[Elecraft] balun

[Charles Greene]

Mike,

The reason is that for small 4:1 baluns, you need more turns of wire 
on them to get the necessary inductance,  more turns means a smaller 
wire to fit, and a smaller wire means the impedance of the two wire 
transmission line is not optimum for a 4:1 balun.  You will have a 
high SWR just due to the balun.  However, I have made many small 1:1 
baluns using several turns of RG-174 on a toroidal core, by placing 
ferrite beads (12 FB43-801 beads work nicely) on the outside of a 
piece of RG-174, or just winding a bifilar pair of #22 enamel 
insulated magnetic wire on a toroidal core.  You need a F114-43 or a 
F140-43 core to get enough impedance for 80 meters, although a 
smaller core will work for 40 up.  Palomar sells a BA-58 bead kit for 
RG-58.  Actually, a 1:1 balun works as well on a random length 
transmission line as a 4:1 balun.  Unless the load is a predictable 
200 ohms or there about like you get on an OCF antenna, the impedance 
of an open wire feed line is just as likely to be near than 50 ohms 
as it is near 200 ohms.   You also can use a Low Power balun for 100 
watts like the Elecraft balun kit, or the one on the NJQRP web site.

DXE baluns are for high power, are large and heavy, and cost a lot of money.

73,  Chas W1CG

At 06:04 PM 10/11/2005, mc wrote:
>trying to get a little more out of this KX1 , I found a site on 
>baluns, is anyone else listening in to the eham.net. there is 
>comment on the balun pages  that says there is no real good balun 
>for low power,  my question is why not, is it not the purpose to 
>keep everything in balance to get the best out of your antenna no 
>matter the power. the eham site does not offer any explanations on 
>this but one HAM operator says DXE balms claim to fame is high power out puts.
>
>mike
>kb7dpc
>
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