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VK3XX > EMC 17.06.07 08:20l 62 Lines 2891 Bytes #999 (0) @ WW
BID : F21555VK3XX
Read: GUEST DJ6ZX
Subj: Re: 10Mhz to be wiped out?
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SR1BSZ<SP7MGD<SV1CMG<ZL2BAU<VK4TRS<VK3FBD
Sent: 070617/0532Z @:VK3FBD.#MEL.VIC.AUS.OC #:48703 [Lilydale] FBB7.00g
From: VK3XX@VK3FBD.#MEL.VIC.AUS.OC
To : EMC@WW
Hi again,
I first wish to thank both Warren and Ray (VK2TV) for direct responses to
my last posting on this subject supporting BoB's(VK6BE) reaction to this
topic. Also the others posting their reactions to the initial posting.
Almost 60 years ago I became involved with the Institution of Electrical
Engineers in the UK and as a member still receive their monthly journal,
now called "Engineering and Technology". The latest issue which arrived a
few days ago has a several page article on the subject of wireless power
transmission which was the subject of a recent BBC broadcast and the
original posting on packet.
I can now say that it isnt a hoax, or internet misinformation. Several US
manufacturers are toying with it as are other companies in the world. It
all gets put into perspective in this article and acknowledges the
attempts made and patented by Nikola Tesla just a bit after the 20th
century commenced. I previously had said just before. Mea culpa!
The whole thing is about searching for practical applications. The
invention is not new at all. The frequencies referred to are nearer 1 GHz
than 10 MHz, specifically between 902 and 938 MHz, the RF power being
about 1 watt output. Distances from the TX source are in the region of 1-2
metres to light small lamps and fluorescent lamps having light outputs
equivalent to 38 watt incandescent lamps. Charging of battery operated
devices in cars are even being considered. There is a picture of a
prototype charging bay incorporated in a vehicle instrument panel! Other
applications mentioned including computer and audio devices which are
already exist by other RF devices such as Bluetooth.
The article even mentions considerations of RFI to mobile phones in nearby
frequency allocations. At least the amateur users of the 10 MHz band have
nothing to fear.
On a technical note even the question of resonant induction circuits is
mentioned. At Teslas experimental power frequencies the reactance of the
"transformer" primary was very low. At 900+MHz the reactance of any
primary winding which could radiate would be so high as to seriously limit
the current that can flow in that coil. By use of a series tuning
capacitor a significant increase in primary current can be created and
hence efficiency too. Just like antenna matching! Even beam and patch
antennas get a mention to increase the range. 14 metres was mentioned
having been achieved!
I hope all readers find this information rather more realistic than the
media reports which I have heard about. It certainly isnt a new invention
just a new application of long known electromagnetic principles.
It may be possible to access this information at
www.theiet.org/engtechmag
73 - GORDON, VK3XX @ VK3FBD.#MEL.VIC.AUS.OC
Message timed: 15:07 AEST on 17 Jun 2007
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