Modulated 3,579545 MHz foxoring transmitter.
pa0nhc 20180223 under construction
All wired components, no SMD.
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 reliefs for easier soldering.
Build-in whip antenna tuner with LED indicator.
Pure solid state, no software. Reliable.
Dil-Xtal oscillator driverfor accurate frequency.
Power : 6-12Vdc - 40 mA.
Stable operation until the battery becomes really empty.
Output ca. 65 mW.
Output filter for 2nd -60 dBc, clean output.
100% AM tone modulation + carrier switching.
2 three positing slide switches for tone frequency, and tone rhythm setting,
for up to 9 different modulation tone & rhythm combinations.
This 130 x 38 mm factory made PCB will be available soon.
This transmitter is ultra simple, after an idea of the ARRL. This foxoring
trasmitter is meant as a milliwatt, very limited range foxhunt transmitter, connected to a low efficiency
>>> 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 circuit. >>> DO NOT use this little transmitter as a driver stage for a power amplifier <<<