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

[Don Wilhelm]

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.
>