[Elecraft] Performance of baluns.

[Geoffrey Mackenzie-Kennedy]

Hello George,

Many thanks for your comments which I shall have to read later - Daughter +
Dog arrived about 30 minutes ago.
First licence late 1946 - a hunted DX morsel - but manners were better then
!!

73

Geoff    GM4ESD
----- Original Message -----
From: "George, W5YR" <w5yr at att.net>
To: "Geoffrey Mackenzie-Kennedy" <gmk at gm4esd.fsworld.co.uk>
Cc: "Elecraft Discussion List" <elecraft at mailman.qth.net>
Sent: Friday, August 06, 2004 5:19 PM
Subject: Re: [Elecraft] Performance of baluns.


> The current balun can be readily demonstrated to provide equal and
opposite
> currents to highly unbalanced loads. A simple test is to connect a balun
to
> a load consisting of a 50 ohm resistor connected to a common or ground
place
> and similarly a 100 ohm resistor. Measurement of the r-f voltage across
the
> resistors will show that equal currents are being forced through each as
the
> voltage across the 100 ohm resistor will be twice that of the 50 ohm
> resistor.
>
> Roy Lewallen W7EL and Walt Maxwell W2DU have both discussed this test and
> Roy described a test fixture for demonstration. I have built the fixture
and
> carried out the test with a simple W2DU bead balun and found almost
perfect
> balance with equal currents being delivered to unequal load resistances.
>
> Simple 1:1 current or choke baluns such as the bead baluns are relatively
> insensitive to load impedance. I use them to transition from ladderline
> feeding multiband balanced antenna loads to coax to enter the shack to the
> tuners. The load seen by the baluns varies widely with band as would be
> expected.
>
> The Elecraft 4:1 balun is unique in its design and is able to provide an
> approximate 4:1 transformation over a wide range of frequencies and load
> impedances. Thus there is little need to restrict its connection to the
> input of a tuning unit.
>
> Teacher wasn't wrong, Geoffrey - it has just been a long time!
>
> 73, George W5YR  (58 years a ham the end of this month)
> Fairview, TX
> w5yr at att.net
> http://www.w5yr.com
>
>
>
> ----- Original Message -----
> From: "Geoffrey Mackenzie-Kennedy" <gmk at gm4esd.fsworld.co.uk>
> To: <w5yr at att.net>
> Cc: "Elecraft Discussion List" <elecraft at mailman.qth.net>
> Sent: Friday, August 06, 2004 10:47 AM
> Subject: [Elecraft] Performance of baluns.