AOR WL500 User guide

®

WL500 - Window Loop antenna 3.5 - 30MHz

The WL500 is a compact active loop antenna specifically designed to provide good reception while travelling or
operating from a temporary / compromised monitoring location where large external antennas are not practical.
The wire loop will fold down and fit into a small bag, operation is even possible using an internal 9V dry battery.

The loop is constructed of flexible twin cable braced by a
centre pole which splits into two sections so that it can be
easily stored away. When set up, the loop forms a
diamond shape with an approximate diameter of 60cm.
The loop covers 3.5 to 30MHz with a range switch
mounted at the termination point of the loop
(switching at 10MHz).

A length of screened cable is supplied which is
terminated in RCA (PHONO) plugs to
connect the loop to the control box.
The control unit provides preselection
and amplification terminated in a
BNC socket for connection to the
receiver. Excellent strong
signal characteristics are
achieved, typically 16dB
gain with an IP3 of
+14.5dBm. The
control unit can be
powered from
an internal
9V 006P
(PP3)

The WL500 comprises of the following:

µ

loop with support fixings (providing cable termination and range switch)

µ

control box (tuning of the antenna and power switch)

µ

screened cable (RCA plugs fitted) for connection of the loop to the control box

µ

BNC patch lead (for connection of the control box to the short wave receiver)

µ

9V battery and support hook (power supply also provided in some market areas)

The optional 500LM ferrite bar antenna detaches from the

base unit, the resulting two packages are compact enough

to easy fit into a small bag or bottom of a case when

travelling.

The WL500 control unit comprises of a quality robust

metal box 93 x 67 x 30mm in size (excluding

projections) with front panel preselection / power

switch and LED. Rubber feet are attached to

the bottom of the control box to prevent

marking of a table top and to stop the

box from sliding during operation.

The opposite end of the control box

has an RCA (PHONO) socket to

accept the screened cable

from the short wave loop

(or optional 500LM

element), the socket is

labelled 'Loop'.

The output feed

to a short wave

receiver is

via a

BNC

battery
(current
consumption
is around
16mA),
alternatively
external 12V DC may
be used

(power supply
included in some market
areas).

While the WL500 will operate
below 3.5MHz, performance on the
lower bands can be enhanced by the
addition of the optional 500LM bar
element. The 500LM bar element is
130mm in length with a selector switch for long
wave (LW) or medium wave (MW) operation and
connects to the control box in place of the short
wave loop. A termination box is provided so that the
500LM bar may be rotated through 360 degrees in
order to make the best use of the directional properties
for peaking the wanted signal while nulling out
unwanted transmissions or local noise. Of course the
directional characteristics when listening to distant sky-wave
signals will not be as pronounced as local ground-wave.

The WL500 is supplied in a

compact display bag measuring

approx 39 x 14 x 8 cm and

weighs just 640g.

socket,

this is

labelled 'RX'

and a BNC-

BNC coaxial patch

lead is provided.

If your

receiver

cannot

accommodate a

BNC plug, inter-

series adapters are

widely available.

The WL500 can be powered

from an internal battery or from

an external 12V DC supply. A

1.3mm power socket is provided

(centre positive) and is labelled

'DC 12V'. If you would like to

operate the WL500 from a vehicle
supply, an optional DC lead with cigar
plug is available (DC8200).

...compact short wave loop - ideal for travelling

Using the WL500 active loop antenna

1. Assemble the short wave loop (see illustration on the front of this page).

Slide the two supporting wooden poles together then feed the threaded
section through the round eyelet at each side of the wire loop, attaching the
wing-nut to hold the assembly together. The top of the loop has a support
ring, attach this to a suitable anchor point on or close to a window, or use
the supplied s-hook.

2. Connect the screened cable between the loop
antenna and 'Loop' socket of the control box using
the RCA (PHONO) connectors.

600mm

BNC coaxial

patch lead

to radio receiver
RCA (PHONO) connectors
screened connecting cable

3. Connect the BNC-BNC coaxial patch lead between the 'RX' socket of
the control box and short wave radio receiver (if your radio cannot
accommodate a BNC plug, use an inter-series adapter).

4. Decide which method of
power you will use, either
internal 9V battery (supplied)
or external 12V DC power.

If using the internal battery,
remove the six screws from
the base of the control box
(cross headed) and remove
the bottom plate. A metal
cradle holds the 9V battery
in place, ensure you
connect observing the
correct polarity. Refit
the bottom plate (its
symmetrical).

Note: If removing the
battery, ensure that the
battery connector cannot
short circuit inside the
control box. Only use quality
batteries and immediately remove exhausted batteries or when not using
the WL500 for a period of time (to reduce the chances of chemical
leakage). The battery should provide many hours operation. There is no
need to remove the battery when powering the WL500 from external DC.

If using an external power supply, keep the power supply as far away from
the WL500 and receiver as practical to reduce noise. If using the optional
500LM element, you may wish to consider use of a low noise regulated
power supply to reduce
the effects of noise from
diode rectifiers.
Recommended power
supply is 12V DC at
150mA (accepted voltage
range is 12 - 16V DC, a
voltage regulator is built­into the WL500 control
unit).

5. The control box
preselection knob is
labelled 'Tuning' and has
a rotary action with an
incorporated power switch
which activates in the fully
anticlockwise position
(7 o'clock).

Rotate the tuning control
clockwise, the front panel
green LED will indicate
that the unit is powered.

6. Decide which frequency band you wish to use
and switch the loop range appropriately. The lower
range is 3.5MHz - 10MHz and the upper range is
10MHz - 30MHz, you will find that the band edges
are quite accurately defined when you start tuning
the loop.

7. Tune the radio receiver to a known active
frequency then adjust the 'Tuning' control of the
WL500 to achieve maximum strength on the
receiver’s signal strength meter (s-meter) so that
the wanted signal sounds clearest. If your receiver
does not have an s-meter, simply adjust the WL500
for best receive signal... the higher the frequency,
the further clockwise the control will need to be rotated.

Adjust the position of the loop element until the signal is strongest and any
interfering signal is nulled. It is advisable to locate the WL500 in or close to
a window in order to achieve the best possible reception. It is possible to
use the WL500 on frequencies below 3.5MHz (such as MW) but
performance will be reduced and the loop will no-longer tune (so no
adjustment is required). To enhance performance on the lower bands,
consider the optional 500LM element. The WL500 is NOT intended for

transmit purposes.

Remember, in order to achieve good results, the WL500 (like all antennas)
should ideally be located with a clear view in the direction you want to
monitor (considering the great-circle map). If the WL500 is hemmed in, the
preselection and directional properties may assist in dragging out signals
from the noise, but will not be a substitute for a well sited antenna. To
avoid the potential pick-up of noise from the receiver (particularly its
display), it may be worth experimenting with the position of the WL500 and
optional 500LM with respect to the receiver (on top / along side / separated
by a few metres etc), also where possible, experiment with the RF earth.

Optional 500LM element

Replace the short wave loop with the 500LM.
The two halves of the 500LM connect via a

6.3mm jack plug to enable rotation for best
results. Select the appropriate band MW / LW
using the toggle switch. Rotate for best signal
and tune using the WL500 control unit.

E&OE © AOR LTD, 2003.

130mm

®

AOR Ltd

2-6-4 Misuji, Taito-ku, Tokyo 111-0055, Japan.

Tel: [phone] Fax: [phone]

[e-mail] www.aorja.com

AOR (UK) Ltd

4E East Mill, Bridgefoot, Belper, Derbys DE56 2UA, England

Tel: [phone] Fax: [phone]

[e-mail] www.aoruk.com

AOR USA, INC.

20655 S. Western Avenue, Suite # 112

Torrance, CA. 90501, USA

Tel: [phone] Fax: [phone]

[e-mail] www.aorusa.com