[Antennas] efficient antenna tuning

DJED1 at aol.com DJED1 at aol.com
Sat Feb 10 15:34:46 EST 2007


OK- here's the answer to what I think you're asking:  
If you use an inexpensive antenna tuner at the rig, and you want to operate  
all of 40 meters, then you should tune the antenna for resonance at  mid-band. 
 This will result in the minimum SWR on the coax, and will  minimize the 
dissipative losses in the coax.  The impedance at the rig end  is affected both by 
the antenna impedance and the electrical length of the coax,  so a general 
purpose tuner is needed. Similarly, if you only want to cover  the CW band, tune 
the antenna to the center of the CW band. 
If you want to make the problem more complicated, you could ask for only a  
capacitor as a tuner.  Then, you would want to tune the antenna and/or  adjust 
the coax length so it looks inductive at the end of the coax.  I  don't think 
I can give you a specific answer without knowing the antenna  impedance versus 
frequency, and an antenna analyzer is more expensive than an  antenna tuner.
Ed  WB2LHI


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