Wavecom W 4010 User Manual page 15

Remember the software first searches for valid keying values, checking the validity of these parameters im-
mediately after release of data. Since noise and interference affect the search for valid parameters, it can
happen that the software restarts. After adjusting the receiver, this can be prevented by pressing the [F2]
key. Experience has shown that best CW reception is obtained when the filter pot is adjusted to 3 o'clock
and the level pot to about 9 o'clock. A considerable increase in decoder performance is obtained by reducing
the audio input level to under 100 mV.
When tuning in a CW signal, the LED display should move completely to the left. Remember tune for the rel-
atively low frequency of 800 Hz. If the display doesn't react, then touch up the level knob, turning it coun-
ter-clockwise. Once the level knob has been mastered, the filter bandwidth can be reduced by turning the
filter knob clockwise. This reduces the interference and makes the adjustment of the level knob easier. If the
bandwidth is made too small, the receiver tuning becomes very critical and difficult. Each operator should
adjust the bandwidth to that which he feels to be the most effective position. With a little practice, CW sig-
nals can be decoded errorfree even with strong interference.
The Morse code is one of the oldest forms of data transmission. An experienced telegraph operator can re-
ceive Morse code even under the most difficult conditions. For this reason CW is still widely used today. Even
modern state-of-the-art circuitry cannot decode Morse as well as an experienced operator. Time distortion of
the dits, dahs, and pauses, together with interference, generate unrecognizable combinations. However, the
sharp filter, the continuously variable minimumamplitude squelch, and the powerful software permit the de-
coding of many CW signals.
[F1] BAUD RATE SELECTOR
[F2] CALL MONITORING MODE
[F3] DELETE U AND S FRAMES
[F4] FORWARD SEQUENCE
[F4]+[F3] REVERSE SEQUENCE
When packet radio mode is selected, the defaults are 1200 baud and copy all packets. On the two meter
band, 1200 baud in FM is usually used, and on shortwave 300 Baud in SSB with AFSK. A commonly used
shortwave frequency is: 14.103 MHz 3 kHz.
The LEVEL and FILTER adjustments are not active with the VHF input. The AFSK signal with 1000 Hz shift
undergoes separate filtering and decoding. The squelch on the FM receiver should be used.
For operation on shortwave, the decoder uses a quadrature demodulator, and the FILTER and LEVEL adjust-
ments are active. The LEVEL adjustment can normally be set counter-clockwise, but can be used as a tuning
aid. The postdemodulation filter has a higher frequency which means the LED tuning display will flicker.
The software offers the possibility of eliminating the U and S control packets by using the [F3] key as a tog-
gle switch. If used, only I (information) packets will be displayed.
With packet radio many stations can be active on the same frequency. Stations are "connected" together
and the other channel activity has no influence on stations that are connected together.
The WAVECOM decoder offers the advantage that all traffic of a certain station can be monitored without
monitoring the rest of the channel activity.
After choosing the packet-radio mode, it becomes active with monitoring mode as default. The last two or
three station call signs are continuously stored in memory and can be selected with the [F2] key. Originator,
recipient, and possible first repeater can be selected one after the other. After going through these 3 possi-
bilities, the monitor mode is selected again where all packets are received. Whenever the Packet-Radio mode
is chosen, the stored call signs are deleted. Until packets are received again, key [F2] has no function.
The call sign of the selected station appears in the command line, and only packets that have this call sign
will reach the output, regardless whether from originator, recipient, or possible first repeater. It is therefore
possible to monitor all activity of a certain station or repeater.
PACKET-RADIO AX.25
Switches between 300, 600, or 1200 Baud. With 300 Baud,
audio input 2 is active; and with 600/1200 Baud, audio input
1 is active.
Selects call sign of station to be copied, or all stations
Enables elimination of certain frames
go to next operating mode
go to previous operating mode
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