[Elecraft] [OT] Re: qrp balun - how about not QRP?

[Jim Miller]

Read all but if lazy just go to cookbook near end:
http://audiosystemsgroup.com/RFI-Ham.pdf

For some useful more detail analysis:
http://fermi.la.asu.edu/w9cf/articles/balun.pdf
Forget you ever heard of the term "balun"

jim ab3cv
On Mon, Nov 5, 2012 at 2:37 PM, Don Wilhelm <w3fpr at embarqmail.com> wrote:

> Randy,
>
> That "balun" will not be very effective below 6 meters.  The inductance
> of each winding is about 1000 nHy, which provides only 60 ohm choking
> impedance at 10 MHz.  Sorry, but there are designs out there on the web
> that do not hold up to scrutiny.
> An effective balun must have a choking impedance of at least 5 times the
> feedpoint impedance, so for a 4:1 balun (200 ohms), the impedance must
> be 1000 ohms or more to be effective.
>
> 73,
> Don w3FPR
>
> On 11/5/2012 2:16 PM, Randy Moore wrote:
> > Can I divert slightly?  I want to build this balun
> > (http://www.combotec.com/projects/balun14/balun14.html)
> > to use with a 40m delta loop from my K3/100, but the only PVC I have is
> about 1.25" in diameter, not 40mm (1.5").  How do I compensate for the
> smaller diameter?  Google searches haven't been productive.
> >
>
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