[Antennas] Re: Your Antenna "pre-selector" Desires....

[Joe Giacobello, K2XX]

OK, George.  Thanks for your comments.  I thought that there always was a
possibility of high voltages appearing at the input or output of a tuner
irrespective of the type of tuner.  I thought is was a function of the antenna
impedance and/or feed line length.  Admittedly, I haven't looked at the question
closely or explored all the possibilities.

>From a practical standpoint, I have been using end fed wires and L-matches for
years when operating portable.  Although I have been nipped by RF on occasion, my
experiences have been relatively trouble-free.  However, most of that experience
has been with rigs without internal tuners.

73, Joe



"George, W5YR" wrote:

> I would be careful about just loading the antenna with an inductor or a
> capacitor alone. That can result in the development of high voltages or
> currents at the antenna connector of the radio and thereby could damage the
> internal tuner. Depends upon a lot of variables that you probably neither
> know or can control.
>
> I agree with Karl - who doesn't? - that what you want to do is to employ an
> impedance-tranforming circuit - a "tuner" -  in the coax line to the end of
> the antenna and set it for the lowest SWR you can get.
>
> Then you can fairly safely let the internal tuner do the rest of the job.
>
> I guess I am a sissy, but I really never use any of my internal tuners
> unless I am absolutely sure that they are not going to see more than about
> a 2:1 SWR from the antenna system, especially so when an external tuner is
> in use.
>
> Internal tuners are basically "tender" and just cannot stand voltage or
> current extremes like a rugged external tuner can. And they are $$$ to
> repair!   <:}
>
> 73/72/oo, George W5YR - the Yellow Rose of Texas
> Fairview, TX 30 mi NE of Dallas in Collin county EM13qe
> Amateur Radio W5YR, in the 56th year and it just keeps getting better!
> QRP-L 1373 NETXQRP 6 SOC 262 COG 8 FPQRP 404 TEN-X 11771 I-LINK 11735
> Icom IC-756PRO #02121  Kachina 505 DSP  #91900556  Icom IC-765 #02437
>
> Tim Billingsley wrote:
> >
> > Well that was my line of thinking in general. If I was to build a selectable
> > inductor and put it inline then I could try to use it to bring the SWR into
> > a more reasonable range and then kick in the autotuner to take up the slack,
> > therefore I am not stressing the TS-570 as bad.
>
> - - -
>
> Your moderator for this list is:
> Larry Wilson KE1HZ antennas-owner@mailman.qth.net
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