ok2bwn SUPERFOX 3,5M User manual

3,5 MHz DIRECTION FINDING RECEIVER
SUPERFOX 3,5M
The SUPERFOX3,5M direction finding receiver is a digital version of the successful receiver
SUPERFOX3,5GX. The SUPERFOX direction finding receivers are modern sports equipment
satisfying even most demanding requirements of top sportsmen. Their ergonomical solution
results from the competitors' demands: low weight and small size, all receiver controllable by
single hand even in full run, shock-resistant, waterproof house. The symmetrical antenna
especially optimized for direction finding provides sharp direction pattern and high receiver
sensitivity. Digital synthesizer provides high frequency stability and low noise.
The SUPERFOX receivers are used by many top competitors and their outstanding results
prove the quality of the equipment.
FEATURES:
Ergonomical solution – single hand controllable
High sensitivity
Optimized symmetrical antenna reaches the front-to-rear ratio 40 dB
Sensitivity control range 120 dB
Stable digital tuning
Shock-resistant, waterproof house
Detachable whip antenna for easy transport and packing
Small size and lightweight
BRIEF OPERATING INSTRUCTIONS:
1. CONTROLS:
FREQ button: frequency tuning
GAIN button: GAIN control
ANT button (silver): switches between “eight” (button released) and “cardioid” (button pressed)
pattern
Threaded hole on the top side of the receiver is the terminal for the whip antenna. Two threaded
holes on the bottom side of the receiver (35 mm spacing) are for mounting the compass holder.
Optional: COMPASS button (blue): see the FINDER09 operation description below.
2. RECEIVER ASSEMBLY
Mount the whip antenna to the terminal on the top side of the receiver
3. ACCUMULATOR:
The receiver is equipped with a built-in Li-Pol accumulator, which lasts for approximately 10 hours of
operation (fully charged). The accumulator status is indicated after switching on in the headphones:
_ _ fully charged, _ 80%, . . . 60%, . . 40%, . 20%
Charging: Use the N40 charger. The yellow light indicates charging in progress, it goes out at the end
of charging (the charger terminates charging automatically). Keep the receiver charged (i.e. charge it
after the activity) - you lenghten the accumulator lifespan.
Note: when the accumulator is fully charged, the charger does not even start charging. As new
accumulators have higher voltage, you have to discharge it at least by 40% or so. Conclusion:
after the competition connect the charger. If yellow indicator in the connector turns on, let the
receiver being charged, otherwise disconnect the charger and try next time (there is certainly
enough energy for several competitions in the accumulator).
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4. WHIP ANTENNA ADJUSTMENT
The direction pattern of whip and ferrite antenna combined asks for exact ratio between voltages
from each antenna. While the voltage from ferrite antenna does not depend to the height above
ground, the voltage from whip antenna depends on it. Therefore you can get optimum direction
pattern only within about 50 cm tolerance of the given height above ground.
Of course, the maximum/minimum can be easily recognized in any height above ground. However, if
you trim your antenna according to your personal height, you will reach excellent front-to-rear ratio
(some 40 dB!).
Trimming procedure:
Install the ARDF transmitter, set it to continuous operation at the center of the 3,5 MHz band.
Stay some 70 m away from the transmitter, away from fences, electric wires, etc.
Tune the receiver, push and hold the antenna button and aim the receiver front panel towards
the transmitter (minimum of the "cardioid" antenna pattern).
Move the receiver up and down. You should see a minimum of the signal at certain height
above ground.
If the minimum is at the level you normally hold the receiver, everything is OK. If the minimum
appears lower than you want, you shall shorten the whip (this is probably your situation). If the
minimum appears higher than wanted, you shall lenghten the whip.
Trim the whip by short pieces (5 mm) until the minimum moves to the wanted height above
ground.
Note: in close vicinity of the transmitter (<10 m) the ratio mentioned above changes again
(magnetic and electric components of the RF field increase differently close to the antenna) -
very close of the transmitter the whip appears as it should be even shorter. Nevertheless, from
such short distance you usually can see a flag and it is better to have an optimum direction
pattern through the rest (>95%) of the competition.
5. INCREASING WATERPROOFNESS
The back cover of the receiver is sealed with a silicone glue inside. If you open the receiver (for
exchanging the battery or drying the receiver), please remember to seal it again (at least with Scotch
tape from outside) after closing the cover back.
6. ELECTRONIC COMPASS MODULE OPERATION (optional)
The FINDER09 allows the competitor to keep stored direction exactly even after the end of the
transmission period.
The FINDER09 is controlled by the blue button on the right side of the receiver. When you short click
the button, the current direction is stored into memory and this is indicated by a short trill in your
headphonest. When you push and hold the button, you activate tracing mode and according to the
current direction you will hear a tone in your headphones (in addition to the normal received signals
from the band).
If the receiver is aimed to the stored direction or up to 20° to the left, you will hear low pitch in your
headphones (833 Hz), if the receiver is aimed up to 20° to the right from the stored direction, you will
hear high pitch (1250 Hz). At the exact direction the pitch just changes. Out of the +-20° range no
tone can be heard in the headphones.
The direction remains stored in the memory until you store another one by clicking the button (even if
you release the button). If you turn off the receiver, the memory content is lost.
Using the compass: Let us assume that you are running towards the transmitter. Before the end of
transmitting period aim the receiver to the desired direction and click the compass button. After the
end of transmitting period, you simply continue to run in full speed and from time to time check the
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direction by pressing and holding the compass button. The main advantage is that you need not to
slow down or stop to check the magnetic compass or even look at the receiver.
At highest GAIN setting (over 6) the compass module produces some interference while in operation.
This cannot be avoided but you will find that the receiver is sensitive enough anyway and normally
you will use lower GAIN settings.
When you operate the compass (storing or tracing), keep the receiver vertical (vertical whip
antenna). The measured azimuth is sensitive to a receiver tilt which will cause the azimuth error up to
the tilt angle (depending to a tilt direction).
Note: the FINDER09 compass does not use a tilt-compensated sensor because it needs for
calculation the direction of the gravity vector (towards the center of Earth), which is normally
measured by the accelerometer sensor. This works fine in steady conditions but running
competitor adds his current (very variable) acceleration to the gravity vector which makes the
measurement unreliable.
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3,5 MHz DIRECTION FINDING RECEIVER SUPERFOX 3,5M
SPECIFICATIONS
Receiver system: double conversion superheterodyne
Antenna: symmetrical ferrite + phased whip
Main lobe minimum width: 10° / -3 dB
Front to rear ratio: > 40 dB
Mode: A1A
Frequency coverage: 3,49 ... 3,66 MHz
IF bandwidth: 1kHz@-3dB, 4 kHz@-60 dB
Unwanted sideband rejection: >45 dB
Frequency stability: <20 ppm
Sensitivity at GAIN switch positions: 7 -135 dBm
6 -120 dBm
(audio output 100mV, 5 -105 dBm
distances valid for 4 -90 dBm (1 km)
3W transmitters) 3 -75 dBm (300 m)
2 -60 dBm (100 m)
1 -40 dBm (30 m)
0 -20 dBm (10 m)
Headphones impedance: > 4 ohms
Supply: built-in LiPol accumulator 7,4 V/ 500 mAh
Consumption (typ.): 35-50 mA
Operation period : min. 10 hours
Compass bearing influence: max. ± 2° (compass mounted according to the picture)
Covering: IP63
Dimensions: 100 (W) x 180(H) x 30 (D) mm
Weight: 300 g
Operating temperature range: -10 ... + 60°C
Storage temperature range: -20 ... + 60°C
SUPPLIED ACCESSORIES
whip antenna
instruction manual
OPTIONS
electronic compass module FINDER09
headphones SL28
accumulator charger N40
accumulator tester T840
compass holder
Jiří Mareček, OK2BWN, CZ-664 01 Bílovice nad Svitavou, Obřanská 593
phone [phone], e-mail: [e-mail]
http://www.ok2bwn.cz
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