Re: Second Best location for an antenna tuner #antenna #tune

Jim Allyn - N7JA

I used random length wire antennas for several decades before there was such a thing as an autotuner (or at least, I was unaware of their existence if they did exist).  So, the manual tuner was always right at the rig where I could tune as needed.  The best place for a tuner is wherever it allows you to get on the air.  Easy peasy.  At the other end of the scale, the impedance of an antenna will vary with frequency, therefore the SWR will vary with frequency.  The loss in a transmission line will vary with frequency and will vary somewhat depending upon the SWR present on the line.  Then you have the losses in the balun, which will vary with frequency and with the impedances presented to it at either end.  Of course the losses in the tuner will also depend upon frequency and SWR presented to it.  So, if you really want to know the best place for your tuner, you need to know the impedance of the antenna at several frequencies in each band of interest, the loss in the transmission lines at every frequency and SWR that will be presented to it, and the loss of the balun and the tuner at every frequency and SWR (and power level) presented to it.  You could probably do the measurements on all that in a month or two.  Then you could write a program to calculate which combination of transmission lines, balun location, and tuner location and settings results in the best efficiency.  If that sounds like a lot of fun to you, then that's what you should do.  Otherwise, put the balun and the tuner wherever they are most convenient, and get on the air and have fun.  And maybe now and then, when you feel like it, change something in your system and see if it works any better.  Or don't.

But to answer your question, yes you are presenting a reasonable degree of understanding, as far as it goes.  Now go get on the air.

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