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RF (Radio
Frequency) Transmitter
Circuits, Page 3 RF (Radio Frequency) Transmitter:
#'sA
- FE - OP - Z Last Updated on:
Monday, October 03, 2011 06:07 PM
Links to electronic circuits, electronic schematics, designs for engineers,
hobbyists, students & inventors:
HAM Radio BFO - circuit diagram of beat frequency oscillator using
BF494 and how to listen amateur radio communication on ordinary BC
receiver..(added 01/05)
Light Sensitive Alarm Circuit - The circuit detects a sudden shadow
falling on the light-sensor and sounds the bleeper when this happens. The
circuit will not respond to gradual changes in brightness to avoid false alarms.
The bleeper sounds for only a short time to prevent the battery running flat.
Normal lighting can be used, but the circuit will work best if a beam of light
…....
Long Range FM Transmitter - The power output of many transmitter circuits are
very low because no power amplifier stages are incorporated. The transmitter circuit
described here has an extra RF power amplifier stage, after the oscillator stage, to raise
the power output to 200-250 milliwatts. With a good matching 50-ohm ground plane antenna
or multi-element Yagi antenna, this transmitter can provide reasonably good signal
strength up to a distance of about 2 kilometres.... [Submitted by Viswanathan Prakash
29-1-10]
Low Frequency Phasing Exciter - As of this writing, two programs are available
for data transmission at low frequencies that use a computer sound card and output the
audio in an I/Q format. JASON has a unique FSK format with a variety of data rates.
The "DigiMode Terminal" in Spectrum Laboratory generates PSK and MSK signals
suitable for LF work. If you are new to all of this, check out the Low Frequency
Transmission Mode article on this site.... [Design by John K. Andrews Holden,
MA FN42ch [ w1tag@charter.net ]
