RadioBanter - View Single Post

Lostgallifreyan · September 13th 14, 07:00 PM posted to rec.radio.amateur.antenna

wrote in news:7c6ef9ff-4081-4fd7-bbab-
:

I generally prefer the loops vs a random wire. In the daytime with
ground wave, no contest. With the loop you can almost totally null
daytime ground wave signals. At night, much less directional with the
sky wave, but the station will still often sound better using the loop.
I did a test in 2002 between a 16 inch round loop, and a 42ft "T" vertical
with a 120 ft long flat top wire. That would be fairly similar to using
a long random wire as far as overall performance.

Those files are very convincing.

As well as the orientation there seems to
be a vast improvement based on capturing energy at a small region in space, a
long wire seems to mush out the signal maybe partly due to occupying so much
space. Maybe I misundrstand, but it does seem like the spatial resolution of
a loop's small occupancy has a direct relation to the resolution of the
demodulated signal.

Anyway, thanks, I'm sold on the idea. I spent a couple of hours last night in
cool damp windy conditions gathering some NDB notes on a 50m longwire
stretched WNW then NNW (to an amazingly well placed tree, the distances
varied by less than one foot!) I lost my notes later that night in little
incident with an Organiser RAMpack and a low main battery, but I can remember
delberately testing the transmissions last thing before I packed up, and
while the longwire did seem to have a directional difference, the mushiness
did not help at all. Also, we have a high pressure region breakign down,
there seemed to be storms in southern Europe, France/Spain most likely. I
imagine a magnetic loop might dramatically reduce the impact of that noise
too.

I think someone posted some design notes or links during one of my first
threads a month or so ago. I'll look at your loop in detail (I like the
narrow but stuff gauge of UPVC pipe (I'll maybe chose a black 20mm conduit
because that's easy and cheap to get here, and I've used it for other stuff
too), and hopefully I'll figure out a good waterproof capacitor for loop
tuning too.

One question: Is this going to be good using the 100 or so turns I put on the
end of the PL-390 ferrite rod? Hopefully this is the ideal way to couple the
signal into the radio, because it will make life very easy if it is.