The F.E.D. Detects digital RF signals -  The F.E.D.  (Frequency Emissions Detector) will, of course, detect anyone's cell phone, so the detector really responds to just about anybody with more than two pennies to rub together.  Most phones occasionally transmit short bursts to the nearest cell tower, even when the phone isn't in use, so a typical 21st century loiterer will eventually set off the detector.  On the other hand, a deer can stare at it for an hour with no effect.  Let's face it, even most burglars emit digital signals these days.  So, in a sense, the F.  E.  D.  is a human detector.  With that in mind, consider using the output to activate a digital camera or video recorder to capture a record of the prowlers.  A recorded barking dog or, one of my favorites, a recording of police radio traffic will scare off most crooks.  Add some hidden flashing red and blue lights to the police chatter and the culprits will actually run away. __ Contact: Charles Wenzel of Wenzel Associates, Inc.

The Jet Propulsion Laboratory-"Smart VOX" -  For creating a COS signal from a radio that doesn't have one.  This circuit was developed to control the retransmission of NASA Select audio over JPL's W6VIO repeaters. __ Designed by Randy Hammock KC6HUR and Jan Tarsala WB6VRN 

The Journey to Forever--Crystal Radio -  You can make a crystal set out of almost anything -- any small box, or just a bit of wood, or a frisbee or a deodorant dispenser (actual examples), or these (recommended for beginners): __ Designed by Keith Addison

The Repeater Builder's Friend -  A device to help to you fix your repeater or program your controller __ Designed by Matt Krick K3MK

Tiny Tuned Loop Antennas for the Minimum Mass Wireless Coupler -  Loop Antennas are considered to be "samall" when their diameter drops below about 1/10 of the wavelength they are intended to be used at.  In this case, I use the term "Tiny" because the antenna's diameter is about 1/30, 000 the wavelength, and at 5.5 cm __ Designed by Dick Cappels

TL431 Crystal Radio Amplifier -  Here is a simple audio amplifier using a TL431 shunt regulator.  The amplifier will provide room-filling volume from an ordinary crystal radio outfitted with a long-wire antenna and good ground.  The circuitry is similar in complexity to a simple one-transistor radio but the performance is far superior.  The TL431. __ Contact: Charles Wenzel of Wenzel Associates, Inc.

T-Match ATU (Antenna Tuning Unit) -  A simple T-Match ATU.   I used silver plated copper wire for L1 and L2.  If you use enamelled copper wire, remove the insulation on one side of the coil, so that you can easily change the number of turns used for each band.  If you don't need to cover 160 Metres, L1 can be reduced to about 25 turns.  L2 is only used on 10 Metres. __ Designed by EI9GQ homebrew radio

Touch CPO -  touch operated code practice oscillator using popular timer IC555.  Practice Morse code in a different way

Transmitter FM 45W with valve -  The catering better it does not become at straight line from the network 220V but via transformer 220V/220V of isolation and safety 1AWhen does not exist the R3, the force of expense is bigger, but respectively is increased also the hum 50Hz, because the simplicity of designingThe control (Audio In) can become from a kasseto'fwno or other powerful source.  If it is microphone it will be supposed precedes amplifier so that it acquires a force of order of 8W roughly. __ Designed by Kyriakos Kontakos

Tuning VFOs with a PN-Junction -  Timing and oscillator circuit diagrams / circuit schematics

TV Signal Amplifier -  This is a small, broad band, signal amplifier which covers the frequencies from 40 to 900 MHz.  These frequencies include TV in VHF and UHF and also the radio broadcasting frequencies in the 88108 MHz FM band. __ Designed by © of this circuit belongs to smart kit electronics

Two Diode Odd-Order Multiplier -  It is often necessary to multiply the frequency of low noise oscillators without significantly degrading the phase noise beyond the theoretical 20 log (N).  Low noise frequency doublers constructed with Schottky signal diodes are readily available but higher-order multipliers often __ Contact: Charles Wenzel of Wenzel Associates, Inc.

Two Transistor Reflex Radio -  Schematic & PC Board, no circuit description] __ Designed by © David Hoult

RF (Radio Frequency) Amplifiers:  #'s - C      D - K        L - R       S - Z