Thursday, March 24, 2022

20-Meter High Performance Direct Conversion Receiver (2)

Partially checked out the RX ckt on the bench today. I powered the board off a 12V supply.   No external components were attached, including the VFO tuning cap and the peaking  cap.  The antenna coil is still missing. 

The voltage at  oscillator transistor Q4 drain is 8.9 volts, so voltage regulation of the oscillator power seems to be working. 

The oscillator, without the front panel tuning cap, operates at 14.365 MHz.    Amplitude is 638 mV pp, so 0.23 V rms.  

Next step will be to install a new antenna coil and repair the peaking variable capacitor.  I went to Four States QRP to order the toroids, but weren't in stock.  I ordered some T30-6 rather than T37-6, so I'll try to use those. 


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