Modulated 3,579545 MHz foxoring transmitter.
pa0nhc 20180223 under construction
Pure solid state, no software. Reliable
All wired components, no SMD.
100% AM tone modulation + carrier switching.
Two three positing slide switches for tone frequency, and tone rhythm setting.
Up to 9 different modulation tone & rhythm combinations.
Output ca. 65 mW.
Clean output, with output filter for 2nd harmonic -60 dBc,
Build-in whip antenna tuner with LED indicator.
Narrow PCB : 130 x 38 mm. Fits inside a 50mm dia. PVC sewage pipe.
Double sided PCB, clean RF-design.
RF ground connections with thermal relief for easier soldering.
Dil-Xtal oscillator driver for accurate and stable carrier frequency.
Power : 40mA @ 6-12Vdc, with stable operation until the battery becomes really
This 130 x 38 mm factory made PCB is
Warning:>>> DO NOT use this little transmitter as a driver stage for a power amplifier <<<
This transmitter is ultra simple, after an idea of the ARRL. It is meant as a milliwatt, very limited range foxhunt
/ foxoring transmitter, connected to a low efficiency
antenna system. 100% modulation is simply done by switching on/off the ports of the 74HC240.
The drawback of this simplicity is: WIDE modulation bandwidth,
only limited by
the Q of the antenna tuning circuit.