Vectronics VEC-162 - Manual (Page 6)

VEC-162 MultiReader Instruction Manual
6
TUNING IN A CW SIGNAL
First of all, scan the bands for a strong, clean signal. Remember, the signal must be the same type as what the
VEC-162 is setup for, in this case CW. If not, then the VEC-162 will not decode the signal properly.
There are a couple of different methods to tune in a CW signal on the radio, which are compatible with the VEC-
162. The first method is to use a NARROW CW filter in your radio, if your radio has such a filter. The filter
passband must be at 700 Hz, which is the center frequency of the CW demodulator in the VEC-162. The second
method is to use the Lower Side Band mode, or LSB on the radio. When using the LSB mode on the radio,
always start on the “higher side” of the desired signal, then tune the radio so the “pitch” of the signal goes down
in frequency.
Using a Narrow CW Filter
For maximum performance while in the CW mode, the DATA/CW switch on the front panel must be IN, to the
CW position. Please follow the steps below for tuning in a CW signal, if your radio has a NARROW CW filter:
1. Set the VEC-162 to the CW operating mode by using the OPTION and SELECT buttons.
2. Set the DATA/CW switch on the front panel to the CW position (the IN position).
3. Set the THRESHOLD control on the front panel fully clockwise. This sets up the demodulator for maximum
bandwidth.
4. Set the SPEAKER SELECT switch on the back panel to the OUT position. This allows the internal speaker
of the VEC-162 to be used to monitor the incoming CW audio signal.
5. Vary the VFO frequency dial on the radio until both the LOCK and DATA leds are flashing with the
incoming CW signal. The LOCK and DATA leds should be bright and flashing together. If either led is
dimly lit, but is still flashing with the other, then slightly vary the VFO dial until the dim led becomes
brighter, but still flashes together with the other. Once the leds are flashing together with the incoming signal,
vary the VFO dial slightly while watching the VEC-162 display until good CW copy is obtained.
6. Now with the VEC-162 decoding the incoming CW signal, turn the THRESHOLD control counter-clockwise
until the LOCK led “loses” the signal.
7. Fine tune the VFO dial on your radio until the LOCK led once again follows the incoming CW signal.
8. Repeat steps 6 and 7 until you have adjusted the THRESHOLD control to the absolute minimum setting
possible for good CW copy. With the bandwidth now set to the absolute minimum possible, the VEC-162 will
demodulate clean CW signals because the input circuit rejects noise that would otherwise interfere with the
decoding of the incoming signal.
Using the LSB Mode
Please follow the steps below for tuning in a CW signal, if you use the LSB mode in your radio:
1. Set the VEC-162 to the CW operating mode by using the OPTION and SELECT buttons.
2. Set the DATA/CW switch on the front panel to the CW position (IN position).
3. Set the THRESHOLD control on the front panel fully clockwise. This sets up the demodulator for maximum
bandwidth.