[Elecraft] Rf in the shack distorting audio - the results

[Bob Nielsen]

On Feb 23, 2007, at 9:29 AM, Darrell Bellerive wrote:

> On February 22, 2007 09:44 am, Don Wilhelm wrote:
>> Look at the Elecraft BL2 for a switchable 1:1/4:1 balun, it will  
>> handle up
>> to 250 watts.  If you do not need the switchable arrangement, the  
>> BL1 can
>> be constructed for either a 1:1 or a 4:1 configuration and its  
>> power rating
>> is 150 watts.  A convenient ground lug is located on the balun  
>> output side.
>
> How can a balun be switchable from 1:1 or 4:1? Surely the  
> characteristic
> impedance of the windings will be missmatched at one of the settings.

Actually the characteristic impedance of the windings will ideally be  
2*Z0.  For a 1:1 balun they will appear in parallel, while for 4:1  
they will appear to be in parallel at one port and in series at the  
other.

Bob, N7XY