On 27 Nov, 22:28, Tony Giacometti wrote:
Owen Duffy wrote:
Tony Giacometti wrote in
news:aeydnehFvJBYatHanZ2dnUVZ_o2vnZ2d@hawaiiantel .net:

I guess the question is this, DX signals would be skywave, a loop is
omni directional to skywave signals I believe. Is this correct?

In free spacem the nulls are orthogoal to the plane of the loop. If you
make the plane of the loop vertical and mount it near ground, the nulls
will be modified somewhat, but the gain at high elevations (eg
ionospheric propagation from nearby) would be pretty much unaffacted by
loop orientation. That cannot be said for very low angle signals.

...
I didn't use a shielded box, I have a plastic box. The instructions
for the loop I built said either was OK.

Well, the instructions had you tuning the loop in a manner that wasn't
very effective too didn't they. Are they credible?

I am not saying a shielded box is necessary, but I wouldn't use a plastic
box without verifying it works as well as a shielded box... and the way
you do that is to build the shielded box version.

Shielded boxes are hard to come by in the middle of the Pacific Ocean.

Radio Shack has a few which I just got. I will be changing over first chance
I get.







Why do you still think that a larger loop has deeper nulls.

If I implied that I didn't intend to do so, what I mean is to "keep"
the deep nulls I now have.

I pointed out in an earlier post that you might well compromise symmetry
with a larger loop and so compromise the depth of the nulls. You only
need enough gain to swamp receiver internal noise under the best band
conditions and loop orientation.

Of course, when the loop becomes large enough, its directivity does
change, and the nulls are a little broader. Proximity to ground modifies
large loops significantly.

Owen

Lets see what happens when I change over to a shielded box.- Hide quoted text -

- Show quoted text -- Hide quoted text -

- Show quoted text -

Tony,
You just are not getting any luck with your present aproach.
Why not go out to a store and buy a hula hoop ($4)Then wire around
the 1 inch or so diameter until the wire covers 3/4 of the loop.
Repeat the winding again over the top of the previous wire but winding
in the opposite direct until you reach the end of the other wire where
you can tie them with a wire nut. Now stretch out the wire further
around the hula hoop till you get a burst at the desired signal.
Feeding at the start of the windings will give you a high resistive
impedance so you will need a transformer there. You can widen the
band
width purely by nudjing the wire further around the loop but that
probably wont be necessary as it is wide band.
Art KB9MZ