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10.7MHz FM Detector:
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Cellular Phone Helper #1:
activates a variety of devices when your cellular
ph1-is in use, PDF file |
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Cellular Phone Helper #2:
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Linearized RF Detector:
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Make a truly linear RF power detector:
09/19/2002 EDN - Design Ideas / Modern
high-performance transmitters require accurate
monitoring of RF power, because most cellular
standards depend on strict power- transmission
levels to maintain an effective network. Regulation
of transmitted-signal strength also lets you build
lower cost systems. Figure 1 shows a
waveform-independent circuit that provides a linear
measurement of RF power.. |
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R / C Switch:
This circuit is a so-called "Radio Controlled
Electronic Switch". It can be used to switch on/off
anything electrical, whatever it is. Here are a
couple of examples: navigation lights, landing gear,
sound systems, Glowplug driver, bomb release,
parachute, search lights, gyros, and so on. This
circuits connects to a RC car controller servo
output. |
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RF Actuated CW Monitor: |
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RF Design Hint Increases Transmit
Signal Rejection In Telephone Hybrids:
11/20/00 Electronic Design - Ideas for Design /
Every telephone signal port used to transmit and
receive voice or modulated data from a modem employs
a hybrid (duplexer) circuit. Such circuits are used
to separate the transmit and receive signals.
They’re also needed to reject the local. . . |
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RF Detector
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RF Dummy Load:
make this simple RF Dummy Load for off-air testing
of your radio transmitter. |
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RF Power Meter for the QRPer: |
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RF Sniffer
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RF Sniffer <.5 to >500 MHz: |
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RF Spectrum Analyzer: |
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Surveillance Transmitter Detector:
This circuit can be used to "sweep" an area or room
and will indicate if a surveillance device is
operative. The problem in making a suitable a
detector is to get its sensitivity just right, Too
much sensitivity and it will respond to radio
broadcasts, too little, and nothing will be heard. |
