[Lowfer] How do I make the ant. work above its resonant frequency ??

[Andy - KU4XR]

Ralph:  Thanks for your advice. Since the antenna is for the
lowFER band, and it's finally in the air; I'll use it to
receive from 1750 meters and down. I tried it out on 2200 meters,
and it is pretty easy to add some Inductance, and Capacitance to
get it down there. And it seems to receive fairly well there.
There were no signals at the time, but it was at least picking 
up lots of static crash noise ;~) ...., and in comparison to the
160/80 crossed dipoles at 32 feet; WWVB booms in on the lowFER
vertical. As for 600 meter reception, the dipoles do OK for the
monitoring I'll be doing occasionally. 73 to you :


Andy - KU4XR - EM75xr - Friendsville, TN. USA
LOWfer Beacon " XR " @ 185.29875 KHz ( QRSS-60 )

*** Temporarily " TESTING " the new antenna ***

Coordinates:  N:  35º 43' 54" - W:  84º 3' 16"
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--- On Tue, 10/12/10, Ralph W5JGV <w5jgv at spectrotek.com> wrote:


> > The new lowFER Vertical is self
> resonant around 290 KHz roughly.
> > It peaks very sharply, and drops out about 15 KHz up,
> and about
> > 20 KHz below, so very narrow with the elevated coil.
> 
> <snip>
> 
> > I'm wondering if it's
> > going to be usable only below its resonant frequency
> ??
> 
> There are several possible options.  You can add a
> series capacitor to the
> antenna at the base, which effectively reduces the
> inductance.  That will
> make it tune to a higher frequency.  The downside is
> that you still have the
> loss of the extra loading inductance in the antenna. 
> Not good.
> 
> You can reduce the inductance by either by tapping down on
> some of the turns
> of the loading coil or by  shorting out some
> turns.  You could also insert a
> length of large diameter copper pipe inside the loading
> coil, which will act
> as a shorted turn and reduce the inductance.
> 
> If it were me, I'd consider adding a switch to the coil to
> change taps on
> the coil.  A pair or poly ropes to the switch would
> let you change the
> switch as needed.  Somehow you need to reduce the
> inductance of he loading
> coil.
> 
> It looks like you are in for another "antenna party!"
> 
> Have fun!
> 
> 73,
> 
> Ralph  W5JGV - WD2XSH/7