Re: Kchibo antenna experiments installment 2


Tony Germanotta
 

Another possible problem could be capacitance from the close winding. I'd use a couple dowels on each side woven through the wires alternating over and under to help offset it. It also helps tighten up the windings and might improve the Q.  You can get more effect by using Popsicle sticks or tongue depressors to get bigger swings if your turns are loose enough.  On a big loop I've used pieces cut from wooden blinds as my stationary shuttles. 

You could even use a turn or two of the unused wire on the other end as your pickup loop, adjusting there for best output as well. Signal shouldn't be a problem on a loop that large. 

If you have enough turns you could put two coils in parallel tuned by the same cap the way they do with some of those ferrite loops. 

It might look like a Frankenstein device but could be a nice compromise. 




On Mar 18, 2015, at 12:43 PM, farmerik@... [ultralightdx] <ultralightdx@...> wrote:

 

That is an interesting approach. I had my son solder on taps already. Someone here or on another group thought the unused windings would be a problem. Combined with the idea of the best selectivity or was it Q at the bottom of the tuning range, it is worth experimenting with the number of turns to get the cap to tune the most intertesting frequency range at the lower end of its range. With a smaller loop you would not have a lot of wire, but with a 4 foot loop I think I should have enough signal. Sounds like it is worth trying. If I can find the cap I had short alligator leads connected to. - Thanks- FARMERIK

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