Stable Portable LF Source
Tue, 12 Jan 1999 20:03:09 -0500
At Frank K0BRA's suggestion, and to be able to test /
calibrate our receivers (and insure that we can indeed hear
_something_ when we set up...) I have built a fairly
precise Xtal controlled source for our forthcoming LF tests
in Nags Head.
The crystal oscillator's nominal frequency of 2.4576 MHz is
then divided by 18, and fed to a 2N2222, the collector load
of which is a ferrite rod antenna from a defunct receiver.
Housed in a insulated sandwich-box, the unit operates on 9
to 14 volts DC.
The unit is thermostatically controlled, and can transmit
either continuously, or "On 5 sec/Off 5 sec".
Its frequency, as measured on my HP5245L counter is
136,529.9-136,530.0 and has remained there for the past 36
Circuit details will appear in the next AMRAD Newsletter