Rob,
I just found my 1530 instruction sheet and it reminded me that the coax
has DC voltage on it (for the circuitry up at the loop base)so don't
short it out. Also, it does say to NOT ground the coax between the loop
and the downstream Antenna Interface box "as it may introduce noise."
Nigel: Not to worry about my using a stake; my wife won't let me play
with anything sharp any more.
Dave
--- In loopantennas@..., "Rob Moore" <rmoore5@...> wrote:
Hi Dave,
Well the shield is grounded by the time it gets into the house but
maybe I'll try it both ways. That may take a little longer.
Rob
--- In loopantennas@..., "n2chi" <davidgriffin@> wrote:
Hi Rob,
I think I'd try something I'm more sure is grounded. If I remember
correctly, the coax shield between the loop and the electronics is
NOT
grounded. I seem to remember the installation materials saying NOT
to
ground that section of coax. So shorting the aluminmum of the loop
to
the shell of the BNC might not yield a ground. But then, that would
probably short out the antenna?
Dave
--- In loopantennas@..., "Rob Moore" <rmoore5@> wrote:
I have one up a tree and can try that tonight. I assume that
grounding the aluminum loop to the shell of the BNC connector is
what
you're referring to?
Rob
--- In loopantennas@..., "n2chi" <davidgriffin@> wrote:
Does someone have a Wellbrook loop in a convenient enough
location to
ground the shield and see what happens? If it's the antenna,
then
it
won't act like one when grounded. If it's not the antenna, would
there
be any noticeable effect of grounding it? Please don't make me
got
out
and drive a stake in the ground......
Dave
--- In loopantennas@..., gandalfg8@ wrote:
In a message dated 14/05/2007 21:08:36 GMT Daylight Time,
christrask@ writes:
Patrick is absolutely correct in stating that the aluminum
shield
(aka
the outer conductor)is the actual antenna. This is the manner
in
which
shielded loops function at their operating frequency. At very
low
frequencies where most electrical field noise exists, the
currents
and
voltages of both arms of the outer conductor are equal in both
potential and
polarity (provided the gap is at the exact centre), with the
currents
being
the same on both surfaces of the outer conductor material and
zero at
the
gap. The currents that are coupled to the inner conductor(s)
cancel
so that
there is no net noise current delivered to the receiver.
-------------------------------------
Hi Chris
The Wellbrook isn't a shielded loop antenna.
There no gap in this loop, other than inside the housing at the
bottom
where
it connects to the amp.
regards
Nigel
GM8PZR
