Cyclone 40 Design Updates and Kit Changes
MODIFICATION NOTE 3:
Purchasers of the original version PC boards (no revision notice printed on the boards) may notice a movement
of the transmit frequency during a QSO. This simple modification will reduce or eliminate that.
Please email Dan, KB9JLO at
for a free TO-92 heat sink and 150 ohm resistor.
Install the heat sink on Q8. Use heat sink compound if you have it. Q8 is the MPF102 and is listed as the drive mixer on the transmitter schematic.
Install the 150 ohm resistor between U1 pin 1 and a ground location close to U1. U1 pin 10 is ground, and the solder strip
on the edge of the board is a good location also. It is preferable to place the resistor on the bottom of the board, and
you may wish to slip some insulation over the leads to prevent accidental contact with the IC pins.
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