The following obs were an annual occurrence until my 85'+ support tree blew
down this year. The 160 antenna described below was supported by the tree, and
was no more than 4' from the trunk in the middle...the top an bottom were
closer, ~1'.
A wire Inv-L (#12 stranded THHN) with tuned
As for the affect of trees on EM waves, below are the results of some simple
measurements I posted earlier on another board.
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Recording the relative readings on the dBµ and S/N displays of a Tecsun
PL-310 tuned to a directional station about 52 miles east of me on 790 kHz,
http://www.spacewar.com/reports/Can_You_Program_a_Radio_to_Dominate_the_Spectrum_999.html
They need to test it on topband!!
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Stew Perry Topband Distance Challenge coming on December 29th.
On Mon, Dec 31, 2012 at 1:12 PM, Jim Brown j...@audiosystemsgroup.com wrote:
My take on the issue, which seems to agree with what science I've seen
published on the topic, is that vegetation, including tall trees, has little
if any effect at HF, but begins to show attenuation in the VHF range
If you have nasty and persistent local Electical noise ie from arcing
insulators and nearby electrical crud from devices and a constant s9 or strong
noise floor the mag loop will work wonders only because it can null the
strongest of the noise (or all if in same direction) and present a
Hi Dale and the Topband group. To trim the vertical portion, and return to
original resonance every winter, I simply folded the wire closely back on
itself in a flat bundle at the feed point and taped it tight. The overall
length was shortened about 3' max.
Just pulling in the wire to reduce
On Tue, Jan 1, 2013 at 4:13 AM, Richard Fry r...@adams.net wrote:
As for the affect of trees on EM waves, below are the results of some
simple measurements I posted earlier on another board.
___
Recording the relative readings on the dBµ and S/N displays of a Tecsun
PL-310
I used eight elevated tuned radials. They angled about 45 deg from about 4' at
the feed to ~15' for their horizontal run. To initially tune, I used my MFJ-259
to feed a pair of radials (dipole), then cut the rest to match them. I set the
system resonance via the length of the
On 2012-12-31 8:46 AM, Tom W8JI wrote:
Years ago, when some fellow proposed that trees would radiate because
they were fractals, I measured the RF resistivity of freshly-cut pine
trees. I firmly attached copper or aluminum plates to a thick one foot
long trunk section, and measured resistance.
