[Elecraft] Baluns & wires & feeders (oh, my!)

Don ehrlich at olypen.com
Mon Oct 2 12:22:08 EDT 2006


You could measure power accuratly using the scope and a dummy load. 
Measuring power at the load with a 300 ohm dummy load and balun and then, in 
a seperate test, measuring it with a 75 ohm load and no balun would give you 
a rough idea of balun losses.  This would show balun losses if they were 
fairly large.  I have never been successful using a scope to measure 
differential rf voltages because of the rf voltage that gets into the scope 
through sneak paths that you do not intend.  Anytime you float a scope 
(measuring relative to a point that is not absolute ground) you will start 
to display rf voltage where "there is none" due to stray rf fields in the 
environment.

Don K7FJ



My question is this: Is there a way to measure the insertion loss of the 
balun? Perhaps setting up my scope to do a differential measurement on the 
output of the balun w/ a 300ohm dummy load? Also, I could rig a way to sweep 
the antenna/window line with the antenna analyzer.
> Any suggestions?
> 72s,
> Pete
> wd4lst
>



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