[Lowfer] New LEK exciter

[Lyle Koehler]

LEK is now using an experimental "bare-bones" version of the ZL1BPU DDS
exciter, built on a 1.8 by 2.9 inch Radio Shack prototype board. No
precision resistor R-2R ladder network, no sine wave output, no TDA7052A
amplifier or output transformer. There is an on-board complementary pair
output stage that could serve as a 1-watt final, but for now it's just
driving the coax going to the final amp in my garage. Still transmitting
MT-Hell, best observed with Argo in 30 second dot, slow mode. At the moment
the base frequency is about 182.2015 kHz (1.5 Hz above BRO), but it may
wander around a bit because I'm using a cheap 12 MHz microprocessor crystal
in the circuit.

With my present haywire setup, the MT-Hell "billboard" display looks good on
the receiver, but the 12 WPM CW identifier at the beginning of each ID cycle
sounds awful. If I can get rid of that bug, I'll publish the circuit of the
simplified DDS exciter on my web page.

Lyle, K0LR