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Hello Miken:
I found my 1981 ARRL Handbook. They have a "marker" generator, which uses an LF-353, a 4001 and a 4013 - all integrated circuits. There is also a simple 2 transistor 100 kHz oscillator. The marker generator puts out 100, 50 and 25 kHz. When I read the request for a circuit to supplement a glowbug, I thought a tube crystal calibrator would be what was wanted, and thought perhaps the later 1981 edition might have abandoned a tube version. So, I pulled out a 1972 ARRL Handbook and even then all they had was solid state. If you are going to use integrated circuits in a glowbug receiver, you need to hide them, since it is unbecoming and might cause others to ridicule the otherwise heroic effort to recreate a glorious radio. A simple tube can do a wonderful job of putting out 100 kHz signals, and if you want 50 kHz, you can use a neon bulb divider. Many of the simple receivers I built would have been lost with a 100 kHz marker. A 1 MHz marker would have been more useful, and even then I was guessing at the which MHz it was. The best marker was simply a crystal in the ham band and a known point. Something like 3550 kHz, which could also be used to spot at 7100 kHz. Even odd marked frequencies are useful - then a properly hand calibrated graph laminated on the front panel (ala HRO) will give a feeling that none of the wonderful new rigs can touch. 73, Colin K7FM |
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