Vy Low Rx Dipole / AO-Journal p911

En attendant l'arrivée imminente du AA-600
test avec désadaptation du transfo 100 ohm / 11.11 ohm
Return Loss 10dB seulement, juste normal.

50 ohm 50 ohm 50 ohm <--Mismatch --> 100 ohm 11.11 ohm 11.11 ohm

Gain Versus Take-Off Angle Comparison (Straw, QST, December, 2005)

Fig 3: Measured Input Impedance
of a resonant horizontal half-wave dipole
above ground where h is height above ground.

(a) Calculated for soil permittivity of 6.
(b) Dry ground.
(c) Wet ground.
(d) Conducting mat (large, fine-mesh copper mat representing
perfectly conducting ground for comparison purposes).
(e) Calculated for Infinite permittivity.

Results quoted are for an open site covered with short grass and
having a gravel subsoil, of which a sample measured a value of six
after a long spell of fine weather.
Above the dielectric ground there is a large increase in the radiation
resistance of the antenna as it approaches ground-level.
Close to the ground the radiation resistance is about double that of a
similar antenna in free space.

(Source: Proctor, Proc IEE, Part 3, May 1950)

Step 1 : Data base compilation

Beverage measurement K9DX
http://nidxa.org/memberWWW/k9dx_beverage_measurements_july_
2003_.htm
--------------------------
K3LR
http://topband.contesting.narkive.com/48cZYSLE/topband-low-rx-dipole

Low height full size dipoles for 160 and 80 meters at 5 meters high
It all depends on what other antennas you have.
I have had up a 14 ft (4.27m) high 1/2 wave dipole on 160
for many years. (soit 2.13m sur 80m) It has always impressed me
as a high angle antenna which limits its prime effectiveness to gray
line use. I also use it in tandem with other antennas and the MFJ
receive antenna noise canceling W8JI magic box (also an effective
antenna phasing unit). My low dipole's claimed fame was a sunrise QSO
with KH2. No other antenna (1100' beverage, vertical array, etc.) could
hear the KH2, but he was 569 on the low dipole.
http://www.k3lr.com/Hardware/
http://www.eham.net/articles/23758
----------------------------------------
NØGW
160-Meter Dipole Height

W8JI
http://lists.contesting.com/_topband/2007-01/msg00191.html

Folded Dipole Impedance
http://www.antenna-theory.com/antennas/foldeddipole.php

K7MEM The folded dipole has several interesting features.
http://www.k7mem.com/Electronic_Notebook/antennas/folded_dipol
e.html

W8JI
http://www.w8ji.com/folded_dipole.htm

W5ALT
http://www.comportco.com/~w5alt/antennas/notes/ant-notes.php?pg
=13

W8HDU
http://hf-antenna.com/003/

Low Band Receiving Antennas
http://aa7a.net/Low_Band_Receiving_Antennas.pdf

160 and 80m Antennas and more
http://www.ok7gu.com/links.htm

Ground Dipole
https://en.wikipedia.org/wiki/Ground_dip
Une théorie fondatrice pour les "BOG" ?

Vy Low
Rx
Dipole

15/04/2016 Vendredi

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