Building the K2 |
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More shots of my K2 under construction.
The finished control board, as installed in the cabinet. The control board and front-panel boards plug into the RF board, and can easily be removed for servicing.
Initial test. When the kit is about 25% complete, the cabinet is partially assembled for an initial test of the control board. This verifies that the microcontroller, the DC circuits, the front-panel controls, and the relays are functioning correctly. So far so good!
The RF board, ready for its initial test. Only the relays, the I/O controller, and a few other parts have been installed so far. Each of the 17 relays is a "latching" relay, which draws current only while it is changing state. These are used for bandswitching, and for VCO range and pre-amp selection. Diodes are used for T-R switching, and varactor diodes are used to dynamically shape the crystal filter.
The RF board, after another 14 hours of construction. Nearly all of the parts have been installed, including 13 of the 21 hand-wound inductors and transformers. The receiver, synthesizer, and VCO are in the front; the bandpass filters for each band are at the left rear; and the low-pass filters are at the right rear. The transmitter components are at center rear; the PA transistors will be mounted on the bottom of the board. A second test and alignment was done after finishing the receiver section of this board; the third and final alignment is performed once the transmitter is complete. |
