I'd be very leery of measuring the resonant freq of this loaded
element close to the ground. The resonant freq of a loaded 40M 402cd
changes many hundreds of KHz from the ground to 70'. It measures too
low on the ground.
This antenna's driven element sounds very close to the 402cd. If the
element spacing is about 21' that is used by CC, why not make it just
2.5% longer like CC does?
73 de Brian/K3KO
K7GCO@aol.com wrote:
>
> In a message dated 9/6/01 4:04:19 AM Pacific Daylight Time, n4kg@juno.com
> writes:
>
> <<
> A 5% lower resonant frequency for the reflector is a good place
> to start. It seems to me that one way to do this is to split and
> insulate the reflector and then either grid dip the element or
> measure the impedance at the center. Once it is tuned, then
> it may be joined and mounted to the boom. Yes, there may be
> some detuning effects but I would expect them to be small for
> a 40M element.
>
> 73 / GL, Tom N4KG
>
> On Wed, 5 Sep 2001 "K&L" <kmccourt@tbaytel.net> writes:
> >
> > Hi All , I am in the process of building a loaded two element 40
> > beam. I
> > have the driven element finished and its total length is 43` it is
> > resonate
> > @ 7.150. What would the most practical way to tune the reflector be
> > ? Should
> > I split & insulate the reflector , mount it on the boom and check
> > the
> > resonate frequency ? Is 5 % longer a good length ? I am not quite
> > sure of
> > the best way method to use . Would like to get some input on this .
> >
> > 73 Kevin
> > VE3KKM
> >>
> I've been able to grid dip aluminum elements without cutting them. If you
> have troubles getting a dip reorientate the coil. Plan B is to make a shunt
> link of 1 or more turns and connect it to the element with hose clamps.
> k7gco.
>
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