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On 25 Oct, 11:32, "Mike Kaliski" wrote:
"art" wrote in message ups.com... On 25 Oct, 09:38, Cecil Moore wrote: art wrote: At first I was considering the actual wire length in the braiding b ut that influence became little compared to the current pertabutations. Sounds like you are working on a self-resonant coil and need to know the length of time for the current to flow from end to end. Both sides of the argument are wrong on that one. The current does not jump from one end of a coil to the other in a very small number of nanoseconds as one "expert" has asserted which implies a VF close to 1.0. Neither does the current follow the wires directly round and round the coil as asserted by the other side which would imply a VF around 0.01. The actual measurable VF of a coil seems to be just about double the round-and-round argument side as there is indeed some coupling between adjacent coils. A typical 75m Texas Bugcatcher 6" dia, 6.5" long, 4 tpi coil has a VF of around 0.02 making it about 40 degrees long at 3.8 MHz. -- 73, Cecil http://www.w5dxp.com No Cecil you are following a fatal aproach by using lumped loaded circuitry which is a no no when measuring current speed. Especially when you are following a path of zero standing waves. To obtain a voltage doubling you can only solve by using distributed loading aproach where a single wire has approx length when measured close to the ground short of two wavelengths . Unfortunately by using braid to get extra current perbutatation the length extends quite a bit longer even tho braiding electrical length is longer that the physical measurement. Ofcourse the introduction of a flyback transformer would be exciting but we must not run before we walk Regards Art Art I think you cannot rely on calculating the braided length as being longer than the physical length. While it is true that the braided wire if unravelled would likely be considerably longer, RF waves propagate along the surface of the wire. They will jump from one wire to the next where the braids cross, following the path of least resistance. You would probably need to use braided Litz wire, where each strand is individually enamelled to achieve what you appear to be trying to do. Regards Mike G0ULI- Hide quoted text - - Show quoted text - I see where you are coming from but braid wicks like mad so a good dose of quick drying polythene varnish solves that problem IF it were to occur, tho the current will not jump but follow the path of resonance. What I am doing now is a combination of insulated wire with doped braiding and it appears so far that the braid is required to be much longer. When time permits I will make seperate models using wire and then with braid on a higher frequency where the single wire form is easily calculated as a datum As far as Litz wire goes there is a frequency transition line when you use that (skin factor) so I am not anxcious to introduce another variable or spend the required extra money. Regarding travelling on the surface of the wire I have often pondered that the use of braid for grounding wire is subject to question compared to a copper wire or ribbon. As I see it the braid is heavily inductive even tho it has the appearance of the field balancing out since the current must still traverse the windings, but that is another subject all together deserving of its own topic title. I know it may sound wierd but I am trying to slow down the current by half so that for the tank circuit I will have four pulses of energy release over the existing two.Single wire windings are just a hair to fast to accomplish that In other words double the power of a particle generator which is what radiation is all about, at least in my mind, since I see the attributed gain of a helix being controlled by the voltage increase in sync with the current flow which I see as not quite correct when using single wire since. I am still seeing standing vaves which are small but does not prevent full traverse of all amateur frequencies using a single antenna with a variometer for use when resistance levels drop below 20 ohms. It just blows my mind how just applying a time varying field to a static field is providing so much more info with respect to radiation assuming one has a true understanding of what equilibrium is really all about and which the majority deride Cheers Art. KB9mz |
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