Using the second crystal oscillator

The second crystal oscillator is brought into use by fitting an appropriate crystal in the base "Q2" and by setting the front-panel switch to "F1" . Carefully adjust the ferrite core of the neighbouring inductor (marked blue/brown) to achieve oscillation. A maximum IF shift of +/- 2MHz is possible.

For example:

To prevent strong stations breaking through on the 2m IF, the LT23S can be set up to use an IF of 146 to148 MHz. (Many 2m transceivers can cover this range!).

The required crystal frequency is calculated as follows:

(fin – IF)/12

(1296 – 144)/12 = 95.8333 MHz

The required crystal frequency is: 95.8333 MHz

Base: HC-25/U

Resonance: series mode resonance

p6

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© GJ Coyne & G Mussler Dec-2003