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Telamon · September 30th 06, 03:24 AM posted to rec.radio.shortwave

In article om,
wrote:

Steve wrote:

One thing you might do is check the cables connecting the different
components of the Wellbrook. At one point I noticed that my loop
wasn't performing as I thought it should and I discovered that the
cable connecting the receiver to the antenna interface had a poor
connection where it meets the interface box. The intermittent
connection became obvious as soon as I jiggled the cable a bit.

Also, where do you have the loop situated? In my experience the
performance of the loop is seriously degraded when used indoors.

Calbe and connectors are good, and have been used to power the
Lankford active dipole I am checking.

I have tried it in a variety of locations.

We even went so far as to drive to the Red River Gorge, an area well
away from houses, power lines etc.

The preformance just doesn't strike me as being worth the fairly high
cost.

The active dipole beat it every time.

That was a self defeating test. The idea here is that you will have a
lower noise floor in a locally noisy area with a shielded loop than a
dipole antenna. There is going to be no advantage to using a loop over
a dipole in an electrically quiet area.

A shielded loop is not better at picking up a distant signal than a
dipole but is less sensitive to local noise generators so in an area
with high local noise you would have better signal to noise than a
full size dipole antenna.

I also expect that a shielded loop would be better than a amplified
electrically small dipole although the difference in advantage would be
smaller than the comparison to a full sized dipole. Depending on the
area a electrically small dipole and shielded loop may not have a
significant difference in local noise floor because you managed to get
both far enough from local noise makers due to their small size.

If you found a problem connection from interface to antenna then I
would suspect your findings. As you well know that connection is the
power supply to the antenna amplifier and the RF path back to the
radio.

"The active dipole beat it every time" is a bit vague. Maybe you could
expand a little on that.

--
Telamon
Ventura, California