Re: [HCDX]: Build a balun

[Vittorio De Tomasi <ik2czl@xxxxxxxxx>]

Nick Hall-Patch wrote:
> Vittorio and the group...
> 
> A problem with the above is that the IMPEDANCE ratio is 1:10
> 
> The winding ratio is the square root of that, so is closer to 1:3.2
> 

Nick, thanks for pointing out my mistake! I should always check twice
what I write after 10 p.m.....

> In fact, it's not easy to derive the impedance of a random length inverted-L
> antenna, but a good guess at the tropical and mediumwave frequencies would
> be in the 1000 ohm range, so the impedance ratio of the transformer could be
> 1:20 .
> Overall, the winding ratio for a random wire matching transformer could be
> in the 1:3 to 1:5 ratio or even higher; you will notice an improvement in
> received signal strength with any of those unless your receiver has a high
> impedance antenna input. 

By the way, has anybody ever tried measuring the impedance of a *real*
long wire ?!? I made some experiments years ago, but I was unable to get
meaningful results. It should be interesting to see how close to the
theory one gets in the "real" world.

73

Vittorio IK2CZL

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