic here, just a better coupling to space by effectively changing the speed of electromagnetic propagation across the small antenna, and I'm guessing finding it's own sweet-spot, which can't have been anticipated. Very clever.
So you can make a big antenna smaller (hiding it), or you can make a small antenna (which are very poor drivers) more efficient. This will be great for phones. How hot does yours get as it desperately tries to drive a signal out there?
Tesla would like it.
Fine, passive antennas can work very well. The classic examples are people who live in a valley and get no TV reception. They put a TV antenna on a hill to pick up the signal then they connect it directly (self powered without amplifiers etc.) to another antenna that beams down into the valley.
This can increase the signal in the valley manifold.
However, he doesn't specifically say this. Moreover, spraying antennas onto trees would be very problematic as trees contain a lot of water especially on the outside in the sapwood and the phloem which transports the nutrients. Spraying a capacitive type antenna onto nearby bark means that it'd be closely coupled (capacitively) to these conductive areas of the tree and thus it would (a) have much of its signal absorbed by this ionic water and (b) the antenna would be detuned and (c) being a passive antenna its radiation-absorbing environment would not make it efficient.
However, if the mobile/cell phone etc. is in a much, much worse area than the sprayed-on antenna is then of course it will be useful (any antenna is better than none).
If this system ever sees the light of day then there will be hundreds of caveats about how it's to be installed.
As I've said, where's the details.
I was taught that silver has fractionaly higher conductivity than copper, and that consequently it makes noticably more efficient antenas of slightly different dimensions than aluminium or copper antennas. But at significantly higher cost, and at horrible risk of getting stolen.
Of course most of the power is in the surface layer for radio waves. Even ordinary HV power cables are made with aluminium conductors and steel cores, and HF wavelengths are much shorter than the 6000 kM wavelength of 50Hz power. So surface conductivity is important for antennas.
Dunno what the real story is on this. Just wanted to point out that there are power losses in antennas, and that it does matter.
I guess if you have to put a broadband antenna in a tiny handheld box this idea could function rather well, but a tuned whip antenna with the bandwidth of the signal would be much better, as the capture area is larger. It would be interesting to see how this paint works on a very large radio telescope array like Arceibo.
How the blazes do such "unintelligentsia" get finance for such rubbish? - I suppose it works by cold fusion.... the trouble is that some jerk "inhumane resources" will believe this male taurean excrement and back it.
The hypothesis is simply destroyed by physics - I don't care what "allegedly" happens at the quantum level (nor did Schrodinger's cat...) but a capacitor can only be two conductors separated by an insulator - now how does that come in a spray can?
Is this yet another "scientific" blog-site that is so far up it's own posterior to regulate itself. Such crap only serves to distort the non-scientific mind of Joe Public...
P.S. - Since when did a properly matched antenna generate heat? - would somebody please explain the alleged physics?
Even if were possible to re-write the laws of physics to make this BS work, it would cause a lot more problems than it solved - at least in the short term until power-levels were revised downwards to negate the extra range.
If an extra-efficient antenna boosted the range significantly, the network falls apart because you run out of channels more quickly.
It'll be great for people who can connect... but for the ones who can't, not so much...
So, I was thinking about this and as an RF engineer I wasn't entirely happy based on my old-skool conventional learnings.
However.... lets assume they know something I don't, which gathering from their video is unlikely, but we'll work on the assumption. It is based on conductive particles suspended in an aerosol which stick to a surface. OK, so if they are conductive but special what might be useful here? Well if the particles had some kind of odd LCR+Transitor characteristics which meant that their propagation capabilities changed in line with frequency then it might just do something different enough to make some new science.
I'm still sceptical, but not enough to call them liars, if this tech gets adopted then it could revolutionise the market, if it is snake oil then I hope that they get a stretch in prison.
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