QCX assembly Rev 1.08
134
17m band
3dB bandwidth:
1,352kHz
Insertion loss:
2.77dB at 18.120MHz centre
Tuning range:
12.64MHz to 35.0MHz
7.8
Quadrature Sampling Detector bandwidth
The following chart shows the attenuation naturally provided by the Quadrature Sampling Detector
from -20kHz to +20kHz from the Local Oscillator frequency. The narrow characteristic of this circuit
is an advantage because it effectively adds an additional narrow RF bandpass filter to the
receiver, preventing strong nearby signals from reaching the audio amplifier stages. This improves
intermodulation performance.
The circuit parameters are optimised for CW operation in this transceiver. A constructor wishing to
use the I-Q outputs from IC5 to feed a computer SDR, would wish to flatten this response. To do
this, reduce the values of the four 470nF capacitors C43 to C46.
Summary of Contents for QCX 5W CW
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