Posted by
Geoffrey Mackenzie-Kennedy-2 on
Aug 06, 2004; 5:51pm
URL: http://elecraft.85.s1.nabble.com/Performance-of-baluns-tp455789p455794.html
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" <
[hidden email]>
To: "Geoffrey Mackenzie-Kennedy" <
[hidden email]>
Cc: "Elecraft Discussion List" <
[hidden email]>
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
>
[hidden email]
>
http://www.w5yr.com>
>
>
> ----- Original Message -----
> From: "Geoffrey Mackenzie-Kennedy" <
[hidden email]>
> To: <
[hidden email]>
> Cc: "Elecraft Discussion List" <
[hidden email]>
> Sent: Friday, August 06, 2004 10:47 AM
> Subject: [Elecraft] Performance of baluns.
_______________________________________________
Elecraft mailing list
Post to:
[hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
http://mailman.qth.net/mailman/listinfo/elecraft
Help:
http://mailman.qth.net/subscribers.htmElecraft web page:
http://www.elecraft.com