SPRAY-ON antennas waved about at Google's techfest [printer-friendly] ? The Register
The implications of this are simply mind boggling.
Doc
The implications of this are simply mind boggling.
Doc
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This IS related to size... as in total surface area of radiator. Height becomes a factor in distance as frequencies go up. Lower frequencies (1MHz AM radio) will bounce off the ionosphere (Skip) and will actually lens a bit over hills, whereas higher frequencies become line of sight only, bounce off near any terrestrial object but sail right on through the ionosphere. TV antennas sit on high towers or mountain tops to gain the greatest distance -line of sight-.
This developement represents an improvement in actually coupling the RF energy itself more efficiently, as every particle of paint acts as a radiator. A 20 db (100x) improvement in an Iphone antenna? Whoa!
Doc
Ah, ok. It's about surface area and not just dimension. I still don't get how nano capacitors can improve the performance of an RF antenna, but I'm not an RF engineer so I guess that's to be expected...
I'm pretty familiar with fractal antennas- the analogy is lost on me. Have you actually seen data from these guys? They appear to be local to you.
His explanation (spraying capacitors) is pure nonsense. Most metal antennas are more than 99% efficient, so improving efficiency does not buy you much. I assume he is not an engineer, although he may employ some real engineers. If spraying a coating on an existing antenna could boost output by 20dB (he actually said 20dBm) then the existing antenna is very poor. Using trees as antennas was investigated by the US military about 40 years ago; it worked, but not brilliantly. I missed the bit about underwater, as the phone rang.
Is there a grain of truth behind the unbelievable claims? Possibly. A metamaterial coating could improve the behaviour of an antenna, but only if this was part of the design.
This is not a HUGE technology development, but an attempt to win some prize money? Perhaps in the hope that then they can really develop something useful? Someone who knew little or nothing about antennas (the prize judges?) might be impressed.
PS Its not about surface area. Antenna surface area may tell you something about bandwidth, but it tells you almost nothing about range.
Is there a grain of truth behind the unbelievable claims? Possibly. A metamaterial coating could improve the behaviour of an antenna, but only if this was part of the design.
This is not a HUGE technology development, but an attempt to win some prize money? Perhaps in the hope that then they can really develop something useful? Someone who knew little or nothing about antennas (the prize judges?) might be impressed.
PS Its not about surface area. Antenna surface area may tell you something about bandwidth, but it tells you almost nothing about range.
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I just read about them this morning an passed it on, so no, I haven't seen their data. The concept is valid however. Long term implimentation and logistics may be something else entirely. I'd be very interested in how they go about input coupling. As to longevity... how does it hold up to rain? Humidity? Bad breath?
Doc
They make it sound like they have developed room temp superconductor. There antennas dont get hot when current runs thru them?
Then your physics should be better. As a recording engineer who took an antenna theory course in my EE days 30 years ago I still remember that power from an omnidirectional antennae drops off as the square of the distance. So going from 1.5m to 200 meters range means a power increase of almost 1800 times. Are present antenna really that inefficient? If something seems to good to be true...
This is more of a question. I also remember from that course that the first term in every recieving antenna gain equation was 1/2 to account for its re-radiation (the EM wave excites a current in the antennae, this current re-radiates an EM wave ) . My question:
does this happen in a trasmitting antennae; the current in the antenna creates an EM wave which in turn induces a current back into the antenna ? My guess is yes and that would limit any antenna to 50% efficient. It might depend on the antenna type (a dish may not, do reflected EM get partly absorbed, isnt EM reflection simply re-radiation). Time has erased or at least erode many things I used to know. If there are any antenna designers out there it would be great to hear from you.
Then your physics should be better. As a recording engineer who took an antenna theory course in my EE days 30 years ago I still remember that power from an omnidirectional antennae drops off as the square of the distance. So going from 1.5m to 200 meters range means a power increase of almost 1800 times. Are present antenna really that inefficient? If something seems to good to be true...
This is more of a question. I also remember from that course that the first term in every recieving antenna gain equation was 1/2 to account for its re-radiation (the EM wave excites a current in the antennae, this current re-radiates an EM wave ) . My question:
does this happen in a trasmitting antennae; the current in the antenna creates an EM wave which in turn induces a current back into the antenna ? My guess is yes and that would limit any antenna to 50% efficient. It might depend on the antenna type (a dish may not, do reflected EM get partly absorbed, isnt EM reflection simply re-radiation). Time has erased or at least erode many things I used to know. If there are any antenna designers out there it would be great to hear from you.
Aw shucks... guess this straw chewing hick form utah is just a sap for all the well known fraud we seem spawn around here.... Ma fisuks is way week... only got practucle nolege.... that I managed to use to keep top 40 FM-AM, a 1.62MW ERP UHF TV, a NPR FM-DFM, PBS VHF/DTV TV, EDNET VHF/DTV TV transmitters on the air and repair virtually every existing type of electronic instrumentaion from power supplies to Millimeter wave sweepers over the past 40 years.
When ya'll can feel distributive capacitance* in your bones you jest get back to me. (*Not Distributed capacitance.)
When ya'll can feel distributive capacitance* in your bones you jest get back to me. (*Not Distributed capacitance.)
I'm sure you can't be claiming that 40 years experience in repairing transmitters means that you understand the physics of antennas sufficiently not to be taken in by nonsense, as that would be a silly thing to claim. That would be like a TV repair man claiming detailed knowledge of quantum electrodynamics, on the grounds that CRTs use electrons and therefore he is an electron expert.
Could be that I really know nothing and I just happen to be phenomonally "lucky" at guessing which part is bad.... also uncommonally fast at it.
I didn't just fix transmitters. I have six new installs to my name. I also served as backup engineer for the largest frequency agile shortwave in America. (125 KW Harris feeding a curtain array with 10 MW ERP.) The other side of my career was instrumentation repair. I fixed Scopes, Meters, RF sweepers, specturm analyzers, network analyzers, synthesizers, BWO's, TWT's (even a Wobulator or Rhumbatron). Usually know where I'm going to look for a problem before I ever take the covers off... usually right.
I also own every book Tesla ever published and quite a substantial phsics library.
So I DO have a fair inkling about what is and isn't possible....
I also know that there is a great deal that we don't know. By definition every great advancement mankind has ever made has come from wackos.... those who believed something the majority didn't. That's the way science works.
BTW a TV repairman will certainly have a BETTER idea about quantum theory than an account executive or shoe salesman.
I'm done.
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