Topband: To Balun or not to Balun that is the question.

[i4jmy at iol.it]

Unless a small reduction of RF energy fixed the problem, for example lowering the voltage just under a semiconductor threshold, hardly those 6 turns works like an effective choke at 7 Mhz.
Only chance is when parasitic capacitance of the coil skyrokets reactance because resonance of the coil goes very close to the used frequency. In such a case the coil made of cable acts as a trap, beeing this the method to choke efficiently at a voltage node.
More probably you fixed the problem altering the cable lenght, or by collapsing the line in the coil, or by legnhtening the coax for adding the 6 turns choke.

73 & HNY
Mauri I4JMY



> 
> It depends on what you are using the balun for.  I found 6 turns to be 
> effective on 40m. in the shack between transmitter and ant changeover relay. 
>   I had an rf feedback problem on that band, that wouldn't go away no matter 
> what (copper ribbon ground strap, 1/4L ground radials under the floor, rf 
> chokes, bypass caps, etc).  The 6-turn balun cured the problem immediately.
> 
> Don K4KYV