On Tue, 2008-06-03 at 20:06 -1000, Ken Brown wrote:
> Hi Jim,
> > Looking back at my notations The Double Bazooka noise floor was a needle
> > width less than the folded dipole on the OMNI VI Plus on 17M.
> A lower S meter reading, when only noise is present, could be an
> indication that the antenna actually somehow responds less to noise,
> while working equally well (compared to the other antenna) on signals.
> It could also be an indication that the antenna has more loss than the
> one you are comparing it
Or that the receiver is responding to noise at frequencies other than
the band of interest (wide band FM heard in a 2 KHz bandwidth sounds
like noise) and the stubs of the bazooka are rejecting that out of band
noise.
> If the two antennas you are comparing have
> essentially the same geometry, that is they span the same distance from
> end point to end point, and have a feed point in the same location, then
> there is a real good chance that the one with lower noise power at the
> receiver also has lower signal power at the receiver, due to higher losses.
>
> On the lower HF bands, there is usually enough atmospheric noise being
> picked up by your antenna (unless it is really, really inefficient) to
> overcome your receiver's noise floor (unless your receiver has a really
> high noise floor or overall low gain). As long as atmospheric noise is
> greater than your receiver's noise floor, you don't lose any receive
> capability due to the losses of the antenna. It's the guy at the other
> end that will have less signal from you due to your antenna loss, who
> may not hear you above the atmospheric and other noise. He might not be
> able to hear you tell him how good your SWR is.
> > Maybe because of my location which is not NOT a IDEAL situation,
> > the Double Bazooka worked better for me on 17M for what ever reason.
> > I challenge any one to put one of these up and compare it side by side
> > to another wire antenna and see what happens.
> That is a problem in antenna comparisons. Two side by side antennas do
> not act independently. They will interact. You would have to take one
> down while you test the other. Even if the one not being tested was
> laying below on the ground, it would likely have an effect on the
> overall performance of the one in the air. Since you cannot keep band
> conditions constant long enough to lower one antenna and raise the
> other, the test effectively cannot be done, unless the noise sources and
> signal sources are all non-skywave .
For sure.
>
> DE N6KB
>
73, Jerry, K0CQ
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