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Re: Center-fed antennas

Posted by K2bew on Oct 11, 2019; 2:15am
URL: http://elecraft.85.s1.nabble.com/KX2-Antenna-Curiosity-tp7655612p7655644.html

That's a sad commentary on the state of modern ham radio....
To, k2bew

On Thu, Oct 10, 2019, 10:12 PM Bob McGraw K4TAX <[hidden email]> wrote:

> I used my Johnson Matchbox at our Field Day event about 3 years ago.   I
> went through each band and several frequencies on each band and compiled
> a written chart identifying the settings for each band/frequency.
> After 2 hours of trying to work stations on 20M,  the radio failed and
> they came to wake me from my late night nap.   The result is the
> Matchbox was adjusted for 80M in the CW portion and the operators were
> complaining of high SWR and no power output on 20M.   It took 2 hrs for
> them to observe this?    I was amazed at the number of "Extra Class"
> operators at the site that thought the tuner was automatic and would
> change with band / frequency changes on the radio.  The radio by the way
> WAS NOT an Elecraft product.
>
> 73
>
> Bob, K4TAX
>
>
>
> On 10/10/2019 7:35 PM, Don Wilhelm wrote:
> > Joe,
> >
> > I agree completely, bring your Johnson Matchbox to the next Field Day!
> > Or even your old plug-in coil open frame link coupled balanced tuner.
> >
> > Who has a link coupled tuner (like the Johnson Matchbox) these days?
> > Those are big boat anchor box these days (and hard to find).  I have
> > one that sees little use, but I am not willing to part with it.  It
> > does a good job when needed.
> >
> > Most autotuners are of the L-network design and the manual tuners are
> > typically T-network - the L-network can be a high pass or a low pass
> > filter, but the more common T-network is always a high pass filter.
> > If one has an old Collins tuner, it may be a Pi-network which is a low
> > pass filter.
> >
> > As you pointed out, the link coupled tuner is a bandpass filter, but
> > fixed tune bandpass filters will do just as well for multi-station
> > operation.
> >
> > 73,
> > Don W3FPR
> >
>
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